When Was Jupiter Discovered? - Universe Today Universe Today by Fraser Cain [/caption] Were you wondering when was Jupiter discovered? Well, there’s no way to know. Jupiter is one of the 5 planets visible with the unaided eye. If you go outside and Jupiter is up in the sky, it’s probably the brightest object up there, brighter than any star; only Venus is brighter. So the ancient people have known about Jupiter for thousands of years, and there’s no way to know when the first person noticed the planet. Perhaps a better question to ask is, when did we realize that Jupiter was a planet? In ancient times, astronomers used to think that the Earth was the center of the Universe. This was the geocentric model. The Sun, the Moon, the planets, and even the stars all orbited around the Earth in a series of crystal shells. But one thing that was hard to explain was the strange movements of the planets. They would move in one direction, then stop and go backwards in a retrograde motion. Astronomers created ever more elaborate models to explain these bizarre movements.

But then in the 1500s Nicolaus Copernicus developed his model of a Sun-centered, or heliospheric model of the Solar System. The Sun was center of the Solar System, and the planets, including Earth and Jupiter orbited around it. This nicely explained the strange movements of the planets in the sky. They were really following a circular path around the Sun, but the Earth was also traveling around the Sun, and this created different speeds based on our perspective. The first person to actually view Jupiter in a telescope was Galileo. Even with his rudimentary telescope, he was able to see bands across the planet, and the 4 large Galilean moons that have been named after him. The moons clearly were orbiting Jupiter, which broke the theory that everything in the Universe was orbiting the Earth. With bigger telescopes, astronomers were able to see more details in Jupiter’s cloud tops and discover more moons. But it wasn’t until the space age that scientists got to really study Jupiter close up. NASA’s Pioneer 10 was the first spacecraft to fly past Jupiter in 1973. It passed within 34,000 km of the cloud tops.

We’ve written several articles about when the planets of the Solar System were discovered. Here’s an article about the discovery of Uranus , and here’s an article about the discovery of Neptune . If you’d like more information on Jupiter, check out Hubblesite’s News Releases about Jupiter , and here’s a link to NASA’s Solar System Exploration Guide to Jupiter . We’ve also recorded an entire episode of Astronomy Cast just about Jupiter. Listen here, Episode 56: Jupiter . Reference: NOVA | Galileo: Discovering Jupiter'... Log in to Teachers' Domain to download, share, rate, save, and match to state standards. Source: NOVA: "Galileo's Battle for the Heavens" This resource was adapted from NOVA: "Galileo's Battle for the Heavens." Background In 1610, when Galileo first pointed his newly built telescope toward the sky, no one had ever had the capability to see distant objects in any detail, and he had no idea what to expect. Focusing on the Moon first, he discovered that its surface was not smooth as people had previously thought, but covered with craters and mountains not unlike those on Earth.

Next, Galileo turned his attention to another bright object in the night sky — the planet Jupiter. Today, we know quite a bit about Jupiter. With a diameter about 11 times greater than Earth's, Jupiter is the largest planet around our Sun. It is so enormous that its mass is more than twice the combined mass of all the other planets in our solar system. Composed mostly of gaseous hydrogen and helium, Jupiter is a gas giant. It has a trademark banded look that results from its turbulent atmosphere, and its Great Red Spot is a giant storm that has been raging for centuries. Jupiter also has a faint ring system and, as of May 2005, 63 known moons surround it. In a very short time, Galileo discovered Jupiter's four largest moons — Io, Europa, Ganymede, and Callisto, now called the Galilean moons. Each moon has unique characteristics that make it stand out in the solar system. For example, Io is the most volcanically active object in the solar system. Europa may have an ocean of liquid water beneath its icy surface and may be the best candidate for another habitable world.

Callisto is one of the most heavily cratered bodies in the solar system, and Ganymede, which is even larger than the planet Mercury, is the largest moon. The four Galilean moons were the first celestial bodies to be discovered with a telescope. Although Galileo at first thought they were fixed stars, his continued observations showed that their positions changed on a nightly basis. Galileo soon recognized that these new objects were satellites of Jupiter. The discovery that celestial objects could revolve around something other than Earth provided strong evidence in support of the heliocentric theory. To learn more about early telescopes, check out The Beginnings of the Telescope and Galileo's Telescope . To learn more about how Galileo's observations changed astronomy, check out Galileo: Sun-Centered System . To learn more about another of Galileo's astronomical discoveries, check out Galileo: Sunspots . Questions for Discussion How did Galileo surmise that Jupiter had moons that revolved around it? How did the discovery of Jupiter's moons support the heliocentric theory? What was so shocking about this discovery in Galileo's time? Why did he rush to publish his discovery?

