PHYS 284 Lecture Notes - Lecture 8: Interstellar Cloud, Oort Cloud, Kuiper Belt
5 Apr 2018
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If a hypothesis fails to explain even one of the four features, then it cannot be correct. If it successfully explains all four, then we might reasonably assume it is on the right track. We generally trace the origins of our modern theory of solar system formation to around 1755, when german philosopher immanuel kant proposed that our solar system formed from the gravitational collapse of an interstellar cloud of gas. French mathematician pierre-simon laplace put forth the same idea independently. Because an interstellar cloud is usually called a nebula (cid:894)lati(cid:374) for (cid:862)(cid:272)loud(cid:863)(cid:895), this idea (cid:271)e(cid:272)a(cid:373)e k(cid:374)o(cid:449)(cid:374) as the nebular hypothesis. During much of the first half of the 20th century, the nebular hypothesis faced stiff competition from a hypothesis proposing that the planets represent debris from a near-collision between the sun and another star. According to this close encounter hypothesis, the planets formed from blobs of gas that had been gravitationally pulled out of the sun during the near-collision.
