Castle Paradox

Bagne · Posted: Sat Jan 30, 2010 8:06 pm Post subject: Aliens OKGO!

This thread is to talk about aliens, because I absolutely adore aliens.

Post anything you have to say about aliens, say to aliens (Hello, please abduct me and teach me cool things!), or heard from aliens (?).

Here's what I think about aliens:

1) They know far more than I can imagine
2) Most of them are probably good natured and peaceful

Consider: The galaxy is 12-13 billion years old. Our civilizatoin took only 4.5 billion years to develop from a molten rock that was once the Earth. To me this suggests that most other civilizations in our galaxy have existed for a much MUCH longer time than we have.

Look at how far science has progressed in the last 150 years, and think of what an alien civilization can learn over 8 billion!

Also, cruel and warlike civilization is unstable - the chances of surviving 8 billion years is way higher for any civilization that is peaceful. If there are any violent races out there (like us), they'd be relatively new because they haven't yet learned to live peacefully and sustainably - failure to do so risks self destruction. We, the violent civilizations therefore are in the minority. It's no wonder that we haven't been visited by others. When we grow up and figure out how to live peacefully, then they might come.
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Baconlabs · Posted: Sat Jan 30, 2010 8:23 pm Post subject:

Protip: Don't haphazardly type in "Alien" into Google image search. Disturbing stuff there.

That said, you're all going to do it now. My warning: beware bloody fetus thingies.

Now then, what do I know about aliens? Well, for starters, I hated the fact that they ended up being the focus of that one Indiana Jones movie. So if I ever meet one I might punch it in the face out of spite.
Wait, do they even have faces?

mjkrzak · Joined: 24 Nov 2009 Posts: 43

Bob the Hamster · Posted: Sat Jan 30, 2010 11:57 pm Post subject:

I have high confidence that extraterrestrial single-cell life will be found withing my lifetime. The panspermia theory is very compelling, and I will be a little surprised if we don't find a moon or two around Jupiter or Saturn that is just teeming with some kind of simple life. (My money is on Enceladus, but we will see)

As for intelligent life, we have to talk about the Fermi paradox. All our estimates of how likely life is suggest that there should be a lot of it, so why hasn't any of it contacted us yet? The SETI still hasn't found any solid signals.

But what about the space between single-celled life and intelligent life? That is a pretty big space.

The earth is estimated to be about 4.5 billion years old, and the first life on earth is estimated to be about 3.7 billion years ago. Multicellular life started something like 1.7 billion years ago. Human life is roughly 250 thousand years old, and civilization is 3 or 4 thousand years old. Radio communications are about 120 years old

Bagne · Posted: Sun Jan 31, 2010 5:35 pm Post subject:

Re: The Drake Equation
Because none of the factors in the Drake equation have been evaluated to anyone's satisfaction, it doesn't really tell us anything other than that there is a non-zero probability for intelligent life to arise (as we did). That's good enough for me.
But ok James, I agree it's fair to say that some species won't make it as a galactic civilization, and some won't... but I would find it hard to believe that *all* intelligent life is doomed to kill/stonageify itself. Even if it turns out that humanity is doomed, I think we've shown enough promise to conclude that there is a non-zero probability of civilization's success.
So - yeah, maybe these civilizations start off with a mixed bag of characteristics, but it's the peaceful ones that will survive the test of time. All those billions of years of galactic history have filtered out the bad dudes - it's survival of the peaceful. Furthermore, they must have spent that time doing *something* ... I would guess they were (and still are) busy with art and science as a galactic (or larger) community. They may also have left this galaxy for higher prospects - like ... another dimension?

Re: Alien Minds
I think it's a good guess that most (if not all) aliens are social. If you life a life of isolation, it is not easy to learn anything ... and it's next to impossible to build a spaceship.

Re: SETI
I wouldn't expect the SETI program to find any signals. Would aliens really still be using E&M waves? I can't imagine a space-age civilization to rely on a means of interstellar communication which works on timescales of thousands of years. Surely, there must be something better, and they have invented it. I think E&M communication is just a phase we're in, and it's not going to last - SETI was worth a shot, but I don't think it will find anything.

