Question: When did President Johnson award him?

Answer: 3 December 1963

<hl> On 3 December 1963 , US President Lyndon B. Johnson posthumously awarded him the Presidential Medal of Freedom, the United States' highest civilian award, in recognition of the good relationship between Pope John XXIII and the United States of America. <hl> In his speech on 6 December 1963, Johnson said: "I have also determined to confer the Presidential Medal of Freedom posthumously on another noble man whose death we mourned 6 months ago: His Holiness, Pope John XXIII. He was a man of simple origins, of simple faith, of simple charity. In this exalted office he was still the gentle pastor. He believed in discussion and persuasion. He profoundly respected the dignity of man. He gave the world immortal statements of the rights of man, of the obligations of men to each other, of their duty to strive for a world community in which all can live in peace and fraternal friendship. His goodness reached across temporal boundaries to warm the hearts of men of all nations and of all faiths".

On <hl> 3 December 1963 <hl>, US President Lyndon B. Johnson posthumously awarded him the Presidential Medal of Freedom, the United States' highest civilian award, in recognition of the good relationship between Pope John XXIII and the United States of America. In his speech on 6 December 1963, Johnson said: "I have also determined to confer the Presidential Medal of Freedom posthumously on another noble man whose death we mourned 6 months ago: His Holiness, Pope John XXIII. He was a man of simple origins, of simple faith, of simple charity. In this exalted office he was still the gentle pastor. He believed in discussion and persuasion. He profoundly respected the dignity of man. He gave the world immortal statements of the rights of man, of the obligations of men to each other, of their duty to strive for a world community in which all can live in peace and fraternal friendship. His goodness reached across temporal boundaries to warm the hearts of men of all nations and of all faiths".

On <hl> 3 December 1963 <hl> , US President Lyndon B. Johnson posthumously awarded him the Presidential Medal of Freedom, the United States' highest civilian award, in recognition of the good relationship between Pope John XXIII and the United States of America.


Question: What is the Presidential Medal Freedom?

On 3 December 1963, US President Lyndon B. Johnson posthumously awarded him the Presidential Medal of Freedom, the United States' highest civilian award, in recognition of the good relationship between Pope John XXIII and the United States of America. In his speech on 6 December 1963, Johnson said: "I have also determined to confer the Presidential Medal of Freedom posthumously on another noble man whose death we mourned 6 months ago: His Holiness, Pope John XXIII. He was a man of simple origins, of simple faith, of simple charity. In this exalted office he was still the gentle pastor. He believed in discussion and persuasion. He profoundly respected the dignity of man. He gave the world immortal statements of the rights of man, of the obligations of men to each other, of their duty to strive for a world community in which all can live in peace and fraternal friendship. His goodness reached across temporal boundaries to warm the hearts of men of all nations and of all faiths".

Answer: the United States' highest civilian award

<hl> On 3 December 1963, US President Lyndon B. Johnson posthumously awarded him the Presidential Medal of Freedom, the United States' highest civilian award , in recognition of the good relationship between Pope John XXIII and the United States of America. <hl> In his speech on 6 December 1963, Johnson said: "I have also determined to confer the Presidential Medal of Freedom posthumously on another noble man whose death we mourned 6 months ago: His Holiness, Pope John XXIII. He was a man of simple origins, of simple faith, of simple charity. In this exalted office he was still the gentle pastor. He believed in discussion and persuasion. He profoundly respected the dignity of man. He gave the world immortal statements of the rights of man, of the obligations of men to each other, of their duty to strive for a world community in which all can live in peace and fraternal friendship. His goodness reached across temporal boundaries to warm the hearts of men of all nations and of all faiths".

On 3 December 1963, US President Lyndon B. Johnson posthumously awarded him the Presidential Medal of Freedom, <hl> the United States' highest civilian award <hl>, in recognition of the good relationship between Pope John XXIII and the United States of America. In his speech on 6 December 1963, Johnson said: "I have also determined to confer the Presidential Medal of Freedom posthumously on another noble man whose death we mourned 6 months ago: His Holiness, Pope John XXIII. He was a man of simple origins, of simple faith, of simple charity. In this exalted office he was still the gentle pastor. He believed in discussion and persuasion. He profoundly respected the dignity of man. He gave the world immortal statements of the rights of man, of the obligations of men to each other, of their duty to strive for a world community in which all can live in peace and fraternal friendship. His goodness reached across temporal boundaries to warm the hearts of men of all nations and of all faiths".

On 3 December 1963, US President Lyndon B. Johnson posthumously awarded him the Presidential Medal of Freedom, <hl> the United States' highest civilian award <hl> , in recognition of the good relationship between Pope John XXIII and the United States of America.


Question: When was President Johnson's speech for John XXIII?

Answer: 6 December 1963

On 3 December 1963, US President Lyndon B. Johnson posthumously awarded him the Presidential Medal of Freedom, the United States' highest civilian award, in recognition of the good relationship between Pope John XXIII and the United States of America. <hl> In his speech on 6 December 1963 , Johnson said: "I have also determined to confer the Presidential Medal of Freedom posthumously on another noble man whose death we mourned 6 months ago: His Holiness, Pope John XXIII. <hl> He was a man of simple origins, of simple faith, of simple charity. In this exalted office he was still the gentle pastor. He believed in discussion and persuasion. He profoundly respected the dignity of man. He gave the world immortal statements of the rights of man, of the obligations of men to each other, of their duty to strive for a world community in which all can live in peace and fraternal friendship. His goodness reached across temporal boundaries to warm the hearts of men of all nations and of all faiths".

On 3 December 1963, US President Lyndon B. Johnson posthumously awarded him the Presidential Medal of Freedom, the United States' highest civilian award, in recognition of the good relationship between Pope John XXIII and the United States of America. In his speech on <hl> 6 December 1963 <hl>, Johnson said: "I have also determined to confer the Presidential Medal of Freedom posthumously on another noble man whose death we mourned 6 months ago: His Holiness, Pope John XXIII. He was a man of simple origins, of simple faith, of simple charity. In this exalted office he was still the gentle pastor. He believed in discussion and persuasion. He profoundly respected the dignity of man. He gave the world immortal statements of the rights of man, of the obligations of men to each other, of their duty to strive for a world community in which all can live in peace and fraternal friendship. His goodness reached across temporal boundaries to warm the hearts of men of all nations and of all faiths".

In his speech on <hl> 6 December 1963 <hl> , Johnson said: "I have also determined to confer the Presidential Medal of Freedom posthumously on another noble man whose death we mourned 6 months ago: His Holiness, Pope John XXIII.


Question: What was he also known as?

He was known affectionately as "Good Pope John". His cause for canonization was opened under Pope Paul VI during the final session of the Second Vatican Council on 18 November 1965, along with the cause of Pope Pius XII. On 3 September 2000, John XXIII was declared "Blessed" alongside Pope Pius IX by Pope John Paul II, the penultimate step on the road to sainthood after a miracle of curing an ill woman was discovered. He was the first pope since Pope Pius X to receive this honour. Following his beatification, his body was moved from its original burial place in the grottoes below the Vatican to the altar of St. Jerome and displayed for the veneration of the faithful.[citation needed]

Answer: Good Pope John

<hl> He was known affectionately as " Good Pope John ". <hl> His cause for canonization was opened under Pope Paul VI during the final session of the Second Vatican Council on 18 November 1965, along with the cause of Pope Pius XII. On 3 September 2000, John XXIII was declared "Blessed" alongside Pope Pius IX by Pope John Paul II, the penultimate step on the road to sainthood after a miracle of curing an ill woman was discovered. He was the first pope since Pope Pius X to receive this honour. Following his beatification, his body was moved from its original burial place in the grottoes below the Vatican to the altar of St. Jerome and displayed for the veneration of the faithful.[citation needed]

He was known affectionately as "<hl> Good Pope John <hl>". His cause for canonization was opened under Pope Paul VI during the final session of the Second Vatican Council on 18 November 1965, along with the cause of Pope Pius XII. On 3 September 2000, John XXIII was declared "Blessed" alongside Pope Pius IX by Pope John Paul II, the penultimate step on the road to sainthood after a miracle of curing an ill woman was discovered. He was the first pope since Pope Pius X to receive this honour. Following his beatification, his body was moved from its original burial place in the grottoes below the Vatican to the altar of St. Jerome and displayed for the veneration of the faithful.[citation needed]

He was known affectionately as " <hl> Good Pope John <hl> ".


Question: Who opened his cause for canonization?

Answer: Pope Paul VI

He was known affectionately as "Good Pope John". <hl> His cause for canonization was opened under Pope Paul VI during the final session of the Second Vatican Council on 18 November 1965, along with the cause of Pope Pius XII. <hl> On 3 September 2000, John XXIII was declared "Blessed" alongside Pope Pius IX by Pope John Paul II, the penultimate step on the road to sainthood after a miracle of curing an ill woman was discovered. He was the first pope since Pope Pius X to receive this honour. Following his beatification, his body was moved from its original burial place in the grottoes below the Vatican to the altar of St. Jerome and displayed for the veneration of the faithful.[citation needed]

He was known affectionately as "Good Pope John". His cause for canonization was opened under <hl> Pope Paul VI <hl> during the final session of the Second Vatican Council on 18 November 1965, along with the cause of Pope Pius XII. On 3 September 2000, John XXIII was declared "Blessed" alongside Pope Pius IX by Pope John Paul II, the penultimate step on the road to sainthood after a miracle of curing an ill woman was discovered. He was the first pope since Pope Pius X to receive this honour. Following his beatification, his body was moved from its original burial place in the grottoes below the Vatican to the altar of St. Jerome and displayed for the veneration of the faithful.[citation needed]


Question: When was Pope John XXIII considered "blessed?"

