We have a pretty good idea of what’s hidden inside our solar system. We know there is no Mars-sized planet between Jupiter and Saturn, and no brown dwarf nemesis headed our way.
Any large and fair object near the Sun will be easily seen. But we can’t rule out a smaller, more distant world, like the hypothetical Planet 9 (or Planet 10 if you want to throw down above Pluto). The odds against such a planet are quite high, and a recent study found it even less likely.
Many astronomers have wondered about the existence of planets that might be lurking on the outskirts of our solar system, especially when the power of our telescopes was quite limited.
But when the Large Sky Survey began scanning the heavens, they found nothing beyond asteroid-sized worlds. But the orbits of the worlds we found looked statistically, in a strange way, as if they were being gravitationally perturbed by something larger.
Provided that this is true, this “Planet 9” would have a mass of around five Earths, and an orbital distance of two or three hundred to 1,000 AU. In other words, just so small and so far away that it won’t be easily seen in sky surveys.
Naturally, this inspired people to explore the world, but it is not easy. Planet 9 will be too far away to see by reflected light, so you’ll have to find it by its faint infrared glow.
And at a mass of only five Earths, it won’t give off much heat. Added to this is the fact that such a distant planet will rotate very slowly, such that within one set of observations you will not see it move at all. That is where this new review comes in.
Scientists Have Found Clues About The Head of Egyptian Mummy Found in Attic
To find the distant planets, the team used two infrared sky surveys, one from the InfraRed Astronomical Satellite (IRAS) and one from the AKARI Space Telescope.
The two surveys were more than twenty years apart, giving any hypothetical planet plenty of time to move to a slightly different part of the sky. They assumed that any distant planets would be close enough to the equator, then combed through the data, noting potential planets.
