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What's the probability that the very first extra-solar object is a light sail? Lets be real...
Like many things when it comes to space: We have no clue.
That same probability applies to the light sail.
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Like many things when it comes to space: We have no clue.
Probability allows you to say with confidence that the object cannot or is very unlikely to be certain things. For example, unlikely that the object is a sperm whale or a giant statue of liberty. That same probability applies to the light sail.
On the other hand, we have essentially no knowledge about what can possibly be flying around out there and thus your claim that it is extremely unlikely to be an artificial object is not based on anything but your own conviction that this is the case.
Probability allows you to say something with confidence if you have information to work out the probability. If you have no information then you have no probability.
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Probability allows you to say with confidence that the object cannot or is very unlikely to be certain things. For example, unlikely that the object is a sperm whale or a giant statue of liberty. That same probability applies to the light sail.
That's because we can be reasonably sure that no sperm whale is going to fly by from outer space, for obvious reasons. On the other hand, we have essentially no knowledge about what can possibly be flying around out there and thus your claim that it is extremely unlikely to be an artificial object is not based on anything but your own conviction that this is the case. Probability allows you to say something with conf…
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That's because we can be reasonably sure that no sperm whale is going to fly by from outer space, for obvious reasons. On the other hand, we have essentially no knowledge about what can possibly be flying around out there and thus your claim that it is extremely unlikely to be an artificial object is not based on anything but your own conviction that this is the case. Probability allows you to say something with conf…
The same "obvious reasons" apply to the light sail. Your biases are just prevent you from seeing the logical implication.
I think that our knowledge of the universe does allow me to conclude with some degree of certitude that it is highly unlikely to find a whale on an extra-solar trajectory.
On the other hand, we know nothing about the sort of objects that could exist out there and about the possibility of alien civilisations.
I am not saying that it is likely or unlikely to be a light sail because the fact is that we don't know enough to assign a likelihood. That's as unbiased as can be.
Paging Elon Musk, Jeff Bezos, et al: the next time one of these objects appears, we should try to capture it somehow, or at least divert its trajectory enough that it stays in the solar system and we can study it further. Nabbing one of these things would be a spectacular achievement, comparable to the moon landings, and would likely be of significant scientific value.
Capturing this object would have required the effort of multiple Apollo prgrams in a timeframe that is shorter by orders of magnitude. It’s far beyond the capabilities of Musk, Bezos and anyone alive today. Pulling it off would make the Moon landing look like parallel parking.
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It’s a fascinating mystery, but I gotta say that’d make a crappy lightsail, considering that even at our current tech level we could make a much lighter one if we could manufacture it in space. (The experiments that have flown were all constrained to survive launch and unfolding.)
Or was it a lighter sail, still carrying a payload?!
say you instead make the space craft tumble but make the sails able to change their albedo (how reflective they are). If you wanted to make a course correction, you'd alternate how reflective they were. If you wanted a push away from a sun, you'd make the side facing a sun bright. If you wanted to fall in more towards a sun, you'd make the side facing a sun dark. Would that work?
How much do light sails depend on brightness (light pressure) vs just absorbing molecules in the Solar wind?
Edit: Wikipedia says light pressure from photons is most of the effect, but still I can't figure out the difference between a black body sail and a reflective sail.
Please bear in mind, the spectra of Oumuamua is very similar to that of a D-type asteroid (organics and carbon), which isn't consistent with it being highly reflective.
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Or was it a lighter sail, still carrying a payload?!
Hm, say you are designing a light sail for interstellar travel. Instead of having it be made of thin film and actuators capable of swinging these sails like on a sail boat... because actuators are more likely to die after millennia in space: say you instead make the space craft tumble but make the sails able to change their albedo (how reflective they are). If you wanted to make a course correction, you'd alternate h…
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Wikipedia says: > In fact, the strong correlation between ʻOumuamua's velocity and the local standard of rest might mean that it has circulated the Milky Way several times and thus may have originated from an entirely different part of the galaxy.
That really does just make it that much more interesting. Here’s hoping we get a perfect sequence of coincidences to inspect a similar object someday.
While I find it highly unlikely, it does raise an interesting point about Fermi's Paradox, which is that even if there were enough alien life out there for its discarded light sails to go hurtling through our solar system every once in a while, we might not get any more evidence of it than this article demonstrates. So, it's almost certainly not a light sail, but even if it were, we would never know.
Fermi's paradox demonstrates it's almost certainly not a light sail. For it to be a light sail which was observed by chance by our totally unprepared observatories after a window of less than a century but also consistent with all our observations of the universe, we would need to hypothesize that we got extraordinarily lucky to observe a super-rare artifact, or that countless (or one vast) interstellar, pan-galactic…