Answer: 3 September 2000

He was known affectionately as "Good Pope John". His cause for canonization was opened under Pope Paul VI during the final session of the Second Vatican Council on 18 November 1965, along with the cause of Pope Pius XII. <hl> On 3 September 2000 , John XXIII was declared "Blessed" alongside Pope Pius IX by Pope John Paul II, the penultimate step on the road to sainthood after a miracle of curing an ill woman was discovered. <hl> He was the first pope since Pope Pius X to receive this honour. Following his beatification, his body was moved from its original burial place in the grottoes below the Vatican to the altar of St. Jerome and displayed for the veneration of the faithful.[citation needed]

He was known affectionately as "Good Pope John". His cause for canonization was opened under Pope Paul VI during the final session of the Second Vatican Council on 18 November 1965, along with the cause of Pope Pius XII. On <hl> 3 September 2000 <hl>, John XXIII was declared "Blessed" alongside Pope Pius IX by Pope John Paul II, the penultimate step on the road to sainthood after a miracle of curing an ill woman was discovered. He was the first pope since Pope Pius X to receive this honour. Following his beatification, his body was moved from its original burial place in the grottoes below the Vatican to the altar of St. Jerome and displayed for the veneration of the faithful.[citation needed]

On <hl> 3 September 2000 <hl> , John XXIII was declared "Blessed" alongside Pope Pius IX by Pope John Paul II, the penultimate step on the road to sainthood after a miracle of curing an ill woman was discovered.


Question: Who declared him "blessed?"

Answer: Pope John Paul II

He was known affectionately as "Good Pope John". His cause for canonization was opened under Pope Paul VI during the final session of the Second Vatican Council on 18 November 1965, along with the cause of Pope Pius XII. <hl> On 3 September 2000, John XXIII was declared "Blessed" alongside Pope Pius IX by Pope John Paul II , the penultimate step on the road to sainthood after a miracle of curing an ill woman was discovered. <hl> He was the first pope since Pope Pius X to receive this honour. Following his beatification, his body was moved from its original burial place in the grottoes below the Vatican to the altar of St. Jerome and displayed for the veneration of the faithful.[citation needed]

He was known affectionately as "Good Pope John". His cause for canonization was opened under Pope Paul VI during the final session of the Second Vatican Council on 18 November 1965, along with the cause of Pope Pius XII. On 3 September 2000, John XXIII was declared "Blessed" alongside Pope Pius IX by <hl> Pope John Paul II <hl>, the penultimate step on the road to sainthood after a miracle of curing an ill woman was discovered. He was the first pope since Pope Pius X to receive this honour. Following his beatification, his body was moved from its original burial place in the grottoes below the Vatican to the altar of St. Jerome and displayed for the veneration of the faithful.[citation needed]

On 3 September 2000, John XXIII was declared "Blessed" alongside Pope Pius IX by <hl> Pope John Paul II <hl> , the penultimate step on the road to sainthood after a miracle of curing an ill woman was discovered.


Question: Who was the last pope before John XXIII to receive the title?

Answer: Pope Pius X

He was known affectionately as "Good Pope John". <hl> His cause for canonization was opened under Pope Paul VI during the final session of the Second Vatican Council on 18 November 1965, along with the cause of Pope Pius X II. <hl> On 3 September 2000, John XXIII was declared "Blessed" alongside Pope Pius IX by Pope John Paul II, the penultimate step on the road to sainthood after a miracle of curing an ill woman was discovered. He was the first pope since Pope Pius X to receive this honour. Following his beatification, his body was moved from its original burial place in the grottoes below the Vatican to the altar of St. Jerome and displayed for the veneration of the faithful.[citation needed]

He was known affectionately as "Good Pope John". His cause for canonization was opened under Pope Paul VI during the final session of the Second Vatican Council on 18 November 1965, along with the cause of <hl> Pope Pius X <hl>II. On 3 September 2000, John XXIII was declared "Blessed" alongside Pope Pius IX by Pope John Paul II, the penultimate step on the road to sainthood after a miracle of curing an ill woman was discovered. He was the first pope since Pope Pius X to receive this honour. Following his beatification, his body was moved from its original burial place in the grottoes below the Vatican to the altar of St. Jerome and displayed for the veneration of the faithful.[citation needed]

His cause for canonization was opened under Pope Paul VI during the final session of the Second Vatican Council on 18 November 1965, along with the cause of <hl> Pope Pius X <hl> II.


Question: When was the 50th anniversary of his death?

The 50th anniversary of his death was celebrated on 3 June 2013 by Pope Francis, who visited his tomb and prayed there, then addressing the gathered crowd and spoke about the late pope. The people that gathered there at the tomb were from Bergamo, the province where the late pope came from. A month later, on 5 July 2013, Francis approved Pope John XXIII for canonization, along with Pope John Paul II without the traditional second miracle required. Instead, Francis based this decision on John XXIII's merits for the Second Vatican Council. On Sunday, 27 April 2014, John XXIII and Pope John Paul II were declared saints on Divine Mercy Sunday.

Answer: 3 June 2013

<hl> The 50th anniversary of his death was celebrated on 3 June 2013 by Pope Francis, who visited his tomb and prayed there, then addressing the gathered crowd and spoke about the late pope. <hl> The people that gathered there at the tomb were from Bergamo, the province where the late pope came from. A month later, on 5 July 2013, Francis approved Pope John XXIII for canonization, along with Pope John Paul II without the traditional second miracle required. Instead, Francis based this decision on John XXIII's merits for the Second Vatican Council. On Sunday, 27 April 2014, John XXIII and Pope John Paul II were declared saints on Divine Mercy Sunday.

The 50th anniversary of his death was celebrated on <hl> 3 June 2013 <hl> by Pope Francis, who visited his tomb and prayed there, then addressing the gathered crowd and spoke about the late pope. The people that gathered there at the tomb were from Bergamo, the province where the late pope came from. A month later, on 5 July 2013, Francis approved Pope John XXIII for canonization, along with Pope John Paul II without the traditional second miracle required. Instead, Francis based this decision on John XXIII's merits for the Second Vatican Council. On Sunday, 27 April 2014, John XXIII and Pope John Paul II were declared saints on Divine Mercy Sunday.


Question: Who celebrated his 50th anniversary?

Answer: Pope Francis

<hl> The 50th anniversary of his death was celebrated on 3 June 2013 by Pope Francis , who visited his tomb and prayed there, then addressing the gathered crowd and spoke about the late pope. <hl> The people that gathered there at the tomb were from Bergamo, the province where the late pope came from. A month later, on 5 July 2013, Francis approved Pope John XXIII for canonization, along with Pope John Paul II without the traditional second miracle required. Instead, Francis based this decision on John XXIII's merits for the Second Vatican Council. On Sunday, 27 April 2014, John XXIII and Pope John Paul II were declared saints on Divine Mercy Sunday.

The 50th anniversary of his death was celebrated on 3 June 2013 by <hl> Pope Francis <hl>, who visited his tomb and prayed there, then addressing the gathered crowd and spoke about the late pope. The people that gathered there at the tomb were from Bergamo, the province where the late pope came from. A month later, on 5 July 2013, Francis approved Pope John XXIII for canonization, along with Pope John Paul II without the traditional second miracle required. Instead, Francis based this decision on John XXIII's merits for the Second Vatican Council. On Sunday, 27 April 2014, John XXIII and Pope John Paul II were declared saints on Divine Mercy Sunday.

The 50th anniversary of his death was celebrated on 3 June 2013 by <hl> Pope Francis <hl> , who visited his tomb and prayed there, then addressing the gathered crowd and spoke about the late pope.


Question: Where were the people gathered at his tomb from?

Answer: Bergamo

The 50th anniversary of his death was celebrated on 3 June 2013 by Pope Francis, who visited his tomb and prayed there, then addressing the gathered crowd and spoke about the late pope. <hl> The people that gathered there at the tomb were from Bergamo , the province where the late pope came from. <hl> A month later, on 5 July 2013, Francis approved Pope John XXIII for canonization, along with Pope John Paul II without the traditional second miracle required. Instead, Francis based this decision on John XXIII's merits for the Second Vatican Council. On Sunday, 27 April 2014, John XXIII and Pope John Paul II were declared saints on Divine Mercy Sunday.

The 50th anniversary of his death was celebrated on 3 June 2013 by Pope Francis, who visited his tomb and prayed there, then addressing the gathered crowd and spoke about the late pope. The people that gathered there at the tomb were from <hl> Bergamo <hl>, the province where the late pope came from. A month later, on 5 July 2013, Francis approved Pope John XXIII for canonization, along with Pope John Paul II without the traditional second miracle required. Instead, Francis based this decision on John XXIII's merits for the Second Vatican Council. On Sunday, 27 April 2014, John XXIII and Pope John Paul II were declared saints on Divine Mercy Sunday.

The people that gathered there at the tomb were from <hl> Bergamo <hl> , the province where the late pope came from.


Question: When did Francis approve John XXIII for canonization?