Explain the importance of Galileo's work on the telescope and its effect on the world at that time and today. Discuss the role of technology in science. Jupiter's Moons - Astronomy Games For Kids - KidsAstronomy.com Try Miamiopia, Our New Free Educational Virtual World The Moons of Jupiter Jupiter has at leaset 62 moons. Most of these moons are very small, and were probably once asteroids that got too close to Jupiter. Jupiter's large size means that it has very strong gravity. This powerful gravity sometimes grabs onto objects that wander too close. Not all of Jupiter's moons are captured asteroids though. Four of them are large moons which formed around Jupiter long ago. We call these moons the Galilean moons, because they were first discovered by an astronomer named Galileo. You can see the Galilean moons yourself through a pair of binoculars. Simply look towards Jupiter. The four tiny dots of light close by are the moons Io, Europa, Ganymede, and Callisto. Inner Moons These four worlds are the closest known moons to the surface of the planet Jupiter. For this reason they are called the Inner Moons.

Metis This moon was discovered by Stephen Synnott in 1979. In ancient mythology, Metis was a Titaness who was the first wife of Jupiter. Metis is the closest moon to the surface of Jupiter and can be found with in the planet's main ring. This moon is probably an asteroid that got caught by Jupiter's immense gravity. Adrastea Adrastea was discovered in 1979 by David Jewitt. In mythology, Adrastea was the god who passed out rewards and punishments, she was also the daughter of Jupiter. This moon is the second closest moon to the surface of Jupiter. Adrastea is probably an asteroid that got caught by Jupiter's immense gravity. Amalthea Amalthea was discovered by Edward Emerson Barnard in 1892. Amalthea nursed Jupiter as a young baby using goat's milk. Amalthea is the third closest moon to the surface of Jupiter. This moon is probably an asteroid that got caught by Jupiter's immense gravity. Thebe The moon Thebe was discovered by Stephen Synnott in 1979. It was named after a nymph, daughter of the river god Asopus.

Thebe is the fourth known moon from the surface of Jupiter. It too was probably and asteroid at one time. Galilean Moons In the early 1600's, an Astronomer named Galileo Galilei looked at the sky for the first time using a telescope. He was the first scientist to ever use a telescope to study outer space. When he looked at Jupiter, he discovered four moons. Today we know that Jupiter actually has at least 62 moons. Only four of its moons are big enough to be seen through the small type of telescope that Galileo was using. Today we call these four large moons the Galilean moons. Io Io is a very violent place where a human would not live long enough to enjoy the beautiful colors it contains in its land formations. Io lies within a dangerous part of Jupiter's magnetic field. The radiation found in this area is a thousand times stronger than what is needed to kill a Human. If you somehow survived the radiation you would still be in trouble because Io is covered with giant volcanoes which erupt with extreme frequency. These volcanoes spurt out large amounts of sulfuric acid into the air which falls, causing the beautiful reds, yellows and oranges of Io's appearance.

Io is the third largest of Jupiter's moons, and slightly larger than the Earth's moon. It was named after a woman whom Jupiter fell in love with. Europa Europa is a cold, smooth, ice covered world. A long time ago in space there was a period of time when it was very common for asteroids and comets to hit other worlds. This is called the Heavy Bombardment Period. During this time most worlds, including Earth, were scarred with bowl shaped impressions called craters. Most worlds remain scarred today. However, some, like the Earth, have since recovered their surfaces with new rock lava or ice, hiding these scars. Because Europa is smooth, we know it too has recovered its surface since the Heavy Bombardment Period. This, along with a few other clues, has led scientists to believe that beneath its icy outer shell lies a liquid water ocean heated by Europa's hot core. This makes Europa the most likely place for life to exist outside of the Earth. Europa was named after a Phoenician princess abducted to Crete by Zeus.

Who Discovered & Found Jupiter – First Discovery of the Planet Jupiter – PlanetFacts.org The Moon Who Discovered Jupiter Jupiter is the Solar System’s largest planet, which makes its name quite appropriate. So while it isn’t the brightest object in the sky at night, its size makes it visible to the naked eye. Because of this, even the people from the pre-historic period knew that Jupiter existed. Of course, it took a while before they realized what Jupiter was. Still, the knowledge of its existence before recorded history makes it impossible to know who specifically discovered Jupiter. The credit is given not to the person who discovered its true nature, but to the person who discovered it exists (for instance, the discoverer of Uranus presented it as a comet, not a planet). Therefore, no one gets the credit for Jupiter’s discovery. Of course, as with the other classical planets, there were astronomers who observed the movement and status of the planet. For instance, Babylonian astronomers observed the planet back in the second millennium—centuries before Galileo Galilee and Nicolas Copernicus discovered the true nature of the planet.

