Merkur
Mercury is very difficult to study, since it is very close to the Sun. That is why it is shrouded in mystery.
Mercury has a large core, and scientists aren't sure why. It also has a magnetic field and an atmosphere of unknown origin. The small planet has a stream of atmospheric particles, suggesting that the atmosphere is constantly being regenerated.
The greatest mystery of all is Mercury's elongated orbit, which over time is increasingly taking on an oval shape, and there is a possibility that it will hit Venus or the Sun after some time.
The question is, will the orbit of the Earth and other planets of the solar system be disturbed?
Venera
Scientists still do not know the answer to the question of how the once "earth-like" Venus became the red-hot planet covered with a thick layer of toxic gases that it is today.
However, a much bigger mystery is that its atmosphere rotates 60 times faster than its spin. It is also unknown why Venus rotates counterclockwise, unlike other planets in our system.
It is also suspected that there are microorganisms in its atmosphere, which in some parts could have a temperature similar to that of the earth.
Earth
Although we live on Earth, we still do not know it completely. For example, how is there water on Earth? Or: what is the nature of its core that apparently transmits seismic waves faster in one direction than in the other?
And our satellite is quite mysterious. Although many scientists believe that the Moon was formed by an asteroid impact with the Earth, there is no geological evidence for this.
Mars
The cold red planet was warm, wet and geologically active 500 or more million years ago. Scientists don't know what went wrong or whether the changes destroyed any life on it.
Also, scientists still don't know why one half is completely smooth, while the other half is completely pockmarked with meteor impact craters.
Jupiter
Jupiter is covered in "bands" of gas of different colors, the brighter ones are called zones, and the darker ones are called belts. However, it is not known whether they are the surface of the concentric cylinders that make up the planet, nor why some stripes disappear without a trace.
Jupiter's famous red spot is also mysterious. Experts hope to learn more when the Juno spacecraft flies by in 2016.
Saturn
For nearly four centuries, astronomers have wondered about Saturn's beautiful rings, but no one knows why they are there. It is assumed that they are the remains of a former moon that disintegrated or pieces of a comet that were torn apart by the planet's gravity.
The dynamics of terrible storms and winds on the surface of the planet, as well as its rotation, are also unknown. So far, three spacecraft have been sent to Saturn with the task of measuring the length of its day, but all three had completely different results.
Uranium
Planets are supposed to emit heat that has been trapped in their guts since the formation process, but this is not the case with Uranus. Perhaps the heat of the seventh planet disappeared in some cosmic upheaval in the distant past (perhaps even due to an asteroid impact).
Or, maybe Uranus somehow stores all the energy under the surface and does not emit it at all?
He also attracts a very unusual object known as Miranda. This strange moon has deep canyons and layers similar to those of Zlemlja, and some of its chasms are more than 20 kilometers deep.
Neptun
Astronomers expected Neptune to be completely "dead", weather-free and deeply frozen. However, the Voyager 2 flyby in 1989 revealed a turbulent atmosphere with light clouds and strong storms.
Miraculously, the fastest winds were recorded precisely on Neptune and blow around 2.100 km/h.
Also, it was discovered that it stores a lot of heat, which is very strange, considering that it is the most distant from the Sun in our system.
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