Answer: 5 July 2013

The 50th anniversary of his death was celebrated on 3 June 2013 by Pope Francis, who visited his tomb and prayed there, then addressing the gathered crowd and spoke about the late pope. The people that gathered there at the tomb were from Bergamo, the province where the late pope came from. <hl> A month later, on 5 July 2013 , Francis approved Pope John XXIII for canonization, along with Pope John Paul II without the traditional second miracle required. <hl> Instead, Francis based this decision on John XXIII's merits for the Second Vatican Council. On Sunday, 27 April 2014, John XXIII and Pope John Paul II were declared saints on Divine Mercy Sunday.

The 50th anniversary of his death was celebrated on 3 June 2013 by Pope Francis, who visited his tomb and prayed there, then addressing the gathered crowd and spoke about the late pope. The people that gathered there at the tomb were from Bergamo, the province where the late pope came from. A month later, on <hl> 5 July 2013 <hl>, Francis approved Pope John XXIII for canonization, along with Pope John Paul II without the traditional second miracle required. Instead, Francis based this decision on John XXIII's merits for the Second Vatican Council. On Sunday, 27 April 2014, John XXIII and Pope John Paul II were declared saints on Divine Mercy Sunday.

A month later, on <hl> 5 July 2013 <hl> , Francis approved Pope John XXIII for canonization, along with Pope John Paul II without the traditional second miracle required.


Question: On what date was John XXIII and Pope John Paul II declared saints?

Answer: Sunday, 27 April 2014

The 50th anniversary of his death was celebrated on 3 June 2013 by Pope Francis, who visited his tomb and prayed there, then addressing the gathered crowd and spoke about the late pope. The people that gathered there at the tomb were from Bergamo, the province where the late pope came from. A month later, on 5 July 2013, Francis approved Pope John XXIII for canonization, along with Pope John Paul II without the traditional second miracle required. Instead, Francis based this decision on John XXIII's merits for the Second Vatican Council. <hl> On Sunday, 27 April 2014 , John XXIII and Pope John Paul II were declared saints on Divine Mercy Sunday. <hl>

The 50th anniversary of his death was celebrated on 3 June 2013 by Pope Francis, who visited his tomb and prayed there, then addressing the gathered crowd and spoke about the late pope. The people that gathered there at the tomb were from Bergamo, the province where the late pope came from. A month later, on 5 July 2013, Francis approved Pope John XXIII for canonization, along with Pope John Paul II without the traditional second miracle required. Instead, Francis based this decision on John XXIII's merits for the Second Vatican Council. On <hl> Sunday, 27 April 2014 <hl>, John XXIII and Pope John Paul II were declared saints on Divine Mercy Sunday.

On <hl> Sunday, 27 April 2014 <hl> , John XXIII and Pope John Paul II were declared saints on Divine Mercy Sunday.


Question: Time has long been a major point of study in which fields?

Time has long been a major subject of study in religion, philosophy, and science, but defining it in a manner applicable to all fields without circularity has consistently eluded scholars. Nevertheless, diverse fields such as business, industry, sports, the sciences, and the performing arts all incorporate some notion of time into their respective measuring systems. Some simple definitions of time include "time is what clocks measure", which is a problematically vague and self-referential definition that utilizes the device used to measure the subject as the definition of the subject, and "time is what keeps everything from happening at once", which is without substantive meaning in the absence of the definition of simultaneity in the context of the limitations of human sensation, observation of events, and the perception of such events.

Answer: religion, philosophy, and science

<hl> Time has long been a major subject of study in religion, philosophy, and science , but defining it in a manner applicable to all fields without circularity has consistently eluded scholars. <hl> Nevertheless, diverse fields such as business, industry, sports, the sciences, and the performing arts all incorporate some notion of time into their respective measuring systems. Some simple definitions of time include "time is what clocks measure", which is a problematically vague and self-referential definition that utilizes the device used to measure the subject as the definition of the subject, and "time is what keeps everything from happening at once", which is without substantive meaning in the absence of the definition of simultaneity in the context of the limitations of human sensation, observation of events, and the perception of such events.

Time has long been a major subject of study in <hl> religion, philosophy, and science <hl>, but defining it in a manner applicable to all fields without circularity has consistently eluded scholars. Nevertheless, diverse fields such as business, industry, sports, the sciences, and the performing arts all incorporate some notion of time into their respective measuring systems. Some simple definitions of time include "time is what clocks measure", which is a problematically vague and self-referential definition that utilizes the device used to measure the subject as the definition of the subject, and "time is what keeps everything from happening at once", which is without substantive meaning in the absence of the definition of simultaneity in the context of the limitations of human sensation, observation of events, and the perception of such events.

Time has long been a major subject of study in <hl> religion, philosophy, and science <hl> , but defining it in a manner applicable to all fields without circularity has consistently eluded scholars.


Question: Fields such as business, industry, sports, science, and performing arts incorporate some notion of what into their measuring systems?

Answer: time

Time has long been a major subject of study in religion, philosophy, and science, but defining it in a manner applicable to all fields without circularity has consistently eluded scholars. <hl> Nevertheless, diverse fields such as business, industry, sports, the sciences, and the performing arts all incorporate some notion of time into their respective measuring systems. <hl> Some simple definitions of time include "time is what clocks measure", which is a problematically vague and self-referential definition that utilizes the device used to measure the subject as the definition of the subject, and "time is what keeps everything from happening at once", which is without substantive meaning in the absence of the definition of simultaneity in the context of the limitations of human sensation, observation of events, and the perception of such events.

Time has long been a major subject of study in religion, philosophy, and science, but defining it in a manner applicable to all fields without circularity has consistently eluded scholars. Nevertheless, diverse fields such as business, industry, sports, the sciences, and the performing arts all incorporate some notion of <hl> time <hl> into their respective measuring systems. Some simple definitions of time include "time is what clocks measure", which is a problematically vague and self-referential definition that utilizes the device used to measure the subject as the definition of the subject, and "time is what keeps everything from happening at once", which is without substantive meaning in the absence of the definition of simultaneity in the context of the limitations of human sensation, observation of events, and the perception of such events.


Question: What is an example of a simple definition of time?

Answer: time is what clocks measure

Time has long been a major subject of study in religion, philosophy, and science, but defining it in a manner applicable to all fields without circularity has consistently eluded scholars. Nevertheless, diverse fields such as business, industry, sports, the sciences, and the performing arts all incorporate some notion of time into their respective measuring systems. <hl> Some simple definitions of time include " time is what clocks measure ", which is a problematically vague and self-referential definition that utilizes the device used to measure the subject as the definition of the subject, and "time is what keeps everything from happening at once", which is without substantive meaning in the absence of the definition of simultaneity in the context of the limitations of human sensation, observation of events, and the perception of such events. <hl>

Time has long been a major subject of study in religion, philosophy, and science, but defining it in a manner applicable to all fields without circularity has consistently eluded scholars. Nevertheless, diverse fields such as business, industry, sports, the sciences, and the performing arts all incorporate some notion of time into their respective measuring systems. Some simple definitions of time include "<hl> time is what clocks measure <hl>", which is a problematically vague and self-referential definition that utilizes the device used to measure the subject as the definition of the subject, and "time is what keeps everything from happening at once", which is without substantive meaning in the absence of the definition of simultaneity in the context of the limitations of human sensation, observation of events, and the perception of such events.

Some simple definitions of time include " <hl> time is what clocks measure <hl> ", which is a problematically vague and self-referential definition that utilizes the device used to measure the subject as the definition of the subject, and "time is what keeps everything from happening at once", which is without substantive meaning in the absence of the definition of simultaneity in the context of the limitations of human sensation, observation of events, and the perception of such events.


Question: According to one of the main viewpoints of time, time is part of the fundamental structure of what?

Two contrasting viewpoints on time divide many prominent philosophers. One view is that time is part of the fundamental structure of the universe—a dimension independent of events, in which events occur in sequence. Sir Isaac Newton subscribed to this realist view, and hence it is sometimes referred to as Newtonian time. The opposing view is that time does not refer to any kind of "container" that events and objects "move through", nor to any entity that "flows", but that it is instead part of a fundamental intellectual structure (together with space and number) within which humans sequence and compare events. This second view, in the tradition of Gottfried Leibniz and Immanuel Kant, holds that time is neither an event nor a thing, and thus is not itself measurable nor can it be travelled.

Answer: the universe

Two contrasting viewpoints on time divide many prominent philosophers. <hl> One view is that time is part of the fundamental structure of the universe —a dimension independent of events, in which events occur in sequence. <hl> Sir Isaac Newton subscribed to this realist view, and hence it is sometimes referred to as Newtonian time. The opposing view is that time does not refer to any kind of "container" that events and objects "move through", nor to any entity that "flows", but that it is instead part of a fundamental intellectual structure (together with space and number) within which humans sequence and compare events. This second view, in the tradition of Gottfried Leibniz and Immanuel Kant, holds that time is neither an event nor a thing, and thus is not itself measurable nor can it be travelled.

Two contrasting viewpoints on time divide many prominent philosophers. One view is that time is part of the fundamental structure of <hl> the universe <hl>—a dimension independent of events, in which events occur in sequence. Sir Isaac Newton subscribed to this realist view, and hence it is sometimes referred to as Newtonian time. The opposing view is that time does not refer to any kind of "container" that events and objects "move through", nor to any entity that "flows", but that it is instead part of a fundamental intellectual structure (together with space and number) within which humans sequence and compare events. This second view, in the tradition of Gottfried Leibniz and Immanuel Kant, holds that time is neither an event nor a thing, and thus is not itself measurable nor can it be travelled.

