For three quarters of a century Pluto was the ninth planet in our Solar System. Many hearts were broken when scientists declared it as a dwarf planet in 2006. This left the Solar System with just 8 bodies that can be termed as planets. But many astronomers, amateur planet finders and planet lovers at large believed in the existence of 9 planets though there was never a concrete evidence to it. For all of them there is something to cheer about.
An astronomer from the University of Tokyo has spotted a planet behind Neptune. This planet has been spotted just once and very less is known about this planet as on date. So little is known about it that we haven't given it a name yet. It is simply referred to as Planet 9. The mass of Planet 9 is believed to be 10 times that of earth. NASA too has released a statement that Planet 9 could be 20 times far from the Sun as compared to the distance between Sun and Neptune i.e. the semi-major axis of its orbit could be 600 AU. Yup, that's very very far.
Astronomers at California Institute of Technology built a computer simulation model of this mysterious planet. The orbits of six known objects of our Solar System, beyond Neptune, line up in one direction. A bigger object with 10 times the mass of Earth is required to maintain this alignment. This bigger object could be Planet 9 (see the image).
|Image: Orbits of 6 bodies beyond Neptune and the orbit of the hypothesized Planet 9|
Whatever its size and mass, whatever its characteristics, one thing is sure - the discovery of Planet 9 is not very far off. But planetary science has many challenges. Due to the sheer distance, this yet hypothetical planet receives very less light from the Sun; which means that very less light reflects from its surface. This makes it very difficult to detect it with telescopes.
Hey! The confusion is not over yet.
There’s good news for Pluto lovers. Pluto may be reinstated as the ninth planet of our Solar System. An object is termed as a planet as per the definition recommended by International Astronomical Union. But planetary scientists at University of Central Florida want to make changes in that definition to include Pluto as a full-fledged planet. If their case is accepted, Pluto will again become the ninth planet of our Solar System and then, of course, the new planet, when discovered, will become Planet X.