Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Have we already been visited by aliens?

newyorker.com

Post reply on HN
Print view View original

291–300 of 366 posts

Re: Have we already been visited by aliens?

#291

Post by keithnoizu »

floatrock wrote: post #134
tiborsaas wrote: post #47

Prof David Kipping did a point-by-point analysis of Loeb's claims: https://www.youtube.com/watch?v=qX_Bj7064Ms TLDW: most likely a natural object.

Thanks for the link. Always good to hear the other side, especially after listening to the Lex interview a while back. Here's the summary: Loeb's argument for Ouamuamua being aliens rests on 6 observed anomalies. All but 1 or 2 have pretty reasonable rebuttals. [1]: Anomaly: There are too few interstellar asteroids to expect something like this, so it must have been aimed at us. The brand new telescope that discovere…

True, but even if we were say 80% confident in each rebuttal being the true reason chained together the odds of those all being correct is pretty small. Although of course it could be due to alternative rebuttals being the correct ones.

At a certain point in time, not that we've reached it, it starts to look like the ptolemaic system, or luminiferous aether, where you keep tacking on exceptions or explanations to fit the data to your model instead of your model to the data.

Re: Have we already been visited by aliens?

#292

Post by sailingparrot »

erklik wrote: post #285
sailingparrot wrote: post #259

Earlier quoted context omitted.

> Yet we haven't sent anything. But we have, quite a few of them actually, and 2 have left the solar system. It's just that none of them will come close to any star for a few hundred thousands of years.

> It's just that none of them will come close to any star for a few hundred thousands of years. I don't believe we have sent anything explicitly for the purpose of reaching another star? Right? Exploring our Solar System with probes, sure. Has there been a probe that was meant to explore another star system?

Not explicitly no, but does it really make a difference if it's explicit? Given enough time our probes are bound to pass very close to some other star systems.

If there are other civilizations, it's likely that most of them would be on average 1 billion years older than us, as the average star is 1B older than our sun.

That's a lot of time for a lot of probes to cross many star systems even just by accident.

Re: Have we already been visited by aliens?

#293

Post by cambalache »

resource0x wrote: post #167
openasocket wrote: post #123

Earlier quoted context omitted.

It's not just science, I can think of an example from pure mathematics. Cantor's work showing the uncountability of the real numbers was derided by prominent members of the mathematical community for decades. This despite the fact that he was able to boil down his argument into a proof so simple it's taught in introductory undergraduate classes. Now, this was at a time when mathematicians were still trying to rigorou…

Bad example. Cantor's theory is controversial to this day. "Classical logic was abstracted from the mathematics of finite sets and their subsets …. Forgetful of this limited origin, one afterwards mistook that logic for something above and prior to all mathematics, and finally applied it, without justification, to the mathematics of infinite sets. This is the Fall and original sin of Cantor's set theory." -- Hermann…

By whom? Almost all mainstream mathematicians rightfully lionize Cantor's main contributions, as David Hilbert so eloquently put it: "No one shall expel us from the paradise Cantor has created for us" Aus dem Paradies, das Cantor uns geschaffen, soll uns niemand vertreiben können

Re: Have we already been visited by aliens?

#294

Post by yters »

sailingparrot wrote: post #251
yters wrote: post #245

Earlier quoted context omitted.

Somewhere else! Dna is too marvelous for evolution, it cannot have originated here!

And yet we have very good evidence it indeed has. If life originated somewhere else, it landed here before DNA evolved.

What is the evidence? Seems hard to have evidence for anything billions of years ago given we don't have historical records past a few millenia. It is all guesswork past that point, and the patterns of organisms and their complexity makes an earth origin of DNA extremely improbable if not impossible. Try reading through a graduate level book on bioinformatics to marvel at the sheer ingenuity, for lack of a better word, of what our dna is capable of far exceeding anything our best engineers can do. I find it impossible to believe mutation and natural selection can do better, even given billion year timescale and all of history's biomass. Just look at how ineffective genetic algorithms are in computer science.

Re: Have we already been visited by aliens?

#295

Post by trestenhortz »

King-Aaron wrote: post #234
trestenhortz wrote: post #97

It’s not aliens. Nothing can convince me that there’s any practical way to travel the distances between the stars. If you don’t agree then I think you fundamentally don’t grasp how incomprehensibly vast those distances are. I absolutely believe in life in other worlds but there’s no way to travel from star to star.