One view is that time is part of the fundamental structure of <hl> the universe <hl> —a dimension independent of events, in which events occur in sequence.


Question: The realist view of time is sometimes referred to as what?

Answer: Newtonian time

Two contrasting viewpoints on time divide many prominent philosophers. One view is that time is part of the fundamental structure of the universe—a dimension independent of events, in which events occur in sequence. <hl> Sir Isaac Newton subscribed to this realist view, and hence it is sometimes referred to as Newtonian time . <hl> The opposing view is that time does not refer to any kind of "container" that events and objects "move through", nor to any entity that "flows", but that it is instead part of a fundamental intellectual structure (together with space and number) within which humans sequence and compare events. This second view, in the tradition of Gottfried Leibniz and Immanuel Kant, holds that time is neither an event nor a thing, and thus is not itself measurable nor can it be travelled.

Two contrasting viewpoints on time divide many prominent philosophers. One view is that time is part of the fundamental structure of the universe—a dimension independent of events, in which events occur in sequence. Sir Isaac Newton subscribed to this realist view, and hence it is sometimes referred to as <hl> Newtonian time <hl>. The opposing view is that time does not refer to any kind of "container" that events and objects "move through", nor to any entity that "flows", but that it is instead part of a fundamental intellectual structure (together with space and number) within which humans sequence and compare events. This second view, in the tradition of Gottfried Leibniz and Immanuel Kant, holds that time is neither an event nor a thing, and thus is not itself measurable nor can it be travelled.

Sir Isaac Newton subscribed to this realist view, and hence it is sometimes referred to as <hl> Newtonian time <hl> .


Question: What does the opposing view of time believe time is a part of?

Answer: a fundamental intellectual structure

Two contrasting viewpoints on time divide many prominent philosophers. One view is that time is part of the fundamental structure of the universe—a dimension independent of events, in which events occur in sequence. Sir Isaac Newton subscribed to this realist view, and hence it is sometimes referred to as Newtonian time. <hl> The opposing view is that time does not refer to any kind of "container" that events and objects "move through", nor to any entity that "flows", but that it is instead part of a fundamental intellectual structure (together with space and number) within which humans sequence and compare events. <hl> This second view, in the tradition of Gottfried Leibniz and Immanuel Kant, holds that time is neither an event nor a thing, and thus is not itself measurable nor can it be travelled.

Two contrasting viewpoints on time divide many prominent philosophers. One view is that time is part of the fundamental structure of the universe—a dimension independent of events, in which events occur in sequence. Sir Isaac Newton subscribed to this realist view, and hence it is sometimes referred to as Newtonian time. The opposing view is that time does not refer to any kind of "container" that events and objects "move through", nor to any entity that "flows", but that it is instead part of <hl> a fundamental intellectual structure <hl> (together with space and number) within which humans sequence and compare events. This second view, in the tradition of Gottfried Leibniz and Immanuel Kant, holds that time is neither an event nor a thing, and thus is not itself measurable nor can it be travelled.


Question: Time is one of how many fundamental physical quantities?

Time is one of the seven fundamental physical quantities in both the International System of Units and International System of Quantities. Time is used to define other quantities—such as velocity—so defining time in terms of such quantities would result in circularity of definition. An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life. The operational definition leaves aside the question whether there is something called time, apart from the counting activity just mentioned, that flows and that can be measured. Investigations of a single continuum called spacetime bring questions about space into questions about time, questions that have their roots in the works of early students of natural philosophy.

Answer: seven

<hl> Time is one of the seven fundamental physical quantities in both the International System of Units and International System of Quantities. <hl> Time is used to define other quantities—such as velocity—so defining time in terms of such quantities would result in circularity of definition. An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life. The operational definition leaves aside the question whether there is something called time, apart from the counting activity just mentioned, that flows and that can be measured. Investigations of a single continuum called spacetime bring questions about space into questions about time, questions that have their roots in the works of early students of natural philosophy.

Time is one of the <hl> seven <hl> fundamental physical quantities in both the International System of Units and International System of Quantities. Time is used to define other quantities—such as velocity—so defining time in terms of such quantities would result in circularity of definition. An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life. The operational definition leaves aside the question whether there is something called time, apart from the counting activity just mentioned, that flows and that can be measured. Investigations of a single continuum called spacetime bring questions about space into questions about time, questions that have their roots in the works of early students of natural philosophy.


Question: Time is one of the fundamental physical quantities in which two systems?

Answer: the International System of Units and International System of Quantities

<hl> Time is one of the seven fundamental physical quantities in both the International System of Units and International System of Quantities . <hl> Time is used to define other quantities—such as velocity—so defining time in terms of such quantities would result in circularity of definition. An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life. The operational definition leaves aside the question whether there is something called time, apart from the counting activity just mentioned, that flows and that can be measured. Investigations of a single continuum called spacetime bring questions about space into questions about time, questions that have their roots in the works of early students of natural philosophy.

Time is one of the seven fundamental physical quantities in both <hl> the International System of Units and International System of Quantities <hl>. Time is used to define other quantities—such as velocity—so defining time in terms of such quantities would result in circularity of definition. An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life. The operational definition leaves aside the question whether there is something called time, apart from the counting activity just mentioned, that flows and that can be measured. Investigations of a single continuum called spacetime bring questions about space into questions about time, questions that have their roots in the works of early students of natural philosophy.

Time is one of the seven fundamental physical quantities in both <hl> the International System of Units and International System of Quantities <hl> .


Question: What is an example of a quantity that time is used to define, mentioned in the paragraph?

Answer: velocity

Time is one of the seven fundamental physical quantities in both the International System of Units and International System of Quantities. <hl> Time is used to define other quantities—such as velocity —so defining time in terms of such quantities would result in circularity of definition. <hl> An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life. The operational definition leaves aside the question whether there is something called time, apart from the counting activity just mentioned, that flows and that can be measured. Investigations of a single continuum called spacetime bring questions about space into questions about time, questions that have their roots in the works of early students of natural philosophy.

Time is one of the seven fundamental physical quantities in both the International System of Units and International System of Quantities. Time is used to define other quantities—such as <hl> velocity <hl>—so defining time in terms of such quantities would result in circularity of definition. An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life. The operational definition leaves aside the question whether there is something called time, apart from the counting activity just mentioned, that flows and that can be measured. Investigations of a single continuum called spacetime bring questions about space into questions about time, questions that have their roots in the works of early students of natural philosophy.

Time is used to define other quantities—such as <hl> velocity <hl> —so defining time in terms of such quantities would result in circularity of definition.


Question: Investigations of what brought questions of space into questions about time?

Answer: a single continuum called spacetime

Time is one of the seven fundamental physical quantities in both the International System of Units and International System of Quantities. Time is used to define other quantities—such as velocity—so defining time in terms of such quantities would result in circularity of definition. An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life. The operational definition leaves aside the question whether there is something called time, apart from the counting activity just mentioned, that flows and that can be measured. <hl> Investigations of a single continuum called spacetime bring questions about space into questions about time, questions that have their roots in the works of early students of natural philosophy. <hl>

Time is one of the seven fundamental physical quantities in both the International System of Units and International System of Quantities. Time is used to define other quantities—such as velocity—so defining time in terms of such quantities would result in circularity of definition. An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life. The operational definition leaves aside the question whether there is something called time, apart from the counting activity just mentioned, that flows and that can be measured. Investigations of <hl> a single continuum called spacetime <hl> bring questions about space into questions about time, questions that have their roots in the works of early students of natural philosophy.


Question: What has been a prime motivation in astronomy and navigation?

Temporal measurement has occupied scientists and technologists, and was a prime motivation in navigation and astronomy. Periodic events and periodic motion have long served as standards for units of time. Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the beat of a heart. Currently, the international unit of time, the second, is defined by measuring the electronic transition frequency of caesium atoms (see below). Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in each day and in human life spans.

Answer: Temporal measurement

<hl> Temporal measurement has occupied scientists and technologists, and was a prime motivation in navigation and astronomy. <hl> Periodic events and periodic motion have long served as standards for units of time. Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the beat of a heart. Currently, the international unit of time, the second, is defined by measuring the electronic transition frequency of caesium atoms (see below). Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in each day and in human life spans.

<hl> Temporal measurement <hl> has occupied scientists and technologists, and was a prime motivation in navigation and astronomy. Periodic events and periodic motion have long served as standards for units of time. Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the beat of a heart. Currently, the international unit of time, the second, is defined by measuring the electronic transition frequency of caesium atoms (see below). Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in each day and in human life spans.


Question: Periodic events and periodic motion have served as standards for what?

Answer: Periodic events and periodic motion

Temporal measurement has occupied scientists and technologists, and was a prime motivation in navigation and astronomy. <hl> Periodic events and periodic motion have long served as standards for units of time. <hl> Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the beat of a heart. Currently, the international unit of time, the second, is defined by measuring the electronic transition frequency of caesium atoms (see below). Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in each day and in human life spans.

Temporal measurement has occupied scientists and technologists, and was a prime motivation in navigation and astronomy. <hl> Periodic events and periodic motion <hl> have long served as standards for units of time. Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the beat of a heart. Currently, the international unit of time, the second, is defined by measuring the electronic transition frequency of caesium atoms (see below). Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in each day and in human life spans.


Question: What is the current international unit of time?

