The Alien Factor discussion

According to astronomers there are 14,600 known stars within 100-light-years of Earth. The star Alpha Centauri B (4.3 light-years away) has one planet within the goldilocks zone, which means it could possibly support life similar to our own world. Gliese 581 is 20.5 light years away, and also appears as though it orbits in a goldilocks zone.

Supposition: If there are two Earth like planets within 20.5 light-years of our planet, and 14,600 known stars at a 100 light-year diameter, the possibility of more Earth Like planets should be quite high.

Proposition: Humans have been transmitting radio waves for over one hundred years. Radio waves travel at the speed of light in the vacuum of space. This would mean that both Alpha Centaur B and Gliese 581 have been receiving our radio transmissions for at least eighty-seven years. It also means that if either planet had been transmitting their own radio waves we should have picked them up with SETI.

One would think that within 100 light-years of Earth some form of intelligent technologically advance life would have heard us by now, or we would have heard from them.

Does this mean they are not out there? Not necessarily. We were without radio one hundred years ago. Perhaps their Marconi is simply a late sleeper.

There are sooo many variables when it comes to determining a statistical analysis of the question that, to my mind, it still comes down to a coin toss -- aha! That's still a 50-50 chance.

I recently posted a quick rundown of the Drake Equation somewhere on these boards in a similar discussion. Of course, that discussion could not resolve the question either, but it is interesting to note that many folks relied on their spiritual beliefs when it came to answering the question for themselves. Some of the non-spiritual people seemed to recoil a bit at that point and the discussion wound down -- a shame because there was still plenty to talk about.

Lately, Stephen Hawking has had quite a bit to say on the topic. Enough so, in fact, that apparently, he believes intelligent life is out there. He's a pretty smart guy, so I'm likely to listen when he says something.

We often talk about the chances for non-carbon based life evolving into intelligence, and that makes for great scifi fodder, but when you consider that we have proven that the laws of physics (and chemical interactions) work the same throughout our solar system (and, by extension, our galaxy), it seems to up the ante for carbon-based life.

There are several great articles on the subject. I'll see if I can locate them and post the addresses.

Thomas C. Stone

Hi Thomas,

I think Frank Drake was on target when he said: The Drake equation is unlikely to settle the Fermi paradox; instead it is just a way of "organizing our ignorance" on the subject.

Perhaps the Kepler Mission will provide some realist data to add to the equation. Yet, knowing Earth-Like planets exist still leaves us guessing if sentient beings inhabit these new-found worlds. Even if we had the technology to probe deeper, recognizing intelligence is something human beings invariably find difficult. After all, our only comparative data set is extracted from our own somewhat primordial intellect.

And yes, I would definitely lend credence to what Stephen Hawking had to say on the subject. I have been a great admirer of his for years. Perhaps one day he will solve the Theory of Everything and last stronghold of the creationist will crumble.

Like you stated, Thomas, there are so many, many variables to consider when contemplating the existence of extraterrestrial life in the universe. We suppose a carbon based life form relying on our know laws of physics. Yet, with the advent of Quantum Physics and Quantum Mechanics, haven’t we found that not all physical laws are constant, given the medium in which they exist?

It seems the more I know, the less I know.


Best Regards,

Claire Marie

Claire,

First, let me address the carbon-based argument. Instead of a lengthy explanation, I'll shamelessly lift the following from "The Bricks of Life: Exploring the Idea of Alien Chemistry" by Seth Shostak, Senior Astronomer, Project Phoenix (complete article can be found here: http://www.space.com/searchforlife/se...

"If you remember your high school chemistry, you'll recall that carbon has half of its outer electron shell filled. In other words, each carbon atom is able (and eager) to bond with up to four other electron-sharing atoms (most atoms prefer to have a filled outer shell of eight electrons). As a common example, a single carbon atom will eagerly take on four hydrogen atoms to make methane (CH4). And because carbons outer shell is both half filled and half empty, it can handily hook up with other carbon atoms, creating the sort of elaborate molecular chains and rings that fuel companies love to pump.

Carbon, in other words, is adept at making complex structures. And complex structures are the bricks of life.

Are there other contenders? Is carbon really so special, or did it just get lucky here on Earth? If you have a periodic table handy, you'll note that the element situated under carbon is silicon, which also has four electrons in its outer shell. Ergo, silicon might also seem to be an obvious basis for life, a point that was first made at the end of the nineteenth century by the German astrophysicist, Julius Scheiner. The optimistic Scheiner was certain that other planets in our solar system (including roasty toasty Mercury) sported life.

But his sunny attitude was misplaced when it comes to silicon-based beings. Silicon may be carbon's chemical cousin, but it's a poor relation. Because the silicon atom is larger, its bonds with other elements are weaker. While carbon hooks up with two oxygen atoms to make carbon dioxide, a nice waste product for both humans and SUVs, the silicon equivalent, silicon dioxide, quickly assembles itself into a crystalline lattice. It's better known as sand, and would make exhaling a gritty experience. The weaker bonds of silicon also preclude the easy formation of those long, same-atom molecular chains that underlie many biological compounds. A slew of complex carbon-based molecules are easily produced in comets, interstellar dust, and university glassware. But if you check out natures chemistry lab for silicon (consider volcanic lava), the products are far less interesting.

If that's not enough to dissuade you from silicon, consider this: there's just a lot more carbon around. Cooked up in the searing interiors of stars, the cosmic abundance of carbon is more than ten times that of silicon. And by the way, if silicon is a distant second in the biology sweepstakes, the elements under it in the periodic table germanium, tin, and lead are worse. They're less abundant, and less inclined to make biologically interesting compounds."

So, the carbon-based argument as the most likely source of life in the galaxy is the most reasonable (to me) for those reasons stated above. It does not preclude the chance of other forms (silicon, methane, etc.) but it seems to enforce the likelihood.

Now, the quantum physics question is something else altogether but equally fascinating. My take is that we (humankind) manifest ourselves at the Newtonian level, with the limits of known physical laws ending at the atomic scale and quite possibly up the ladder of scale as well, ending with what we can call the post-macro level (for lack of a better term). Smaller than sub-atomic, and we enter the realm of particle physics, a realm in which the laws of Newtonian physics do not appear to apply, or at least to not apply in ways with which we fully comprehend (yet; although how long will it be before a grand unified field theory is mathematically proven and accepted?). So, yes, it could very well be that intelligent forms of life exist at these other levels of reality, both at the sub-micro and post-macro levels.

Of course, we can only speculate about these other levels as they are far less accessible as our own Newtonian level of existence. So, I'll probably stick to dreaming about contacting carbon-based life elsewhere in the universe as opposed to any other kind.

In the book I am currently finishing up, I have lightly touched upon some of these ideas with notions of manipulating reality by accessing Higgs fields.

[Shameless plug here: the book is entitled MINERVA'S SOUL and is the third book in the Harry Irons Trilogy -- coming soon to a bookstore near you! Ha!]

Thomas C. Stone

Exciting news increases possibilities:

NASA's Deep Space Camera Locates Host of 'Earths'

http://www.foxnews.com/scitech/2010/0...