The Indian astronomers also observed the planet and wrote the observations in their Surya Siddhanta, credited to astronomer Brahmarishi Mayan. Eastern astronomers also observed the planet and estimated its distance from Earth. However, it is perhaps Galileo who made the first ground-based research on the planet, thanks to his telescope. Because of this, he was the first to discover the moons of Jupiter. Callisto, Europa, Io, and Ganymede, the Jupiter’s four largest moons, were also called the Galilean moons. All in all, Jupiter has 60 moons and irregular satellites. omg this was great good information 🙂 Amar Thakre Who Discovered Jupiter? - Universe Today Universe Today by Fraser Cain [/caption] Jupiter is one of the 5 planets visible with the unaided eye. That means you can go out on a clear night, when Jupiter is up in the sky, and see it with your own eyes. No telescope is necessary. In fact, it’s one of the brightest objects in the sky. When Jupiter is there, it’s hard not to see it. So it’s kind of hard to wonder who discovered Jupiter, since humans would have known about it for tens of thousands of years.

Ancient astronomers didn’t have telescopes, but they knew there was something strange about the planets. They tracked the motion of the planets with incredible accuracy and believed that they were somehow associated with gods in their mythologies. Jupiter is named after the Roman god, thought to be the head of the gods; he’s the same as Zeus in Greek mythology. Perhaps a better question might be, who discovered Jupiter the planet. In other words, when did astronomers realize that Jupiter was really a planet. That discovery happened when astronomers realized that the Earth was really just a planet as well, orbiting the Sun in the Solar System. The new model for the Solar System was developed by Nicolaus Copernicus in the 16th century. By placing the Sun at the center of the Solar System, Copernicus developed a model that better explained the motions of the planets as they moved through the sky. This model was confirmed when Galileo pointed his first rudimentary telescope at Jupiter. What he saw was the disk of Jupiter and the 4 largest moons orbiting the planet. Since all the heavenly bodies were thought to orbit the Earth, it was thought to be impossible for objects to orbit one another.

Once astronomers knew that Jupiter was a planet, and they had better telescopes to study it, the exploration of Jupiter could really begin. Better and better images were taken of the planet, and more moons and even rings were discovered orbiting the planet. And then in the space age, the first spacecraft were sent to explore Jupiter. The first spacecraft to arrive at Jupiter was NASA’s Pioneer 10 in 1973, followed by Pioneer 11 a few months later. These spacecraft returned images of Jupiter’s swirling cloud tops, discovered more about its composition, and revealed features of its moons. We have written many articles about the discovery of planets in the Solar System. Here’s an article about the discovery of Uranus , and another about the discovery of Neptune . You can also learn more about Jupiter from NASA’s Solar System Exploration Guide to Jupiter . We have also recorded an episode of Astronomy Cast all about Jupiter. Listen to it here, Episode 56: Jupiter . Reference: Galileo and the Telescope Galileo and the Telescope Questions The science of astronomy took a huge leap forward in the first decade of the 1600s with the invention of the optical telescope and its use to study the night sky.

Galileo Galilei did not invent the telescope but was the first to use it systematically to observe celestial objects and record his discoveries. His book, Sidereus nuncius or The Starry Messenger was first published in 1610 and made him famous. In it he reported on his observations of the Moon, Jupiter and the Milky Way. These and subsequent observations and his interpretations of them eventually led to the demise of the geocentric Ptolemaic model of the universe and the adoption of a heliocentric model as proposed in 1543 by Copernicus. Galileo's drawings of phases of the Moon. Question: What features are visible here that cannot be seen with the unaided eye? Galileo's Telescopes The basic tool that Galileo used was a crude refracting telescope. His initial version only magnified 8x but was soon refined to the 20x magnification he used for his observations for Sidereus nuncius. It had a convex objective lens and a concave eyepiece in a long tube. The main problem with his telescopes was their very narrow field of view, typically about half the width of the Moon.

