Jupiter is the largest planet in our solar system. It’s so big, it can be seen from Earth with binoculars or a small telescope. Space probes have shown its colors to be tan, reddish-brown, orange, and white, which result from the chemical composition of its atmosphere. But just what is Jupiter made of? And does this planet have water?
- Jupiter was named after the Roman chief god, equivalent to the Greek Zeus.
- Jupiter is big enough that 1,300 Earths could fit inside it.
- It’s possible to see the disk of the planet and four of its moons through a small telescope or binoculars.
- Space probes have shown Jupiter has a thin dusty ring system and nearly 100 moons.
- The planet is made of different layers: a rocky core; metallic hydrogen; an ocean of liquid hydrogen and helium; and an atmosphere of hydrogen, helium, ammonia, and water.
- One of the most distinctive features of Jupiter is the Great Red Spot. This 10,000-mile diameter hurricane has lasted more than 350 years.
- Jupiter and the other giant planets, Saturn, Uranus, and Neptune, destroy comets and asteroids that get close to them. This prevents them from reaching the planets of the inner solar system, like Earth.
- The presence of water on Jupiter highlights how plentiful this resource is. We may be likely to find life in other parts of the universe.
Jupiter in History
Some of the earliest observations of Jupiter were recorded in Babylon in the 7th century BCE. The Babylonians and other peoples of antiquity were intensely interested in the motions of the stars. They believed that these movements predicted the future. They noticed most stars followed predictable paths across the sky. However, some “wandering stars” would move for a time in one direction, then reverse course. What they couldn’t know was that these were actually planets, like Earth, orbiting the sun. As Earth would pass planets, like Jupiter, they would appear to reverse course in the sky.
In 1610, Italian astronomer Galileo was the first to observe Jupiter through a small telescope of 20x magnification. He saw the planet, along with its four largest moons, lo, Europa, Ganymede, and Callisto. They appeared as a disk and four pinpoints of light. These lights moved toward the planet, disappeared, then reemerged on the other side. He inferred that these were moons orbiting Jupiter, as our Moon orbits the Earth. These are observations you can make yourself with a small telescope or binoculars.
In modern times, NASA and the European Space Agency have sent multiple space probes to Jupiter that have greatly expanded our knowledge. For example, they discovered that it actually has nearly 100 moons and a thin ring system that was previously unknown. Here are the missions to Jupiter that have been conducted since the 1970s:
- Pioneer 10, 1972
- Pioneer 11, 1973
- Voyager 1 and 2, 1977
- Galileo, 1989
- Ulysses, 1990
- Cassini, 1997
- Juno, 2011
The Layers of Jupiter
The atmosphere of Jupiter is only about 44 miles thick. It has three layers made of ammonia ice, ammonium hydrosulfide crystals, and water ice and vapor. So, YES, Jupiter does have water. But it is not a large percentage of the chemical composition of the planet.
Jupiter has the largest, deepest ocean in the solar system. But instead of water, it is made of liquified hydrogen and helium. Normally we think of those as gases, but because Jupiter has such tremendous mass and pressure, they are liquids there.
The Metallic Core
Below Jupiter’s ocean, the pressure is so great that hydrogen changes to a metal. This has created a metallic core about 25,000 miles thick. It’s a good electrical conductor that helps create a powerful magnetic field around the planet.
The Rocky Core
At the very center of the planet is a core of rock, metal, and ice perhaps 10-20 times the size of Earth. The pressure at the center of it is 650 million pounds per square inch, compared to just eight pounds per square inch of pressure at the deepest point of Earth’s ocean, the Mariana Trench. The pressure at Jupiter’s core is enough to turn carbon into unimaginable liquid, metallic diamonds!
The Great Red Spot
The Great Red Spot is a storm 10,000 miles across that has lasted over 350 years. It has an estimated wind speed of 263 mph. In comparison, the highest wind speed of any hurricane measured on Earth was 215 mph. This was measured in Hurricane Patricia in 2015 off the Pacific Coast of Mexico.
How Does Jupiter Protect Earth?
Jupiter and the other giant planets perform an important protective role for Earth and the other planets of the inner solar system. Their tremendous gravity pulls in comets and meteors that stray too close, keeping some of them as moons and burning up others in their upper atmospheres. A good example of this occurred in 1994, when comet Shoemaker-Levy 9 was captured by Jupiter’s gravity, broke up into over 20 pieces, and exploded in its atmosphere. Although the impact points were on the far side of the planet, astronomers photographed bright flashes rising from the horizon of the planet and saw a string of huge black spots in the atmosphere as the planet rotated. The largest explosion was estimated to be 48,000 megatons. This is a thousand times larger than the largest nuclear explosion ever detonated on Earth, the Cold War era Tsar Bomba tested by the Soviet Union.
Life on Jupiter?
Does Jupiter have water? The answer is yes. Life on our planet can’t exist without water, so finding water on other planets raises the possibility that life exists elsewhere. However, in the case of Jupiter, the kind of life we have on Earth would never be able to survive because of the deadly chemicals in the planet’s atmosphere and ocean and its violent weather systems. However, that doesn’t rule out the existence of radically different life forms.
Better sites to search for life in the Jovian system are on its many moons. But even if there is no life on Jupiter or its moons, the presence of water helps us determine how plentiful this resource is in the universe, and thus, how likely we are to find it in other places. And that helps us not only in our search for extraterrestrial life, but in our plans to become extraterrestrial space colonists ourselves one day.
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