Jupiter, the largest planet of our solar system is the fifth planet after the Sun, and lies between the planets Mars and Saturn. It is also the fourth brightest object in the sky after the Sun, Moon, and Venus and is also called the 'ruler of the night skies'. It is the first gaseous planet (Saturn, Uranus, and Neptune being the other gas planets) to be discovered in our solar system and radiates twice as much as heat than it absorbs from the sun.
When was Jupiter discovered and how did it get its name?
There is no information regarding who were the first people to discover this large planet. Jupiter is a planet that is visible to the naked eye and is usually the brightest star appearing in the night sky. Which means anyone and everyone can see it. Then, who gave Jupiter its name? It's known that the Romans were the ones who named this large planet, Jupiter after the king of Roman Gods- 'Jupiter'. Jupiter happened to be the Roman name of the supreme Greek God, Zeus. Since Jupiter appeared big and bright in the sky, they named it after their God. Interestingly, most of the moons of Jupiter are named after the daughters of Jupiter.
How do we know all that we know about Jupiter?
It was Galileo Galilei in 1610, who through his telescope found that Jupiter had four moons orbiting it. Further, in 1660, Cassini came across bands and spots on Jupiter's surface, and as a result was able to calculate the planet's period of rotation. However, the first spacecraft to visit and explore Jupiter was Pioneer 10, in 1973.
Pioneer 11(1974), Voyager 1 & 2 (1979), and Ulysses (1992) followed Pioneer 10's lead and have to be given due credit for bringing to us all these interesting facts about Jupiter. In 1995, Galileo of NASA (only spacecraft to orbit Jupiter) revolved around Jupiter and is orbiting around the planet even today. Cassini in 2000 and NASA's New Horizons spacecraft in 2007, made their flyby across Jupiter.
What is Jupiter actually made of?
Jupiter, called the gaseous giant is a gas planet, unlike Earth and Mars which are rocky. What does this mean? It means that Jupiter lacks solid surfaces and is gaseous in composition. It's a humongous gas cloud comprising gases like hydrogen, helium (90% hydrogen, 10% helium) and few traces of methane, water, ammonia, and rock dust. These gases get converted by immense pressure to the liquid state, as they go deeper into the planet. The core of Jupiter consists of a molten metal, metallic hydrogen, and rock materials. It happens to be much bigger than our planet Earth, and is about three times hotter than the Earth's core.
How many moons does Jupiter have?
Another interesting fact about Jupiter is that it constitutes a miniature solar system within itself. The first four moons of Jupiter were spotted by Galileo, thus are called Galilean satellites. When Galileo made this discovery, he realized that not everything revolved around the Earth in the existing universe. The four moons are named: Io, Europa, Ganymede, and Callisto after the Greek Gods, and are the largest of Jupiter's moons. By far, 63 moons have been discovered, most of which have been discovered after 1979.
Can we actually see Jupiter?
Yes, Jupiter is so large that we don't need any telescopes to view it. When we look up to the sky at night, the large bright star that we see is Jupiter. In fact, this planet is so large that one can view this yellowish-orange planet, by using a regular pair of binoculars. Wait there's more!
If you're patient, you can even see some of Jupiter's moons right from your terrace. Since the moons are always in motion, you can see at least one moon at any time you choose. Just place your binoculars on some solid surface and adjust your binocular to the planet. You will be able to see the planet. Cool! Isn't it? But, how will you know which moon your viewing. Thanks to tools like Sky and Telescope's Jupiter's moons, we can even obtain information pertaining to the moon we're viewing.
Jupiter is big, but how big?
Jupiter's mass (1.9 x 1027 kg ) is 318 times the mass of the Earth, and is 2.5 times the mass of the summation of masses of the other 8 planets in the solar system. Wow! Now, that's what you call massive! But here's another interesting fact about this planet: If Jupiter gets any bigger, it's actually going to start shrinking. Any increase in mass would make the planet more dense resulting in its pulling of itself.
