The question as to whether there is life in outer space has occupied humans for millennia. Indeed, the US National Aeronautics and Space Administration (NASA) recently announced that in less than 20 years, the world should have an answer.
With advances in space probe technology, the prospect of finding extraterrestrial life has become real since scientists shifted focus from finding signals from outer space to searching for habitable planets. The most promising, life-supporting earth-like planets recently discovered are Keplar-186f and Gliese 667 Cc.
But scientists are basically searching for extraterrestrial life in its rudimentary form, not necessarily intelligent life. Even just finding cellular life would be a historical discovery like no other.
In their 35-year odyssey, US spacecraft Voyager 1 and 2 have not sent anything concrete indicating life in Earth’s neighbourhoods.
The strongest indication of alien communication is the “Wow!” signal. A strong, narrowband radio signal was detected by Dr Jerry R. Ehman on 15 August, 1977, while working on a Search for Extraterrestrial Intelligence (SETI) project at the Big Ear radio telescope of Ohio State University.
It is on the vastness of the universe that some scientists rely to determine the probability of extraterrestrial life.
Statistically, the observable universe is just too huge to rule out other life-supporting planets.
Our galaxy is 10 billion kilometres wide. There are between 100 and 200 billion galaxies in the universe, each with billions of stars. Many of the stars have their own planets, moons, and asteroids orbiting them. And that is only what current technology allows us to see.
During a recent interview with the Sunday Times , Stephen Hawking, one of the most respected space scientists, said: “To my mathematical brain, the numbers alone make thinking about aliens perfectly rational. The real challenge is working out what aliens might actually be like.”
Hawking said they could just be microbes or basic animals such as worms or much more developed forms of life. He offers several theories.
If the argument about the time scale for the appearance of life on Earth is correct, he says, “There ought to be many other stars, whose planets have life on them. Some of these stellar systems could have formed five billion years before Earth. So why is the galaxy not crawling with self-designing mechanical or biological life forms?”
He continues: “What is the explanation for why we have not been visited? One possibility is that the argument about the appearance of life on Earth is wrong. Maybe the probability of life spontaneously appearing is so low that Earth is the only planet in the galaxy, or in the observable universe, in which it happened. Another possibility is that there was a reasonable probability of forming self-reproducing systems like cells, but that most of these forms of life did not evolve intelligence.”
There might also be a reasonable probability for life to form and evolve into intelligent beings, but at some point in their technological development “the system becomes unstable, and the intelligent life destroys itself. This would be a very pessimistic conclusion. I very much hope it isn’t true”.
But he prefers the possibility that there are other forms of intelligent life out there and that we have been overlooked by more advanced civilisations.
The question as to why there is no recorded extraterrestrial contact with Earth is called the Fermi question (where are they?) or the Fermi Paradox, named after the Nobel laureate and “father of atomic bomb”, Enrico Fermi, who in 1950 asked: “In the vastness of our galaxy (and the universe), how is it that we have no evidence of there being other intelligent life forms? Is life actually so rare that Earth is the only one where it developed? If intelligent life is not an anomaly, there are plenty of worlds that are teeming with life. Are we then truly alone as a species that can contemplate the universe around us? Does intelligent life develop, but then get snuffed out by disaster, internal conflicts, or war with other intelligent life? Or are they out there, but are unwilling or unable to communicate with us?”
One is that there is a great filter in the evolution process, which only a few, if any, species get past.
Another hypothesis is that there are alien civilisations out there, but for some reason, we cannot contact one another. The timing could be off, meaning that when they were sending out signals or passing through this section of space, our distant ancestors were too primitive to notice.
The Wow! signal might, therefore, have taken thousands or millions of years to reach our planet.
In this regard Lord Martin Rees, a British royal astrophysicist, says: “I suspect there could be life and intelligence out there in forms we can’t conceive… It could be there are aspects of reality that are beyond the capacity of our brains.”
Then there is the zookeeper hypothesis: that there are aliens out there and they are watching us, but our technology is too primitive to detect any signals, spaceships, or structures they use to visit our planet. Another possibility is, as Prof Hawking argues, they too do not want contact out of fear.
“The long-term survival of the human race is at risk as long as it is confined to a single planet,” says Hawking. “Sooner or later, disasters such as an asteroid collision or nuclear war could wipe us all out.” If something happens to Earth and there is nowhere like it in the solar system, we would have to go to another star. That would guarantee our future, at least for several billions of years.
Indeed, rich countries like the US spend billions of dollars on space exploration with the thinly veiled intention of colonising them in the future.
Experts on jet propulsion have suggested that Star Trek-style rockets could be used to colonise suitable planets orbiting other stars. Already, Sir Richard Branson of the Virgin Group of Companies has started a venture for civilian tours into space, which are being viewed as the precursor of future longer stays in space or even on other planets.
Scientists have warned that contact with aliens would not necessarily be pleasant, and that earthlings should think twice before meeting inhabitants of other planets — if any are found.
In his famous lecture, “Life in the Universe”, Prof Hawking echoes these fears: “We only have to look at ourselves to see how intelligent life might develop into something we wouldn’t want to meet. I also imagine they might exist in massive ships, having used up all the resources from their home planet. Such advanced aliens would perhaps become nomads, looking to conquer and colonise whatever planets they can reach.
“If aliens ever visit us, I think the outcome would be much as when Christopher Columbus first landed in America, which didn’t turn out very well for the native Americans.”
“If we should pick up signals from alien civilisations,” Hawking warns, “We should be wary of answering back until we have evolved a bit further.”
