The scientific briefing with Luke Boulter
I’m all for science fiction, (I have indeed been known to read the New Scientist from time to time), so imagine my surprise a couple of nights ago when I found myself wincing horribly and wishing that my broken sofa would eat me. I had, for the first time in my life, experienced the film Contact. The general gist is: human scientist contacts alien race, alien race tells us how to make machine and along with some flashy CGI Jodie Foster ends up a few million light years from home. I hope that from this brief but acute description I can enlighten you to my turmoil and for all the people out there who are still mistaking War of the Worlds for a real political broadcast, the next 1000 words or so should, I hope, give a sense of perspective.
Firstly I must make it clear that I do believe that there is some form of life other than ours; it is far more implausible that our planet alone is occupied than the converse. However I do have concerns as to whether the massively evolved brains and feeble bodies stereotypical of extraterrestrials are credible. Having said this, we may soon find those elusive beings. In our search for life, and in an attempt to isolate the beginnings of the universe, new radio telescopes are being commissioned. These shiny new receptacles are designed to pick up radio waves emitted by neutral hydrogen molecules in the early, primordial universe. In times past (billions of years ago in fact) the wavelength of these signals was 21cm, but as a result of universe expansion this wavelength has stretched to several meters, corresponding to a frequency of a few thousand megahertz. It is a lucky coincidence then that the signals constantly being pumped out by us in the form of TV signals, radio and radar fall in a similar range, meaning if an alien culture is listening out for the local weather or watching alien Family Guy then we are increasingly likely to find them. Telescopes such as these should also be able to discern the tilt and revolution of a planet, as well as speculate whether there is surface water present, just in case there aren’t any inhabitants.
One of the more reassuring points made recently is that alien life (no matter how basic) can exist throughout the universe; Life’s little building blocks seem to lurk even in the darkest corners. Polycyclic aromatic hydrocarbons (PAHs), which are readily abundant in space, seem to have more in common with Earthly molecules than originally thought. In late October 2005, Douglas Hudgins and colleagues at the NASA-run Ames Research Centre in California showed that many of these compounds contain nitrogen, one of the principle components in proteins and DNA, both necessary for the perpetuation of life, but also required in chloroplasts and haemoglobin, both of which are indicative of higher life – so the potential is there, even if it hasn’t been realised in the immediate vicinity of Earth.
Once you have PAHs scattered all over the place, all you really need is a star to give light and heat and coax molecules to rearrange, combine and break down. There has often been some question about stars and their actual importance in the formation of life. After all, a lot of stars are binary (i.e. two stars per solar system), they can be too hot, too cold, and the way they were thought to form was generally seen as not conducive to the formation of planets. Stellar nurseries are where stars form; massive gas giants about three light years across churn out clusters of stars, often in sibling pairs. However, research submitted earlier this year to the Astrophysical Journal suggests that red dwarfs, which are suns with a lower energy, are born singularly, meaning there is a greater chance that an extra planetary system, such as our solar system, could occur, without the worry of a jealous sister star ripping us to shreds.
Having said this I realise I haven’t really discussed the likelihood of finding ET on a planet near Earth. That could be because we have been looking in totally the wrong place; for years we have been looking at stars, picking out the wobbling silhouette of a terrestrial planet and mapping it down just in case. Ultimately though the future of alien life may not be on these shadows at all, they could be on our moon.
Ian Crawford, a researcher from Birkbeck College, London told SETI researchers earlier this year that if in the next 20-30 years we land on the moon again, we should sift through a portion of its surface looking for elusive alien artefacts. It is not actually as ridiculous as it seems; both Voyager 1 and 2 carry gold plaques containing information as pictures and sounds, which are meant to give any alien civilisation an accurate representation of what we, the human race, is about. In 2004 it was suggested in Nature that this transient “message in a bottle” approach may be the best way of telling other intelligent races what we as humans are about, but we are talking interstellar distances, so if you were waiting for a reply, you may be holding out for a while. Far-fetched, I appreciate, and scientists seem to back this up. After all ,some 382Kg of lunar material was brought back to earth by astronauts, and they’ve been through it and found nothing of interest, in fact rocks from Earth and Mars show more evidence of impact than that of our majestic satellite.
So the jury is still out on whether we are likely to find extra terrestrial life soon: we can plough the moon for clues; look at distant planets and dream; attempt to listen in on ET’s evening news, or we can down a bottle of Sprite, stick a note in and send it into space… failing that I can always find a film with Jodie Foster and no aliens!