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Alien Comet May Have Infiltrated the Solar System
Posted by
kdawson
on Wed Dec 03, 2008 06:37 AM
from the starseed-lure dept.
from the starseed-lure dept.
New Scientist has a piece about Comet Machholz 1, whose uncommon molecular composition suggests, but does not prove, that it may be an interloper from another star system. "Comet Machholz 1 isn't like other comets. David Schleicher of the Lowell Observatory in Flagstaff, Arizona, measured the chemical makeup of 150 comets, and found that they all had similar levels of the chemical cyanogen (CN) except for Machholz 1, which has less than 1.5% of the normal level. Along with some other comets, it is also low on the molecules carbon-2 and carbon-3."
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Oh, no, Alien Comet! (Score:5, Funny)
Re:Oh, no, Alien Comet! (Score:5, Insightful)
It's hardly surprising that we actually can get objects that originates from outside our solar system. There isn't much of a fence around the solar system.
What could be really interesting is to pick samples from this comet to check for more complex molecules. It's not really that we have seen our "own" comets all the way through yet, so we don't know much about possible variations.
We don't even know much about how the comets were created, and that means that there is a lot of uncertainty involved. A possible scenario is that the comets originates from a larger object that has cracked up, which may explain why most of them are similar in composition and that this new comet is from another source. Just compare the variations in composition of the planets we have in the solar system.
There is still so much to learn about the universe.
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Re:Oh, no, Alien Comet! (Score:5, Insightful)
There are no fences, but to a significant gravitational barrier to overcome when leaving the original star system. Also, to fall into orbit around or sun would require a third body to take away the excess energy. I guess this could be one of our planets, but on overall I'm suspecting more "boring" origins, such as a cold spot in our own solar system.
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Re:Oh, no, Alien Comet! (Score:5, Informative)
the Oort cloud, hypothesized to be the source of all comets.
Actually the very existence of the Oort cloud is hypothetical. While it provides a reasonable explanation for the existence of comets in our system there was no further independent confirmation until 2000, when more powerful telescopes identified one object that could belong to the cloud. Given that the number of comets could be into the trillions, having found a handful does not constitute definitive evidence, so it remains a mere hypothesis until more data is gathered.
For a foreign body to enter the system, it would have to pass through the Oort cloud and that would be highly unlikely. It's most probably an Oort cloud comet of a new type.
Comets in the Oort cloud are tens of millions of kilometers apart. An exo-solar comet would have no problem "sneaking" in.
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In related news.. (Score:5, Funny)
Scientists have discovered a Buddhist monk who is not human.
food for thought...
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Entry is Free. (Score:5, Funny)
Re:Entry is Free. (Score:5, Insightful)
Me thinks this news smells a bit like trying to get some funding...
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Re:Entry is Free. (Score:4, Insightful)
well, given that comets inhabit the outer reaches of our solar system already, it wouldn't take too much effort. Add in the vastness of space and the fact that gravitational attraction exists I'd conjecture that any body heading in our general direction would be captured by our gravitational pull. It wouldn't have to aim straight at us, just in the general vicinity.
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Re:Entry is Free. (Score:5, Informative)
The Sun alone can't capture a 'stray' comet - it'll just give it a gravity assist. You need at least three-bodies interaction for the orbital capture.
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Re:Entry is Free. (Score:5, Funny)
I could go for some three-bodies interaction.
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Re:Entry is Free. (Score:5, Funny)
African or European?
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Re:Entry is Free. (Score:5, Funny)
Is the comet carrying coconuts?
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Re:Entry is Free. (Score:5, Informative)
Besides that, how would it have come here anyway? What is the escape velocity for getting out of a star system?
There is nothing mysterious or difficult to believe here.
We see about four comets per century that have hyperbolic trajectories - that is to say, they are never coming back.
These hyperbolic comets are either interstellar interlopers already and have not been captured by the solar system (which would typically occur by losing part of its kinetic energy to one of the gas giants through gravitational interaction), or they are solar system comets being ejected into interstellar space (through gaining energy by the same mechanism) to become future interlopers in other star systems. Either way, we see the effect of comet ejection regularly, every few decades.
Since the Oort Cloud is much denser with comets compared to the density of wandering comets in interstellar space, most hyperbolic comets are going to be the latter type.
Machholz 1, if it is alien, was captured by the solar system some time in the past. Although this type of capture may be rare, since it would be going on since the formation of the solar system a substantial population of alien comets should have built up by this time, and captured aliens may be a more common sight than one-shot hyperbolic visitors.
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Alien bastards (Score:4, Funny)
Re:Alien bastards (Score:4, Funny)
Dek uur deeewww!!! [youtube.com]
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Determining origin (Score:4, Insightful)
Besides, its only speculation that suggests it didn't come from our own Kuiper belt in the first place - we don't know enough about that to be sure.
Re:Determining origin (Score:5, Interesting)
Lets face it, even if we retrieved a sample and analysed it in a lab, we wouldn't be able to say with any real certainty where it came from.
With an actual sample, and isotope analysis, we could say whether or not it came from this solar system. This is done all of the time for tiny grains found in meteors and collected directly, some of which do not come from this solar system [skyandtelescope.com].
True, saying where it did come from might require sampling most of the star systems in our region of the galaxy and that will take... a while.
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Re:Determining origin (Score:4, Informative)
Videos here [nasa.gov] illustrate the effects of the comet's (abnormal) very close trajectory to the sun. Collected dust is pretty much sandblasted away on a regular base.
But since it doesn't contain assembly language I don't really know what I'm talking about.
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Does anybody know (Score:4, Interesting)
What that line is that runs parallel to the comet from the centre of the sun to the bottom left of the image?
Re:Does anybody know (Score:5, Informative)
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Re:Nuke it! Nuke it now! (Score:4, Funny)
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Re:Nuke it! Nuke it now! (Score:5, Funny)
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Naquadah (Score:5, Funny)
No, if it's made of naquadah, they'll WANT you to nuke it.
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Re:Naquadah (Score:4, Funny)
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Re:Umm, Carbon-2 and Carbon-3? (Score:5, Informative)
Space chemistry is completely unrelated to "normal" earthly chemistry - for example, the second most popular molcule in the universe is H3+ (after H2).
What is discussed here are molecules composed exclusively of 2 and 3 carbon atoms:
http://en.wikipedia.org/wiki/Diatomic_carbon [wikipedia.org]
http://en.wikipedia.org/wiki/Tricarbon [wikipedia.org]
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