Re:Aliens Might Have Sent Cigar-Shaped Probe to Monitor Eart...
by dragonwriter on Wednesday November 07, 2018 @06:29PM
(#18403230)
> Does this mean all the comets we see/track, all of them originated in the Solar system?
It means that none of them individually are known to have originated outside, yes.
Re:Aliens Might Have Sent Cigar-Shaped Probe to Monitor Eart...
by JoeAltmaier on Wednesday November 07, 2018 @06:31PM
(#18403238)
They're supposed to originate in the Oort cloud. And our star system currently seems to be the only one with an Oort cloud, which seems singularly unlikely. I imagine once we figure out why we can't see any other star's cloud, we'll relax the assertion that all comets are solar-local
Re:Aliens Might Have Sent Cigar-Shaped Probe to Monitor Eart...
by dragonwriter on Wednesday November 07, 2018 @06:43PM
(#18403287)
> They're supposed to originate in the Oort cloud.
Long-period comets are thought to originate in the Oort cloud, short-period comets in the scattered disc or the Kuiper belt, and main-belt comets in the asteroid belt.
> They're supposed to originate in the Oort cloud.
AFAIK, our Oort cloud hasn't been observed, only hypothesized from the behavior of long-period comets.
Given that, it's kind of unsurprising we wouldn't have concrete evidence of extra-solar Oort clouds.
Re:Aliens Might Have Sent Cigar-Shaped Probe to Monitor Eart...
by JoeAltmaier on Wednesday November 07, 2018 @06:44PM
(#18403290)
I wonder if we could see comets transiting other stars, and make the same kind of inferences...
Does this mean all the comets we see/track, all of them originated in the Solar system? I would have imagined at least few comets would have originated outside our solar system.