Do new planets mean a new home for humans?

Belgian and U.S. scientists have discovered three planets which they believe could be inhabitable.

To be potentially inhabitable the distance from a planet to its respective star or sun has to be such that its surface temperatures allow for the existence of water. An inhabitable planet can be neither too hot nor too cold.

An inhabitable planet would also have to be similar in size and mass to Earth - otherwise gravitation becomes a problem.

And all of the newly found candidate-planets fulfill these conditions.

They were found orbiting an "ultra-cool dwarf."

This means their star is only about one eighth of the size of our sun, making it considerably cooler. Their distance from the star is within the zone where life could be possible.

Discovery with a small infrared telescope

The researchers used the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) to find the three Earth-like planets.

TRAPPIST is operated by the Belgian University of Liege and is part of the European Southern Observatory (ESO) in La Silla Chile.

The small telescope is only 60 centimeters in length. But it uses a clever method to detect planets and calculate their mass - it registers the intensity of light emitted by a planet's star when the planet passes in front of the star, as the intensity changes. The difference in intensity holds the valuable information about the character of the planet, its size and orbit. The weaker a star is, the easier it is for scientists to get the information.

One day, the astronomers in Liege hope, it will be possible to discover extraterrestrial life.

They have published their findings in the journal "Nature."

Too far for a trip

The three Earth-like planet hopefuls are relatively near to our solar system in the constellation of Aquarius. But at about 39 light years away it is too far for an astronaut to ever travel. Even the journey of a conventional unmanned spacecraft would take about 30,000 years. The newly discovered planets are however close enough for scientists to study them using existing technologies. For instance, they will aim to find out whether the planets have an atmosphere.

"If we want to find life elsewhere in the universe, this is where we should start to look," Michael Gillon of the University of Liege and lead author of the research said in a statement to the Reuters news agency.

Co-author Julien de Wit from the Massachusetts Institute of Technology (MIT) told AFP that the question of the existence or non-existence of life on the respective planets may be answered in "our generation."

Will we ever break out of our solar system?

In the remote future - and providing long term planning and a lot of patience - we may be able to send an unmanned space probe beyond our solar system.

Russian billionaire Jurij Milner, physicist Stephen Hawking and Facebook founder Mark Zuckerberg presented such a concept in mid-April.

Their idea is to launch a tiny space probe, accelerated using a laser beam at one fifth the speed of light. Then the journey to our closest neighboring solar system Alpha Centauri would only take only 20 years.

fs/za (Reuters, AFP)