Loved these humorous comments ...
florid_snow wrote: ↑
Tue Nov 20, 2018 6:24 am
GCV Of Course I Still Love You <Broadcast>:: You engaged your sub-light drive??!
AlanNY wrote: ↑
Tue Nov 20, 2018 2:01 pm
An obvious question someone is probably looking into: Will the altered trajectory take it past another star?
Likely out gassing, but worth further consideration.
Clear skies, Alan
Yahchanan wrote: ↑
Tue Nov 20, 2018 9:53 pm
Maybe it contains a significant amount of bismuth?
At least I think the last one was humorous, though it may have been serious.
BDanielMayfield wrote: ↑
Tue Nov 20, 2018 1:27 pm
I want to accept "the leading natural hypothesis" of comet like out gassing, but I'm sort of hung up on this question: If it was just from natural heating, why was no cometary activity noticed when it was closer to the sun and therefore much warmer than it is now?
This is a good question and has been puzzling some researchers, it seems.
We do know the following:
- Oumuamua came through our system and got fairly close to the Sun. When it did, and thereafter, it did not appear very cometary at all.
And one would not expect it to become more so as it gained distance from the Sun and cooled back down.
- It was seen to be tumbling, which would cause any out-gassing to tend to have a random effect on its trajectory, not the best for accelerating.
- As it passed our Sun, of course, it experienced two major stresses at least: A temperature spike above anything it had experienced in millions of years, and a gravitational acceleration well above any it would have experienced in millions of years.
It would also have experienced higher magnetic field gradients than normal, but I am doubtful that those forces were notable, compared to the other two effects.
One idea is that it is reasonable that the stress would have caused something on Oumuamua to have been loosened. If a small piece came off during the inner arcing pass by the Sun, it could be thrown in a direction that would have increased Oumuamua's exit velocity from the solar system. But the professional "dynamicists" may have ruled that out, if their observations were past the perihelion. Still, as it continues tumbling away from us, it might further be apt to throw off a chunk or two for a fair amount of time, or perhaps some significant pieces of dust or gravel. In any case, larger and fewer than the items in a comet's tail, but ejecta, nonetheless. Such pieces would be impossible for our telescopes to see. If thrown off under the right conditions, then, just like out-gassing, such pieces might explain Oumuamua's increase in velocity, at least the main piece that we can still see.
If either out-gassing or more solid debris, the increase in velocity should be countered by a loss of angular momentum for the body. But again, I would doubt a slowed rotation would be large enough to measure.
(Of course back to little green men, perhaps the ejecta was a small capsule sent back toward us. Our utter failure to have defended against Oumuamua's approach would be a sign to aliens that our system's lone habitable planet was not populated by an advanced civilization, and was probably free for sterilization and colonization without guilt.)