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Alien Planet

Ran Targas

SOC-14 1K
Peer of the Realm
Anyone else watch it?

Not as good as the book but interesting enough to tape it. Definitely sparked some new ideas.
 
I watched it. Some of the ideas were a bit of a stretch to believe such as the huge animals with tree like plants growing upon their backs. The flying animals that use methane burning jet engines for propulsion was a stretch also. IMO there were too many large airborne animals. Most of the animals IIRC have a lower density than that which is found of Earth, something I think the creators used too often merely to justify the existance of extremely large animals.

As to the odds of finding intelligent life (as intelligent, as civilized, and as technologically advanced as us) I think they were very, very overly generous with the chances. All of the scientists expressed a great anticipation of finding intelligent life and several mentioned it's potential of social-philosophical-religous ramifications. Only one made a passing reference to the potential meaning of not finding intelligent life which was dismissive in tone.

It was a nice overview on some of the ideas about potential alien life. I would be interested in a more in-depth look into the possibility of alien life, something that deals with the evolutionary line of life on other worlds.
 
Lets take the "many universes" theory of life and the "anthropomorphic principle" and put those together to see what possible conclusions we might draw as to the possible existance of extraterrestrial life.

If you assume there are many universes with different laws of physics, then according to the "anthropomorphic principle", we must live in one universe whose laws are set to permit life, but its possible that those laws only just permit life and the probability of that life in a universe like ours is very small. So small in fact that ours may be the only planet in this universe that permits life.

On the other hand we must also examine the entire multiverse with a view that some universes may be more permissive toward the development of life than others that only just allows it. The more permissive universes will have many more examples of life bearing planets that the universes that only just allow it in some very rare and improbably cases. Now if we examine the probabilities of our Earth existing in one of the Universes that only just allows the development of life vs those universes that produce many examples of life bearing planets, I think that you'll see that the probability is greater that we live in a universe with many Earthlike planets rather than a universe with only one.
 
Right now the only sort of life we've been looking for has been intelligent civilizations that emit radio signals, then there is the Fermi parasox to contend with, "why aren't the aliens here?

That life is rare is only one possible solution to this. Another answer is that lifeforms don't necessarily reproduce like crazy to fill their spaces, and if some do, somthing stops them.

Civilizations that weild the powerful technology to travel between the stars are very dangerous to themselves. Just think of how many tons of antimatter are required to reach an appreciable fraction of the speed of light, and imagine all that antimatter used as a bomb instead. Of simply the energy of a spaceship traveling close to the speed of light hitting a planet! Nanotechnology would be very helpful in terraforming and planet or destroying all life on its surface! Civilizations that travel between the stars might not last very long as they unleash these powerful energies on themselves. They usually destroy themselves long before they reach other civilizations that they can harm, but space too adds distance, and civilization can spread its eggs in many different directions and diffuse it enough so that the destruction of one part doesn't destroy all.
 
Originally posted by Tom Kalbfus:
That life is rare is only one possible solution to this.
Of course, it could also be that you really can't travel FTL ...
 
Except that the Universe is 15 billion years old, plenty of time for a single civilization to colonize the entire Galaxy, even at slower than light speeds. In all likelyhood, the speed of light helps prolong civilizations through its time slowing relativity at near light speeds.

Imagine a star ship that travels through the Galaxy in a vast circle around the galaxy. The city is powered by a Bussard Ramjet, and whenever they get over populated, they send out some colonists to a planet they are passing by. That civilization might grow and then die by the time the go around the Galaxy and return to that planet. 100,000 years for the colonists on the planet, while a mere 500 years passes for the inhabitants of the starship.
 
It's "Anthropic Principle" (it's not a principle stating that the universe looks human, which is what Anthropomorphic means ;) ).

http://en.wikipedia.org/wiki/Anthropic_principle is a good summary of it.

And the universe is (as best as we can tell) 13.7 billion years old. Still old enough though ;) .


Consider though, that earth has existed for 4.6 billion years, and intelligent civilisations has apparently only existed on it for 10,000 years, and intelligent, technlogically advanced (ie building and using machines and computers) civilisation have only existed on it for what, 200 years tops?

Consider also that we are by no means out of the realms of self-destruction, and it is possible that - unless we change drastically - our technological civilisation may destroy itself, collapse, implode through other means or render the world environment uninhabitable at any point within the next 200 years.

If (and this is a big if) every intelligent lifeform in the universe evolves the same way, then it's not very likely that they'd be able to survive long enough to spread through the cosmos. It's possible that there may be lots of planet-bound life (or ruins of it), but very very little space-bound life.

Consider also that advanced lifeforms may not actually WANT to go into space. Perhaps they may choose instead to devolve themselves having reached a high enough level of technology. They may choose to upload themselves into machines or vast city- or world-sized computers and live virtual lives. And so on.

Personally, I suspect that if we do go into space we'd end up finding not a lot of living alien civilisations, and a lot of alien ruins.

But I'd think that we'd find a lot of alien life though (mostly microbial, but there would still be worlds that had more complex forms would be around).
 
One of the easiest solutions to "If there are aliens out there, why haven't they visited" is "interstellar travel is not viable". This does, obviously, prevent us from going out and checking.

At the moment, we couldn't detect a technological civilization at any significant range (more than a few hundred lightyears) unless they were making a special effort to communicate, which they probably aren't.
 
