Planet Jupiter

The planet Jupiter is the largest planet in the solar system and is 5th from the sun. The planet has been named after the Roman god, Jupiter, earlier referred to as Jove, who was regarded as the supreme deity amongst other gods, the patron of the state of Rome, and the ruler of Mt. Olympus, whose counterpart in Greek mythology was Zeus.

With an equatorial diameter of 142,984 km and a mass of 1.900e27 kg, the planet Jupiter is about two times as massive compared to all the rest of the planets of the solar system combined. As a matter of fact, scientists think that if it had been more massive by 100 times when it was created, Jupiter would have turned into a star and not a planet, which would have meant that instead of the single star system, there would have been a double star system in the Solar System.

After the Sun, Moon, and Venus, Jupiter is the brightest object in the sky. In fact, people knew about Jupiter since prehistorical times, and it has been known since then as a wandering, bright star.

The Surface Features of the Planet Jupiter

Jupiter being a gaseous planet is quite different compared to a terrestrial planet like the Earth. The composition of Jupiter’s surface is akin more to stars, made up almost fully of liquid and gas. Plus, it has an internal source of energy along with huge magnetic fields.

The gaseous matter that makes up Jupiter’s surface just becomes denser the deeper it gets. Jupiter is made up of about 90 percent hydrogen and about 10 percent helium, small amounts of ammonia, water, methane, and rock. This composition is not very different from the Solar Nebula, which turned into the Solar System. It is thought that Jupiter's core does have rocky matter, which amounts to approximately 10-15 masses of the Earth.

Above this core is a layer of liquid metallic hydrogen, which forms the main mass of Jupiter. Liquid metallic hydrogen only forms when hydrogen is put under the tremendous pressure of more than 4 million bars (a term used to measure the atmospheric pressure), which exists in the interior part of Jupiter. At that kind of pressure hydrogen gas turns into liquid, consisting of protons and electron that are ionized. It conducts electricity and is the source of the massive magnetic field of Jupiter. This liquid hydrogen layer also contains various types of ices and some helium.

The uppermost layer is made up mostly of ordinary hydrogen as well as helium, which at the deeper levels are in liquid form, and become gaseous at higher levels. When Jupiter is viewed through the telescope, what is seen is just the topmost surface of these deep layers that make up the planet. The surface layer also contains miniscule amounts of methane, carbon dioxide and water.

Another unique feature of Jupiter is that it radiates out more energy than it gets from the Sun. It has a very hot interior, with the temperature of its core being as high as 20,000 K. The Kelvin-Helmholtz mechanism is responsible for this heat, which involves a gradual compression of a star or planet due to gravitational forces. Therefore, unlike the Sun, the heat produced by Jupiter is not due to nuclear fusion, since Jupiter is too small in size and thus has an interior that is not hot enough to set off nuclear reactions. However, the heat in the interior is high enough to cause convections in the deeper liquid levels of Jupiter, and is thought to be the cause of the complex motions of the winds seen on the surface.

The Colored Bands and The Great Red Spot of Jupiter

Like the other gaseous planets, Jupiter’s atmosphere consists of winds that blow at high velocity, which form broad bands of latitude over the planet, with the winds of each band blowing in the opposite direction in relation to the band adjacent to it. These are vividly colored due to slight temperature and chemical differences between each. The bands that are lighter in color are known as zones, and the darker colored ones are called belts. The complex vortices that form at the edges of these bands extend thousands of kilometers down into the inner parts of the planet. The atmosphere of Jupiter is also highly turbulent, indicative that the winds are formed mainly due to the intense internal heat of the planet, unlike that of the Earth, which are caused due to solar activity.

People on Earth have observed the vivid and famous Great Red Spot on the surface of Jupiter for over 400 years. The Great Red Spot is a large oval shaped physical feature on Jupiter’s surface that measures around 12,000 by 25,000 kilometers, large enough to accommodate 2-3 Earths. In fact, it is a huge high-pressure, anti-cyclonic storm, which is similar to the hurricanes that occur on the Earth. Because it is anti-cyclonic, occurring in the southern hemisphere of Jupiter, the winds rotate in a counterclockwise direction, with a 6-day period. Hurricanes in the southern hemisphere of the Earth rotate in a clockwise direction since they are low-pressure systems. There are other similar, albeit smaller spots that are also in existence on Jupiter’s surface. Scientists still do not know how such features last for so long.

The Moons of the Planet Jupiter

It was back in 1610 that Galileo discovered four of the largest moons of Jupiter, Callisto, Ganymede, Europa, and Io, which are now referred to as Galiliean moons. In fact, if Ganymede had not been orbiting Jupiter, it would have been regarded as a planet by itself, being larger in size than Mercury. Callisto is almost the size of Mercury. Io is often compared to a pizza due to its volcanic surface, which spew sulfuric acid, giving Io its vivid colors. Europa is one of the smoothest natural objects in the Solar System and is often compared to a billiard ball. Scientists think that there is water under the icy surface of Europa, and hence the possibility of it having life.

All in all, there are 63 moons orbiting Jupiter, discovered as of now, not all of which have been named yet. Some of their names are Thebe, Amalthea, Andrastea, Metis, Elara, Lysithea, Himalia, Leda, Themisto, and more. The 33 outer moons orbit the planet in the opposite direction in which it spins.

The Rings of Jupiter

Jupiter’s rings are made up of three ring patterns: one, the halo, which is the innermost ring; second, the main ring in the middle; and third, the gossamer ring, which is the outermost one. In fact, the Galileo probe discovered that the gossamer ring is actually made up of two rings, with one ring embedded into the other. These rings have a very thin consistency, and are made up mostly of microscopic dust particles and fragments of rocks. The rings of Jupiter lose material continuously and are replenished with new dust which form from the micrometeors that hit the four inner moons of Jupiter, namely, Thebe, Amalthea, Andrastea, and Metis.

Jupiter, in fact, is often cited as a micro Solar System, due to the many small objects it controls via its gravity.