Little Green Men

October 27, 2008

The truth is out there, for those who believe in the mythology surrounding Area 51, a military base in the middle of a Nevada desert rumored to be a cover-up for alien visitations. Purported UFO sightings are common, and the town of nearby Rachel gets so many tourists looking for the Mother Ship, eager to embrace their Alien Overlords, that the local diner was renamed the Little A'Le'Inn. And since 1996, local state Highway 375 bears the official name "The Extraterrestrial Highway."

Honestly? There's not much of anything "out there" in the Nevada desert, save the little town of Rachel and its scant inhabitants, most of whom came to the area when a local tungsten quarry reopened in the late 1970s. The only landmark on the Extraterrestrial Highway for a good 40 miles is a battered, bulletproof mailbox, known as the Black Mailbox -- even though it's actually white.

It used to be black, when local cattle rancher Steve Medlin and his wife Glenda first put it up after moving to the area in 1973. He was surprised when it evolved into a weird sort of "mecca" for the UFO-loving crowd, who keep making pilgrimages to the mailbox in hopes of being abducted. Why? Who knows? Given the aliens' well-known propensity for anal probes -- and don't forget, they gave Dana Scully cancer and implanted a chip in her neck! -- I, for one, would give them a wide berth.

It also spawned some pretty wild rumors. Obviously, the conspiracy buffs surmise, the sinister-looking black box is connected to the mysterious activities are Area 51 -- despite the fact that Steve Medlin's name and address are clearly marked on the side. Some attribute special qualities to it, believing it serves as prime magnet for flying saucers.

Medlin himself is rumored to have a government contract to provide cattle for the space aliens to mutilate in their "experiments." The couple's mail was opened, in hopes of intercepting "classified" military correspondence as evidence of the conspiracy. People left messages for the aliens. And a few of the crazier sorts used the mailbox for target practice. That's why Medlin replaced the original black mailbox with the white bulletproof version that stands there today. He very kindly attached a second box just for the UFO worshipers, labeled "ALIEN DROP BOX." Who knows? ET might actually read your letter some day.

At first glance, other civilizations doesn't seem that far-fetched. There are around 250 billion stars in the Milky, and 70 sextillion stars (that's 7 followed by 22 zeros!) in the visible universe, many of which have orbiting planets. So even if intelligent life is quite a rare occurrence, statistically speaking, there should still be Something Out There. So why aren't we negotiating trade agreements and such with our extraterrestrial friends? Where are they? This is the basis for the Fermi Paradox, and folks have been arguing the pros and cons ever since.

In 1950, physicist Enrico Fermi had a casual conversation with his colleagues at Los Alamos National Laboratory (Emil Konopinski, Edward Teller, and Herbert York), discussing a recent spate of UFO sightings. As physicists are wont to do, the conversation turned to the subject of faster-than-light travel, when suddenly Fermi exclaimed, "So where is everybody?" Meaning, why haven't alien civilizations visited, or at least contacted earth? He did a quick back-of-the-envelope calculation and concluded that we should have received a visit long ago -- not once, but many times over.

Ten years later, Frank Drake attempted to devise a more systemic means for estimating the likelihood of other civilizations in the universe. It's known as the Drake Equation, and takes into account such factors as the rate of star formation in the galaxy; the number of stars with planets and the number of those planets that should be habitable; the number of those planets which should develop life and subsequently, intelligent civilizations; and the expected lifetimes of those civilizations. But we can only guess at the fraction of planets with life, the odds of that life becoming intelligent, then becoming intelligent with communication abilities, and finally, the lifetime of those communicating civilizations. Without a ballpark figure for those values, the Drake Equation is little more than a curiosity.

Now Duncan Forgan of the University of Edinburgh's Institute of Astronomy has devised a way to narrow down the Drake Equation to make it a bit more precise, according to his new paper: "A Numerical Testbed for Hypotheses of Extraterrestrial Life and Intelligence." His method involves multiple simulations for what he considers the most likely (or at least reasonable) values in the Drake Equation. He used those statistics to calculate an average value with a standard deviation to arrive at a more exact number for how many advanced civilizations should be populating our galaxy.

The answer: 31,573.52. Of course, the number you end up with depends on which of the three basic models of civilization creation you're using. The above assumes the "tortoise and hare" hypothesis, namely, that earth-like planets are common but it is difficult for advanced civilizations to develop.