Well, there's nothing to suggest that Interstellar travel is not POSSIBLE, assuming you had the technology to build a large ship that could travel between the stars at sublight velocities, and depending on if you minded that it would take many years to get to where you want to go. (maybe that's a big assumption in itself though ;) ). Of course, the question is whether that would be considered viable by any other races out there, as Anthony said.

One thing I never did quite get though is why SETI tends to look in the hydrogen alpha band for signals from other races. But Earth has been broadcasting radio signals strong enough to be heard in space for 70 years or so (unless this is urban myth, IIRC the first broadcasts strong enough to be detected from outside our solar system would be the 1936 olympics isn't it?). So why aren't we looking for similar 'radio spheres'? Or is it just that these would be swamped by the signals we're emitting ourselves?
 
As to the interstellar sublight travel I seem to recall that a while back some bright light (Asimov or Sagan maybe) figured out what it would take resource wise to mount a reasonable mission to the nearest star. There wasn't much left of the outer solar system once it was used for the construction and supplies if I remember rightly. One thing that would help a lot would be reliable cryogenics. Life support for thousands of people for thousands of years is huge. Recycling only gets you so far in a small closed system even today.
 
Doesn't EM radiation (such as radio waves) loose strength the further out it progress beyond the solar system? What about signal degradation due to background noise, doesn't the sun produce EM across the entire spectrum at a much higher strength that those radio signals? If an intelligent alien race does intercept the signals they would have to filter out the noise and then greatly enhance the signal strength using technology similar to vacuum tube, transitor, or IC ampliphers, correct?
 
I think SETI is looking where they can find a signal. The analogy is like the old joke...

Cop to Man under streetlight on a dark night "Lose something sir?"

Man "Yes, I lost my car keys somewhere along this street."

Cop "Have you looked anywhere else on this street?"

Man "Nope, it's too dark to see anything except under this streetlight."

So although the keys (signal) may very well be somewhere else the only place you can find them is where there is enough light (silence). You can't find them where it's too dark (noisy).

The reasoning is any intelligent ETs will also realize this quiet band, which is also good for long range detection, is the best bet and use that to broadcast (and listen) if (and it's a huge if with all the other huge ifs) they want to.
 
I think we've been broadcasting radio a little longer than the '36 Olympics broadcast. That was the first high strength TV broadcast wasn't it? And pretty much alone in it's spectrum, today we have a lot of generated noise, not just from communications but other EM generation.

And as Randy says the signal loses strength (distance squared loss I think) and there is a lot of natural background to get lost in too.

Even being able to pick out a clean signal today with the crowding of our comm frequencies would be a trick for an alien.
 
There is an excellent series of novels which have what amounts to "archaeologists in space trying to solve a grand mystery" plots by Jack McDevitt.

The series starts with Engines of God. In the novels' "universe" man has reached the stars and has found that planets with life are relatively few. Even fewer are planets with intelligent life. Of those, none (or is it one?) still harbors intelligent life that has any siginificant technology. The others never developed it or lost it. However, on a number of worlds, there is evidence that other civilizations developed space technology, crossed the stars, and left evidence behind before disappearing.

One of the more interesting novels somewhat relevant to this discussion is Chindi which turns out to be a huge automated, but sublight knowledge collector ship sent out eons ago by some unknown race. It basically goes from star to star, dropping off satellites to record interesting events in a planets' history and eventually comes back to collect that knowledge (and non living samples).

Ron
 
Ron, dude, don't give the whole thing away! ;)

I think Engines of God is the only one out of that series that I haven't read yet (It goes EoG, Deepsix, Chindi, and then Omega doesn't it?). They are very good - very digestible reads too.

The Alasdair Reynolds books are a bit like that too. Lots of ruins, no living aliens. The books are about what happens when humans find out why
.
 
Originally posted by Tom Kalbfus:
Imagine a star ship that travels through the Galaxy in a vast circle around the galaxy. The city is powered by a Bussard Ramjet, and whenever they get over populated, they send out some colonists to a planet they are passing by. That civilization might grow and then die by the time the go around the Galaxy and return to that planet.
No need to imagine it. Just read 'The Platinum Horde', Tharg's Future Shocks, 2000AD. OK, so it was a few decades ago, you might have trouble finding a copy.
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Originally posted by Malenfant:

I think Engines of God is the only one out of that series that I haven't read yet (It goes EoG, Deepsix, Chindi, and then Omega doesn't it?). They are very good - very digestible reads too.
Yep, that's the order of the books.

Engines of God introduces the character of Priscilla Hutchins along with the Omega Clouds. Of the four books, I like Engines of God and Deepsix the best.

For those of you who haven't read the books, the Omega Clouds are these huge clouds of *something* which sweep through star systems every 8000 years or so and seem to be drawn to rectangular structures on the surfaces of planets (which they blast to rubble, causing the downfall of a number of civilizations). What the Omega Clouds are (ancient weapon? "urban" reclamation project? evidence of a malicious universe?) isn't explained (or at least given a plausible theory) until Omega.

Deepsix is about an old living world that is about to be torn apart by a rogue planet. There are scientists and tourists who arrive to watch the destruction when someone spots ruins on the planet and decides that they need to be investigated.

Ron
 
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