Are we being attcked by Aliens, and the public don't know about it?

Originally posted by twhitehead
Your strategy does require that their goal be to eliminate us and to not really care about the environment.
In my opinion real space faring aliens probably wouldn't care too much about us militarily but might be interested in studying the the environment (biology in particular including us).
If we discover life on Mars our first thought wouldn't be 'lets nuke them'.

There is a difference between discovering 'life' and discovering a 'technological space faring civilisation'.

There was a video I posted in the "of course it's aliens" thread from a scientist looking at exploratory
engineering and what it can tell us about the Fermi paradox.

von Neumann probes and Dyson spheres: what exploratory engineering can tell us about the Fermi paradox
https://www.youtube.com/watch?feature=player_embedded&v=zQTfuI-9jIo

It's a slightly irritating video in that it's a fairly informal lecture being video'd and not a professional presentation
but the subject matter is interesting enough that it's worth ignoring that.
[EDIT: the other irritation in the video is that some of the interruptions/questions are a bit annoying.]

The basic conclusion which I agree with [although I take issue with a couple of simplifications in the argument
but they don't actually change the outcome] is that if you have the capability to build automated construction
robots [which we do, in theory if not yet in practice] then you can build a Dyson Sphere and colonise almost
the entire visible universe. [basically everything close enough that it's not already beyond a light speed
horizon]

Which means that any OTHER civilisation with that level of technology could also do the same.

Which means you have a problem where whoever does it first conquers then entire universe.

So any other alien civilisation has the potential to do this, and is thus a threat.

To stop them, you must do it first.

Thus game theory makes a strong case that you should build a Dyson Sphere and conquer the universe to
stop anyone else doing it.


The easiest way to stop alien civilisations is to wipe them out as fast as possible before they become
a multi-star-system species and much harder to kill. So you send a relativity bomb to any nascent civ'
you spot, with the understanding that sending a probe to survey them and then get the results back
would take years/centuries/millennia depending on how far away they are. In which time they could
develop past the point of easy elimination. And indeed, past the point at which they have already sent out
a vast fleet of von Neumann probes to colonise the universe.



Now, it might be IF there are alien civilisations that they are peaceful and won't try to kill us. Not a possibility
I would want to bank on, but it could be the case.
However, IF we are talking about a hostile civilisation, I see no reason not to go strait for the relativity bomb.

Originally posted by pawnpaw
I can not decide...
https://www.youtube.com/watch?v=SCaa_1_zURg

Almost certainly.
Its a good job the Aliens don't have the technology to
block these youtube videos or we would all still be in the dark.

Originally posted by pawnpaw
I have come to realise that you have quite an extensive knowledge on the scientific side of these things. I appreciate that, and also the fact that I do not have that.
But I was hoping that you, and some other poster with the same knowledge, would latch onto the Vortex issue, which I beleive also happened in over Norway some years ago.
It's all in the vide ...[text shortened]... henomenon, does it really happen, is that also just a figment of someone's imagination, or what?

WIthout us being there, it is hard to judge what actually happened. It could have been an elaborate hoax.

BTW, it seems now you were not being flippant in your OP, sorry that we took it that way.

There are many really stupid video's such as the moon landing hoaxes and such and ancient aliens, like the one that says humans were WAY too stupid to have EVER built the pyramids all by themselves, therefore aliens exist and they came down and helped them build the pyramids. It rankles me when I hear stuff like that.

In the same vein.

This TEDx talk on Skepticism is probably worth your time [23:52 to be precise 🙂 ]

YouTube

It is not likely that aliens are attacking us. But I can imagine a meteorite or a passing comet depositing some compound in our biosphere which a) replicates itself (or combines with native Earth compounds and then replicates itself), and b) is inimical to life. It needn't be intelligent or even alive (as we know it); it might be something like a prion which triggers a fatal disease (e.g., BSE) but is not itself a living organism. We might not discover it until it's too late to stop it. Now that's scary.

