Are We Alone in the Universe?
Geoffrey Dobson sums up the state of current scientific knowledge on extra-terrestrial life Dr. Geoffrey Dobson lives in the Pas de Calais and writes on a number of science related topics. This is a very condensed and simplified version of one of his articles.
Philosophers have always wondered whether mankind is unique in the universe. Ancient civilisations had many stories about demons and gods. The ancient Greeks thought that an infinite universe must contain an infinite number of populated worlds, but the idea of our uniqueness became dominant in Christianity, although the idea of extraterrestrial life always existed in Hinduism, Judaism and Islam. Copernican theories made it clear that Earth is a small planet orbiting a minor star. Western philosophers began to argue that there must be other inhabited worlds in an infinite universe.
The idea of extra terrestrial life continued in science fiction, and in serious science as we developed space technology. For life to start a planet must be in the “Goldilocks Zone” where liquid water could be formed. Within our own solar system it is possible that, in the past, some form of life existed on Mars, Venus and the moons of Jupiter. There are billions of stars in the universe, each one with its own solar system. Many planets will exist in the Goldilocks Zone. In 1976 NASA landed the Viking probes on Mars. They tested Martian soil for evidence of bacterial life and results appeared to be positive, but later the answers were judged to be inconclusive and the tests have never been repeated. The search has moved to find evidence that the planet surface might have contained water in the past.
If there are a million civilisations dotted at random through the universe, the distance from us to the nearest one is likely to be about 200 light years. (1 light year is the distance that light will travel in a year, i.e. 6 x 1012 miles or 6 followed by 12 zeros) The nearest star to us (Alpha Centauri) is four light years away so our nearest neighbour might be that close. “SETI” (search for extra terrestrial intelligence) was founded in the 1970s. If we tried to send out a signal when radio was first invented, it might be another three hundred years before we receive a reply so SETI concentrates on using radio telescopes to listen for intelligent signals from space. In 1977 a radio telescope did pick up the possibly intelligent “Wow” signal. Unfortunately nothing like it has been received since and interest in SETI has fallen away due to the lack of success.
Many planets in the Universe are suitable for developing life and on at least some of them the same processes that happened on earth would happen independently. In 1982 Fred Hoyle proposed that life on earth started as viruses from space carried by meteorites.
The Daily Telegraph, on 21st October (2009), reported that the European Southern Observatory (ESO) has found several “low mass” planets that might be conducive to developing life. This is important because most planets discovered so far have been “high mass” planets, bigger than Jupiter. Such planets would have gravity that is too strong to allow the development of any advanced life forms. Astronomers at ESO now believe that more than 40 percent of stars similar to our sun do have low mass planets around them.
Since the search began in 1995, more than 400 planets have been found. However Professor Colin Pillinger the leading British scientist has cautioned that for life to exist on planets they must be in the “Goldilocks Zone” where temperatures are just right for liquid water to form. This is why NASA is so interested in Mars but not in Venus.
He also points out that the nearest possibly habitable planet is 10 light years (sixty million million miles) away so there is no great possibility of visiting them. He does however refuse to rule out the possibility “Who knows what we will invent? If Stone Age men ever saw France, they probably thought that they would never get there.”
There is no good reason to expect that intelligent life on other planets will be anything like us. Evolution relies on random events that lead to widely differing results. On Earth the dinosaurs were wiped out by an asteroid strike allowing other life forms to develop, including early apelike creatures. The ice age cleared the great forests producing savannah grasslands. Apes emerged from the trees and became hunter-gatherers developing into early humans. Many other scenarios are possible on individual planets. Most science fiction writers assume that any alien civilisation that we encounter would be in a similar development stage as ourselves, give or take a few hundred years. There is almost no possibility of this given the vast distances that they would need to cover to get to us.
Like us aliens would be curious to discover whether there are other forms of intelligent life in the universe. They might well develop some means of inter stellar travel way beyond our imagination. The bad news is that any aliens with sufficiently advanced technology to reach us would regard us as no better than ignorant savages. We hope that they have developed better ways than early European explorers.
All speculations about alien visits suffer the same problem – how on earth do they cover such enormous distances. Maybe they could start by colonising planets in their surrounding galaxy and grow outwards. In this way aliens on a distant star might take a million years to get to us.
- First Kind: Sighting unidentified flying objects.
- Second Kind: Experiencing physical effects from a UFO
- Third Kind: Observing “animate beings” from a UFO
- Fourth Kind: Human abduction by aliens
- Fifth Kind: Cooperative activity with aliens
Despite all this people believe that alien contact takes place and UFOs are regularly sighted. The most famous conspiracy story is that a UFO crashed at Roswell, New Mexico in 1947. The US military insists that what crashed was a secret high altitude surveillance balloon. UFO enthusiasts insist that a crashed UFO and alien bodies are being kept at a secret base. It is even claimed that one alien survived the crash and was used to contact his home planet. The story will not go away and has become part of popular folklore.
Experts investigating UFO sightings conclude that most are natural if unfamiliar phenomena. They include experimental aircraft, conventional aircraft with unusual lighting, high altitude balloons, luminescent insects, Chinese lanterns launched by hoaxers, clouds, optical illusions created by unusual atmospheric conditions, satellites, meteorites, nosecones and rocket boosters.
Five percent of Americans believe that aliens have abducted them. In most accounts it is dark outside and they are awake but unable to move. Small beings with pear shaped bald heads surround their bed. They are taken outside to a flying saucer and into an operating theatre where their body is probed with various instruments, taking sperm or ovary samples. Finally they are taken back to bed and the aliens disappear. Sometimes, they are travelling by car in a remote location. They see a light in the sky and the engine stops. The rest of the story continues in a similar way to bedroom abductions. Have they really had some terrifying experience or are they suffering nightmares based on a delusion sparked by all the science fiction stories about aliens?
Taking American stories at face value and scaling them up for the world population, hundreds of millions of people have been abducted at some time. Why should an advanced civilisation need to study millions of people to find out how the human body works, and why are the medical instruments they use so similar to those on Earth? Why do they need to steal human reproductive material when they must have the technology to clone it from DNA?. Stories of alien abduction are similar to mediaeval stories of demon abduction. Either abductions have been going on for centuries or abductees have some common psychological problem believing in hell and demons. Most stories of close encounters with aliens are regarded as simple delusions at best or elaborate hoaxes at worst.