Re:Have Aliens Found Us? (2019)
by tlb on Friday January 03, 2020 @02:15PM
(#21949280)
No, it also depends on effects like the pressure from the solar wind and outgassing. Outgassing is caused by water on the side facing the sun evaporating, emitting a gentle pressure away from the sun. If the object is rotating, the force pushes at an angle to the sun because the outgassing rate lags insolation due to the surface water's thermal mass (ie, each point on the surface continues to evaporate for a while after its apparent sunset.)
The effects aren't significant for planets, but they are for asteroids. It seemed more significant for Oumuamua than most, suggesting a high surface area to volume ratio.
Re:Have Aliens Found Us? (2019)
by saagarjha on Friday January 03, 2020 @02:22PM
(#21949349)
I thought outgassing and solar wind was only really relevant when applied for a long time over many periods of an orbit? Would it have a significant impact on a one-time hyperbolic trajectory like this one?
The effects aren't significant for planets, but they are for asteroids. It seemed more significant for Oumuamua than most, suggesting a high surface area to volume ratio.