Originally posted by moonbus
It is not likely that aliens are attacking us. But I can imagine a meteorite or a passing comet depositing some compound in our biosphere which a) replicates itself (or combines with native Earth compounds and then replicates itself), and b) is inimical to life. It needn't be intelligent or even alive (as we know it); it might be something like a prion which ...[text shortened]... lf a living organism. We might not discover it until it's too late to stop it. Now that's scary.

The Andromeda Strain.

Originally posted by moonbus
It is not likely that aliens are attacking us. But I can imagine a meteorite or a passing comet depositing some compound in our biosphere which a) replicates itself (or combines with native Earth compounds and then replicates itself), and b) is inimical to life. It needn't be intelligent or even alive (as we know it); it might be something like a prion which ...[text shortened]... lf a living organism. We might not discover it until it's too late to stop it. Now that's scary.

It's far too improbable to be scary.

The likelihood of a random virus/bacteria that evolved extra-terrestrially being able to
survive, let alone be an apocalyptic threat to life on the Earth, is minuscule.

Viruses and bacteria on the Earth have co-evolved with the other life on this planet and
thus have defences against those other life forms and ways of attacking them. As well
as being optimised to their environments.

An extraterrestrial version of a virus or bacteria would not have evolved those defences
or methods of attack and would probably simply become food for some bacteria or
other life form that encountered it.

Originally posted by googlefudge
It's far too improbable to be scary.

The likelihood of a random virus/bacteria that evolved extra-terrestrially being able to
survive, let alone be an apocalyptic threat to life on the Earth, is minuscule.

Viruses and bacteria on the Earth have co-evolved with the other life on this planet and
thus have defences against those other life forms a ...[text shortened]... nd would probably simply become food for some bacteria or
other life form that encountered it.

Besides, alien bacteria/virus attacks have had 4 odd billion years to hit us and we are still around (Earthy life in general). If we haven't been hit with deadly diseases in all that time, it is likely we will go the next 4 bil without much trouble.

Originally posted by sonhouse
Besides, alien bacteria/virus attacks have had 4 odd billion years to hit us and we are still around (Earthy life in general). If we haven't been hit with deadly diseases in all that time, it is likely we will go the next 4 bil without much trouble.

Indeed.

It is in fact very likely that if such inter-stellar cross pollination is possible, and that
there are extra-solar life forms, that such cross pollination would not just have happened
already, but would be a [on geological time scales] 'frequent' occurrence.

The fact that it hasn't happened already [we have no evidence at all where evidence should
be obvious if existent] is therefore strong evidence as to the implausibility [if not impossibility]
that such a disaster will occur.

And if you are going to then go to the possibility of intelligently planned alien attack...
Then the Relativity Bomb is still simpler and more effective.

Originally posted by googlefudge
Indeed.

It is in fact very likely that if such inter-stellar cross pollination is possible, and that
there are extra-solar life forms, that such cross pollination would not just have happened
already, but would be a [on geological time scales] 'frequent' occurrence.

The fact that it hasn't happened already [we have no evidence at all where evid ...[text shortened]... lligently planned alien attack...
Then the Relativity Bomb is still simpler and more effective.

The difficulty with a relativity bomb (I assume you're talking about a kinetic weapon) is that the object has to be accelerated to relativistic speed and that requires an unfeasible amount of energy.

Originally posted by DeepThought
The difficulty with a relativity bomb (I assume you're talking about a kinetic weapon) is that the object has to be accelerated to relativistic speed and that requires an unfeasible amount of energy.

Did you miss the part of the argument where every spacefaring civ' basically turns
just about every star in every galaxy in range into a Dyson swarm?
For the very purpose in fact of lobbing large chunks of matter across the universe
as significant fractions of the speed of light?

In which case are we not talking about totally feasible amounts of energy.

Originally posted by googlefudge
Indeed.

It is in fact very likely that if such inter-stellar cross pollination is possible, and that
there are extra-solar life forms, that such cross pollination would not just have happened
already, but would be a [on geological time scales] 'frequent' occurrence.

The fact that it hasn't happened already [we have no evidence at all where evid ...[text shortened]... lligently planned alien attack...
Then the Relativity Bomb is still simpler and more effective.