Other space scientists concur: Lord Rees says humans might not be able to recognise or understand the forms of life they stumble across in space, leading to serious conflict.
However, in an interstellar version of the “prisoner’s dilemma”, each civilisation could stay quiet and safe, but there is a bigger payoff in contacting one another, because the exchange of information — science, art, culture — could yield benefits for both and push the limits for their development.
Humanity will probably have to wait a few decades to find out if there is life beyond our solar system.
“To find evidence of actual life is going to take another generation of telescopes,” Matt Mountain, the director of the Space Telescope Science Institute, said at a recent conference.
To do that, humans need new rockets, new approaches to getting into space, new large telescopes with highly advanced optical systems.
While NASA’s James Webb Space Telescope (JWST), scheduled to launch in 2018, will be capable of finding signs of life on nearby stars, a general hunt for life beyond Earth’s neighbourhood will require bigger spacecraft that are not yet available.
Then there is the problem of distance. The nearest planet thought to be habitable, Gliese 667 Cc, is about 120 trillion years away. Using the New Horizons Probe, the Pluto-bound vessel and the fastest man-made spacecraft travelling at 200 km per second, it would take between 70 and 100 years to reach it.
That is the normal human lifespan, so we would have to put a newly born child into a spaceship with enough food, oxygen and other life-supporting equipment. And we would never see the vessel and its occupants again!
A spaceship travelling at the speed of light (which is technically not possible) would take 20 years to reach it, and another 20 years for the signal that it has landed, to reach Earth!
The energy to reach there is another story altogether. Space scientists peg their hopes on the yet-to-be developed matter/antimatter propulsion technology. This technology, scientists believe, would create energy to propel engines through huge distances at speeds thousand of times more than currently possible.
The amount of antimatter needed to supply energy for the engine for a year’s trip to Mars could be as little as 10 grammes, according to a report in the Journal of Propulsion and Power . Matter and antimatter reactions could be 1,000 times more powerful than nuclear reaction. The problem is generating and storing enough antimatter. A gramme of the stuff could cost several trillion shillings to generate.
When Kenneth Arnod was flying over the Cascade Mountains in Washington DC, US, in July 1947, he saw something strange; flashing past his plane were nine saucer-like objects.
He reported it to the airport authorities. The CIA and FBI took up the matter. It quickly became national news as more people reported seeing what the media quickly dubbed flying saucers. It is considered the largest sighting of multiple unidentified flying objects (UFOs).
In 1954, the US air force then defined UFOs as “any flying object, which by performance, aerodynamics characteristics, or unusual features do not conform to any presently known aircraft, or which cannot be positively identified as forbidden flying object”.
Contrary to common belief, UFO sightings are not new. In fact, some verses in the Bible seem to describe UFO-like objects. “This was the appearance and structure of the wheels: They sparkled like chrysolite, and all four looked alike. Each appeared to be made like a wheel intersecting a wheel.” (Ezekiel 1:16)
Alexander the Great records two great silver shields spitting fire around the rims in the sky, which dived repeatedly at his army as they were attempting to cross a river. The strange happening so panicked his elephants, horses, and men that they abandoned crossing the river until the following day.
UFOs have been sighted in Africa as well. While flying past Mt Kilimanjaro on the way from Nairobi to Mombasa in 1952, Capt Jack Bicknell reported: “Through the glasses, I saw a metallic bullet-like object, which must have been over 200 feet long. At the end was square-cut vertical fin. Its colour was dull silver, and there was no haziness about it at all.”
The passengers aboard the East African Airways plane discounted suggestions that it might have been a light, cloud or weather balloon, reported the Nairobi Sunday Post of 25 February, 1952.
However, most UFOs have been identified as conventional objects or natural phenomena, while some have been hoaxes.
A study by the French Aerospace centre in Toulouse in 2002 said that 22 per cent of the 600 cases studied could not be explained using modern science and were real physical flying machines beyond human knowledge.
But studies in the UK have dismissed UFOs as “misidentified or ordinary objects or phenomena, optical illusions, psychological misperceptions, or hoaxes.”
And fearing mass panic, Winston Churchill, the British wartime Prime Minister, once banned UFO reporting for 50 years.
Scientific studies generally steer clear of the subject, with some scientists dismissing reported sightings as the work of creative minds.
But Dr Charles Keen, a well known aero-physician says: “You simply cannot dismiss the possibility that some of these UFO sightings are actually some object created by… a civilisation perhaps millions of years ahead of us in technology.”
Ever wary of extraterrestrials, Prof Hawking says, “I discount suggestions that UFOs contain beings from outer space. I think any visits by aliens would be much more obvious, and probably also much more unpleasant.”
Inadequate technology. Even though NASA’s James Web Space Telescope, to be launched in 2018, will be capable of finding signs of life on nearby stars, a general hunt for life beyond Earth will require spacecraft that are not yet available.
Distance. It will take between 70 and 100 years to reach the nearest planet thought to be habitable, Gliese 667 Cc, using the Pluto-bound New Horizons Probe, the fastest man-made spacecraft that travels 200km per second.
Energy. Space scientists peg their hopes on the yet-to-be-developed matter/antimatter technology, which they believe would create energy to propel engines through huge distances at speeds thousands of times more than currently possible.
Cost of energy. While the amount of antimatter needed to supply energy for a year’s trip to Mars could be as little as 10gms, according to a report in the Journal of Propulsion and Power , it could cost trillions of shillings.
Storage. Matter and antimatter reactions could be 1,000 times more powerful than nuclear reactions, but the real problem is generating and storing enough antimatter.