Jupiter is the largest planet in our solar system and is so large that approximately 1300 Earths can fit in it. Its diameter is 11.2 times of that of the Earth, and its volume is 1321 times the volume of the Earth. If you still haven't been able to grasp how enormous Jupiter is, then consider the sizes of a watermelon and a grape. How a watermelon is to a grape, so is Jupiter to the Earth.
What about the rings of Jupiter? Why can't we see them?
We are used to associating Saturn with rings and have assumed Saturn to be the only planet with rings. Jupiter's ring system was the third ring system to be discovered, after Saturn's and Uranus'. It was NASA's Voyager 1 in 1979, that first discovered Jupiter's faint, fine, dark rings. However, the rings of Saturn and Jupiter have several differences. Saturn's rings are brighter and made of ice lumps, whereas Jupiter's rings are darker, comprising dust and rock particles. Jupiter's rings are not prominent like that of Saturn, and are very difficult to see.
However, thanks to the spacecraft we now know that the rings have three sections. The innermost section: Halo ring which is a fine donut-shaped ring composed of fine dust particles. Extending beyond the inner ring is the brightest ring called the main ring, and is followed by an outer ring system called the Gossamer ring. The Gossamer ring consists of two rings: inner Amalthea Gossamer ring and outer Thebe Gossamer ring. When the moons are struck by meteors, the dust generated enters the orbits in the form of rings.
What about the well-known 'Great Red Spot'?
Jupiter's Great Red Spot (GRS) is like the planet's birth mark, and was initially discovered by Giovanni Cassini way back in 1665. Storms are not uncommon on Jupiter's surface, however, the storms occurring in the GRS region are fiercer. Although GRS is merely an oval spot on the planet's surface, it is two times the size of the Earth. Jupiter's color ranges from shades of orange, yellow and brown, however, GRS appears to be a darker shade of red.
Astronomers believe this is because GRS draws darker compounds from the planet's interior, which when exposed to the sunlight become brownish red. Until a century ago, GRS measured up to 40,000 km, however, its size appears to be shrinking and now measures half its size. Astronomers are not sure if this legendary Great Red Spot will disappear forever or not. So, if you still haven't seen it, it's high time you do.
How long is a day and a year on Jupiter?
Having the fastest rotation in the entire solar system, a day in Jupiter consists of only 9.9 hours. Due to its fast spinning feature, it is flattened at the poles and bulged at the equator. But, here's another interesting fact: not all parts of Jupiter complete rotating in the same amount of time. For example, the parts near Jupiter's poles take 9 hours and 56 minutes, whereas the parts near its equator take 9 hours 50 minutes.
Even though Jupiter's rotation is faster than any other planet, its revolution around the Sun is slow. This is because it is situated far away from the Sun (average of 470 million miles), and as a result takes 11.86 Earth years to complete one revolution. Jupiter follows an elliptical path around the Sun, and at its closest point is only 741 million km from the Sun, whereas at its farthest point is 817 million km.
Can human beings live on Jupiter?
First and foremost, if at all we get a spacecraft and head for Jupiter, when we land on Jupiter we won't find any place for landing. Why? Because Jupiter has no solid surfaces and is composed of gases. The gaseous clouds of Jupiter continue to get denser towards the core, thereby resulting in an increase of pressure. And what would happen if we tried to jump onto Jupiter's surface from the spacecraft? We would sink into the clouds and the increase in pressure would crush us to bits. If the increase in pressure somehow fails to kill us, then the high temperatures near the core are sure to vaporize us. So, either way we're doomed!
Jupiter sucks anything and everything that's around it by exerting its tremendous gravitational force on them. Just like how dust gets sucked into a vacuum cleaner, so also asteroids, meteors, comets, and other rocky materials traveling around it are seen to be sucked into the planet's atmosphere. Jupiter, truly is a fascinating planet!