If you assume the "rare-life" hypothesis -- that earth-like planets are, in fact, quite rare, but that life develops into advanced civilizations very well on those that do exist -- then Forgan's method predicts there are only 361.2 advanced civilizations that should populate our galaxy. And if you're a fan of panspermia -- which assumes that life on one planet can spread to others in a system -- there should be 37,964.97 advanced civilizations in our galaxy.

That is still pretty darned precise, but as KFC over at The arXiv Blog points out, "The results of simulations like this are no better than the assumptions you make in developing them.... The real question is whether we'll ever have good enough data to plug into a model like this to give us a decent answer, without actually discovering another intelligent civilization. And the answer to that is almost certainly not."

I guess it depends on what you mean by "evidence." Sometimes it's in the eyes of the beholder. People want to believe, and thus are capable of twisting the most innocuous coincidences to support those cherished beliefs -- as should be evident in this hugely entertaining tale, delivered by The Great John Hodgman for TED:

Comments

[Sarah]

I saw a great story in Weekly World News once comparing experimental aircraft with purported UFOs. It's hard to get excited about strange flying objects seen around military airbases. I mean, duh.

I once wondered how it is that Christians reconcile their belief in God with their belief that aliens are visiting earth. I found a lousy christian ufo mag, but that failed to resolve the theological questions, though it did feature reader ufo art. So I asked my roommate, and she sees no incompatibility at all, liberal Catholic ufo believer that she is. Nor does she have any problem with aliens being so very very far away, since they apparently possess mystical technological powers and there's no proving they don't exist, anyway.

[Lab Lemming]

Bad arxiv link for "A Numerical Testbed for Hypotheses of Extraterrestrial Life and Intelligence.":
Paper identifier '0810.222' not recognized

You might instead try to search for papers using title or author information.

For additional help on arXiv identifiers, see understanding the arXiv identifier.

[Lab Lemming]

try:
http://arxiv.org/abs/0810.2222

[John R Ramsden]

If advanced alien civilizations are assumed to exist, one obvious explanation for the Fermi paradox hasn't to my knowledge been considered: They all spend most time (to "stationary" observers such as ourselves) on the move, at 0.99c!

The conventional scenario is civilizations spreading out in the galaxy, and people have estimated how fast this might occur. But it seems more likely they will progress in a more coordinated manner by sallying forth from a point in various groups to different stars, investigating these for a few years, and then converging back at the same time on a previously agreed rendezvous further on to compare notes.

In other words, rather than expanding in a sphere, they will progress in a series of waves, like so <><><> if that makes sense, round the ecliptic plane of the galaxy for example.

To them there will be no point in "owning" a solar system, or settling there indefinitely. Their goal will be only to find novelties in nature, and compare their findings with those of other groups.

Obviously this takes a long time, and by our reckoning as static bystanders they would appear to spend most of their time at high speed, tucked up in cryogenic chambers, and incommunicado - What's the point of communicating? They know where they're headed, and will arrive there almost as fast as the fastest signal.

Time is their big resource and they burn through it just as we consume our supplies of oil. Conversely, we are still in the primitive stage of "natural time", analogous to stone age people using drops of oil from a tar pit.

A couple of years ago, before learning of the large proportion of dark matter compared with normal matter, I even speculated in a mad moment whether the anomalous motion of stars (orbiting the galaxy faster than Newton's laws dictate) might somehow be the result of hordes of advanced civilizations all progressing round the galaxy in the same direction, as described above, some kind of back-reaction to their propulsion. After all they might well have planet-sized starships, and use stars for slingshot maneouvres. That would *really* make things tough for physicists here on Earth, but it seems exceedingly unlikely and can probably easily be ruled out by the diffuse nature of dark matter.

[Neil B]

I think "the Fermi paradox" is a hoot. Here's one bunch of scientists saying, ETs should have been able to make it here. But then they ask "why aren't they here?" despite UFO reports possibly indicative of just that. Then there's other scientists, like "skeptics" who say, "Yes people claim to see UFOs but we don't think those are spacecraft because it's so hard to get here." Huh? They can't both be right.

"tyrannogenius"

[John P. Kolb, Jr a/k/a The Wizard]

Just spent the weekend at Little A'Le'Inn, setting up a booth selling the little glaxies that I place in glass (Lampworking)! It was a dream come true to me. Almost every visitor that stopped, purchased one to wear as a pendent. I do think we all somehow believe.