Is the Oort Cloud simply a theory or have people seen it?

Question

Everything I've read about the Oort cloud seems to qualify statements with phrases like "is said to" or "seems to". Do we know that the Oort cloud exists for sure? Have we seen other Oort clouds around other solar systems? If we haven't seen them around other solar systems then why would we assume that there is one around ours?

Answer 1

It cannot be seen, but it makes perfect sense. Long period comets (as opposed to short period comets, like Halley's, which return every few years) are all observed approaching from far out in space, swinging by the Sun and disappearing in deep space again. We know from orbital mechanics and observations that these comets do not come from interstellar space, they are not moving fast enough. But we also know that objects in very elongated elliptical orbits around the Sun, like comets, move faster when close to the Sun and VERY VERY slowly far from the Sun, so they must spend thousands of even millions of years out past Pluto for every year they spend close to the Sun. We see a few comets pass near the Sun every year, and each one has spent thousands or millions of years out past Pluto, so there must be thousands or millions more out there, because they just keep coming, year after year.

Curiously, creation science people seem to have something against the idea of the Oort cloud and I can't figure out why. Nothing about the idea contradicts the bible or supports Darwin's theory of evolution or disproves the existence of God or proves that the universe is really old or anything like that, as far as I can tell. Maybe I should post a question!

Answer 2

We have seen little bits of it. Sometimes objects from the Oort cloud pass close enough that we can see them, and we can compute their orbits. Thus we know where the Oort cloud is, and we use statistical tools to compute the number of objects, etc.

Answer 3

No one has actually seen it. We can only infer its existence for the time being.