Answer: the second

Temporal measurement has occupied scientists and technologists, and was a prime motivation in navigation and astronomy. Periodic events and periodic motion have long served as standards for units of time. Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the beat of a heart. <hl> Currently, the international unit of time, the second , is defined by measuring the electronic transition frequency of caesium atoms (see below). <hl> Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in each day and in human life spans.

Temporal measurement has occupied scientists and technologists, and was a prime motivation in navigation and astronomy. Periodic events and periodic motion have long served as standards for units of time. Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the beat of a heart. Currently, the international unit of time, <hl> the second <hl>, is defined by measuring the electronic transition frequency of caesium atoms (see below). Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in each day and in human life spans.

Currently, the international unit of time, <hl> the second <hl> , is defined by measuring the electronic transition frequency of caesium atoms (see below).


Question: The electronic transition frequency of which element defines the second?

Answer: caesium atoms

Temporal measurement has occupied scientists and technologists, and was a prime motivation in navigation and astronomy. Periodic events and periodic motion have long served as standards for units of time. Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the beat of a heart. <hl> Currently, the international unit of time, the second, is defined by measuring the electronic transition frequency of caesium atoms (see below). <hl> Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in each day and in human life spans.

Temporal measurement has occupied scientists and technologists, and was a prime motivation in navigation and astronomy. Periodic events and periodic motion have long served as standards for units of time. Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the beat of a heart. Currently, the international unit of time, the second, is defined by measuring the electronic transition frequency of <hl> caesium atoms <hl> (see below). Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in each day and in human life spans.


Question: Time has personal value due to awareness of it's limited nature in what?

Answer: each day and in human life spans

Temporal measurement has occupied scientists and technologists, and was a prime motivation in navigation and astronomy. Periodic events and periodic motion have long served as standards for units of time. Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the beat of a heart. Currently, the international unit of time, the second, is defined by measuring the electronic transition frequency of caesium atoms (see below). <hl> Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in each day and in human life spans . <hl>

Temporal measurement has occupied scientists and technologists, and was a prime motivation in navigation and astronomy. Periodic events and periodic motion have long served as standards for units of time. Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the beat of a heart. Currently, the international unit of time, the second, is defined by measuring the electronic transition frequency of caesium atoms (see below). Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in <hl> each day and in human life spans <hl>.

Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in <hl> each day and in human life spans <hl> .


Question: What is a mathematical tool used for organizing intervals of time?

Temporal measurement, chronometry, takes two distinct period forms: the calendar, a mathematical tool for organizing intervals of time, and the clock, a physical mechanism that counts the passage of time. In day-to-day life, the clock is consulted for periods less than a day whereas the calendar is consulted for periods longer than a day. Increasingly, personal electronic devices display both calendars and clocks simultaneously. The number (as on a clock dial or calendar) that marks the occurrence of a specified event as to hour or date is obtained by counting from a fiducial epoch—a central reference point.

Answer: the calendar

<hl> Temporal measurement, chronometry, takes two distinct period forms: the calendar , a mathematical tool for organizing intervals of time, and the clock, a physical mechanism that counts the passage of time. <hl> In day-to-day life, the clock is consulted for periods less than a day whereas the calendar is consulted for periods longer than a day. Increasingly, personal electronic devices display both calendars and clocks simultaneously. The number (as on a clock dial or calendar) that marks the occurrence of a specified event as to hour or date is obtained by counting from a fiducial epoch—a central reference point.

Temporal measurement, chronometry, takes two distinct period forms: <hl> the calendar <hl>, a mathematical tool for organizing intervals of time, and the clock, a physical mechanism that counts the passage of time. In day-to-day life, the clock is consulted for periods less than a day whereas the calendar is consulted for periods longer than a day. Increasingly, personal electronic devices display both calendars and clocks simultaneously. The number (as on a clock dial or calendar) that marks the occurrence of a specified event as to hour or date is obtained by counting from a fiducial epoch—a central reference point.

Temporal measurement, chronometry, takes two distinct period forms: <hl> the calendar <hl> , a mathematical tool for organizing intervals of time, and the clock, a physical mechanism that counts the passage of time.


Question: What is a physical tool that tracks the passage of time?

Answer: the clock

<hl> Temporal measurement, chronometry, takes two distinct period forms: the calendar, a mathematical tool for organizing intervals of time, and the clock , a physical mechanism that counts the passage of time. <hl> In day-to-day life, the clock is consulted for periods less than a day whereas the calendar is consulted for periods longer than a day. Increasingly, personal electronic devices display both calendars and clocks simultaneously. The number (as on a clock dial or calendar) that marks the occurrence of a specified event as to hour or date is obtained by counting from a fiducial epoch—a central reference point.

Temporal measurement, chronometry, takes two distinct period forms: the calendar, a mathematical tool for organizing intervals of time, and <hl> the clock <hl>, a physical mechanism that counts the passage of time. In day-to-day life, the clock is consulted for periods less than a day whereas the calendar is consulted for periods longer than a day. Increasingly, personal electronic devices display both calendars and clocks simultaneously. The number (as on a clock dial or calendar) that marks the occurrence of a specified event as to hour or date is obtained by counting from a fiducial epoch—a central reference point.

Temporal measurement, chronometry, takes two distinct period forms: the calendar, a mathematical tool for organizing intervals of time, and <hl> the clock <hl> , a physical mechanism that counts the passage of time.


Question: Which tool is used in day to day life?

Answer: the clock

<hl> Temporal measurement, chronometry, takes two distinct period forms: the calendar, a mathematical tool for organizing intervals of time, and the clock , a physical mechanism that counts the passage of time. <hl> In day-to-day life, the clock is consulted for periods less than a day whereas the calendar is consulted for periods longer than a day. Increasingly, personal electronic devices display both calendars and clocks simultaneously. The number (as on a clock dial or calendar) that marks the occurrence of a specified event as to hour or date is obtained by counting from a fiducial epoch—a central reference point.

Temporal measurement, chronometry, takes two distinct period forms: the calendar, a mathematical tool for organizing intervals of time, and <hl> the clock <hl>, a physical mechanism that counts the passage of time. In day-to-day life, the clock is consulted for periods less than a day whereas the calendar is consulted for periods longer than a day. Increasingly, personal electronic devices display both calendars and clocks simultaneously. The number (as on a clock dial or calendar) that marks the occurrence of a specified event as to hour or date is obtained by counting from a fiducial epoch—a central reference point.

Temporal measurement, chronometry, takes two distinct period forms: the calendar, a mathematical tool for organizing intervals of time, and <hl> the clock <hl> , a physical mechanism that counts the passage of time.


Question: Which tool is used in periods longer than a day?

Answer: the calendar

<hl> Temporal measurement, chronometry, takes two distinct period forms: the calendar , a mathematical tool for organizing intervals of time, and the clock, a physical mechanism that counts the passage of time. <hl> In day-to-day life, the clock is consulted for periods less than a day whereas the calendar is consulted for periods longer than a day. Increasingly, personal electronic devices display both calendars and clocks simultaneously. The number (as on a clock dial or calendar) that marks the occurrence of a specified event as to hour or date is obtained by counting from a fiducial epoch—a central reference point.

Temporal measurement, chronometry, takes two distinct period forms: <hl> the calendar <hl>, a mathematical tool for organizing intervals of time, and the clock, a physical mechanism that counts the passage of time. In day-to-day life, the clock is consulted for periods less than a day whereas the calendar is consulted for periods longer than a day. Increasingly, personal electronic devices display both calendars and clocks simultaneously. The number (as on a clock dial or calendar) that marks the occurrence of a specified event as to hour or date is obtained by counting from a fiducial epoch—a central reference point.

Temporal measurement, chronometry, takes two distinct period forms: <hl> the calendar <hl> , a mathematical tool for organizing intervals of time, and the clock, a physical mechanism that counts the passage of time.


Question: How is the number that marks the occurrence of an event obtained?

Answer: by counting from a fiducial epoch—a central reference point

Temporal measurement, chronometry, takes two distinct period forms: the calendar, a mathematical tool for organizing intervals of time, and the clock, a physical mechanism that counts the passage of time. In day-to-day life, the clock is consulted for periods less than a day whereas the calendar is consulted for periods longer than a day. Increasingly, personal electronic devices display both calendars and clocks simultaneously. <hl> The number (as on a clock dial or calendar) that marks the occurrence of a specified event as to hour or date is obtained by counting from a fiducial epoch—a central reference point . <hl>

Temporal measurement, chronometry, takes two distinct period forms: the calendar, a mathematical tool for organizing intervals of time, and the clock, a physical mechanism that counts the passage of time. In day-to-day life, the clock is consulted for periods less than a day whereas the calendar is consulted for periods longer than a day. Increasingly, personal electronic devices display both calendars and clocks simultaneously. The number (as on a clock dial or calendar) that marks the occurrence of a specified event as to hour or date is obtained <hl> by counting from a fiducial epoch—a central reference point <hl>.

The number (as on a clock dial or calendar) that marks the occurrence of a specified event as to hour or date is obtained <hl> by counting from a fiducial epoch—a central reference point <hl> .


Question: Artifacts from which era suggest that the moon was used to reckon time around 6,000 years ago?

