The planet Earth is a noisy and active place. Full of radio transmissions, pollution, bustling cities, and billions of people making it all happen. Assuming that in our universe, we are accompanied by other highly developed intelligent life forms, they most likely would be doing something similar on their worlds. If that is the case, then we should have a very clear picture of what to look for during our search. Last time we looked at humanity’s willingness to accept the concept of alien life. Now we examine our efforts to find it.
Radio Telescope. Two words most people do not associate together. Yet today there are more professional instruments listening to our skies then there are (in the truest sense of the word) observing them. Since 1896 when Nikola Tesla first proposed listening for signs of alien life, have we been turning our receivers to heavens. In some of his early experiments with his now famous Tesla coil, Tesla picked up signals from space that to him seemed deliberate and of intelligent design. Being that Mars had long captivated the imagination of writers and scientist alike, it instantly shot to suspect number one. For the next 30 years, both amateur and professional radio sets would eagerly turn an ear towards the red planet, only to hear nothing surprising.
The sounds Tesla had heard in his experiments were absolutely extraterrestrial, just void of any intelligent design and most certainly not from Mars. Cosmic rays travel throughout the universe emitting from every corner of the cosmos, some right in our solar system. Stars and nebular gases exciting molecules of hydrogen and burping them into space like a case of bad gas. This is what Tesla picked up and this is what is mostly commonly heard from space. Yet not all signals are gassy in origin.
Karl Jansky in the early 1930’s provided the next (all be it unexpected) leap forward in the fledgling field of radio astronomy. While working as an engineer with Bell Telephone Laboratories, he noticed that the large directional antennae being used for his experiments was picking up unknown and very regular spikes in intensity every 24 hours. He first assumed that the signal was cosmic rays emanating from the sun, coming in contact with the array every 24 hours due to the rotational period of the earth. However, after closer scrutiny, it was clear he had a bigger puzzle on his hands. Rather then being exactly 24 hours the signal always repeated on the 23:56th minute. What was going on? After consulting with specialists in the field astrophysics it was discovered that the antennae was receiving its spikes precisely when the densest part of the Milky Way passed overhead. This heavily crowded area of our galaxy is home to a wide verity of stellar phenomenon all emanating a verity of different signals.
Soon astronomers would hear and learn the sounds of our universe, from pulsars to red dwarfs, our universe is a noisy place. Everything heard so far has been natural, but what if we heard something deliberate – a message for example. That’s what early SETI pioneer and astronomer Frank Drake set out to do in 1960. Using a radio telescope 26 meters in diameter, he examine the stars Epsilon Eridani and Tau Ceti. Even though nothing of extraterrestrial origin was discovered, it did encourage many others around the globe to perform their own experiments. The following year in November of 1961, ten of the world’s leading authorities in astronomy, physics, biology, and neurology would meet in the first ever SETI conference. The decisions made that day impacted our search for ET to this day. Thanks to spokesmen like Carl Sagan, SETI gained popularity, and the world started to invest in the pursuit.
So Either We Die or it Says Hi
For many years, SETI’s focus lay heavily on the use of radio telescopes. Listening for ET seem like the most logical way to make contact. Considering how many signals emanate from our own planet, it really isn’t a bad idea. The problem is, with the number of naturally occurring signals and in addition to the interference caused by our own atmosphere, finding and differentiating a deliberate alien message is very difficult. To this day, no such signal has been identified. This has discouraged many of the governments who funded these project from contributing further. By the late 1990s, SETI was nearly dead in the water.
Supporters of SETI turned to private investors and the community alike to continue funding for the larger projects planned or already in existence. Keeping them afloat was important, but to do so required sacrificing numerous other small scale projects. What SETI needed was a fresh approach to win back investors. That came finally when propionates of optical SETI had at last had their voices heard.
From the 1960s onward, only a few individuals in the SETI community were performing any serious research into optical SETI projects. The idea is that if a technologically advanced and intelligent alien species did want to contact us, they may use a visual means to so. Despite the logic behind it, the idea didn’t catch on. That was until SETI projects got into a rut and needed to reinvent themselves. These days optical SETI is the direction they’re going. Even telescopes at University of California Lick Observatory (somewhere I know very well) are engaged in optical SETI research. The likelihood of seeing an alien message might be just as probable as hearing one, but the chances of misinterpreting it are far less, making it seem a lot more worthwhile then its radio counterpart.
We can see a good amount of the observable universe, much more then in years past. Radio interferometry is the next step in radio astronomy, giving us the ability to “view” through the gasses in the universe and generate images from a multitude of signals all over the electromagnetic spectrum. Space telescopes of this nature can show us in detail one of the most destructive forces in existence, Gamma ray bursts. These highly violent phenomena (the brightest in the universe) are the result of dieting stars. Some have gone as far to suggest that if an alien civilization wanted to get noticed, engineering the death of a super massive star would do the trick. Let’s just hope they don’t point it at us; I’d hate to die of radiation exposure just as we learn we aren’t alone.
Destroying Our Planet: Not Just For Humans
We may not know if intelligent life exists outside of our solar system, but we know a few places it might be hanging out. We once thought that planetary systems like ours were scarce and sparsely scattered throughout the galaxy. Now with both ground and space based telescopes discovering planets around other stars in great frequency, the concept of a very habitable universe in now coming into view.
What the scientific community as a whole wants to find are planets like Earth, small and rocky with lots and lots of water. What SETI would like to find are planets also like ours, full of lots and lots of pollution! It stands to reason that some alien civilization is going to be at least as advanced as our own. If so then it’s likely to produce as many pollutants as ours. Toxins and radiation leave behind very specific signatures, by measuring their concentrations in an atmosphere we can discover the probability of whether or not a technologically advanced species inhabits that world.
This may sound like science fiction, but experiments are underway currently that will pave the way for this type of research. High powered spectrographs can already tell us the composition of stars and gas Giants. It’s only a short time before Earth like planets will be examined too. This may be the best method for discovering alien life, but how do we talk to it?
Time To Pitch
It’s only a matter of time before we either hear from an alien civilization, see a signal be sent out into the universe or identify a seemingly inhabited planet. Considering the distances between objects in space, it would be likely decades or centuries before communication could be established with any of these. So why not start now? We should be sending radio signals and making visual attempts at communication to every earthlike planet we have discovered thus far. In the event that we do identify any of them as planets with atmospheric conditions that support life, then we will have already taken the first step.
ET might very well be listening and looking just as, if not more, intently than we are. I think it’s high time we do a better job of saying hello. We might be surprised who is listening.
Do you want to support SETI? Go over to SETI@home website and see what you and your personal computer can do in the pursuit of the search for extraterrestrial life.