RE: Evidence for ET?
November 21, 2018 at 1:00 pm
(This post was last modified: November 21, 2018 at 1:57 pm by Anomalocaris.)
R
The chance that an collision large enough to effect its keplarian orbital motion occurring within a observational period of a few month is extremely small.
A far higher likelihood would be pockets of volatiles on the object sublimated into space, and provided the equivalent of a small jet thrust as they did so.
Even if it were not tumbling, it would not be evidence of intelligence at all.
Tumbling means axis of rotation changes overtime. So there is no real way for the object to settle into a perfect equilibrium with a steady centrifugal force. Because the object is neither perfectly rigid, nor likely to be perfectly elastic, the rotational energy of a tumbling object must gradually be dissipated through internal friction and the rate of tumbling slows down, until it finds a stable rotational direction and stop tumbling. I read an estimate that for an rocky or metallic object the size of this asteroid, the period it would take for its rotation to evolve past the tumbling stage would be on the order of 1 billion years. After that it would settle into a stable slow orderly rotation.
Since the universe is far older than 1 billion years, we can expect most interstellar objects similar to this asteroid would exhibit orderly rotation rather than be found tumbling.
(November 21, 2018 at 4:16 am)ignoramus Wrote: Why couldn't it something as simple as some smaller object hitting it and slightly steering it off course?
The chance that an collision large enough to effect its keplarian orbital motion occurring within a observational period of a few month is extremely small.
A far higher likelihood would be pockets of volatiles on the object sublimated into space, and provided the equivalent of a small jet thrust as they did so.
(November 20, 2018 at 10:48 pm)AFTT47 Wrote:(November 20, 2018 at 10:37 pm)Jehanne Wrote: It's a rather large deviation:
The Unexpected Trajectory of Interstellar Asteroid 'Oumuamua
What if the thing was artificial and ET is making a course correction?
The thing was tumbling. If it wasn't, that would be major evidence of intelligence. The fact that it was tumbling strongly suggests against it.
Even if it were not tumbling, it would not be evidence of intelligence at all.
Tumbling means axis of rotation changes overtime. So there is no real way for the object to settle into a perfect equilibrium with a steady centrifugal force. Because the object is neither perfectly rigid, nor likely to be perfectly elastic, the rotational energy of a tumbling object must gradually be dissipated through internal friction and the rate of tumbling slows down, until it finds a stable rotational direction and stop tumbling. I read an estimate that for an rocky or metallic object the size of this asteroid, the period it would take for its rotation to evolve past the tumbling stage would be on the order of 1 billion years. After that it would settle into a stable slow orderly rotation.
Since the universe is far older than 1 billion years, we can expect most interstellar objects similar to this asteroid would exhibit orderly rotation rather than be found tumbling.
