If it only was that easy, The search for ET is one that has consumed mankind for centuries. This search has intensified in recent years with the growing number of Exo-Planets being discovered and it is only going to be a matter of time before we discover one that harbors life.
Indeed a telescope is currently being built that may very well find Earths Twin. It is called the European Extremely Large Telescope (E-ELT). this is due to be completed in 2022.
While discovering extra-terrestrial life would be a massive moment in human history, the real prize would be to discover intelligent extra-terrestrial life. There are number of ways which we might be able to detect Intelligent ET.
SETI (Search for Extra Terrestrial Intelligence)
In 1977 at the Big Ear radio telescope in Ohio, astronomer Jerry Ehman picked up a strange signal. It had all the hallmarks of an artificial source, but after 72 seconds it wasn’t picked up again. Its origin remains a mystery This was dubbed the ‘WOW’ signal after Ehman scrawled the word on the computer readout, its the closest we have come to listening to Aliens.
SETI is a private organisation, which is targeting all planetary systems found by Kepler, especially those with planets in the habitable zone (Planets whose orbits are in the Goldilocks Zone of its parent star, not to Hot not to Cold).
Infrared telescopes may offer a way to spot technologically advanced civilisations . Dr Duncan Forgan has studied infrared emissions from asteroid belts and believes that any mining activity could be recognised.
First the heat and dust generated by mining activities would be detectable by infrared space telescopes such as the Herschel Space Observatory.
Second, studying light spectrum of dust clouds would revel whether precious metals suck as platinum were present in reduced amounts.
Another way to detect life is to look for the light from Alien cities – an idea put forward by Professor Abraham Loeb at Harvard University. A 50Km-wide city like Toyko emits enough light to be easily visible with existing scopes if it were on Pluto. A space telescope more than a 100 times wider than Hubble could potentially see city lights on planets around other stars.
I believe it is a matter of when and not if we discover intelligent life on other planets, the sheerÂ size and scale of the universe makes it almost inevitable. Life on Earth sprang up relatively quickly about 500 million years after it was formed, which would lead me to believe that it is a fairly common easy process and anywhere were the conditions are just OK for life, I believe life will start there, and some of these will be intelligent, and some of those like us will leave clues to their existence whether purposely or not.
We just need to find those clues.