Galileo's drawing of the optical path of his telescope The earliest known sketch of a telescope, August 1609. One of Galileo's telescopes. The focal length is 1330 mm with a 26 mm aperture, it magnifies 14x. It has an objective bi-convex lens and a plano-concave eyepiece. Galileo's Observations Galileo made several key discoveries through his systematic use and refinement of the telescope. The Moon According to Aristotelian principles the Moon was above the sub-lunary sphere and in the heavens, hence should be perfect. He found the "surface of the moon to be not smooth, even and perfectly spherical,...,but on the contrary, to be uneven, rough, and crowded with depressions and bulges. And it is like the face of the earth itself, which is marked here and there with chains of mountains and depths of valleys." He calculated the heights of the mountains by measuring the lengths of their shadows and applying geometry. One of Galileo's lunar drawings. Note the craters, mountains and mare or "seas". The terminator between lunar day and night is clearly seen down the centre.

Moons of Jupiter Observations of the planet Jupiter over successive night revealed four star-like objects in a line with it. The objects moved from night to night, sometimes disappearing behind or in front of the planet. Galileo correctly inferred that these objects were moons of Jupiter and orbited it just as our Moon orbits Earth. For the first time, objects had been observed orbiting another planet, thus weakening the hold of the Ptolemaic model. Today these four moons are known as the Galilean satellites; Io, Europa, Ganymede and Callisto. Galileo's drawings of the moons of Jupiter of successive nights The Phases of Venus Venus was observed to go through a sequence of phases similar to the Moon. This could not be explained in the Ptolemaic model but could be accounted for by either the Sun-centered Copernican model or the Earth-centered Tychonic model that had the other planets orbiting the Sun as it orbited the Earth. Galileo rejected Tycho's model as an unnecessary hybrid and used the discovery to consolidate his support of the Copernican model.

Sunspots Along with contemporaries such as Thomas Harriot, David Frabicius and Christoph Scheiner, Galileo observed dark regions that appeared to move across the surface of the Sun. Debate centered on whether these were satellites of the Sun or actual spots on its surface. Galileo, in his Letters on Sunspots supported the sunspot interpretation and used it to show that the Sun was rotating. Its blemishes and imperfections again undermined the Aristotelian ideal of a perfect cosmos. "Appendages" on Saturn Galileo noted two appendages from the sides of Saturn. These disappeared then later reappeared. It was not until 1656 that the Dutch scientist, Christiaan Huygens correctly described them as rings. Stars in the Milky Way Even through a telescope the stars still appeared as points of light. Galileo suggested that this was due to their immense distance from Earth. This then eased the problem posed by the failure of astronomers to detect stellar parallax that was a consequence of Copernicus' model. On turning his telescope to the band of the Milky Way Galileo saw it resolved into thousands of hitherto unseen stars. This posed the question as to why there were invisible objects in the night sky?

More stars are resolved in this drawing by Galileo of the Pleiades than are visible to the unaided eye. Further Information An excellent online source for all things related to Galileo is: The Galileo Project. It is hosted by Rice University and includes his writings, details on his experiments and observations and links. It is also the source for the image of Galileo at the top of this page. Another worthwhile site is The Art of Renaissance Science: Galileo and Perspective . It has a wealth of diagrams matched with clear. concise text. There are some animations of his experiments. The Institute and Museum of the History of Science in Florence has a wealth of detail on the history of astronomy including Galileo's work. Their new website is worth exploring. Much of it is in English although some sections, including an excellent simulation of early telescopes, is only available in Italian at present. They also have an excellent new site: Galileo's Telescope, the Instrument that Changed the World . Afocal CCD Images Through a Galilean Telescope is an excellent resource that provides CCD images that approximate what the human eye would see through a Galilean telescope. It has images of the Sun, Moon, Venus, stars and nebulae.

The site provides historical background and technical details. Galileo's Sidereus nuncius or The Sidereal messenger is available in translation by A. van Helden from University of Chicago Press, 1989. The Cambridge Illustrated History of Astronomy, ed Michael Hoskin, Cambridge University Press, 1997 provides a wealth of information and diagrams and is an authoritative yet readable guide to the topic. The Sleepwalkers by Arthur Koestler is a classic book dealing with the development of astronomical thought up to the time of Newton. There are numerous other books and web sites covering Galileo's work and the history of astronomy. Questions Why was the telescope an advance over naked-eye astronomy? What did Galileo's observations of the Moon reveal? What was the significance of Galileo observing phases of Venus? How did Galileo's observations help undermine the existing paradigm of the Ptolemaic model of the Universe and Aristotle's physics?

