Posted on by Fraser Cain

How Far is Jupiter from the Sun?

Jupiter's Red Spot

The distance from the Sun to Jupiter is approximately 779 million km, or 484 million miles. The exact number is 778,547,200 km.

This number is an average because Jupiter and the rest of the Solar System follows an elliptical orbit around the Sun. Sometimes it’s closer than 779 million km, and other times it’s more distant. When Jupiter is at its closest point in its orbit, astronomers call this perihelion; for Jupiter, this is 741 million km. At its most distant point, called aphelion, Jupiter gets out to 817 million km.

Astronomers use the term “astronomical unit” as another method for measuring distances in the Solar System. An astronomical unit, or AU, is the average distance from the Sun to the Earth – 150 million km. Jupiter’s average distance from the Sun is 5.2 AU. Its closest point is 4.95 AU, and its most distant point is 5.46 AU.

We have written many articles about Jupiter for Universe Today. Here’s an article about how Jupiter might be able to wreck the Solar System, and here’s an article about Jupiter’s Great Red Spot.

If you’d like more info 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.

Posted on by Fraser Cain

Who Discovered Jupiter?

Jupiter from the newly refurbished Hubble. Credit: NASA, ESA, M. Wong (Space Telescope Science Institute, Baltimore, Md.), H. B. Hammel (Space Science Institute, Boulder, Colo.), and the Jupiter Impact Team

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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:
NASA