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Have we already been visited by aliens?

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Re: Have we already been visited by aliens?

#221

Post by openasocket »

alisonkisk wrote: post #201
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…

Cantor proved that R, the set of all reals, cannot be countable. That was never controversial. What's controversial is claiming that R (or any uncountable set) exists, as no one has rigorously proved without adding an axiom.

What axiom do you have to add, are you talking about the axiom of infinity, defining the set of natural numbers? Because you do need that, but without that wouldn't even be able to define uncountability. After that, you can define the reals using Dedekind cuts or Cauchy sequences, which was known at the time (I believe Cantor actually worked on the Cauchy sequence construction). But there's an even simpler uncountable set: the power set of the natural numbers. Super easy to define, and the diagonalization argument falls right out.

Re: Have we already been visited by aliens?

#222

Post by eloff »

GoblinSlayer wrote: post #157
eloff wrote: post #34

Earlier quoted context omitted.

Again, if we had the technology to do that it would be amazing. We can't generate even within a couple orders of magnitude of the acceleration needed to do that.

AFAIK, Japan conducted an experiment of asteroid exploration by collision and it revealed chemical composition. But if it's not an asteroid, it might be seen as rude.

There's a huge difference between doing that and doing it with an interstellar object going incredibly fast and extremely far away.

Re: Have we already been visited by aliens?

#223

Post by andrewmutz »

excitom wrote: post #11

Such an object would function as a sail—one powered by light, rather than by wind. The natural world doesn’t produce sails; people do. What about jellyfish that move about the oceans pushed by wind?

I think by natural world the author meant non-biological.

If the object was biological, then it would be even more support for the existence of extraterrestrial life.

Re: Have we already been visited by aliens?

#224

Post by JALTU »

sailingparrot wrote: post #218

I don't understand what is happening with Avi Loeb. I was not familiar with him before Omouamoua but from what I gathered he is a respected academic in the field. So how can someone like that be so disingenuous about this topic? There is currently basically no evidence whatsoever that Omouamoua is an alien constructs. If we are generous we can consider this at most a plausible explanation among others (certainly not…

Avi Loeb's work was "validated" by his school's chair of astronomy, so we have to remember that to do science is to mitigate against being human. We all have different standards as to what is science as the anti-vax'ers demonstrate. What is interesting to me is that Loeb's chair notes that the object's trajectory differs from the expected by a statistical difference. While such difference implies a great deal of energy we can't account for, it's a hurdle to overcome in the search for understanding of this event/object.

Here's the chair of Harvard's astro dept.: https://blogs.scientificamerican.com/observations/6-strange-...

Re: Have we already been visited by aliens?

#225

Post by pvaldes »

excitom wrote: post #11

Such an object would function as a sail—one powered by light, rather than by wind. The natural world doesn’t produce sails; people do. What about jellyfish that move about the oceans pushed by wind?

That is a very good example of a sail produced by a non human 'city'. Yep. Same shape and function.

Re: Have we already been visited by aliens?

#226

Post by erdos4d »

bostonsre wrote: post #54
eloff wrote: post #45

Earlier quoted context omitted.

> I don't think very many people are saying it is impossible that Oumuamua was an alien construct and actively discouraging science based on the idea it could be. Actually yes. You'll be laughed out of the virtual room, not get funding, and potentially damage your career. As he points out in his interview with Lex (linked elsewhere in the comments here) is fine to propose a multi billion dollar experiment to detect o…

Ridiculing scientists for plausible hypothesis seems very unscientific.

"Ridiculing scientists for plausible hypothesis" => chopping the legs out from under a competitor because they stepped in something taboo.

Happens all the time. Academia is a snake pit and this is low hanging fruit.

Re: Have we already been visited by aliens?

#227

Post by nobody9999 »

Coriolis3 wrote: post #165
wait_a_minute wrote: post #39

Earlier quoted context omitted.

That's one of the biggest problems I have with Star Trek. If we were literally gods by comparison to some fledgling species, the only ethical approach would be to elevate them and cure their diseases and advance their knowledge as quickly as humanly possible.

Check out Iain M. Banks's "Culture" novels for a sci fi society that takes that approach to other civilizations. The Culture tries to raise up every lesser species of aliens to their own level of hedonist, post-scarcity wealth and technology. "The Player of Games" is both a good introduction to the series and an example of their cultural outreach at work.

>The Culture tries to raise up every lesser species of aliens to their own level of hedonist, post-scarcity wealth and technology.

That's not strictly true throughout the series (I'll avoid any spoilers here), in many situations, civilizations are denied certain technologies by the Culture in the novels.

I just finished reading the entire series and there's always quite a bit of skepticism from both members of the "Culture" and members of other civilizations as to the value and positive impact of The Culture's intervention/meddling.

I'd say that Banks is pretty even handed with that, although he usually seems to fall on the side of "Special Circumstances."

All that said, it's definitely worth the read.

Re: Have we already been visited by aliens?

#228

Post by userulluipeste »

eloff wrote: post #86
bostonsre wrote: post #54

Earlier quoted context omitted.

Ridiculing scientists for plausible hypothesis seems very unscientific.

This is very common in science. New theories are usually rejected and ridiculed until/if they develop enough evidence behind them to sway people. Some careers are destroyed. Some scientists are only vindicated posthumously. The process can take many decades. Scientists, like most humans, are not that open-minded and are subject to the same group-think blind spots. I think if we could get better at being open-minded a…

On one hand, this is because it's such a safe thing to cause damage to the image of another fellow scientist that happens to dare looking at something new or in a new way. (Crab mentality, perhaps?) If this effect would be as costly to the individual attacker as it is for the collective, we would probably "move fast and break things" more. On the other hand, we already have way too many non peer-reviewed papers as it is, and those papers get cited by other papers, and so on. Not enough action to ensure quality. In such case, what the critiques with good intentions for the world but with limited time and attention are to do but go after the most audacious claims in their field?

Re: Have we already been visited by aliens?

#229

Post by erdos4d »

sailingparrot wrote: post #218

I don't understand what is happening with Avi Loeb. I was not familiar with him before Omouamoua but from what I gathered he is a respected academic in the field. So how can someone like that be so disingenuous about this topic? There is currently basically no evidence whatsoever that Omouamoua is an alien constructs. If we are generous we can consider this at most a plausible explanation among others (certainly not…

Have you read any of his arguments? They are sound and nobody has come up with anything substantive to dispute them. Can you offer an actual rebuttal?

Re: Have we already been visited by aliens?

#230

Post by nobody9999 »

avz wrote: post #116
Xcelerate wrote: post #41

Tangential to the article, but I’m not sure why more isn’t mentioned about what I consider to be the most likely reason we haven’t been visited by aliens: they probably exist somewhere due to the sheer size of the universe, but the speed of light is indeed the fundamental limit to classical information transfer as our current understanding of physics predicts, and therefore we are simply too far away from any sort of…

I don't find the argument that distances are too great for intelligence to meet particularly convincing. At its core lies unjustified extrapolation that the ratio of average lifespan to typical interstellar distance - a pure accident of Earthly biology - somehow extends to the whole universe. The key quantity on which the argument hinges is T * c / D where T is the average lifespan of the intelligent being in questio…

>The key quantity on which the argument hinges is

    T * c / D
I'd think that it's also important to have a component that quantifies the lifetime of a technologically advanced civilization, as the universe isn't just separated by space, but also by vast expanses of time as well.

I'm not belittling your example, just trying pointing out that when speculating in this area, it's useful to include a time component related to civilizations as well as an individual lifetime component.

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