IMA Hero: Galileo Galilei HH Contents: Galileo Galilei | Young Galileo | Earth Revolves Around the Sun | Moons of Jupiter | Our Moon | Observing the Universe | Father of Modern Science | Laws of Pendulum & Falling Bodies | Honoring Galileo Galileo Galilei (1564-1642) Galileo was one of the greatest astronomers in the world. He changed the way we think about the universe. Galileo was the first person to use a telescope to look at the universe. He studied the sun, the planets, and the moon. Galileo was born in Pisa, Italy, on February 15, 1564. Did you know Galileo was born in the same year as William Shakespeare? It is also the same year in which Michelangelo died. When Galileo was born, Italy was not called Italy. Instead, Italy was made up of independent city-states. The city-states were in regions controlled by powerful families. Pisa was located in the Tuscany region and controlled by the Medici family. Top of Page Young Galileo Galileo's father was named Vincenzio, and his mother was named Giulia.

Vincenzio was a gifted musician and mathematician, and he was also a cloth merchant to earn extra money. Galileo was educated by his father until he was 10 years old. In 1574, Galileo's family moved to Florence. The next year, Galileo attended the Benedictine Monastery of Santa Maria di Vallombrosa, and he studied Latin, Greek, music, logic, and religion. Galileo's education prepared him to study at a university. The Earth Revolves Around the Sun Before Galileo, people believed the earth was the center of the universe and the sun revolved around the earth. This theory is known as the Ptolemaic theory. It is named after the Roman astronomer Ptolemy. The Greek philosopher Aristotle and the Roman Catholic Church also believed the sun revolved around the earth. In 1543, Nicolaus Copernicus published a new theory stating the earth revolves around the sun. This is known as the Copernican theory. This theory was considered a serious challenge to the Ptolemaic theory and the Roman Catholic Church. Copernicus died before he could prove his theory.

Top of Page The Moons of Jupiter Galileo studied the Copernican theory and set out to prove or disprove it. He did this by observing the universe through the telescope. In 1610, Galileo made an important discovery about the planet Jupiter. He noticed there were four "stars" near Jupiter. Galileo then realized these "stars" were revolving around Jupiter. These "stars" were really moons. This observation helped prove the Copernican theory that the earth revolves around the sun. People knew the moon revolved around the earth. They thought if the moon revolved around the earth, then the sun must also revolve around the earth. However, Galileo's discovery of four moons revolving around Jupiter proved one object in space can revolve around a second object in space while the second object revolves around a third object in space. To put it in a more simple way, it proved the moon can revolve around the earth while the earth revolves around the sun. After Copernicus and Galileo, we know the earth revolves around the sun. As you know, Galileo discovered four of the moons of Jupiter. Did you know Jupiter's other moons have been discovered by observations from Earth and by the spacecraft Voyager?

In May, 2002, astronomers observed eleven new moons around Jupiter. This made Jupiter the planet with the highest number of known moons in our solar system. Until the May, 2002, discovery, Saturn held the record for the most known moons with 30. In February, 2003, seven more moons were discovered around Jupiter. In March, 2003, four more moons were discovered around Jupiter. As of April, 2003, Jupiter has 60 known moons. Keep checking back because the number of moons could increase. The four moons discovered by Galileo are Jupiter's largest moons. They are Io, Europa, Ganymede, and Callisto. Today, these moons are named after Galileo and are known as the Galilean moons. Jupiter is the largest planet in our solar system. Our solar system is in the The Milky Way galaxy. Top of Page Our Moon In December, 1609, Galileo looked at the earth's moon through the telescope, and he observed many things regarding the moon that could not have been known by looking at the moon with the human eye. First, the moon does not create light itself.

The moon shines because it reflects light from the sun. Second, the moon's surface is not smooth and perfect as Aristotle had believed. It has mountains, craters, and valleys just like the earth. In 1637, Galileo also discovered the moon has a regular libration. A libration is a rocking movement. This means a person can always see more than half of the moon's surface. Galileo made other important observations of the universe with the telescope. He discovered: the Milky Way is made up of billions of stars Venus has phases similar to the moon Saturn has "ears" which are the rings of Saturn sunspots move across the surface of the sun These observations by Galileo led to the development of astronomy as a major branch of science. Astronomy is the study of stars and planets. Top of Page The Father of Modern Science Galileo is known as the Father of Modern Science. He was one of the first people to use the scientific method to conduct experiments. This means Galileo observed a situation, developed a theory, and then carried out experiments to test his theory. The idea of testing and experimenting to prove or disprove a theory was revolutionary during Galileo's time.

