Posted on 11/08/2001 7:52:53 AM PST by MeekOneGOP
Thursday November 08 09:37 AM EST
This puzzle, known as the Fermi Paradox, has burned up a lot of cerebrum cycles when scientists tried to reconcile the lack of company with the expectation that there are many advanced alien societies.
One possible explanation is that interstellar travel is just too costly. Consider how expensive it would be for us to populate another star system. Imagine sending a small rocket to Alpha Centauri, one that’s the size of the Mayflower (180 tons, with 102 pilgrims on board). Your intention is to get this modest interstellar ark to our nearest stellar neighbor in 50 years, which requires about 150 billion billion joules of energy.
No one’s sure what aliens pay for energy, but here on Earth the going rate is about ten cents a kilowatt-hour. So the transportation bill per pilgrim would be $40 billion. That’s a lot of moolah, a lot more than it takes to buy each emigrant a few thousand six-bedroom palaces and set him up for life. The fact that the trip is costly, in whatever currency, is reason enough to deter any alien society from trying to settle distant real estate. With far less expenditure, the extraterrestrials could pursue the good life at home.
Of course, if energy costs can be brought way down, for example with fusion or matter-antimatter technology, or by capturing more of the radiation spewed into space by the home star, this explanation might not hold water.
But even if the aliens can afford colonization, maybe they haven’t got the stamina to see it through. Subduing the Galaxy takes more than sending a ship full of restless nomads to the next star. The nomads have to settle that star, and then spawn pilgrims of their own. And those émigrés have to produce yet more settlers. And so on. If each and every colony eventually founds two daughter settlements (a pretty decent accomplishment), then 38 generations of colonists are required to bring the entire Galaxy under control. Even the Polynesians, who swept across the western Pacific domesticating one island after another, didn’t manage this. Maybe the aliens can’t do it either.
On the other hand, if a few of them remain committed to expansion, their project might still succeed – just more slowly.
Some researchers suggest that the Galaxy is colonized, but we just don’t notice. Arthur C. Clarke pointed out that truly advanced engineering projects would be indistinguishable from magic. Perhaps the evidence of alien presence is so beyond us that we simply don’t recognize it (somewhat like mice in The Louvre checking out the Mona Lisa). Another thought is that the aliens find Earth an interesting nature park, and have arranged matters so that, while they can observe us, we can’t observe them. The idea that we may be some aliens’ high-tech ecological exhibit is called the "zoo hypothesis."
These explanations, and a bushel-basket more, have been proffered to deal with the Fermi Paradox. Any of them might be true. Nonetheless, some scientists find them too contrived, too unlikely to work in every case. Will all the aliens find colonization too costly? Will they all run out of empirical steam? Are we so special that someone has really gone to the trouble to put us behind invisible bars?
Or is there a much simpler explanation?
Next time, we’ll consider some of the more obvious – if more disquieting – resolutions of the Fermi Paradox.
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Love this. I am going to use it myself with your permission! :)
Two things: 1. The s/n ratio goes through the roof as we shrink our detection into narrower and narrower bands. 2. We are looking a millions and sometimes billions of frequencies simultaneously.
OK, I can buy that. So how much do we gain in signal strength advantage if we don't need to decode modulation? Could we pick up Pioneer 10 at 1 watt from 5 billion miles away? I think we just lost it recently and I thought it was around 5-7 billion miles away and transmitting at more than 1 but less than 10 watts.
By all means. Tell 'em who said it, and maybe I'll end up in Bartlett's someday. Or not.
Guaranteed you get the credit! :)
They found it again in April, after missing it for 8 months. Its signal strength is about 8 Watts. It's about 7.5 billion miles away.
Good, then that is an excellent example of our sensitivity limit. So at 10 billion miles we need about 12.5 watts from an 8 foot dish. I'm assuming that Pioneer's dish is about 8 feet. So at 1 ly we need approximately 4.3 million watts from an 8 foot dish or 43000 watts from an 80 foot dish and so on. Are you starting to see my point? The nearest star is 4.3 ly away, as I'm sure you know, needing 4.3 squared times as much power per square foot of antenna or 4.3 squared times as much antenna area on some combination thereof.
For a given total power, the transmitter size doesn't matter. Bigger transmitters just let you put more power into the signal, not less.
In that case, our responsibility is to spread life as far as we can, at least across the solar system. The authoritarian measures you propose will stand in the way of that. And in any case, why preserve a life not worth living? I'd rather we live unsustainably as men than sustainably as animals.
Life on Earth will continue until the Earth is destroyed. Earth has been hit by cosmic disasters before, and life has sprung back every time, different from what it was, but objectively no better or worse. Life takes care of itself. Our concern is human life, and we preserve that best by remaining free.
"Natural" is not "better". Disease, famine and predation are the enemies of mankind. In order for ecology to mean anything, it must mean striving for an environment that is suitable for human life. It was good environmental policy to eradicate smallpox. It was good environmental policy to eradicate dire wolves. It was good environmental policy to reduce the buffalo herds and devote the Great Plains of North American to food production.
What kind of quality life do you think you (well who knows you might be one of the very few lucky rich) would have when our population really starts to exceed the carrying capacity of the earth?
It can only be a problem if human ingenuity is held in check. Human population exploded in the 20th century, but the carrying capacity of the Earth more than kept pace with it. Famine and pestilence have never been as uncommon as today.
As long as we are permitted to discover and exploit new energy resources, to exploit the machinery of life to improve human health and food production, and to learn how to live well outside the surly bonds of Earth, mankind will not merely live long, but prosper.
Maybe we are it? Since many are so fond of "evidence" give us the "evidence" of other civilizations around other stars.
FTL travel would be great, but outside of science fiction I have not seen it.
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