The debate of extraterrestrial life has always been never ending.With many claims and unproven citing of UFOs have created a huge stir among the scienctists fraternity.However no solid proof has surfaced yet.The famous astronomer Carl Segan previously assumed that the solar system is filled with bacteria, however no concrete proof has been received yet.He ,along with famous Russian astronomer I. S. Shklovshii wrote a book named ” Intelligent life in the Universe ” .Just the year before the release of the book Sagam attended first summit of the the new wing of NASA , Search for Extra Terrestrial Research and is acronym as SETI.
Celebrity physicists Stephan Hawking says that other than carbon life form, life can also exist as silicone based lifeform.
To understand the massive tast of finding life.We can take an example- consider the vast ocean on the earth, now we know that marine life exists inside it.Take a tumbler and pour some water from the ocean.You won’t notice any fish inside the tumbler. But fish do exist inside the ocean.
The tumbler here gives the magnitude of universe which has been explored by humans for the search of aliens.
Another probability of life on the planet can be given by Drakes Equation which takes parameter such as distance of planet from its star, size of planet and start etc etc and gives out the actual result.
On the contrary, some scientists also believe that finding alien life could proof lethal to humanity as the alien race might be hostile to us.You would be watching Star Trek , but in real.
On the last notes, its too early to say that aliens do not exist.With new advancements, a clue of extra terretrial life can certainly be found.