Galileo used the scientific method to disprove some of the beliefs of ancient Greek philosophers, like Aristotle. Top of Page The Laws of the Pendulum and Falling Bodies Galileo began experimenting with pendulums after he saw a chandelier swinging in the Pisa Cathedral. He noticed each swing of the chandelier took the same amount of time, even though each swing was shorter than the previous swing. This led to Galileo's discovery of the Law of the Pendulum. Galileo also conducted experiments with falling objects. Aristotle believed heavier objects fall to the ground faster than lighter objects. As legend has it, Galileo dropped two objects from the Leaning Tower of Pisa to prove or disprove Aristotle's theory. These objects were the same size, but different weights. They fell to the ground at the same speed. This disproved Aristotle's theory and led Galileo to discover the Law of Falling Bodies. Top of Page Honoring Galileo Galileo died on January 8, 1642, in Arcetri, near Florence, Italy. He was 77 years old. He is buried in the Santa Croce cemetery in Florence. Galileo's observations of the planet Jupiter were very important.

To honor his contributions, the four moons of Jupiter which Galileo discovered are called the Galilean Moons. These are Jupiter's largest moons. There is also a spacecraft named after Galileo. It was launched on October 18, 1989, to orbit Jupiter. It went into orbit around Jupiter in 1995. Galileo proved the earth revolved around the sun. He was a great astronomer and scientist, and he is a hero in our hearts. Who Discovered Jupiter? Who Discovered Jupiter? Who Discovered Jupiter? Jupiter is among the five planets in our solar system that are visible in the night sky. You can observe this planet without any aid from binoculars or telescopes. Because of its night time visibility, we know that this planet has been seen by people even before anyone has ever recorded history. Because of this we can’t really tell who discovered Jupiter. The planet has always been known even in ancient times. It has also been observed for thousands of years by many different people. Galileo’s Discovery Jupiter was observed by Galileo Galilei on January 7, 1610.

Not only was he able to discover the planet he was also able to discover three of the many moons orbiting it. On January 13 of the same year, which is only six nights after, he discovered a fourth moon. The four moons were later dubbed the Galilean Moons. All the moons were named after the lovers of the god Zeus. However, even after Galileo’s discovery we may not credit him as the astronomer who discovered Jupiter. Challenge to Galileo’s Discovery His discovery is thought to be the earliest discovery of other moons other than that of the Earth’s. However this discovery of Galileo’s does not go unchallenged. A Chinese astronomy historian by the name of Xi Zezong claims that an earlier discovery of Jupiter’s moons occurred centuries earlier. He claims that a Chinese astronomer Gan De discovered one of moons of Jupiter in 362 BCE. Though Gan De’s discovery predates that of Galileo’s by centuries he may not be deemed as the one who discovered Jupiter. Discovery by Simon Marius An interesting occurrence in the discussion on who discovered Jupiter is that of Simon Marius.

Just a few nights after Galileo made his observations Simon Marius, a Dutch astronomer, saw Jupiter’s moons using his telescope. He was responsible for naming the said moons after Greek gods. Galileo named them using numbers. Marius was ridiculed and ostracized since no one would honor the names he gave the moons spoken of. The names he gave eventually were honored in recognition of his work and they are the names we know such moons today. Big Red Spot In finding out who discovered Jupiter you’ll come across one of this planet’s mysteries known as the big red spot. It was first reported in 1664 by Robert Hooke. Several fly by missions took photographs of it. However we do not have any information as to why this red spot diminishes and grows in size. Since Jupiter is among the planets in our solar system that is visible to the naked eye we can be sure that it has been sighted even before recorded history. Because of this we can’t credit any people or single individual as the ones who discovered Jupiter.

VN:F [1.9.22_1171] Planet Jupiter: Facts About Its Size, Moons and Red Spot Planet Jupiter: Facts About Its Size, Moons and Red Spot By Charles Q. Choi, Space.com Contributor | November 14, 2014 12:59am ET MORE This photo of Jupiter was taken on Sept. 20, 2010 when Jupiter made its closest approach to Earth since 1963. (Uranus [insert] was visible through telescopes near Jupiter.) Credit: Jimmy Eubanks Jupiter is the largest planet in the solar system. Fittingly, it was named after the king of the gods in Roman mythology. In a similar manner, the ancient Greeks named the planet after Zeus, the king of the Greek pantheon. Jupiter helped revolutionize the way we saw the universe and ourselves in 1610, when Galileo discovered Jupiter's four large moons — Io, Europa, Ganymede and Callisto, now known as the Galilean moons.

