Three of these four different planets on Jupiter contain water, even liquid water!

Jupiter, the largest planet in the solar system, has a total of 79 satellites, accounting for 43% of the total number of satellites in the solar system.

So many satellites form a huge Jupiter satellite system similar to the solar system. Some are near, some are far, some are large, some are small, just like a galaxy.

However, most of these satellites are relatively small.

There are almost more than 60 satellites with a diameter of less than 10 kilometers, and even the smallest satellite is only 1 kilometer in diameter.

But there are also big ones. The four largest satellites have a diameter of more than 3,000 kilometers. You must know that the diameter of the moon is 3,476 kilometers, which means that these four satellites are comparable to the moon.

In fact, these four satellites are Io, Europa, Ganymede, and Callisto, and they will also be collectively called the Galilean satellites.

In 1610, Galileo discovered these four satellites after he invented the astronomical telescope, so the Galilean satellites got their name from this.

These four Galileo satellites are also different and have their own unique characteristics.

Let’s take a look at the differences between these four satellites.

1. Io

Io is the closest satellite to Jupiter among the four Galilean satellites. It is 420,000 kilometers away from the center of mass of Jupiter, which is longer than the distance between the earth and the moon. The average distance between the Earth and the Moon is 38.4 kilometers.

The diameter of Io is also slightly larger than that of the moon. The diameter of Io is 3637 kilometers, which is about 160 kilometers larger than the diameter of the moon. It is also the fourth largest satellite in the solar system.

Io is not only about the same size as the moon, but also has the same characteristic, that is, its revolution period is equal to its rotation period.

Everyone knows that because of the tidal force of the earth on the moon, the moon's revolution period and rotation period are strictly consistent, both 27.32 days.

The orbital period and rotation period of Io are also the same, but they are only 1.77 days, which is much shorter than the moon. After all, the mass and gravity of Jupiter are so great, and Io is so close to Jupiter, that only by moving at a faster speed can a huge centrifugal force be generated to counteract the gravity.

In fact, the four Galilean satellites have very short orbital periods and are all tidally locked.

From the photos, Io seems to have many colors, mainly yellow. In fact, these colors are mainly caused by sulfur and sulfur compounds.

It is also the only planet in the solar system besides the Earth that has frequent volcanic eruptions and geological activities.

Many satellites have craters like those on the moon, but there are only a few craters on Io. Its surface is rich in terrain, with craters thousands of meters deep and high-temperature lava lakes. , there are continuous mountains and so on.

The temperature difference on Io is also relatively large. Under normal circumstances, the temperature is around minus 140 degrees Celsius, but when the volcano erupts, the temperature can reach over four to five hundred degrees Celsius.

2. Europa

Europa is the smallest of the Galilean satellites, with a diameter of 3138 kilometers, a little smaller than the moon.

Its distance from Jupiter is only slightly further than Io, its orbital radius is 670,000 kilometers, and its orbital and rotational periods are both 3.5 days.

Europa is also relatively famous in the solar system, because Europa is a planet other than the earth that may have liquid water, and it is known that the liquid water storage capacity of Europa even exceeds The earth!

Huge fountains with a height of more than 200 kilometers often appear on the surface of Europa. This is the best proof that Europa may have liquid water under its extremely thick ice layer. Scientists have also been studying Actively exploring Europa, hoping to confirm whether there is life on Europa.

Liquid water is the source of life, but the conditions for the birth of life are too harsh. Although there is no hope that Europa can produce life, human beings may not be able to produce life when technology develops to a certain stage. Can immigrate to Europa.

After all, Europa is very advantageous compared to other planets. Its atmosphere contains a lot of oxygen and the most important water resources.

Another feature is that the most striking feature on the surface of Europa is the dark cross stripes all over the planet. These stripes are basically cracks on the surface of Europa, which may be huge. Caused by the effects of geysers and Jupiter's tidal forces.

3. Ganymede

Ganymede is the third closest to Jupiter among the Galilean satellites, and is 1.07 million kilometers away from Jupiter.

Ganymede has a diameter of 5262 kilometers, which is 1.5 times the diameter of the moon. It is also the largest satellite in the solar system, with a diameter even larger than Mercury!

It is also tidally locked by Jupiter, and its rotation and revolution periods are both 7 days.

Ganymede is also a planet with huge ice layers. Some scientists even believe that there is a liquid salt water sea under the ice layer of Ganymede, which may exceed the amount of water on Earth by more than 30 times. But this has not been confirmed, it can only be said that it is very likely.

Ganymede also has the same thin oxygen-containing atmosphere as Europa, but Ganymede is the only satellite in the solar system with a magnetic field.

The surface of Ganymede is covered with craters. It is estimated that the age of Ganymede has exceeded 3 billion years, but Io and Europa are still young planets.

4. Callisto

Callisto is the farthest from Jupiter among the Galilean satellites, with an orbital radius of 1.88 million kilometers. It is also tidally locked, and its orbital period and rotation The cycle is 16.7 days.

The diameter of Callisto is also very large, 4800 kilometers, which is 1.38 times the diameter of the moon. At the same time, Callisto is also the third largest satellite in the solar system, second only to Ganymede and Titan. .

Callisto also has a huge ice layer, which means that among the four Galilean satellites of Jupiter, except Io, the other three satellites all contain water.

Although Callisto has not been proven to have liquid water, it is also considered one of the most likely planets to harbor life.

The surface topography of Callisto is relatively complex, and it is also very old. The craters on the surface have begun to collapse, and some small craters have disappeared in the process of decline.

Another strange phenomenon is that some of the craters on Callisto are arranged in a straight line. This is probably because some asteroids were torn apart when they approached Jupiter and then hit Callisto. formed on.

After a brief introduction to these four Galilean satellites, I feel that these four satellites have similarities and differences. They really have their own characteristics!

The most important thing is that three of these four contain a lot of water, and one even contains liquid water. They are the most likely planets to have life. I hope that with the development of science and technology in the future, we can truly explore these magical planets. planet.