How Might We Discover We Are Not Alone? Part 2 – Signals From Beyond

SETI

The Arecibo Radio Telescope, most commonly
associated with the SETI project

Probably the single greatest public effort to detect signals from beyond our world, is the SETI ('Search for Extra Terrestrial Intelligence') project. We've all heard of it, and on the off chance you haven't, you should have, so click here. Aside from being used in numerous science fiction stories, it also crops up in almost any serious discussion about the existence of alien life.

This kind of search is probably one of the only mainstream and publicly acceptable outlooks on potential alien contact, next to the discovery of microbial or simple life somewhere close-by. Essentially it works on the principle “We think they might be out there, but even if they are, they're nowhere near us.” For some reason, this logic makes the subject more palatable to most people, organisations and governments. It's the 'polite' side of looking for ET. Most humans will only imagine what's beyond, in the context of their current level of socially-acceptable knowledge. So our belief that there could be life, combined with our disbelief that anyone out there would be capable of traversing the distances, makes it the seemingly 'logical' method. Not to mention, it is more comforting. If we do find anything, it's safe. Confined by distance and our belief that said distance makes physical contact nigh on impossible.

However, don't make any mistakes. Regardless of the reasons, the SETI project and those like it are a good thing. They're at least trying, but there are some serious problems.

WOW!

The (in)famous 'WOW' signal

Firstly, even if we run with the idea that other planets are putting out signals in the form we are looking for, it's a needle in a haystack. A signal must be regular enough and strong enough, that when astronomers look at the right portion of sky, they can detect it. Famously, they did once pick up something referred to as the 'WOW' signal (called such, because one of the astronomers wrote the word 'wow' beside the numerical print-out). The signal itself provided little information, except that the frequency number closely matches that at which hydrogen resonates. The thought is, that Hydrogen being the most common element in the Universe, the number could be used by different species as a baseline of mutual knowledge from which to begin communication. Unfortunately, even after repeated checks of the same portion of space with more powerful telescopes, it was never repeated. SETI has since had very little luck.

When, Where, How

Who's sending, and who's receiving?

The sceptic perspective, is of course usually based around the Fermi Paradox. “We've not found anything yet, after so much searching. Obviously it's because there's nothing out there.” If you've read 'Part 1', you already know why I think this is a complete misfire of logic.

Having said that, I also don't think we'll have much luck with this kind of search. For starters, it is perhaps a mistake to assume that other cultures will use communication methods akin to our own. You could argue that some are bound to, but then I believe another problem creeps into the mix. There has been a logical progression to our human communications technology that possibly implies similar races would find similar solutions. Of course I could be completely wrong, but it makes sense (to me, at any rate). If their progression follows a similar path, we have an obvious and simple difficulty.

Everyone from scientists to science fiction writers, love to talk about how we have been sending signals out into the distant reaches of space for the last hundred years. If science fiction is to be believed, they're either fascinated by repeats of 'I Love Lucy' or deciding to eradicate us because of old broadcasts of Hitler, war atrocities, and our 'destruction' of the planet.

The thing is, our communication methods are changing. Television signals are increasingly broadcast via satellite, a medium that transmits inward, not outward. Meanwhile the ever-growing internet is primarily transmitted via cable. While our transmissions are increasing, their methods are becoming refined and targeted. If this progresses, our civilisation will soon have very few broad, outward transmissions. The logical conclusion is that we will have had a short one-to-two hundred year window during which we have output hoards of signals for aliens to eventually pick up.

On a cosmic scale, imagine a thin circle radiating out from a small dot, eventually passing over other tiny dots very quickly. Now imagine that each of those dots has to be at a sufficient technological level and just happen to be listening at the right time, to pick up those faint messages radiating out from a tiny blue planet.

Reverse the situation. Imagine that a few of those worlds send signals out in a similar way to ours. What are the odds that we will be listening at just the right time, to pick up such a short period of transmission? Especially given the absurdly huge length of time that our world and others have been around, in comparison to the period we've had the technology to listen?

Whilst I think it's great that we're listening, I believe the odds of our discovering something through these methods are so low (even if the universe is teeming with life), that we shouldn't expect to hear anything. Even so, it is important that we don't make snap judgements based on our lack of success in this area. Detecting nothing should not make us believe we are alone, or be used as an excuse to give up the search.

Tomorrow, we shall discuss 'Something Small', the possibilities of microbial or primitive life.

Click here for:
Part 1 - Equations and Paradoxes
Part 2 - Signals from Beyond
Part 3 - Something Small
Part 4 - Remnants and Arefacts

WOW signal image credit: The Ohio State University Radio Observatory and the North American AstroPhysical Observatory (NAAPO).
Arecibo Radio Telescope and Adromeda Galaxy image credit: http://www.nsf.gov/news/special_reports/astronomy/downloads.jsp

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