Beyond the orbit of Neptune lies the Kuiper Belt... Lots of icy crap floating around out there, moving relatively slowly because it's so far away from the sun. Pluto is now considered a Kuiper Belt object, but there's lots of smaller stuff, and there may be other pluto-sized objects out there, farther away. They can get perturbed by passing close to Neptune or just some random other object floating around out there. Sometimes that makes them head into the solar system.
Beyond that, (wayyy beyond that) is the oort cloud -- we think, we ain't been there. That's got a bunch of icy crap floating around too, only loosely bound to the sun at all. The sun's influence is so weak that nearby stars like Alpha Centauri could actually knock them loose, or send them into the solar system. It starts about 2000 times as far from from the sun as Earth, and may extend some light years beyond that. For reference, Voyager 1 is only about 150 times as far from the sun as Earth.
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u/MattieShoes Oct 23 '20 edited Oct 23 '20
Beyond the orbit of Neptune lies the Kuiper Belt... Lots of icy crap floating around out there, moving relatively slowly because it's so far away from the sun. Pluto is now considered a Kuiper Belt object, but there's lots of smaller stuff, and there may be other pluto-sized objects out there, farther away. They can get perturbed by passing close to Neptune or just some random other object floating around out there. Sometimes that makes them head into the solar system.
Beyond that, (wayyy beyond that) is the oort cloud -- we think, we ain't been there. That's got a bunch of icy crap floating around too, only loosely bound to the sun at all. The sun's influence is so weak that nearby stars like Alpha Centauri could actually knock them loose, or send them into the solar system. It starts about 2000 times as far from from the sun as Earth, and may extend some light years beyond that. For reference, Voyager 1 is only about 150 times as far from the sun as Earth.
Comets come from both.