Artifacts from the Paleolithic suggest that the moon was used to reckon time as early as 6,000 years ago. Lunar calendars were among the first to appear, either 12 or 13 lunar months (either 354 or 384 days). Without intercalation to add days or months to some years, seasons quickly drift in a calendar based solely on twelve lunar months. Lunisolar calendars have a thirteenth month added to some years to make up for the difference between a full year (now known to be about 365.24 days) and a year of just twelve lunar months. The numbers twelve and thirteen came to feature prominently in many cultures, at least partly due to this relationship of months to years. Other early forms of calendars originated in Mesoamerica, particularly in ancient Mayan civilization. These calendars were religiously and astronomically based, with 18 months in a year and 20 days in a month.

Answer: the Paleolithic

<hl> Artifacts from the Paleolithic suggest that the moon was used to reckon time as early as 6,000 years ago. <hl> Lunar calendars were among the first to appear, either 12 or 13 lunar months (either 354 or 384 days). Without intercalation to add days or months to some years, seasons quickly drift in a calendar based solely on twelve lunar months. Lunisolar calendars have a thirteenth month added to some years to make up for the difference between a full year (now known to be about 365.24 days) and a year of just twelve lunar months. The numbers twelve and thirteen came to feature prominently in many cultures, at least partly due to this relationship of months to years. Other early forms of calendars originated in Mesoamerica, particularly in ancient Mayan civilization. These calendars were religiously and astronomically based, with 18 months in a year and 20 days in a month.

Artifacts from <hl> the Paleolithic <hl> suggest that the moon was used to reckon time as early as 6,000 years ago. Lunar calendars were among the first to appear, either 12 or 13 lunar months (either 354 or 384 days). Without intercalation to add days or months to some years, seasons quickly drift in a calendar based solely on twelve lunar months. Lunisolar calendars have a thirteenth month added to some years to make up for the difference between a full year (now known to be about 365.24 days) and a year of just twelve lunar months. The numbers twelve and thirteen came to feature prominently in many cultures, at least partly due to this relationship of months to years. Other early forms of calendars originated in Mesoamerica, particularly in ancient Mayan civilization. These calendars were religiously and astronomically based, with 18 months in a year and 20 days in a month.


Question: Which calendars were among the first to appear?

Answer: Lunar calendars

Artifacts from the Paleolithic suggest that the moon was used to reckon time as early as 6,000 years ago. <hl> Lunar calendars were among the first to appear, either 12 or 13 lunar months (either 354 or 384 days). <hl> Without intercalation to add days or months to some years, seasons quickly drift in a calendar based solely on twelve lunar months. Lunisolar calendars have a thirteenth month added to some years to make up for the difference between a full year (now known to be about 365.24 days) and a year of just twelve lunar months. The numbers twelve and thirteen came to feature prominently in many cultures, at least partly due to this relationship of months to years. Other early forms of calendars originated in Mesoamerica, particularly in ancient Mayan civilization. These calendars were religiously and astronomically based, with 18 months in a year and 20 days in a month.

Artifacts from the Paleolithic suggest that the moon was used to reckon time as early as 6,000 years ago. <hl> Lunar calendars <hl> were among the first to appear, either 12 or 13 lunar months (either 354 or 384 days). Without intercalation to add days or months to some years, seasons quickly drift in a calendar based solely on twelve lunar months. Lunisolar calendars have a thirteenth month added to some years to make up for the difference between a full year (now known to be about 365.24 days) and a year of just twelve lunar months. The numbers twelve and thirteen came to feature prominently in many cultures, at least partly due to this relationship of months to years. Other early forms of calendars originated in Mesoamerica, particularly in ancient Mayan civilization. These calendars were religiously and astronomically based, with 18 months in a year and 20 days in a month.


Question: How long were the original lunar calendars?

Answer: either 12 or 13 lunar months (either 354 or 384 days)

Artifacts from the Paleolithic suggest that the moon was used to reckon time as early as 6,000 years ago. <hl> Lunar calendars were among the first to appear, either 12 or 13 lunar months (either 354 or 384 days) . <hl> Without intercalation to add days or months to some years, seasons quickly drift in a calendar based solely on twelve lunar months. Lunisolar calendars have a thirteenth month added to some years to make up for the difference between a full year (now known to be about 365.24 days) and a year of just twelve lunar months. The numbers twelve and thirteen came to feature prominently in many cultures, at least partly due to this relationship of months to years. Other early forms of calendars originated in Mesoamerica, particularly in ancient Mayan civilization. These calendars were religiously and astronomically based, with 18 months in a year and 20 days in a month.

Artifacts from the Paleolithic suggest that the moon was used to reckon time as early as 6,000 years ago. Lunar calendars were among the first to appear, <hl> either 12 or 13 lunar months (either 354 or 384 days) <hl>. Without intercalation to add days or months to some years, seasons quickly drift in a calendar based solely on twelve lunar months. Lunisolar calendars have a thirteenth month added to some years to make up for the difference between a full year (now known to be about 365.24 days) and a year of just twelve lunar months. The numbers twelve and thirteen came to feature prominently in many cultures, at least partly due to this relationship of months to years. Other early forms of calendars originated in Mesoamerica, particularly in ancient Mayan civilization. These calendars were religiously and astronomically based, with 18 months in a year and 20 days in a month.

Lunar calendars were among the first to appear, <hl> either 12 or 13 lunar months (either 354 or 384 days) <hl> .


Question: Where did some of the other early forms of calendars originate?

Answer: Mesoamerica

Artifacts from the Paleolithic suggest that the moon was used to reckon time as early as 6,000 years ago. Lunar calendars were among the first to appear, either 12 or 13 lunar months (either 354 or 384 days). Without intercalation to add days or months to some years, seasons quickly drift in a calendar based solely on twelve lunar months. Lunisolar calendars have a thirteenth month added to some years to make up for the difference between a full year (now known to be about 365.24 days) and a year of just twelve lunar months. The numbers twelve and thirteen came to feature prominently in many cultures, at least partly due to this relationship of months to years. <hl> Other early forms of calendars originated in Mesoamerica , particularly in ancient Mayan civilization. <hl> These calendars were religiously and astronomically based, with 18 months in a year and 20 days in a month.

Artifacts from the Paleolithic suggest that the moon was used to reckon time as early as 6,000 years ago. Lunar calendars were among the first to appear, either 12 or 13 lunar months (either 354 or 384 days). Without intercalation to add days or months to some years, seasons quickly drift in a calendar based solely on twelve lunar months. Lunisolar calendars have a thirteenth month added to some years to make up for the difference between a full year (now known to be about 365.24 days) and a year of just twelve lunar months. The numbers twelve and thirteen came to feature prominently in many cultures, at least partly due to this relationship of months to years. Other early forms of calendars originated in <hl> Mesoamerica <hl>, particularly in ancient Mayan civilization. These calendars were religiously and astronomically based, with 18 months in a year and 20 days in a month.

Other early forms of calendars originated in <hl> Mesoamerica <hl> , particularly in ancient Mayan civilization.


Question: How many months were in a year in the original Mayan calendars?

Answer: 18

Artifacts from the Paleolithic suggest that the moon was used to reckon time as early as 6,000 years ago. Lunar calendars were among the first to appear, either 12 or 13 lunar months (either 354 or 384 days). Without intercalation to add days or months to some years, seasons quickly drift in a calendar based solely on twelve lunar months. Lunisolar calendars have a thirteenth month added to some years to make up for the difference between a full year (now known to be about 365.24 days) and a year of just twelve lunar months. The numbers twelve and thirteen came to feature prominently in many cultures, at least partly due to this relationship of months to years. Other early forms of calendars originated in Mesoamerica, particularly in ancient Mayan civilization. <hl> These calendars were religiously and astronomically based, with 18 months in a year and 20 days in a month. <hl>

Artifacts from the Paleolithic suggest that the moon was used to reckon time as early as 6,000 years ago. Lunar calendars were among the first to appear, either 12 or 13 lunar months (either 354 or 384 days). Without intercalation to add days or months to some years, seasons quickly drift in a calendar based solely on twelve lunar months. Lunisolar calendars have a thirteenth month added to some years to make up for the difference between a full year (now known to be about 365.24 days) and a year of just twelve lunar months. The numbers twelve and thirteen came to feature prominently in many cultures, at least partly due to this relationship of months to years. Other early forms of calendars originated in Mesoamerica, particularly in ancient Mayan civilization. These calendars were religiously and astronomically based, with <hl> 18 <hl> months in a year and 20 days in a month.


Question: What was the most accurate clock-like device in the ancient world?

The most precise timekeeping device of the ancient world was the water clock, or clepsydra, one of which was found in the tomb of Egyptian pharaoh Amenhotep I (1525–1504 BC). They could be used to measure the hours even at night, but required manual upkeep to replenish the flow of water. The Ancient Greeks and the people from Chaldea (southeastern Mesopotamia) regularly maintained timekeeping records as an essential part of their astronomical observations. Arab inventors and engineers in particular made improvements on the use of water clocks up to the Middle Ages. In the 11th century, Chinese inventors and engineers invented the first mechanical clocks driven by an escapement mechanism.

Answer: the water clock, or clepsydra

<hl> The most precise timekeeping device of the ancient world was the water clock, or clepsydra , one of which was found in the tomb of Egyptian pharaoh Amenhotep <hl> I (1525–1504 BC). They could be used to measure the hours even at night, but required manual upkeep to replenish the flow of water. The Ancient Greeks and the people from Chaldea (southeastern Mesopotamia) regularly maintained timekeeping records as an essential part of their astronomical observations. Arab inventors and engineers in particular made improvements on the use of water clocks up to the Middle Ages. In the 11th century, Chinese inventors and engineers invented the first mechanical clocks driven by an escapement mechanism.

