The Jovian Planets
Far past Earth and Mars lays enormous planets known as the Jovian planets. These planets get there name for being giant and Jupiter like. The four Jovian planets are (in order) Jupiter, Saturn, Uranus, and Neptune. The Jovian planets are unlike the rest of the terrestrial planets because of their size, structure and massive rotation structure. These planets are known as gas giants that contain several rings of ice, dust, and debris from outer space as well as many moons that surround each planet. The Jovian planets formed farther from the sun allowing their inner core to collect mass amounts of ice, rock, and metals which allowed the planet to grow rapidly in size. As these planets accumulated size their gravity eventually pulled in other space debris which created the structure of these giant planets. These planets are much too far for man to travel and explore up closely, however unmanned space craft have ventured out in exploration of these four giant planets.
The Jovian planets formation occurs outside of what astronomers and scientists call the ???frost line.??? Here hydrogen compounds form to ice which combines with rock and metal to form a cluster mixed with gasses. As these particles and elements cluster larger and larger they create what is known as a planetesimals. These planetesimals are the planets beginning to take shape into what they will become, a giant ball of gas, rock and ice which gain intense gravitational pull which collects even more particles and elements, gaining massive size. The leftover parts that occur during the break up of the solar nebula become moons and rings to these giant masses which explains why these planets have a large number of moons and many rings orbiting them. These planets are what we know today as the Jovian Planets.
As you would first set off to explore the Jovian planets you would come across Jupiter, the largest of the four Jovian planets. Jupiter??™s atmosphere is primarily made up of hydrogen and helium. Along Jupiter??™s outer atmosphere there are rings, but they are not clearly visible and has a total of 16 known moons, the larger four ( Io, Europa, Ganymede, and Callisto) can all be seen from earth Jupiter itself is slightly denser than water but gives off twice the amount of energy that the sun gives it due to the heat from the formation of the planet. Jupiter essentially has no surface as the clouds just get thicker and thicker down to the gasses which make up and surround the core. We know that Jupiter is essentially made of gas because of its differential rotation in which the equator spins faster than the north and south poles; this is only possible if the planet was made out of gas. Jupiter has a large notable spot on it known as ???The Great Red Spot??? which is made up of strong winds spinning in opposite directions forming a hurricane.
The next stop you move on to Saturn which is visible from Earth by only using binoculars at times. Saturn is best known for its large complex system of rings along its outer atmosphere. These rings are primarily composed of ice and rock and cover over 50,000 miles around Saturn and go 200 yards deep. Also along Saturn??™s atmosphere there are 33 known moons, the largest and most interesting one being Titan. Titan is slightly larger than Mercury and contains its own atmosphere which is denser than Earth??™s and made up of mostly nitrogen and small amounts of methane. This leads astronomers and scientists to believe that life could be found on Titan. Saturn is about three times smaller than Jupiter however is very similar to it with its composition and atmosphere.
As you move on farther out in our solar system you come across two ???ice giants??? the first being Uranus, which is named after the roman god of the sky. Uranus has an atmosphere composed of helium and methane which essentially gives it the bluish look and has a slight amount of rings. Uranus has a known 27 moons, the largest being Titania which was discovered by William Herschel in 1787. Uranus??™s are categorized in two groups, inner and outer moons. There are six larger moons that orbit far out from the planet as the inner ones tend to stay close with the rings more toward the planet itself. The way that Uranus??™s axis is tilted makes it different from any other planet in our solar system by having the majority of the planet being polar. Uranus would most likely have 42 years of darkness followed by 42 years of Light. This also would amount to Uranus??™s cold temperatures lows of around -200C and having a cool core unlike the other giants, making it the coldest of the planets.
The second of the ???ice giants??? is Neptune which is named after the roman god of the sea and was discovered by English and French astronomers. Neptune is similar to Uranus in size and has an atmosphere composed of helium and methane giving it the similar bluish look to that of Uranus. Neptune however has a fierce more atmosphere than Uranus??™s with much faster and stronger winds reaching up to 1000 miles per hour. Neptune??™s atmosphere is the coldest in the solar system; however its inner core is not nearly as cold as to that of Uranus??™s. Neptune has 13 known moons with the largest being Triton. Triton is similar to Saturn??™s Titan due to it having its own atmosphere; however its atmosphere is a lot thinner than that of Titans. In 1989 when Voyager 2 made its mission around Neptune it sent back pictures of a storm similar to that of the one on Jupiter. This storm came to be known as ???The Great Dark Spot.???
As astronomers and scientists continue to explore and gain knowledge about these four Jovian planets they have been aided by the success of space missions set up and sent out during ???flybys??? to gather information. Jupiter has had two main successful missions that of the Pioneer 10 in 1973 and Galileo providing good information from the pictures of Saturn and some of its moons. Saturn has been visited by the Pioneer 11 in 1979, Voyager 1 in 1980, and Voyager 2 in 1982. These missions also brought back pictures of Saturn??™s moon Titan. Uranus has been visited by Voyager 2 in 1986, the only mission that has visited the planet which captured visual of the planet and some of its nearby moons. Neptune, just like Uranus, has only had one visit, that coming from Voyager 2 in 1989 which captured images of the planet and its largest moon Triton.
Fortunately with today??™s technology all of these missions have brought astronomers and scientist closer to understanding the Jovian Planets and how they were formed. It is apparent that human travel is impossible for human landing on these planets due to none of them containing any surface are from being composed of gas, however it cannot be ruled out that human travel may someday be possible to these Jovian planets. The more information astronomers and scientists can gain about these planets only improves science theory??™s, technology, and history about these massive giant planets in our solar system.
American Association of Armature Scientists. The Jovian Planets. November 29th, 2009.
NASA/JPL University of Arizona. The Outer Planets. November 29th, 2009.