This was the first time celestial bodies were seen circling an object other than Earth, major support of the Copernican view that Earth was not the center of the universe. Physical characteristics Jupiter is the most massive planet in our solar system , more than twice as massive as all the other planets combined, and had it been about 80 times more massive, it would have actually become a star instead of a planet. Its atmosphere resembles that of the sun, made up mostly of hydrogen and helium, and with four large moons and many smaller moons in orbit around it, Jupiter by itself forms a kind of miniature solar system. All told, the immense volume of Jupiter could hold more than 1,300 Earths. The colorful bands of Jupiter are arranged in dark belts and light zones created by strong east-west winds in the planet's upper atmosphere traveling more than 400 mph (640 kph). The white clouds in the zones are made of crystals of frozen ammonia, while darker clouds of other chemicals are found in the belts. At the deepest visible levels are blue clouds. Far from being static, the stripes of clouds change over time . Inside the atmosphere, diamond rain may fill the skies.

The most extraordinary feature on Jupiter is undoubtedly the Great Red Spot , a giant hurricane-like storm seen for more than 300 years. At its widest, the Great Red Spot is three times the diameter of the Earth, and its edge spins counterclockwise around its center at a speed of about 225 mph (360 kph). The color of the storm, which usually varies from brick red to slightly brown, may come from small amounts of sulfur and phosphorus in the ammonia crystals in Jupiter's clouds. The spot grows and shrinks over time, and every now and again, seems to fade entirely. Jupiter's gargantuan magnetic field is the strongest of all the planets in the solar system at nearly 20,000 times the strength of Earth's. It traps electrically charged particles in an intense belt of electrons and other electrically charged particles that regularly blasts the planet's moons and rings with a level of radiation more than 1,000 times the lethal level for a human, damaging even heavily shielded spacecraft such as NASA's Galileo probe.

The magnetosphere of Jupiter, which is composed of these fields and particles, swells out some 600,000 to 2 million miles (1 million to 3 million km) toward the sun and tapers to a tail extending more than 600 million miles (1 billion km) behind Jupiter. Jupiter spins faster than any other planet, taking a little under 10 hours to complete a turn on its axis, compared with 24 hours for Earth. This rapid spin makes Jupiter bulge at the equator and flatten at the poles, making the planet about 7 percent wider at the equator than at the poles. Jupiter broadcasts radio waves strong enough to detect on Earth. These come in two forms — strong bursts that occur when Io, the closest of Jupiter's large moons, passes through certain regions of Jupiter's magnetic field, and continuous radiation from Jupiter's surface and high-energy particles in its radiation belts. These radio waves could help scientists to probe the oceans on its moons.

Composition & structure Atmospheric composition (by volume): 89.8 percent molecular hydrogen, 10.2 percent helium, minor amounts of methane, ammonia, hydrogen deuteride, ethane, water, ammonia ice aerosols, water ice aerosols, ammonia hydrosulfide aerosols Magnetic field: Nearly 20,000 times stronger than Earth's Chemical composition: Jupiter has a dense core of uncertain composition , surrounded by a helium-rich layer of fluid metallic hydrogen, wrapped up in an atmosphere primarily made of molecular hydrogen. Internal structure: A core less than 10 times Earth's mass surrounded by a layer of fluid metallic hydrogen extending out to 80 to 90 percent of the diameter of the planet, enclosed in an atmosphere mostly made of gaseous and liquid hydrogen. Orbit & rotation Average distance from the sun : 483,682,810 miles (778,412,020 km). By comparison: 5.203 times that of Earth Perihelion (closest approach to the sun): 460,276,100 miles (740,742,600 km).

By comparison: 5.036 times that of Earth Aphelion (farthest distance from the sun): 507,089,500 miles (816,081,400 km). By comparison: 5.366 times that of Earth (Source: NASA .) Jupiter's moons Jupiter has at least 63 moons , which are often named after the Roman god's many lovers. The four largest moons of Jupiter, now called Io, Europa, Ganymede, and Callisto, were discovered by Galileo Galilei himself, and are appropriately known today as the Galilean satellites. Ganymede is the largest moon in our solar system, larger even than Mercury and Pluto. It is also the only moon known to have its own magnetic field. The moon has at least one thick ocean between layers of ice, although it may contain several layers of both materials. Io is the most volcanically active body in our solar system. The sulfur its volcanoes spew out gives Io a blotted yellow-orange appearance that is often compared to a pepperoni pizza.

