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This is an interesting paper and Oumuamua will remain fascinating for a long time. Maybe the answer to the Fermi Paradox (or 'Where the hell are they?') is tha
by david927 4y ago
This is an interesting paper and Oumuamua will remain fascinating for a long time.
Maybe the answer to the Fermi Paradox (or 'Where the hell are they?') is that they're around and doing interstellar drive-bys and we're just starting to notice.
- newZWhoDis 4y agoMy pet theory is they’re using gravity waves for coms and we’re the dumb apes still looking around in the electromagnetic spectrum. Once we can reliably detect and generate gravity waves much of our knowledge of electromagnetic waves can apply. 802.11gr anyone?
- thriftwy 4y agoGravity is so many orders of magnitude weaker than electromagnetism that it is not even funny.
- buildbot 4y agoTrue, but you can theoretically format a gravity wave to not follow the inverse square law - these are called solitons (apparently, I just looked this up)
- jerf 4y agoYes. Now look into how you construct a soliton, and try to figure out what monstrous levels of control you'd have to exert over solar-system sized quantities of degenerate matter to create them, and how much energy it would take. Now compute how much laser light you can generate for, oh, let's say, 6 orders of magnitude less energy. And how tightly you'd expect a civilization that apparently can casually wiggle dozens of solar masses at multiple Hz, in a modulated manner no less (so just a several Hz orbit is not sufficent, we are wiggling these things under power), to be able to collimate such a beam. This is the problem with gravity waves. It isn't some sort of supreme cheat code of the universe for super awesome communication. It's transparently obviously idiotic. Like, not just, "well, it's not necessarily the best way, but even if it's not great someone may have tried it", like, you're burning dozens of orders of magnitude more energy per bit. Plural dozens, of orders of magnitude. Not dozens of times, ten to the power of dozens. This is not sensible no matter how advanced the civilization. We're talking levels of stupid that would greatly exceed spending the entire output of Earth's collective industrial civilization for all of history on a single pack of Skittles. This is not a bright thing to do, and it only gets dumber the smarter you suppose the aliens are.
- marginalia_nu 4y agoTo be fair, because we don't know how to construct gravity waves does not mean such a means does not exist. Keep in mind, not too long ago we thought we needed to heat up a fillament surrounded by an inert gas in order to make artificial light, and our understanding of gravity is fairly poor (to the point where it's largely considered an unsolved problem quite how it fits together with other parts of physics).
- SketchySeaBeast 4y agoIf we make assumptions like that then the sky is the limit for other baseless assumptions, right? We're basically just picking our favourite pseudomagical science and arguing for it?
- marginalia_nu 4y agoWell that is the basic posture of all science, uncertainty. We must assume we don't know until we are convinced otherwise.
- SketchySeaBeast 4y agoBut you don't use that to suggest new unsupported ideas. In that case why can't I postulate for FTL communication by form of anti protons to be the best communication method?
- marginalia_nu 4y agoI've never talked about FTL communication.
- SketchySeaBeast 4y agoI didn't say you were. I was trying to make the point we're both suggesting science fiction now and it's not terribly helpful when trying to talk about the current science.
- all2 4y agoYes, but does it propagate faster than the speed of light? Even if a gravitic field is weak, it would be my preferred mode of communication if it propagated "instantly" across space/time. And it moves at the speed of light [0] so there's no speed advantage here. I see no reason a sufficiently advanced species would choose gravitic waves over any other EM wave. Does someone with a clue (not me) have any ideas why this would be the case? [0] https://en.wikipedia.org/wiki/Speed_of_gravity https://en.wikipedia.org/wiki/Speed_of_gravity
- jerf 4y agoIt does not. The concrete evidence of this is relatively recent; theoretically nobody has expected that it would for a long time, but it has been theory. But yes, we've coordinated detections between LIGO and radar astronomy now, and there's no reason to believe gravity travels FTL. As always, there are error bars, but they're tight enough not to get excited about. That is, who cares if gravity travels at 1.00000000000001 the speed of light? (The theoreticians would go absolutely ballistic, but pragmatically that would mean nothing.)
- nwiswell 4y ago> but pragmatically that would mean nothing Well except the part where you could use gravity waves to send messages to the past, I imagine that would have some pragmatic implications.
- raverbashing 4y agoThis is the answer Something like a neutrino bean sounds more plausible as a communication medium than gravitational waves
- JohnBooty 4y agoWhat would be the advantage of that?
- Reason077 4y agoUnlike radio waves or light, gravity waves aren't impeded by obstacles like stars, planets, interstellar dust, or anything else that might be out there. Nothing could block or jam them and you'd always have a clear signal.
- vecter 4y agoIt takes so much energy to create gravity waves and so much effort to detect them that it's silly to try to use them as a medium of communication.
- lowbloodsugar 4y ago*For Kardashev Type 1 civilizations like us. (And we’re only 0.74 not even 1)
- moloch-hai 4y agoWe are not even 0.01 Kardashev.
- deleted 4y ago[deleted]
- nmeagent 4y ago~0.73 seems about right. 0.01 is about 1.26 MW. https://en.wikipedia.org/wiki/Kardashev_scale#:~:text=equivalent%20to%20an%20average%20power%20consumption%20of%2018.87%20TW%20or%200.73 https://en.wikipedia.org/wiki/Kardashev_scale#:~:text=equiva...
- moloch-hai 4y ago
- landswipe 4y agoIt'll be more likely something subatomic, like they're chain entangling photons, we just don't know how to interpret it yet.
- whycome 4y agoThey keep ringing our sun and we never even respond! And now they're just annoyed with us and won't respond when we eventually call back.
- jjtheblunt 4y agowe generate gravity waves every time we move something with nonzero mass, don't we?
- vecter 4y agoYes but not in any practically detectable way.
