Oumuamua asteroid discussion

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Main Question or Discussion Point

Given the evidence available as of today, is it reasonable to believe there is even a miniscule chance that the Oumuamua asteroid was built by aliens? Or is this just sensationalist journalism?
 

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  • #2
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Please post a reference. I doubt any reliable sources are claiming it's alien built.
 
  • #4
davenn
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Given the evidence available as of today, is it reasonable to believe there is even a miniscule chance that the Oumuamua asteroid was built by aliens? Or is this just sensationalist journalism?
It's acting like a lump of rock following a trajectory easily undertood by Newtons mechanics.
It's now on the way out of the the solar system., so if it were an alien craft, it's not particularly interested in visiting Earth,
 
  • #7
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It's the end over end tumbling that is different than other space rocks. Also, it came from outside the solar sytem,looped past Earth and is now leaving the solar system.
 
  • #8
davenn
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It's the end over end tumbling that is different than other space rocks.
no it isn't, that isn't uncommon


Also, it came from outside the solar system, looped past Earth and is now leaving the solar system.
It actually looped around the Sun in a large hyperbolic path which confirms it's origin beyond the Solar System. Lots of asteroids and comets do farther and closer approaches to Earth. in this case the Earth was just a bit closer to one part of the orbit
... nothing unusual there
closest approach to the Earth was 33 million km

1280px-Oumuamua_orbit_at_perihelionsm.jpg



Dave
 

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  • #9
It actually looped around the Sun in a large hyperbolic path which confirms it's origin beyond the Solar System. Lots of asteroids and comets do farther and closer approaches to Earth. in this case the Earth was just a bit closer to one part of the orbit
... nothing unusual there
closest approach to the Earth was 33 million km
Dave
Seriously? There is NO comparison between a Solar System trajectory and an interstellar path. The only way this object could have approached us so closely is if there are billions of them out there. Adding in its unique light-curve and lack of volatiles makes it a worthy candidate for every possible telescopic investigation.
 
  • #10
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There is NO comparison between a Solar System trajectory and an interstellar path.
Of course there is. The very message you are responding to is such a comparison.

. The only way this object could have approached us so closely is if there are billions of them out there.
Yes. And? The number of such objects is measured in the quadrillions.
 
  • #11
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Maybe it's just extremely wishful thinking on his part, but Stephen Hawking seems to think there's a chance this could be some sort of defunct alien probe.

If a vast amount of resources were invested in this, would it even be possible to corral this thing and at least bring it into orbit around the sun?
 
  • #12
Yes. And? The number of such objects is measured in the quadrillions.
That statement is based on extrapolation from a sample of one - this object. You are probably right, otherwise this is an alien craft, but there are at least 3 properties here which no scientist would have predicted beforehand.
 
  • #13
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Seriously? There is NO comparison between a Solar System trajectory and an interstellar path. The only way this object could have approached us so closely is if there are billions of them out there. Adding in its unique light-curve and lack of volatiles makes it a worthy candidate for every possible telescopic investigation.
According to this paper, the density of these objects should be higher than the density of comets in the Oort cloud.
 
  • #14
According to this paper, the density of these objects should be higher than the density of comets in the Oort cloud.
On the other hand here's a paper stating that the first interstellar object was significantly more likely to be an asteroid than a comet, so take your pick -

https://arxiv.org/abs/1711.09599

Some estimates suggest that 20,000 times more cometary material than asteroidal should be ejected. And yet we've never seen a comet not from the Oort cloud.

Also yet another statistical oddity should not be underestimated : 'Oumuamua is remarkable for showing both negligible radial (U) and vertical (W) motion, while having a slightly sub-Keplerian circular velocity... any formation mechanism for this interstellar asteroid should account for the coincidence of 'Oumuamua's velocity being so close to the Local Standard of Rest' -

https://arxiv.org/abs/1710.11364
 
  • #15
davenn
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Seriously? There is NO comparison between a Solar System trajectory and an interstellar path

yeah, seriously !
you should go do some reading before criticising
A lot of unsubstantiated comments that are not even worthy of response :rolleyes::frown:
 
  • #16
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That statement is based on extrapolation from a sample of one - this object.
No, it's not. I'd tell you how I did this, except that you seem to want to put your own spin on what I am saying. Sorry, I am not interested in that.
 
  • #17
sophiecentaur
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A small object could be any shape and it would stay that way. A larger object (much larger) would eventually end up near- spherical due to its own gravity overcoming its structural strength.
An object that small that was a highly polished sphere would be much more interesting and much more likely to be an artefact.
A single sample of any shape would otherwise not be significant.
Makes you wonder, though. WTF would we do about it is we actually detected intelligent signals coming from it?
 
  • #18
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WTF would we do about it is we actually detected intelligent signals coming from it?
See if it responds to signals sent from Earth?
Then again it's probably safer to build an armada of nuclear bombing spacecraft and try to destroy it,
(It's the only way to be sure)
 
  • #19
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Given the evidence available as of today, is it reasonable to believe there is even a miniscule chance that the Oumuamua asteroid was built by aliens? Or is this just sensationalist journalism?
Let me guess, this is an inferred reference to "Rendezvous with Rama" by Arthur C. Clarke, right? :woot::biggrin:

Which was a very good book, even though nothing happens. :wink:
 
  • #20
sophiecentaur
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See if it responds to signals sent from Earth?
Then again it's probably safer to build an armada of nuclear bombing spacecraft and try to destroy it,
(It's the only way to be sure)
It would have been cheaper to have turned off all our radio sources until it goes past! ("I don't think he spotted us.")
 
  • #22
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Even with our current technology it would be trivial to spot signs of life on Earth from within the inner solar system. An image of the night side with sufficient contrast would work, a radio receiver would work, spectroscopy of Earth would see methane and oxygen as signs of life and couple of artificial compounds as signs of a civilization. We might be able to shut down the radio emissions, but not everything else.

And we'll have much better technology long before we have the means to make interstellar trips, even at such a slow speed.

If that would be an artificial object, "staying silent" wouldn't work.
 
  • #23
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I also imagine that shooting a nuclear missile at it would be the equivalent of shooting an aircraft carrier with a bow and arrow.
 
  • #25
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I also imagine that shooting a nuclear missile at it would be the equivalent of shooting an aircraft carrier with a bow and arrow.
The asteroid is not that big. A nuclear weapon would most likely vaporize the 230 x 35 x 35 meter asteroid. Assuming it has an equivalent, or less, density than Earth. If the asteroid were to impact Earth and we could be assured that all the pieces of the asteroid after the nuclear blast were smaller than 20 meters in diameter, then that would be the way to go.

A 20m diameter asteroid with 5.51g/cm3 density traveling at 50 km/s approaching the Earth at a 90° angle would begin to break up at an altitude of 48,900m (161,000 ft) and bursts into fragments at an altitude of 11,000m (36,200 ft.). The air blast would release 2.89 x 1016 Joules (6.89 MegaTons TNT) of energy. At a distance of 100 km the air blast will arrive approximately 5.08 minutes after the asteroid explodes in the atmosphere. The peak overpressure would be 987 Pa (0.14 psi) with a maximum wind velocity of 2.32 m/s (5.18mph) and have a sound intensity of 60 dB (heavy traffic). If you were directly beneath the air blast, the overpressure wave would arrive 47.2 seconds after the blast and peak at 14,700 Pa (2.09 psi) with a maximum wind velocity of 32.6 m/s (73 mph) and have a sound intensity of 83 dB (loud heavy traffic).

Anything larger than ~20m (or denser than Earth) and there is a good possibility that it could reach the surface of the planet.
 
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