‘Tens of billions’ of planets in habitable zones
PARIS: A scan of small, cool stars in the Milky Way suggests our galaxy has “tens of billions” of rocky planets located like Earth in zones where life can exist, European astronomers say.
The European Southern Observatory (ESO) says it found nine “super-Earths”in a sample survey of 102 stars known as red dwarves.
“Super-Earths” are rocky planets — as opposed to gassy giants — that orbit their stars in the so-called Goldilocks zone, where the temperature is neither too hot nor too cold but just right to have the potential to nurture life.
In this balmy region, the planet is neither scorched nor frozen, and water can exist in liquid form.
The ESO team used a powerful 3.6-metre (11.7-feet) telescope, known by its acronym of HARPS, at their observatory in Chile’s Atacama desert.
“Our new observations with HARPS mean that about 40 percent of all red dwarf stars have a super-Earth orbiting in the habitable zone where liquid water can exist on the surface of the planet,” said Xavier Bonfils of the Observatory of the Sciences of the Universe in Grenoble, southeastern France.
“Because red dwarves are so common — there are about 160 billion of them in the Milky Way — this leads us to the astonishing result that there are tens of billions of these planets in our galaxy alone,” he said in an ESO press release issued on Wednesday.
By ESO’s estimate, there could be around 100 “super-Earths” in stars less than 30 light years from Earth.
In cosmic terms, such distances are just a flea jump, but they are an impossible gap for Man to bridge with current space technology.
A total of 763 exoplanets, the term for a planet in another solar system, have been found since the first was detected in 1995, according to the Extrasolar Planets Encyclopaedia.