As Io orbits Jupiter, the planet's immense gravity causes 'tides' in Io's solid surface that rise 300 feet (100 meters) high, generating enough heat for volcanic activity. The frozen crust of Europa is made up mostly of water ice, and it may hide a liquid ocean holding twice as much water as Earth does. Icy oceans may also exist beneath the crusts of Callisto and Ganymede. Some of this liquid spouts from the surface in newly spotted sporadic plumes at the southern pole. Its potential to host life caused NASA to request funding for a mission to explore Europa . Callisto has the lowest reflectivity, or albedo, of the four Galilean moons. This suggests that its surface may be composed of dark, colorless rock. Jupiter's rings Jupiter's three rings came as a surprise when NASA's Voyager 1 spacecraft discovered them around the planet's equator in 1979. Each are much fainter than Saturn's rings. The main ring is flattened. It is about 20 miles (30 km) thick and more than 4,000 miles (6,400 km) wide.

The inner cloud-like ring, called the halo, is roughly 12,000 miles (20,000 km) thick. The halo extends halfway from the main ring down to the planet's cloud tops and expands by interaction with Jupiter's magnetic field. Both the main ring and halo are composed of small, dark particles. The third ring, known as the gossamer ring because of its transparency, is actually three rings of microscopic debris from three of Jupiter's moons, Amalthea, Thebe and Adrastea. It is probably made up of dust particles less than 10 microns in diameter, about the same size of the particles found in cigarette smoke, and extends to an outer edge of about 80,000 miles (129,000 km) from the center of the planet and inward to about 18,600 miles (30,000 km). Ripples in the rings of both Jupiter and Saturn may be signs of impacts from comets and asteroids.

Research & exploration Seven missions have flown by Jupiter — Pioneer 10 , Pioneer 11 , Voyager 1 , Voyager 2 , Ulysses, Cassini and New Horizons — while another, NASA's Galileo, actually orbited the planet. Pioneer 10 revealed how dangerous Jupiter's radiation belt is, while Pioneer 11 provided data on the Great Red Spot and close-up pictures of its polar region. Voyager 1 and 2 helped astronomers create the first detailed maps of the Galilean satellites, discovered Jupiter's rings, revealed sulfur volcanoes on Io, and saw lightning in Jupiter's clouds. Ulysses discovered the solar wind has a much greater impact on Jupiter's magnetosphere than before suggested. New Horizons took close-up pictures of Jupiter and its largest moons. In 1995, Galileo sent a probe plunging towards Jupiter, making the first direct measurements of its atmosphere and measuring the amount of water and other chemicals there. When Galileo ran low on fuel, the craft was intentionally crashed into Jupiter's atmosphere to avoid any risk of it slamming into and contaminating Europa, which might have an ocean below its surface capable of supporting life.

Another spacecraft, named Juno , is heading toward Jupiter and will reach the planet in 2016. It will study Jupiter from a polar orbit to figure out how it and the rest of the solar system formed, which could shed light on how alien planetary systems might have developed. Jupiter's gravitational impact on the solar system As the most massive body in the solar system after the sun, the pull of Jupiter's gravity has helped shape the fate of our system. It may have violently hurled Neptune and Uranus outward , according to calculations published in the journal Nature. Jupiter, along with Saturn, may have slung a barrage of debris toward the inner planets early in the system's history, according to an article in Science magazine. It may even nowadays help keep asteroids from bombarding Earth, and recent events certainly have shown that it can absorb potentially deadly impacts . Currently, Jupiter's gravitational field influences numerous asteroids that have clustered into the regions preceding and following Jupiter in its orbit around the sun. These are known as the Trojan asteroids, after three large asteroids there, Agamemnon, Achilles and Hector, names drawn from the Iliad, Homer's epic about the Trojan War.

Possibility of life on Jupiter If one were to dive into Jupiter's atmosphere , one would discover it to grow warmer with depth, reaching room temperature, or 70 degrees F (21 degrees C), at an altitude where the atmospheric pressure is about 10 times as great as it is on Earth. Scientists have conjectured that if Jupiter has any form of life, it might dwell at this level, and would have to be airborne. However, researchers have found no evidence for life on Jupiter. Additional reporting by Nola Taylor Redd, Space.com Contributor Explore the solar system

Question: Who was the first person to see the moons of Jupiter?
Answer: Galileo Galilei