tidal hypothesis; near-collision hypothesis
Astronomy term for a historical hypothesis about the origin of the solar system, proposing that a close encounter or near-collision with another star pulled material from the sun to form planets. Now largely superseded by the nebular hypothesis.
The tidal hypothesis is one of the old hypotheses about the origin of the solar system.
Nowadays, the nebular hypothesis is more widely accepted than the near-collision hypothesis.
Compound of 遭遇 (そうぐう, 'encounter') and 説 (せつ, 'theory'), referring to the hypothesis that a stellar encounter formed the solar system.