NASA has revealed that its Hubble Space Telescope made a new discovery: evidence of a planet forming at a record distance from its star, something that – if proven to be true – could then shake up current theories regarding planets and their formation. The discovery was made in the Hydra the Sea Serpent constellation.
Thus far, a total of just under 900 planets have been confirmed beyond our solar system, and of those none have such a distance between the planet and its star. This discovery concerns the red dwarf TW Hydrae star and what is believed to be a planet located 7.5 billion miles from it. TW Hydrae is about 176 light-years from our planet.
NASA believes the planet exists because of a 1.9 billion mile gap in a gas and dust disk that is about 41 billion miles across. This gap, says NASA, is likely caused by a planet passing through it, essentially pushing dust and such out of its way as it moves. The space agency describes this as being similar to what happens when a snow plow goes down a snowy street.
This is where the finding would challenge current beliefs about how planets form, which say that such formation is the result of a planet gathering debris from the protoplanetary disk slowly as it passes through. The farther a planet is from its star, the slower it will move because of the larger circumference, meaning it will develop more slowly than closer planets, which are gathering up debris faster.
NASA believes TW Hydrae, which the suspected planet orbits, to be 8 million years old, but the planet – at such a distance – would take an estimated 20 million years to reach its current size (6 to 28 times the size of Earth). The obvious problem, then, is that the planet would have to start forming before the star that it orbits, which isn’t possible. One other theory being tossed around is that instability caused part of the disk to collapse, which would result in the planet being able to form in the given timeline.