Discovery greatly increases odds of alien life existing

SMALL rocky planets like Earth may outnumber Jupiter-sized “gas giants” by three-to-one, a recent discovery suggests.

The odds greatly increase the chances of alien lifeexisting in the universe.

Almost all of the nearly 300 planets found outside the Solar System to date have been huge gaseous worlds whose gravity and pressure would make Earth-like life impossible.

Giant planets are much easier to detect by observing how their parent stars “wobble” in response to the tug of their gravity.

But improving technology is starting to allow astronomers to spot smaller planets.

One group of scientists has located 45 more extra-solar planets in our galaxy, the Milky Way — all of them less than one tenth the mass of Jupiter.

The discovery, from the High Accuracy Radial Velocity Planet Searcher survey based at the European Southern Observatory in La Silla, Chile, suggests rocky planets are common.

New Scientist magazine, which reported the planetary haul yesterday, said: “The discovery of a large number of small planets suggests they are abundant in our galaxy, and outnumber Jupiter-sized giants by three-to-one.”

News of the planets broke at a meeting of the International Astronomical Union in Boston, Massachusetts.

The worlds were detected using the gravitational tug method. Many are likely to be “hot Neptunes”, planets composed mainly of water with a layer of hydrogen and helium on top. But it is probable some will turn out to be rocky “super-Earths” a few times more massive than Earth.

In future, it may bepossible to observe one or more of these planets as they pass directly in front of their star. Such “transits” can reveal many of a planet’s characteristics, from its internal structure to the make-up of its atmosphere.

Dr Sara Seager, from the Massachusetts Institute of Technology, who attended the IAU meeting, said: “This really changes things. It marks the beginning of the detailed exploration of super-Earths.”

Meanwhile, a poll has found 70% of respondents believe extra-terrestrial life exists and one-in-two would like to have contact with an alien.

The online poll of 2,356 adults was commissioned as part of the Doritos Broadcast Project, the first attempt to transmit an advert to a distant solar system.

The message, promoting the Doritos tortilla chips to a potential audience of aliens, will be transmitted from the EISCAT Space Centre in Svalbard, Norway, on June 12. It is being aimed at the star 47 Ursae Majoris in the constellation of the “Great Bear” Ursa Major, 42 light years away. The star is said to be similar to the Sun and has a family of planets.