I've wondered why no aliens have openly come to visit us, and this is my conclusion:
Even if the aliens arrive on Earth with the best of intentions, the whole planet would be thrown into turmoil. To whom would the aliens speak? The Chinese? The Argentinians? All the nations on Earth would be yapping at them like children trying to get an adult's attention: Imagine the reaction of the U.S. government if the aliens chose to build an embassy in Iran!
So, if they land here now, we'd become a danger to ourselves, and to the aliens. I think they're waiting for us to unite under a world government - one which represents all of humanity, not just a faction.

Other:
It might be worth mentioning that our solar system formed from supernova remnants - that's why we have heavier elements (Berylium and higher) on Earth. Many of these elements are needed by life - I'm guessing that any solar system capable of supporting life was formed from clouds of heavier elements that was expelled by a star.
I'm not familiar with star life cycles... are supernovae the only means through which these heavier elements can be expelled from stars?

I am super pumped about the prospects of Martian life.
I'm with Peter Ward on this one: we ought to send a Palaeontologist to Mars to look for fossils.
Oh, and if we're open to the possibility of non-Earthlike life (doesn't necessarily rely on CHNOPS, doesn't necessarily rely on water as a solvent), those gas planet moons look pretty good.

I read somewhere that there has been enough meteor impacts for panspermia occur multiple times between Earth and Mars.
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Bob the Hamster · Posted: Sun Jan 31, 2010 7:51 pm Post subject:

Bagne · Posted: Sun Jan 31, 2010 9:17 pm Post subject:

Bob the Hamster · Posted: Sun Jan 31, 2010 9:46 pm Post subject:

Bagne · Posted: Sun Jan 31, 2010 10:31 pm Post subject:

Bob the Hamster · Posted: Mon Feb 01, 2010 8:44 am Post subject:

@Wormholes - Despite the solid math, and the agreement with GR, I still have to file these under "wishful thinking". Assuming that the exotic matter necessary to create a wormhole actually exists, and the energy required to keep a wormhole stable turns out to be smaller than the available energy in the universe, an extraterrestrial who had mastered wormhole travel would still have to make the first trip to visit us with slower-than-light travel, towing an end-point of the wormhole behind them so they could park it in our neighborhood for later commerce.

That actually reminds me of a book called Menoetius by Jeff Lait. In this book, humans have developed a FTL drive, and all the other intelligent civilizations in the galaxy use a network of wormholes-- the catch is the space that the humans have explored and the space that the galactic coalition has set up wormholes to don't overlap, so neither group knows about the other yet.

Anyway, I should stop harping on the physics and focus on the aliens! :)

I wonder if the insides of stars would be a good place for exotic life? Maybe stable self-replecating patterns could emerge in the soup of continuous nuclear explosions? Maybe such life would live on such a fast timescale that millions of generations could live and die in the span of a single solar flare.

This article is really fun

Bagne · Posted: Mon Feb 01, 2010 9:55 am Post subject:

I figure Newton felt the same about the idea of embarking on a round trip to the moon.
His laws state that - in principle - it is possible to get there and back ... but the devil is in the details - how to build a cannon of the necessary size and scope? How will the explorer survive the cannon blast? Or, if he were to build a rocket, how would he load sufficient gunpowder to make the trip without weighing the rocket down, or blowing it to pieces?
He probably considered flying machines and space travel to be wishful thinking.

Wow - that article looks very cool! I'll definitely give it a read.
I noticed a section of that article that mentions non-green photosynthesis, and it reminds me:
I read about a fungus living in Chernobyl's crater that appears to be supplementing its energy intake by absorbing gamma rays. I insist that this is very cool.

With a million generations in a single solar flare, your solar dudes would evolve pretty awesomely fast ... unless they have a small rate of mutation.

The closest system I know of to approximating the dynamical complexity of chemistry (and hence support its own form of 'life') is modern computers ... which makes my MacBook a little creepy.
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Bob the Hamster · Posted: Thu Feb 04, 2010 2:34 pm Post subject:

@panspermia
Xanthoria elegans lichen can survive for 18 months in the vacuum of space. http://www.esa.int/esaCP/SEM72XRJR4G_index_0.html

Bagne · Posted: Fri Feb 05, 2010 5:20 am Post subject:

Wow, that's wicked.

This reminds me of a term paper I wrote on Deinococcus radiodurans, the most radiation-resistant organism known.

