In recent years, more and more new discoveries have been made in astronomy. At the same time, scientists are re-evaluating existing theories, hypotheses, and data on already seemingly well-known space objects. Take Jupiter for example. In some aspects, the opinion of astronomers about it has changed in a radically opposite direction.
A giant with many moons
Jupiter is known to be a giant. All the planets in the solar system combined would weigh half as much as Jupiter alone. It is logical that such a heavyweight should have more satellites than other planets. And so it was: at the beginning of this year, 12 new satellites were discovered near the gas giant, and their total number increased to 92, which was nine more than Saturn. However, already in the spring, as many as 62 new moons were discovered near the latter.
Thus, Saturn officially has 145 moons, and it does not matter that most of them are small boulders a couple of kilometers in diameter.
Astronomers have always been particularly interested in how Jupiter became so large and kept in balance with all the other inhabitants of the solar system. A conservative hypothesis says that it formed somewhere outside the solar system or at its very edge, where the Oort cloud and countless space debris, the collision with which slowed it down.
According to Einstein’s theory of relativity, there is no gravity in itself, then, having lost the speed of counteraction, Jupiter began to approach the Sun. Other planets, which by that time had already developed, were able to stop it. It is believed that Saturn played a key role in this and, probably, centrifugal forces, which are always directed away from the axis of rotation in such cases.
That is, the speed of rotation, which Jupiter did not have enough to stay in its orbit, became sufficient when the planet approached the star and the angular speed of rotation increased.
Last year, NASA’s Juno interplanetary station, launched specifically to study Jupiter, was able to refute the theory that Jupiter’s core is stones and dust collected bit by bit. It turned out that all the material inside the gas giant is unevenly distributed. In addition, so many heavy metals have accumulated inside it that it is enough for 15 or even 30 Earths.
But the paradox is that Jupiter was originally a rocky planet, like ours or Mars. It became a gas giant after gravity became so powerful that, in addition to dust, it sucked in gaseous substances and more. How did Jupiter get its mass if small stones burn out in the atmosphere?
Most likely, Jupiter is a noble cannibal, and there is so much metal in it because on its way it swallowed more than one protoplanet. And when it did this – before or after turning into a gas giant – is still unknown.
Next, Jupiter breaks all our ideas about the seasons and weather. Everyone knows that the Earth’s axis of rotation is tilted by 23 degrees, so we observe four seasons. Jupiter’s axis is rotated only by 3 degrees.
In theory, all its parts should receive the same amount of heat. However, the weather on it changes, even in a cyclical way.
Looking at Jupiter, you can understand what temperature its regions have. Where it is cold, the shades are light; where it is hot, the shades are browner. Only for some reason, when the temperature drops in certain latitudes of the northern hemisphere, the mirror latitudes of the southern hemisphere immediately cool down. These latitudes are distributed over vast distances, greater than on Earth, but this process is instantaneous. So scientists have yet to figure out why the climate on the gas giant changes regardless of the tilt of the axis of rotation.
No less interesting surprises are presented by the satellites of the gas giant. For example, Europa most likely does not have a core at all or it was formed not so long ago. This fact is knocked out of our idea that the solar system has finally formed and is in balance. Europa is 90% not water, but stone and metal. New data on its density say that there is simply no liquid core and mantle in its internal structure.
Thanks to computer models, it becomes obvious that Europa was formed in colder conditions, and metal and stone could not melt, but cling to each other and freeze. The ocean may have melted under the influence of Jupiter, but a full-fledged liquid metal core could appear after a billion years, but not the fact that it exists at all. There is a high probability that the satellite is still in the phase of internal melting.
A place for extraterrestrial life
Another moon of Jupiter, Ganymede, may be in the forefront of candidates for the presence of life. In 2021, the Hubble telescope recorded traces of water vapor in its atmosphere. There is also a lot of liquid water on it, only all of it is at a depth of 160 kilometers below the surface.
Theoretical calculations led scientists to the conclusion that in the diameter of Ganymede, a whole third falls on alternating layers of ice and water. And then it turned out that the satellite has its own full-fledged magnetic field, moreover, induced and dipole, almost like that of the Earth. It covers it from both solar radiation and Jupiter’s magnetic field.
This fact allows us to say that Ganymede has a liquid iron core, and internal processes similar to the Earth’s, which can lead to the same geothermal sources that begin their life in the ocean, which Ganymede also has. So for alien life, the place is quite a reliable place.