Evidence may show up later in this century or the next, say if we sent biologists and geneticists to Europa, say, and find life in the ocean of Europa but buried 40 miles deep to get to it and that life form still had Earthy type DNA, would be a bit of evidence pointing to pan-spermia where life in our neck of the galaxy at least, would have been started by say, a cloud that had pre biotic material but the same material and that cloud in space finding its way to many solar systems and thus all those stars' life forms basically all alike in it's use of variations of regular DNA,

If that were the case, we would never know what other kinds of life forms there are till we get to real interstellar distances, say 1000 ly or so.

The gist of that is we may have been invaded by alien life forms but they were mostly just like Earthy life.

Originally posted by sonhouse
Besides, alien bacteria/virus attacks have had 4 odd billion years to hit us and we are still around (Earthy life in general). If we haven't been hit with deadly diseases in all that time, it is likely we will go the next 4 bil without much trouble.

It need not be anything living (like a bacterium); that's why I mentioned prions--it could be something which merely interferes with the chemical processes necessary to life here.

There have been mass extinctions in the distant past. And major impacts. So a connection is (or was) at least possible.

Originally posted by moonbus
It need not be anything living (like a bacterium); that's why I mentioned prions--it could be something which merely interferes with the chemical processes necessary to life here.

There have been mass extinctions in the distant past. And major impacts. So a connection is (or was) at least possible.

Much more likely we just live in a universe basically hostile to life. For instance, there are many more red dwarf stars that could harbor life but they have a bit of a problem, in that they spew out a lot more corona discharges than our relatively benign sun. We get hit now and then with a CME, (Coronal Mass ejection) that actually hits Earth with bad temporary consequences like the one that knocked out most of the Eastern US and Canadian power grids a few decades ago. We learn from such things and are better prepared for the next hit but other stars are not so benign, slashing out at its retinue of planets on a regular basis. So life there will have to develop early on defenses against that onslaught of radiation in order to survive and evolve.

It seems we have only found a very small number of planets around other stars in the 'goldilocks zone' where liquid water can appear. Most of the planets we have found so far are so close to their sun they are like a thousand degrees hot and not a chance in a trillion of ever having a benign enough habitat for life to ever start since complex molecules can never become complex with so much energy pulling them apart the moment they are developed.

In our solar system however, my guess is we will find life on just about every planet and moon half way habitable, like in the oceans of Europa or maybe on Mars. Certainly not on the surface of Venus, it is hell there with a 1500 PSI atmosphere of CO2 and CO and sulfuric acid, not a nice place to spend a weekend. The Russians managed to actually land a probe there and despite a huge engineering effort made to cool it down, it only lasted about 20 minutes in that hellish environment before it burned itself out. Got a few pictures out though. That would be the fate of any probe sent to most any of the planets we have discovered around the vast majority of stars we have shown that has planets.

Part of that is of course, our technology is sill primitive and unable to spot small Earthy planets. For instance, I would send as the first interstellar probe when they come about, to Alpha, Beta and Proxima Centauri, a three for one visit, three stars visited for basically the price of one, however they manage it, microwave driven nano machines, whatever. So far none of our best telescopes have been able to spot any planets around those three stars, maybe one or so. If we actually go there, I am sure we will find plenty of planets we just can't see and THAT is the closest set of stars to us at just over 4 light years away. The next planet they spotted in the goldilocks zone is over 700 light years away which pretty much proves it is OUR technology lacking not small Earthy planets. Anyway, we know what Prions are, just proteins bent over in lethal ways.

We have been here billions of years, surviving supernovae, world wide volcanism, many asteroid strikes and we are still here. So while we live in a basically hostile universe, our little mecca of our solar system is a haven for life and we will most likely find it everywhere on most moons and maybe even comets.

http://www.theguardian.com/science/2015/jul/06/philae-comet-could-be-home-to-alien-life-say-top-scientists

Those scientists examining that comet think maybe there are bacteria or viruses right on the surface. I think it highly unlikely but you never know till humans or robots pick up a piece of it and send it to the fine laboratories we have on Earth. I think it much more likely to find life on the outer moons, maybe even Pluto.

I'm putting my money on the moons of Saturn for the first discovery of exo-life

http://www.bbc.co.uk/programmes/p0396yvh