It's a bacteria which can be exposed to obscene amounts of radiation, shattering its genome into *hundreds* of pieces, and then make a full recovery. I forget exactly how it repaired its DNA ... uh ... it had 7 or 8 redundant copies, and the good copies somehow made a template for the broken ones ... I forget how.

Anyways, you wonder "where on Earth would there exists a selective pressure to evolve such a crazy amount of radiation resistance?" After all, this bacteria is resistant to radiation levels many orders of magnitude higher than any natural source on Earth. Some papers couldn't resist to suggest panspermia - space has high radiation levels.

As it turns out - the most serious DNA damage from radiation (double strand breaks) also occurs under severely desiccating conditions.
Apparently some scientists went to the desert of Tataouine (yes that's a real place) and found lots of Deinococcus living in the sand, as well as other radiation resistant strains of bacteria. So - they're not radiation adapted, they're desiccation adapted!

So maybe panspermia isn't necessary to explain the radioresistance, but ... the radioresistance easily makes it possible for spores of the bacteria to survive the radiation levels experienced during space travel. All you need is a really dry desert to evolve the radioresistance.
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Bob the Hamster · Posted: Fri Feb 05, 2010 9:03 am Post subject:

Actually, I was reading more about the lichen-in-a-vacuum experiment, and they said that one of the harshest aspects of the vacuum of space is the dryness. Water in space vaporizes away instantly, so the same lichens that did best in space are the ones that do best in ultra-dry conditions.

Although still unresolved in the panspermia theory is how life could survive exiting and entering an atmosphere. It would have to be able to survive (A) being blasted into space by a meteor impact and (B) survive the intense heat of falling through the atmosphere of a planet and impacting the surface inside a meteor.

Some test are planned on this. But I don't know if this involves dropping lichen filled rocks from orbit or attaching them to the underside of a re-entering spacecraft, or what. [EDIT: actually, somebody already did that with success in 2007 http://adsabs.harvard.edu/abs/2008cosp...37..660D ]

The difficulties of entry an exit do suggest to me that panspermia would be hella easer between asteroids and comets than it would be between planets like earth and mars. If there was some sort of bacteria or something that could live on comet ice and solar radiation, then the solar system could probably be *filthy* with it. [EDIT: a space probe lander sent to examine the surface of some tholin covered moons would be fantastic]

Bagne · Posted: Sat Feb 06, 2010 7:58 am Post subject:

Those experiments are pretty amazing! It goes to show just how terribly tough you need to be in order to stick to a rock your whole life :-)

Do you know if anyone has produced any numbers on how large a meteor it takes to eject something large enough for life to piggy-back?
Ooh - this could be extremely cool: we find bacteria in space, sequence its genome, and realized that this strain of bacteria branched from a common Earth species 65 million years ago, coinciding with the meteor impact of the Cretatious Tertiary boundary.

I wonder what methods they we would use to look for alien bacteria. You know how scientists often say "Well, if alien life is not Earth-like, we don't know what to look for."
I developed a new appreciation for this notion upon learning about Prochlorococcus cyanobacteria. Here's why: as far as we know, Prochlorococcus is the most abundant organism on Earth, and is responsible for an estimated 20% of the Earth's photosynthesis. Now, people have been studying bacteria for over a hundred years, and during all this time we have been developing techniques for culturing and observing them ... but Prochlorococcus wasn't discovered until 1986!! How can we miss this?!?!?
It's the most common organism on Earth!
Oh, and anammox bacteria - same story! Recent estimates have anammox bacteria being responsible for 1/3 - 1/2 of the Earth's total N2 gas production ... but we haven't been able to successfully identify anammox bacteria in a natural environment until 2003!!!
It's madness! It's like scientists all of a sudden realize that world is balancing on the back of a giant elephant.

Anyways, how do we look for life on other planets, if we can't even find it here on Earth?
I'd probably start by looking for Earthlike DNA, lipids, proteins ... uh ... and then move on to looking for complex organic molecules - anything with a lot of carbon in them ... and then ... uh ...
Hm, if I had a set of substrate samples, I could expose each one to a different amount of light to see if this affects the substrate's chemistry.
If I got a response, that would be a good sign of life.
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