Is there anybody out there? What are the chances that other planets have life?

WHY ARE WE SEARCHING FOR EXTRATERRESTRIAL INTELLIGENCE?

Scientists think that there is a reasonable probability that other planets have life. This is because that they think life originated spontaneously through chemistry either on earth or on another planet and then got transmitted to earth. The chemicals and the laws that govern life on earth work throughout the universe.

WHAT ARE THE CHANCES THAT OTHER PLANETS HAVE LIFE?

There are 300-400 billion stars in the Milky Way , our home galaxy . There are at least another 100 billion similar galaxies in the universe. Many of these stars will have planets, but only a small fraction of these planets can have life. They need to be in a quiet part of the galaxy and at an optimum distance from the parent star to form life. Since there are so many stars around, there could still be billions of planets that have the conditions that help form life.

WHAT ARE THE CHANCES THAT OTHER PLANETS HAVE INTELLIGENT LIFE?

Many biologists think that it would be easy for life to start with the right conditions, but not so easy for complex organisms to form from single-cell life forms. It is an even longer and difficult journey from complex organisms to intelligent life. And yet they think there will be other intelligent life in the universe because it is so big.

WHAT ARE THE CHANCES OF SUCCESS NOW?

The chances of success are low at the moment, because we have the ability to look only at nearby stars in our own galaxy . To find a message from an alien source is extremely hard, as the earth needs to be in the way of a message that has been sent from a place not too far away . It might be much easier to spot a planet that has life, as oxygen can be spotted on a nearby planet from the earth, and it is a good clue to life's presence.

WHAT ARE THE FUTURE PROJECTS?

$100-milllion funding by the Russian millionaire Yuri Milner can help scientists build new equipment and buy time at some of the best radio telescopes.

Space telescopes that are to be launched over the next decade or two will be able to look at a nearby planet's atmosphere and figure out its composition. With such small efforts, scientists need a lot of luck to hit something big.