Ah! Now I see it
Where does E.T. come from?
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It’s just an attempt to gain some insight into the existence of aliens. Anyone is free to introduce any secondary points, or state that they don’t believe in aliens at all. But as I said as my opening statement, this is a continuation of my previous “Aliens?” thread, in which the main topic of discussion was whether or not they exist.
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Do you mean intelligent life or one-celled bacteria?
There’s a high probability that aliens do exist, but nobody knows for sure.
Isaac Asimov didn’t include aliens in his Foundation series, I don’t know why–can someone tell me
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Unlike myself I’m guessing he did believe in the possibility of aliens, but I’m fairly certain that his reason for not including any is because the premise for the Foundation Series is Gibbon’s The Decline and Fall of the Roman Empire set in space.
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In order to have life on a planet (let alone intelligent life), you need a medium sized star containing the right amount of metals and hydrogen, a planet with the right amount of mass, the planet has to be at the right distance from the star,the planet has to be in a nearly circular orbit, the planet has to have enough water and nitrogen and carbon, and a gas giant farther out to deflect comets wouldn’t hurt.
We have detected about 200 extra solar planets so far, and only a handful have some of the above criteria (two of the stars are called 47 Ursae Majoris, 44 light years away, and Gliese 777A, 52 light years away www.extrasolar.net These two star systems have Jupiters at the right distance for comet deflection and would be stable with an Earth-like planet closer in).
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Oh ya. You could also have life on the moon of a gas giant if the moon had an ocean (covered by ice or not) and an internal heat source if it was covered by ice (like Europa).
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Madscientist…
The only issue I have with your post is that it is based on assumptions regarding life based on a single example… Earth.
It MAY be correct for Carbon based life, but it may not. With only a single example, and all life here living under the same criteria, of course it all needs the same basic things.
But could carbon based life have evolved differently under different circumstances?
What about Solicon based life (another often considered example in Sco-Fi)
Or perhaps life of a totally different type all together? One that is Hydrogen or helium based and lives in the high energy environment of the sun? (has been speculated about in fiction, sorry, I cannot place my hands on the book a tthe moment, Angel and I are redoing the office and my library is in a score of 6’ stacks in the guest room). -
Uh, yeah, but that would be a totally alien species. Scientists don’t think it’s possible to have hydrogen or helium-based organisms… Just imagine–hydrogen is the lightest element and helium is not abundant enough!
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It is on the surface of the sun…
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I like the idea that the planet Mercury actually may have ice at its caps. If you move further south eventually a barrier of say 100 miles exists where the temp goes to 600 degrees. I wonder if life can be sustained in the “in between region”
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Robotic life-forms have been mentioned earlier in this forum. Just remember the 3 Laws of Robotics:
1. A robot may not harm a human being, or, through inaction, allow a human being to come to harm.
2. A robot must obey the orders given to it by human beings except where such orders would conflict with the First Law.
3. A robot must protect its own existence, as long as such protection does not conflict with the First or Second Law.In Asimov’s Robot books machines started to become more human and expanded the meaning of artificial intelligence. This is speculative sci-fi but if robots develop feelings they can be considered aliens too. Biorobotics is the study of making robots emulate or simulate biological organisms. And clones can be considered aliens, too. If you know the story “Island of Dr. Morreau,” he engineered clones, mixed their genes with animal DNA (recombinant DNA), and then they became not human anymore.
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@Imperious:
I like the idea that the planet Mercury actually may have ice at its caps. If you move further south eventually a barrier of say 100 miles exists where the temp goes to 600 degrees. I wonder if life can be sustained in the “in between region”
It can’t, it’s too close to the sun
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@Gen:
If you know the story “Island of Dr. Morreau,” he engineered clones, mixed their genes with animal DNA (recombinant DNA), and then they became not human anymore.
That is the movie with Val Kilmer. In the short story by H.G. Wells, the “beasts” were all created by vivisection… he CUT them to make them Human.
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@Gen:
Uh, yeah, but that would be a totally alien species. Scientists don’t think it’s possible to have hydrogen or helium-based organisms… Just imagine–hydrogen is the lightest element and helium is not abundant enough!
The term “carbon-based” is just a reference to the fact that carbon can form long, long chains, like in DNA. I don’t remember ever hearing that hydrogen or helium have this characteristic as well, but I do think silicon can… However, I do know that helium is certainly abundant enough. If the Big Bang is correct, (and it is the leading theory as to the beginning of the universe) then helium makes up about 20% of the universe. And with the sky being loaded with billions of stars, that is a huge amount!
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And that is the concept behind the Sci Fi stories…
Carbon is rather rare in the universe, but life developed based on it. If life formed in the case of this rare set of circumstances… (carbon in large quantities, specific temp, specific high energy source, etc.), then perhaps a related chain of events led to life with somethign far more common…
And Helium is not THAT out there… stable, exists in one of the HIGHEST energy environments known, with an abundance of radiation to allow for mutation…
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I’ve just read that hydrogen and helium are the most abundant elements in the universe. (stars) Stars begin by burning hydrogen via fusion, and then when all their hydrogen fuel runs out, having been fused into helium, then the stars will simply begin burning helium. By the way, supposedly when that happens in our solar system, in about 5 billion years, then the sun will puff up dramatically, enough to engulf the Earth’s orbit. :cry:
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Actually, I don’t have a periodic table in front of me right now, but isn’t helium one of the Noble Gases? That would mean that it is IMPOSSIBLE for any helium-based life-forms, since the Noble Gases’ valences are so low, (zero) that they don’t ever bond with anything else.
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Except themselves…
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@ncscswitch:
Except themselves…
I don’t know if that’s true… I thought elements with noncovalent bonding can’t bond with anything, even themselves
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An element’s valence just means how many available “slots” it has with which to form covalent bonds. So I might just say that they can’t even bond with themselves either.
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The available bonding slots has a lot to do with whether you can get life out of molecules. Hydrogen has a valence of 1 (one slot), so you can only bond it to one molecule. Oxygen has a valence of 2, Nitrogen has a valence of 3, and Carbon has a valence of 4. Silicon also has a valence of 4, which is why Silicon is considered as a possibility for forming life. Having a valence of 4 means that you can bind the maximum number of atoms to the atom, and can form all kinds of chains. Helium is a noble gas, so it is most stable not bonded to anything.
Another factor is whether you have a solution in which reactions can take place on the base molecule. Water happens to be the perfect solution for carbon based reactions to take place, which is why scientists look for water when they are looking for life.
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