The most precise timekeeping device of the ancient world was <hl> the water clock, or clepsydra <hl>, one of which was found in the tomb of Egyptian pharaoh Amenhotep I (1525–1504 BC). They could be used to measure the hours even at night, but required manual upkeep to replenish the flow of water. The Ancient Greeks and the people from Chaldea (southeastern Mesopotamia) regularly maintained timekeeping records as an essential part of their astronomical observations. Arab inventors and engineers in particular made improvements on the use of water clocks up to the Middle Ages. In the 11th century, Chinese inventors and engineers invented the first mechanical clocks driven by an escapement mechanism.

The most precise timekeeping device of the ancient world was <hl> the water clock, or clepsydra <hl> , one of which was found in the tomb of Egyptian pharaoh Amenhotep


Question: A clepsyrda was found in the tomb of which Pharaoh?

Answer: Egyptian pharaoh Amenhotep

<hl> The most precise timekeeping device of the ancient world was the water clock, or clepsydra, one of which was found in the tomb of Egyptian pharaoh Amenhotep I (1525–1504 BC). <hl> They could be used to measure the hours even at night, but required manual upkeep to replenish the flow of water. The Ancient Greeks and the people from Chaldea (southeastern Mesopotamia) regularly maintained timekeeping records as an essential part of their astronomical observations. Arab inventors and engineers in particular made improvements on the use of water clocks up to the Middle Ages. In the 11th century, Chinese inventors and engineers invented the first mechanical clocks driven by an escapement mechanism.

The most precise timekeeping device of the ancient world was the water clock, or clepsydra, one of which was found in the tomb of <hl> Egyptian pharaoh Amenhotep <hl> I (1525–1504 BC). They could be used to measure the hours even at night, but required manual upkeep to replenish the flow of water. The Ancient Greeks and the people from Chaldea (southeastern Mesopotamia) regularly maintained timekeeping records as an essential part of their astronomical observations. Arab inventors and engineers in particular made improvements on the use of water clocks up to the Middle Ages. In the 11th century, Chinese inventors and engineers invented the first mechanical clocks driven by an escapement mechanism.


Question: Which inventors made significant improvements on the water clock up until the Middle Ages?

Answer: Arab inventors

The most precise timekeeping device of the ancient world was the water clock, or clepsydra, one of which was found in the tomb of Egyptian pharaoh Amenhotep I (1525–1504 BC). They could be used to measure the hours even at night, but required manual upkeep to replenish the flow of water. The Ancient Greeks and the people from Chaldea (southeastern Mesopotamia) regularly maintained timekeeping records as an essential part of their astronomical observations. <hl> Arab inventors and engineers in particular made improvements on the use of water clocks up to the Middle Ages. <hl> In the 11th century, Chinese inventors and engineers invented the first mechanical clocks driven by an escapement mechanism.

The most precise timekeeping device of the ancient world was the water clock, or clepsydra, one of which was found in the tomb of Egyptian pharaoh Amenhotep I (1525–1504 BC). They could be used to measure the hours even at night, but required manual upkeep to replenish the flow of water. The Ancient Greeks and the people from Chaldea (southeastern Mesopotamia) regularly maintained timekeeping records as an essential part of their astronomical observations. <hl> Arab inventors <hl> and engineers in particular made improvements on the use of water clocks up to the Middle Ages. In the 11th century, Chinese inventors and engineers invented the first mechanical clocks driven by an escapement mechanism.


Question: Which engineers came up with the first mechanical clocks?

Answer: Chinese

The most precise timekeeping device of the ancient world was the water clock, or clepsydra, one of which was found in the tomb of Egyptian pharaoh Amenhotep I (1525–1504 BC). They could be used to measure the hours even at night, but required manual upkeep to replenish the flow of water. The Ancient Greeks and the people from Chaldea (southeastern Mesopotamia) regularly maintained timekeeping records as an essential part of their astronomical observations. Arab inventors and engineers in particular made improvements on the use of water clocks up to the Middle Ages. <hl> In the 11th century, Chinese inventors and engineers invented the first mechanical clocks driven by an escapement mechanism. <hl>

The most precise timekeeping device of the ancient world was the water clock, or clepsydra, one of which was found in the tomb of Egyptian pharaoh Amenhotep I (1525–1504 BC). They could be used to measure the hours even at night, but required manual upkeep to replenish the flow of water. The Ancient Greeks and the people from Chaldea (southeastern Mesopotamia) regularly maintained timekeeping records as an essential part of their astronomical observations. Arab inventors and engineers in particular made improvements on the use of water clocks up to the Middle Ages. In the 11th century, <hl> Chinese <hl> inventors and engineers invented the first mechanical clocks driven by an escapement mechanism.


Question: When were the first mechanical clocks created?

Answer: the 11th century

The most precise timekeeping device of the ancient world was the water clock, or clepsydra, one of which was found in the tomb of Egyptian pharaoh Amenhotep I (1525–1504 BC). They could be used to measure the hours even at night, but required manual upkeep to replenish the flow of water. The Ancient Greeks and the people from Chaldea (southeastern Mesopotamia) regularly maintained timekeeping records as an essential part of their astronomical observations. Arab inventors and engineers in particular made improvements on the use of water clocks up to the Middle Ages. <hl> In the 11th century , Chinese inventors and engineers invented the first mechanical clocks driven by an escapement mechanism. <hl>

The most precise timekeeping device of the ancient world was the water clock, or clepsydra, one of which was found in the tomb of Egyptian pharaoh Amenhotep I (1525–1504 BC). They could be used to measure the hours even at night, but required manual upkeep to replenish the flow of water. The Ancient Greeks and the people from Chaldea (southeastern Mesopotamia) regularly maintained timekeeping records as an essential part of their astronomical observations. Arab inventors and engineers in particular made improvements on the use of water clocks up to the Middle Ages. In <hl> the 11th century <hl>, Chinese inventors and engineers invented the first mechanical clocks driven by an escapement mechanism.

In <hl> the 11th century <hl> , Chinese inventors and engineers invented the first mechanical clocks driven by an escapement mechanism.


Question: Which device uses the flow of sand to measure time?

The hourglass uses the flow of sand to measure the flow of time. They were used in navigation. Ferdinand Magellan used 18 glasses on each ship for his circumnavigation of the globe (1522). Incense sticks and candles were, and are, commonly used to measure time in temples and churches across the globe. Waterclocks, and later, mechanical clocks, were used to mark the events of the abbeys and monasteries of the Middle Ages. Richard of Wallingford (1292–1336), abbot of St. Alban's abbey, famously built a mechanical clock as an astronomical orrery about 1330. Great advances in accurate time-keeping were made by Galileo Galilei and especially Christiaan Huygens with the invention of pendulum driven clocks along with the invention of the minute hand by Jost Burgi.

Answer: The hourglass

<hl> The hourglass uses the flow of sand to measure the flow of time. <hl> They were used in navigation. Ferdinand Magellan used 18 glasses on each ship for his circumnavigation of the globe (1522). Incense sticks and candles were, and are, commonly used to measure time in temples and churches across the globe. Waterclocks, and later, mechanical clocks, were used to mark the events of the abbeys and monasteries of the Middle Ages. Richard of Wallingford (1292–1336), abbot of St. Alban's abbey, famously built a mechanical clock as an astronomical orrery about 1330. Great advances in accurate time-keeping were made by Galileo Galilei and especially Christiaan Huygens with the invention of pendulum driven clocks along with the invention of the minute hand by Jost Burgi.

<hl> The hourglass <hl> uses the flow of sand to measure the flow of time. They were used in navigation. Ferdinand Magellan used 18 glasses on each ship for his circumnavigation of the globe (1522). Incense sticks and candles were, and are, commonly used to measure time in temples and churches across the globe. Waterclocks, and later, mechanical clocks, were used to mark the events of the abbeys and monasteries of the Middle Ages. Richard of Wallingford (1292–1336), abbot of St. Alban's abbey, famously built a mechanical clock as an astronomical orrery about 1330. Great advances in accurate time-keeping were made by Galileo Galilei and especially Christiaan Huygens with the invention of pendulum driven clocks along with the invention of the minute hand by Jost Burgi.


Question: How many hourglasses did Magellan use on each ship during his famous voyage across the globe?

Answer: 18

The hourglass uses the flow of sand to measure the flow of time. They were used in navigation. <hl> Ferdinand Magellan used 18 glasses on each ship for his circumnavigation of the globe (1522). <hl> Incense sticks and candles were, and are, commonly used to measure time in temples and churches across the globe. Waterclocks, and later, mechanical clocks, were used to mark the events of the abbeys and monasteries of the Middle Ages. Richard of Wallingford (1292–1336), abbot of St. Alban's abbey, famously built a mechanical clock as an astronomical orrery about 1330. Great advances in accurate time-keeping were made by Galileo Galilei and especially Christiaan Huygens with the invention of pendulum driven clocks along with the invention of the minute hand by Jost Burgi.