- euroderf 4y agoCan a gravity wave be (in theory) directionally focused ?
- basch 4y agoOr they exist at a completely different scale than us. Their neurons are the size of galaxies or they live in Whoville in a snowflake.
- jerf 4y agoNeurons the size of galaxies, even if one stipulates them magically coming into existence as early as possible, couldn't have hardly thought "hello" to themselves since the universe began. In the meantime, on that time scale, incredible violence has occurred througout the universe. Round trip times of millions of years for the simplest communications are not feasible in this era of spacetime. You'll need to be waiting many tens or hundreds more billions of years before that is conceivable, in the long quiet dark before heat death. The snowflake hypothesis is at least in the range of the "things we can't disprove", at least if by "snowflake" you mean neutron star surfaces: https://en.wikipedia.org/wiki/Dragon%27s_Egg https://en.wikipedia.org/wiki/Dragon%27s_Egg Of course, one must consider that I'm citing a science fiction book, with all understanding of what that means. But that is at least one hypothesis I don't think we can disprove at the current time, unlike most other ideas put forth. I'd still call it an absolute long shot, and an even longer shot that such beings could leave their star.
- TheOtherHobbes 4y agoI'm fascinated by the idea that the same creatures can live in the same universe and have very different experiences of it. Ants, cats, and humans are all going to perceive the same objects in very different ways. And only humans can understand what human-specific objects are for. A cat will see a book as a flat surface which probably smells of its owner and go to sleep on it. It has no other concept of "book." And if it sees an open book it can't see the contents as writing, because it has no concept of writing. The fascinating part is that a human will see the same object but perceive it very differently because of the added human-specific knowledge and cognition. Unless you're going to make the very bold claim that humans are the most sophisticated and advanced life in the universe, our perceptions will be limited in an analogous way. We see clouds of dust and gas, star systems, and random background noise. An intelligence a few million years ahead of us may see the same objects as [symbol] and [relationship] in ways we literally can't imagine.
- floxy 4y agoDark sector. 85% of the mass of the universe. Those dark sector astrophysicists have a tougher time, since their book keeping is only 15% off, and everyone just thinks they aren't measuring things precise enough.
- distortionfield 4y agoI firmly believe that the chance humans have been visited by aliens is (admittedly) slim but _not non-zero_. I would say the chance has a few leading zeros of precision, and I understand that the universe is _huge_, but by the same logic, the universe is _huge_.
- Teever 4y agoWhat does 'visit' mean to you? While I find it unlikely that aliens have travelled to our solar system specifically to visit humans, I find it incredibly unlikely that human activity have not been detected by a Sentinel probe and that this probe has not relayed this info to its creators.
- deleted 4y ago[deleted]
- distortionfield 4y ago"Visit" to me means either they entered or observed our solar system with some decent degree of resolution. Enough to get a baseline of information about us, I think.
- misnome 4y agoHow often do you imagine that the solar system is being visited? Radio waves have only been emitted for ~80 years. Industrialisation changing our atmosphere ~200 years. Even if something was persistently monitoring you are relying on “The creators” being within a short distance in light years to even have been notified. Even being extremely optimistic about the speed of light not being absolute, other than wishful thinking - what makes you think that this scenario is “incredibly likely”?
- Teever 4y agoI think that it is very likely that numerous civilizations have seeded the star systems of this galaxy and others with probes that sit and watch for interesting/threatening things. The probes have arrived far before humans or even life existed on earth and have been waiting and watching ever since, with some of them possible reporting back to their creators on the state of earth while others still watching without yet sending a message because the state of earth hasn't reached some threshold. As for if these signals have made it back to the probes' creators yet, I consider that unlikely due to the scale of the universe.
- idiotsecant 4y agoI think the most convincing answer to Fermi is the dark forest theory. The reason no one speaks up is that there is good incentive not to - you get to survive as a species if you stay small and quiet.
- jjallen 4y agoExcept we are already violating this by sending things out into interstellar space.
- coredog64 4y agoNot just “some things”: Nudes, a mix tape, and directions back to our house.
- catskul2 4y agoIf you haven't already, read "the 3-body problem".
- SketchySeaBeast 4y agoYeah, seems to me there'd be a bit of time in there before any civilizations decided it was better to stay silent. But that time might not be astronomically relevant.
- idiotsecant 4y ago
- deleted 4y ago[deleted]
- redeux 4y agoI worry that this is the case. The idea that we’re in some advanced species sphere of influence is a bit unnerving. Given the ability to create deep space probes, it should be fairly easy for someone to keep tabs on a large swatch of the galaxy. If a species had a mere 1 million year technological lead on us, they’d certainly have nothing to fear and would only need to do a drive by every ten-thousand years or so, to keep tabs on things. Perhaps more concerning is that we could be in between two competing species and they’re monitoring to make sure the other hasn’t colonized this system. When it comes to aliens there are many possibilities, and few of them are good for us imo.
- Reason077 4y agoAt least Oumuamua's light sail will only accelerate it to 15-20% of the speed of light. Unless they have some kind of warp drive we haven't seen yet, that should give us (at very least) 20-30 years before the invasion fleet gets here. Probably much longer.
- yojo 4y agoUnless it seeded a little self-replicating factory on the way by. The invasion force could already be growing exponentially out in the Oort Cloud. Or not. To paraphrase: sometimes a cigar-shaped interstellar mass is just a cigar-shaped interstellar mass.
- euroderf 4y agoAny factory way out there is going to operate exceedingly slowly, innit ? Unless there is power from nuclear, or some other source TBD (to be discovered, by us).
- jjtheblunt 4y agowhy worry that interstellar drive by visits might be real? also, might you presume such possibilities are rarely good for us because of implicit recognition how bad we humans are to other species?