Open Features: Are We Alone In The Universe?
Wendy Ogbourne asks the big question.
eAre We Alone In The Universe?
This is a question that most of us will have pondered at some stage of our lives. As yet we have no answer, and can only list statistics and probabilities.
We know that there are roughly 400 billion stars in our own Milky Way galaxy, and there are nearly 100 billion other galaxies. Our little Earth is a very ordinary star in a very ordinary galaxy. Some people find it impossible to believe that in all that immensity, the human race on our planet are the only thinking beings to have evolved. There could be millions of civilizations out there – only we don’t know about them. On the other hand, it requires an amazing number of conditions and combination of those conditions to be exactly right for even the possibility of life occurring. Maybe even in an infinite universe, those conditions only came together once, to create us.
So how can we try to find out?
With improvements in technology in the past few decades, scientists have now been able to detect the existence of other ‘earth-like’ planets orbiting suns in our own Milky Way galaxy. One of the most recent of these orbits a red dwarf sun named Gliese 581, which is relatively close to us – only 20.5 light-years* away or 120 trillion miles. And more and more are constantly being found. Other planets previously located have all suffered from the ‘Goldilocks problem’ - too hot, too cold, too small, too big etc. However, just because conditions are similar to those on earth, doesn’t mean that life has in fact evolved.
Then of course, it depends on what you mean by ‘life’. It could well be that primitive life, such as microbes and bacteria are common, given the right conditions, but how many, if any, of those have further evolved into life that we would recognise as intelligent. Are we talking about beings who look like us, or Daleks or huge spiders, beloved of science fiction? Or maybe life itself can come in many different forms. The only life we know on Earth is carbon-based, but if other forms of life could be based on silicon, for example, then different conditions could be necessary to produce and sustain it.
An organisation called SETI – Search for Extraterrestrial Intelligence believes there is a better way to look. SETI is a non-profit organisation sponsored by many prestigious scientific institutions including NASA. SETI believes that the best way to find intelligence is to search for the technology developed by that civilisation. Project Phoenix, started in 1995, is the name of the research project set up to search for these signals. It uses a series of huge radio telescopes worldwide, including in Australia, West Virginia and Puerto Rico. Compared to space exploration, this is a relatively cheap project, costing about 4 to 5 million dollars per annum, provided solely by private donors.
How does it work? I am neither a physicist nor a radio buff, but as I understand it, there is a continuous white noise in the universe of all kinds of radiation. However, any signal which is being artificially produced will occur as a constant or slowly-pulsed signal in a very narrow bandwidth. It would be like hearing a flute note against a waterfall. These signals are most likely to occur in the microwave or short radio wave frequency. Once a signal is located, it would still only be a ‘carrier’, and more sophisticated equipment would be needed to actually read any message that it contained. The telescopes working on Project Phoenix scan the heavens continuously, working methodically over areas that seem the most promising. Computers analyse the readings and pinpoint any anomalies.
Have any signals been detected? None that have been independently verified. There have been a few moments of excitement, especially one in 1977 in Ohio, called the ‘Wow’ signal. The astronomers were convinced they had found what they were looking for, but sadly it was never able to be detected a second time. Maybe no signal will ever be found, maybe we will be looking in the wrong place at the wrong time, but SETI intends to keep trying. After all, the universe is a very big place.
No, it will not be kept a secret. If they ever find the answer to the big question, the whole world will know. If you would like to find out more about all this, start by having a look at the websites below.
http://en.wikipedia.org/wiki/Extraterrestrial_life
* a light-year is the distance light travels in a year, at 186,000 miles per second. This measure is used, as otherwise the figures are just too mind-boggling.
© Wendy Ogbourne