Once upon a time, it was inconceivable that there could be any practical way to travel between continents. I feel that making this assertion based on our current understanding of the universe is fundamentally flawed.

This is a comparison that really doesn’t work.

It takes month in a sailing ship to cross the ocean. It would take thousands of years at the very least to cross space.

Re: Have we already been visited by aliens?

#296

Post by ChainOfFools »

godelski wrote: post #265
PaulDavisThe1st wrote: post #237

Earlier quoted context omitted.

I think this is a mistaken way of thinking in general, because you're omitting time. Your assuming that intelligent/thinking/conscious creatures would necessarily function on timelines that make sense to us. If that were true, then what you're saying makes sense - there are real bounds on how fast you can move chemical energy from A to B, for example. But I see nothing preventing intelligent life from operating on ma…

I think this is strange thinking because it breaks our laws of physics. The clock ticks at the same rate in internal reference frames, it is only different when looking at two different frames. But if you're talking about them acting at slower speeds or faster, then that brings along other problems similar to the mechanics ones we discussed (assuming we're not counting that they are in a slower reference frame). It r…

https://archive.org/details/OnBeingTheRightSize-J.B.S.Haldan...

Re: Have we already been visited by aliens?

#297

Post by sjy »

zelon88 wrote: post #275
matteocantiello wrote: post #231

Earlier quoted context omitted.

I thought the idea of searching for industrial pollution was actually a pretty bad one. We've been polluting at detectable levels for just ~100 years. And if we keep doing it we'll likely wipe us out in a few hundred more. Overall it seems very likely industrial pollution is a very short-lived phase of any civilizations, so chances of detecting this signature are tiny.

I believe that we've probably altered the geography of Earth to an extent that it would be trivially easy to determine from great distance that it was once inhabited by intelligent beings. Even if all of our cities are gone, the mineral deposits left behind would be so concentrated. Nevermind the nuclear endeavors. We were able to detect dinosaurs on our own planet 65 million years after they went extinct, and they d…

I recommend Schmidt and Frank’s article on the Silurian hypothesis [1] for a surprisingly different take on this. The full text is on arXiv [2]. “We summarize the likely geological fingerprint of the Anthropocene, and demonstrate that while clear, it will not differ greatly in many respects from other known events in the geological record” – that is, the record we can observe from a distance of zero!

[1] https://en.wikipedia.org/wiki/Silurian_hypothesis

[2] https://arxiv.org/abs/1804.03748

Re: Have we already been visited by aliens?

#298

Post by hawkice »

flatiron wrote: post #27
mig39 wrote: post #19

Earlier quoted context omitted.

Yeah, I can think of a lot of examples of sails in the natural world. Dandelion seeds, winged tree seeds, etc.

I think the comment was poorly worded with “people” and should be “life” which is still an interesting thought.

Distinguishing between things produced by the natural world, and things produced by life seems like the type of communication strategy that would not help a general audience. I mean, I get what you mean, but 'natural' and 'organic' are taken to be synonyms in common usage.

Re: Have we already been visited by aliens?

#299

Post by bobsmooth »

gfxgirl wrote: post #90
6gvONxR4sf7o wrote: post #64

Earlier quoted context omitted.

There seems to be a giant mismatch about what side is open minded. People who think its most likely aliens think it’s closed minded to assign that low probability, presumably because we’re this tiny corner of the universe. People who think it’s most likely not aliens Think it’s closed minded to assign everything else low probability, presumably because aliens are a tiny corner of everything else. Is it a misapplicati…

I thought the idea that there are gazillions of advanced aliens has been pretty much disproven by the fermi paradox. If there are gazillion, at least one out of all the diversity out there should have already colonized the entire galaxy and evidence should be plentiful.

It really hasn't. [1]

[1]https://arxiv.org/pdf/1806.02404.pdf

Re: Have we already been visited by aliens?

#300

Post by greentimer »

Worth noting that you can’t conclude time travel is impossible or irrelevant just because other people have. There could exist time travelers who secretly have control either of your life or the world with advanced technology (potentially up to the level of mind control chips) who are keeping the evidence from getting out.
Post reply on HN