Question: GMT used what instead of atomic clocks?
Answer: telescopes

Question: When did observations at the Greenwich Observatory cease?
Answer: 1954

Question: The terms GMT and Greenwich Mean Time are also used informally to refer to what?
Answer: UT or UTC

Question: How many main viewpoints divide many philosophers?
Answer: Two

Question: The realist view states that time is part of the fundamental structure of what?
Answer: the universe

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

Question: The opposing view states that time is an intellectual concept that allows people to what?
Answer: to sequence and compare events

Question: What are the earliest texts of Indian/Hindu philosophy?
Answer: The Vedas

Question: How long ago are the earliest texts of Indian/Hindu philosophy dated?
Answer: back to the late 2nd millennium BC

Question: How long does each cycle of birth and destruction of the universe last according to Ancient Hindu texts?
Answer: 4,320 million years

Question: Which ancient Greek philosophers wrote essays on the concept of time?
Answer: Parmenides and Heraclitus

Question: Aristotle defined time as "number of movement in respect of the before and after" in which book?
Answer: Book IV of his Physica

Question: Who commented on the nature of time in Book 11 of his confessions?
Answer: St. Augustine of Hippo

Question: By what does St. Augustine of Hippo begin to define time?
Answer: by what it is not rather than what it is

Question: What does Augustine call time in Confessions 11.26?
Answer: a “distention” of the mind

Question: In what did Immanuel Kant describe time as a priori intuition that allows humankind to understand sense experience?
Answer: the Critique of Pure Reason

Question: What did Kant portray space and time to be?
Answer: both are elements of a systematic mental framework

Question: Kant thought of time as a fundamental part of what?
Answer: an abstract conceptual framework

Question: What type of measurements are used to quantify the duration of events?
Answer: temporal measurements

Question: What type of measurements are used to quantify the distances between objects?
Answer: Spatial measurements

Question: Who suggested that humankind does not exist inside time, but is time?
Answer: Martin Heidegger

Question: The relationship to the future is the state of anticipating what?
Answer: a potential possibility, task, or engagement

Question: What is considered a qualitative experience rather than a quantitative one?
Answer: The present

Question: According to Heidegger, what can we do, in our thoughts?
Answer: step out of (ecstasis) sequential time.

Question: Minkowski spacetime combines the three dimensions of space with what?
Answer: a single dimension of time

Question: In Minkowski spacetime, how can distances in space be measured?
Answer: by how long light takes to travel that distance

Question: What are two events in Minkowski spacetime separated by?
Answer: by an invariant interval

Question: The invariant interval between events is independent of what?
Answer: of the observer (and his velocity)

Question: The invariant interval that separates two events in Minkowski spacetime can either be what?
Answer: space-like, light-like, or time-like

Question: What Newtonian concept can be used in the formulation of an idea for the synchronization of clocks?
Answer: concept of "relative, apparent, and common time"

Question: In which century did physicists encounter problems with the understanding of time?
Answer: the late nineteenth century

Question: The behavior of which two phenomena caused physicists to encounter problems with their understanding of time in the late 19th century?
Answer: the behavior of electricity and magnetism

Question: Which famous scientist resolved these issues?
Answer: Einstein

Question: Historically, time has been closely related with what?
Answer: space

Question: In which of Einstein's two theories do time and space merge into spacetime?
Answer: special relativity and general relativity

Question: According to Einsteins two relativity theories, the concept of time depends on what?
Answer: the spatial reference frame of the observer, and the human perception

Question: A crew in a spaceship travelling nearly the speed of light will not notice the change in what?
Answer: in the speed of time on board their vessel

Question: How will the above mentioned spaceship appear to a stationary observer?
Answer: the spaceship appears flattened in the direction it is traveling

Question: How does the crew on board the spaceship perceive the stationary observer?
Answer: slowed down and flattened along the spaceship's direction of travel

Question: The crew's perception of what is different from a stationary observer?
Answer: time

Question: What the crew perceives as seconds might be seen as how long to a stationary observer?
Answer: hundreds of years

Question: What remains unchanged in both the cases of the spaceship crew and of the stationary observer?
Answer: causality

Question: Who showed, in his thought experiments, that people travelling at different speeds measured time differently?
Answer: Einstein

Question: In what case do these effects become much more noticeable?
Answer: for objects moving at speeds approaching the speed of light.

Question: How long do most subatomic particles exist for in a lab?
Answer: a fixed fraction of a second

Question: Einstein showed how what could be altered by high speed motion?
Answer: both temporal and spatial dimensions

Question: What laws do not specify an arrow of time?
Answer: the laws of physics

Question: The standard description of measurement in quantum mechanics is what?
Answer: time asymmetric

Question: The direction of the arrow of time is sometimes what?
Answer: arbitrary

Question: Which law states that entropy must increase over time?
Answer: the Second law of thermodynamics,

Question: The violation of what implies that there should be a small counterbalancing time asymmetry?
Answer: CP symmetry

Question: In which publication does Hawking say that any events that existed before the Big Bang would not be accessible to us?
Answer: A Brief History of Time

Question: Stephen Hawking makes a connection between time and what?
Answer: the Big Bang

Question: What does Hawking suggest started with the big bang?
Answer: time

Question: Hawking also states that questions about what happened before the Big Bang are what?
Answer: meaningless

Question: Which philosopher has criticized Hawking's formulation?
Answer: Aristotelian philosopher Mortimer J. Adler

Question: The Big Bang model is solidly established in what?
Answer: cosmology

Question: How much is known about the early states of the universe?
Answer: i

Question: Which theorems require the existence of a singularity at the beginning of time?
Answer: The Penrose–Hawking singularity theorems

Question: These theorems have to assume what theory is correct?
Answer: general relativity

Question: These theorems state that general relatively must break down before what?
Answer: before the universe reaches the Planck temperature

Question: How long has time travel been a topic in science fiction?
Answer: since the 19th century

Question: Traveling which direction in time has never been verified and presents many problems?
Answer: backwards

Question: A time machine is known as any technological devise that is used for what purpose?
Answer: to achieve time travel

Question: What is another solution to the problem of temporal paradoxes?
Answer: paradoxes cannot arise simply because they have not arisen

Question: In several works of fiction, what ceases to exist in the past which causes paradoxes not to arise?
Answer: free will

Question: What paradox cannot be enacted because it is a fact that your grandfather was not killed before your parent was conceived?
Answer: the grandfather paradox