The hourglass uses the flow of sand to measure the flow of time. They were used in navigation. Ferdinand Magellan used <hl> 18 <hl> glasses on each ship for his circumnavigation of the globe (1522). Incense sticks and candles were, and are, commonly used to measure time in temples and churches across the globe. Waterclocks, and later, mechanical clocks, were used to mark the events of the abbeys and monasteries of the Middle Ages. Richard of Wallingford (1292–1336), abbot of St. Alban's abbey, famously built a mechanical clock as an astronomical orrery about 1330. Great advances in accurate time-keeping were made by Galileo Galilei and especially Christiaan Huygens with the invention of pendulum driven clocks along with the invention of the minute hand by Jost Burgi.


Question: What method did temples and churches use to measure time?

Answer: Incense sticks and candles

The hourglass uses the flow of sand to measure the flow of time. They were used in navigation. Ferdinand Magellan used 18 glasses on each ship for his circumnavigation of the globe (1522). <hl> Incense sticks and candles were, and are, commonly used to measure time in temples and churches across the globe. <hl> Waterclocks, and later, mechanical clocks, were used to mark the events of the abbeys and monasteries of the Middle Ages. Richard of Wallingford (1292–1336), abbot of St. Alban's abbey, famously built a mechanical clock as an astronomical orrery about 1330. Great advances in accurate time-keeping were made by Galileo Galilei and especially Christiaan Huygens with the invention of pendulum driven clocks along with the invention of the minute hand by Jost Burgi.

The hourglass uses the flow of sand to measure the flow of time. They were used in navigation. Ferdinand Magellan used 18 glasses on each ship for his circumnavigation of the globe (1522). <hl> Incense sticks and candles <hl> were, and are, commonly used to measure time in temples and churches across the globe. Waterclocks, and later, mechanical clocks, were used to mark the events of the abbeys and monasteries of the Middle Ages. Richard of Wallingford (1292–1336), abbot of St. Alban's abbey, famously built a mechanical clock as an astronomical orrery about 1330. Great advances in accurate time-keeping were made by Galileo Galilei and especially Christiaan Huygens with the invention of pendulum driven clocks along with the invention of the minute hand by Jost Burgi.


Question: Which abbot of St. Alban's abbey built a mechanical clock around 1330?

Answer: Richard of Wallingford

The hourglass uses the flow of sand to measure the flow of time. They were used in navigation. Ferdinand Magellan used 18 glasses on each ship for his circumnavigation of the globe (1522). Incense sticks and candles were, and are, commonly used to measure time in temples and churches across the globe. Waterclocks, and later, mechanical clocks, were used to mark the events of the abbeys and monasteries of the Middle Ages. <hl> Richard of Wallingford (1292–1336), abbot of St. Alban's abbey, famously built a mechanical clock as an astronomical orrery about 1330. <hl> Great advances in accurate time-keeping were made by Galileo Galilei and especially Christiaan Huygens with the invention of pendulum driven clocks along with the invention of the minute hand by Jost Burgi.

The hourglass uses the flow of sand to measure the flow of time. They were used in navigation. Ferdinand Magellan used 18 glasses on each ship for his circumnavigation of the globe (1522). Incense sticks and candles were, and are, commonly used to measure time in temples and churches across the globe. Waterclocks, and later, mechanical clocks, were used to mark the events of the abbeys and monasteries of the Middle Ages. <hl> Richard of Wallingford <hl> (1292–1336), abbot of St. Alban's abbey, famously built a mechanical clock as an astronomical orrery about 1330. Great advances in accurate time-keeping were made by Galileo Galilei and especially Christiaan Huygens with the invention of pendulum driven clocks along with the invention of the minute hand by Jost Burgi.


Question: Who is credited with the invention of the minute hand?

Answer: Jost Burgi.

The hourglass uses the flow of sand to measure the flow of time. They were used in navigation. Ferdinand Magellan used 18 glasses on each ship for his circumnavigation of the globe (1522). Incense sticks and candles were, and are, commonly used to measure time in temples and churches across the globe. Waterclocks, and later, mechanical clocks, were used to mark the events of the abbeys and monasteries of the Middle Ages. Richard of Wallingford (1292–1336), abbot of St. Alban's abbey, famously built a mechanical clock as an astronomical orrery about 1330. <hl> Great advances in accurate time-keeping were made by Galileo Galilei and especially Christiaan Huygens with the invention of pendulum driven clocks along with the invention of the minute hand by Jost Burgi. <hl>

The hourglass uses the flow of sand to measure the flow of time. They were used in navigation. Ferdinand Magellan used 18 glasses on each ship for his circumnavigation of the globe (1522). Incense sticks and candles were, and are, commonly used to measure time in temples and churches across the globe. Waterclocks, and later, mechanical clocks, were used to mark the events of the abbeys and monasteries of the Middle Ages. Richard of Wallingford (1292–1336), abbot of St. Alban's abbey, famously built a mechanical clock as an astronomical orrery about 1330. Great advances in accurate time-keeping were made by Galileo Galilei and especially Christiaan Huygens with the invention of pendulum driven clocks along with the invention of the minute hand by <hl> Jost Burgi. <hl>


Question: Which timekeeping devices are the most accurate?

The most accurate timekeeping devices are atomic clocks, which are accurate to seconds in many millions of years, and are used to calibrate other clocks and timekeeping instruments. Atomic clocks use the frequency of electronic transitions in certain atoms to measure the second. One of the most common atoms used is caesium, most modern atomic clocks probe caesium with microwaves to determine the frequency of these electron vibrations. Since 1967, the International System of Measurements bases its unit of time, the second, on the properties of caesium atoms. SI defines the second as 9,192,631,770 cycles of the radiation that corresponds to the transition between two electron spin energy levels of the ground state of the 133Cs atom.

Answer: atomic clocks

<hl> The most accurate timekeeping devices are atomic clocks , which are accurate to seconds in many millions of years, and are used to calibrate other clocks and timekeeping instruments. <hl> Atomic clocks use the frequency of electronic transitions in certain atoms to measure the second. One of the most common atoms used is caesium, most modern atomic clocks probe caesium with microwaves to determine the frequency of these electron vibrations. Since 1967, the International System of Measurements bases its unit of time, the second, on the properties of caesium atoms. SI defines the second as 9,192,631,770 cycles of the radiation that corresponds to the transition between two electron spin energy levels of the ground state of the 133Cs atom.

The most accurate timekeeping devices are <hl> atomic clocks <hl>, which are accurate to seconds in many millions of years, and are used to calibrate other clocks and timekeeping instruments. Atomic clocks use the frequency of electronic transitions in certain atoms to measure the second. One of the most common atoms used is caesium, most modern atomic clocks probe caesium with microwaves to determine the frequency of these electron vibrations. Since 1967, the International System of Measurements bases its unit of time, the second, on the properties of caesium atoms. SI defines the second as 9,192,631,770 cycles of the radiation that corresponds to the transition between two electron spin energy levels of the ground state of the 133Cs atom.

The most accurate timekeeping devices are <hl> atomic clocks <hl> , which are accurate to seconds in many millions of years, and are used to calibrate other clocks and timekeeping instruments.


Question: What method do atomic clocks use to measure seconds?

Answer: the frequency of electronic transitions in certain atoms

The most accurate timekeeping devices are atomic clocks, which are accurate to seconds in many millions of years, and are used to calibrate other clocks and timekeeping instruments. <hl> Atomic clocks use the frequency of electronic transitions in certain atoms to measure the second. <hl> One of the most common atoms used is caesium, most modern atomic clocks probe caesium with microwaves to determine the frequency of these electron vibrations. Since 1967, the International System of Measurements bases its unit of time, the second, on the properties of caesium atoms. SI defines the second as 9,192,631,770 cycles of the radiation that corresponds to the transition between two electron spin energy levels of the ground state of the 133Cs atom.

The most accurate timekeeping devices are atomic clocks, which are accurate to seconds in many millions of years, and are used to calibrate other clocks and timekeeping instruments. Atomic clocks use <hl> the frequency of electronic transitions in certain atoms <hl> to measure the second. One of the most common atoms used is caesium, most modern atomic clocks probe caesium with microwaves to determine the frequency of these electron vibrations. Since 1967, the International System of Measurements bases its unit of time, the second, on the properties of caesium atoms. SI defines the second as 9,192,631,770 cycles of the radiation that corresponds to the transition between two electron spin energy levels of the ground state of the 133Cs atom.


Question: Which system bases its unit of time on the properties of caesium?

Answer: the International System of Measurements

The most accurate timekeeping devices are atomic clocks, which are accurate to seconds in many millions of years, and are used to calibrate other clocks and timekeeping instruments. Atomic clocks use the frequency of electronic transitions in certain atoms to measure the second. One of the most common atoms used is caesium, most modern atomic clocks probe caesium with microwaves to determine the frequency of these electron vibrations. <hl> Since 1967, the International System of Measurements bases its unit of time, the second, on the properties of caesium atoms. <hl> SI defines the second as 9,192,631,770 cycles of the radiation that corresponds to the transition between two electron spin energy levels of the ground state of the 133Cs atom.

The most accurate timekeeping devices are atomic clocks, which are accurate to seconds in many millions of years, and are used to calibrate other clocks and timekeeping instruments. Atomic clocks use the frequency of electronic transitions in certain atoms to measure the second. One of the most common atoms used is caesium, most modern atomic clocks probe caesium with microwaves to determine the frequency of these electron vibrations. Since 1967, <hl> the International System of Measurements <hl> bases its unit of time, the second, on the properties of caesium atoms. SI defines the second as 9,192,631,770 cycles of the radiation that corresponds to the transition between two electron spin energy levels of the ground state of the 133Cs atom.