Immigration conditions in Europa

Jupiter, the largest in the solar system, has 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, which is near and far, big and small, just like a galaxy.

But most of these satellites are relatively small.

Almost more than 60 satellites are within 10 km in diameter, and even the smallest satellite is only 1 km in diameter.

But there are also big men. The four largest satellites are all over 3000 kilometers in diameter. You should know that the diameter of the moon is 3476 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 referred to as Galileo satellites.

Galileo discovered these four satellites after he invented the astronomical telescope in 16 10, hence the name Galileo.

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

Let's see what's the difference between these four satellites.

io

Io is the closest satellite to Jupiter among the four Galileo satellites, with a distance of 420,000 kilometers from Jupiter's center of mass, which is a little longer than the distance from the earth to the moon. The average distance between the earth and the moon is 38.4 kilometers.

Io is also a little bigger in diameter than the moon. Io is 3637 kilometers in diameter, about 160 kilometers more than the moon, and it is also the fourth largest satellite in the solar system.

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

As we all know, due to the tidal force of the earth on the moon, the period of revolution of the moon is strictly consistent with the rotation period, which is 27.32 days.

Io's period of revolution has the same rotation period, but only 1.77 days, which is much shorter than the moon. After all, Jupiter's mass and gravity are so great, and Io is so close to Jupiter that it can only move at a faster speed to produce a huge centrifugal force to counter gravity.

In fact, the period of revolution of the four Galileo satellites is very short, and they were all lost because of tidal locking.

Io looks like there are many kinds of colors, mainly yellow. In fact, these colors are mainly caused by sulfur and sulfur-containing compounds.

It is also the only planet in the solar system with frequent volcanic eruptions and frequent geological activities except the earth.

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

Io's temperature difference is also relatively large. Under normal circumstances, the temperature is around minus 140 degrees Celsius, but when a volcano erupts, the temperature can be as high as four or five hundred degrees Celsius.

Second, Europa.

Europa is the smallest satellite in Galileo, with a diameter of 3 138 km, which is a little smaller than the moon.

It is only a little farther from Jupiter than Io, with a revolution radius of 670,000 kilometers, a period of revolution and a rotation period of 3.5 days.

Europa is also quite famous in the solar system, because Europa is a planet with liquid water besides the earth. It is known that Europa's liquid water storage even exceeds the earth!

Europa often has a huge fountain more than 200 kilometers high on its surface, which is the best proof that liquid water may exist under Europa's extremely thick ice layer. Scientists have been actively exploring Europa, hoping to confirm whether Europa has life.

Liquid water is the source of life, but the conditions for the birth of life are too harsh. Although there is little hope that Europa can produce life, when technology develops to a certain stage, humans may immigrate to Europa.

After all, Europa has advantages over other planets. Its atmosphere contains a lot of oxygen and the most important water resources.

Another feature is that Europa's surface has one of the most striking features, that is, dark cross stripes all over the planet. These stripes are basically cracks on Europa's surface, which may be caused by giant fountains and Jupiter's tidal force.

3. Ganymede

Ganymede is the third closest to Jupiter among Galileo satellites, with a distance of 654.38+0.07 million kilometers.

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

Also by Jupiter's tidal locking, the rotation period and period of revolution are 7 days.

Ganymede is also a planet with huge ice. Some scientists even think that there is an ocean of liquid salt water under the ice layer of Ganymede, and its water volume may be more than 30 times that of the earth. But this has not been confirmed, only that it is very possible.

Ganymede also has a thin oxygen-containing atmosphere like 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 Ganymede is over 3 billion years old. I don't want Io and Europa to be young planets.

4. Callisto

Callisto is the farthest one from Jupiter in Galileo satellite, and its revolution radius is 1.88 million kilometers, which was also captured by tidal locking. Its period of revolution and rotation period are both 16.7 days.

Callisto is also very large in diameter, 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 Europa and Titan.

Callisto also has a huge ice layer, that is to say, among Jupiter's four Galileo satellites, except Io, all the other three satellites contain water.

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

Callisto's surface topography is complex and ancient. The surface craters have begun to collapse, and some small craters disappeared in the process of falling.

Another strange phenomenon is that some craters on Callisto are arranged in a straight line, which may be because some asteroids were torn when they approached Jupiter and then hit Callisto.

This paper briefly introduces these four Galileo satellites. I feel that these four satellites have similarities and differences, and they really have their own characteristics!

Most importantly, three of these four planets contain a lot of water, and even one contains liquid water, which is the most likely planet for life. I hope that after the development of science and technology in the future, we can really explore these magical planets.