Way back in August 1982, when none of you were around on Earth, there was a cute little story about an alien child who is left behind on Earth by his parents and others in their space ship. That story, titled E.T. (Extra Terrestrial) became one of the most famous movies of all time. If you have not seen this adorable film, tell your mum and dad to get it on DVD or Blu-Ray for you. There are many other movies, TV series and books about such alien creatures who visit the Earth.
There are many people who claim to have seen alien spacecraft like the one in E.T. These are called Unidentified Flying Objects (UFOs) or Flying Saucers. But none has been positively identified as an alien spaceship, which brings us to the question – do aliens really exist ?
It is very difficult to think that life exists only on Earth, because there are billions of stars in the universe. Most of them have planets orbiting them (like our Sun and the nine planets including Earth) and chances are that life exists in at least some of them. Scientists have already discovered 3,815 such planets orbiting distant stars. Some of them might harbour life, even 'intelligent' life like animals and Man here on Earth.
What is the key to life ? It is what we drink everyday - water. The key for life is for a planet to be in its star’s 'habitable zone', where temperatures could allow liquid water to exist as oceans and rivers. Now, scientists have identified a group of such 'Exoplanets' which have the same chemical conditions thought to have led to life on Earth. The planets identified so far have stars with sufficient light and also lie within the habitable zones of their stars. Several of the planets identified in the study were discovered by the Kepler Space Telescope, including Kepler 452b, about 1,400 light-years away, which has become known as 'Earth’s cousin.' It is estimated to have a weight five times that of Earth, is likely to be rocky, and orbits within its sun-like star’s habitable zone. We simply do not have the technology capable of visiting these planets now, so scientists can only study them from the Earth.
In the meantime, scientists are looking for life outside the Earth through other methods. These are collectively called SETI, or Search for Extra Terrestrial Intelligence. These scientists basically listen to space radio frequencies to see whether there are any radio signals of artificial origin. Just one week ago, scientists in Canada detected one such 'Fast Radio Burst' which some scientists say could have been sent by advanced aliens. We are also sending similar radio signals out to space with the hope that aliens may come across them one day. A few spacecraft are also carrying audio and video recordings about the Earth to deep space in the hope that aliens may find them. One of them carries the Sri Lankan greeting “Ayubowan” as well.
What will intelligent aliens look like, if we come across them ? Could they be ugly and cute at the same time, as in E.T. ? Could they be downright disgusting as in the movie Independence Day ? Interestingly, another alien movie called The Thing came right after E.T. way back in 1982, which featured a shape-shifting alien monster. No one liked that alien. But we cannot hope that all aliens will be adorable. Scientists say that we will probably come across evidence of alien life within the next 20 years. Perhaps one of you will be the first to meet an alien from outer space one day and say “Ayubowan” or “Vanakkam”.