Does a ninth planet exist in our solar system? This question has been bothering scientists for several years. In 2006, Pluto was excluded from the list of planets, and now we know of only eight planets. However, some researchers believe that there may be another planet beyond Neptune that has not yet been discovered. This hypothetical planet is called Planet 9.
Transneptunian space and extreme transneptunian objects
Over the past 20 years, scientists have made significant advances in the study of the outer solar system. They have turned their attention to the so-called Transneptunian Space, which lies outside the realm of the giant planets. In this space, scientists discovered an amazing population of inhabitants called extreme transneptunian objects. Their characteristics have sparked much controversy in the scientific community.
The existence of Planet 9
Some researchers believe that the extreme transneptunian objects may be a manifestation of the invisible presence of Planet 9. They suggest that this planet must be very large, with a mass 4-8 times that of Earth. In addition, it must be very far from the Sun, about ten times the distance to Pluto. If it existed, it would be a new type of planet, different from others currently known to us in the solar system.
Categories of planets
Our planetary neighbors basically fall into two types. They are either small rocky worlds with solid surfaces (Mercury, Venus, Earth, and Mars) or gas giants (Jupiter, Saturn, Uranus, and Neptune). Planet 9 would fall somewhere in between these categories. It could be what is known as Super-Earth, a rocky planet larger than ours, or Sub-Neptune, a gaseous world less massive and slightly smaller than Neptune.
How do you detect Planet 9?
Detecting Planet 9 is not easy. Being so far away, its brightness would be extremely dim and we would need powerful telescopes. The problem is that these telescopes usually have a very small field of view. Considerable observational efforts have been made in recent years to try to discover this elusive world, but so far without success.
Why is Planet 9 needed?
The discovery of Planet 9 will open the door to a detailed study of a category of planets that is almost unknown today. We have found similar planets around other stars, but being this far away, we know very little about them. If Planet 9 exists, it would be a new step in the study of the solar system and would expand our knowledge of the cosmos and its inhabitants.