‘Tens of Billions’ of Potentially Habitable Planets Found in Milky Way

Astronomers at the ESO in Europe conclude that there are tens of billions of rocky planets in potentially habitable zones in our galaxy.

A multiyear study done by the European Southern Observatory (ESO) concludes there are tens of billions of rocky planets in potentially habitable zones in the Milky Way. Photo: NASA's Marshall Space Flight Center/Flickr

Researchers found out that at least 100 of the ”super-Earths” may be on our galactic doorstep, at distances of less than 30 light years, or about 180 trillion miles, from the sun, reports The Telegraph.

A European team of astronomers announced that about 40 percent of red dwarf stars – the most common type in the Milky Way – have a so-called “super-Earth” planet orbiting in a habitable zone that makes it possible for water to flow on the surface.

According to scientists, where there is water, there also could be life. However, they said that being in the habitable zone is no guarantee that life has evolved on a planet.

If there are around 160 billion red dwarfs in the Milky Way, the number of worlds that are potentially warm enough and wet enough to support life is enormous, tells Guardian (UK).

“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,” team leader Xavier Bonfils from the Observatoire des Sciences de l’Univers in Grenoble, France, said in a statement.

“Because red dwarfs 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.

CNET writes that the analysis also found there are about 100 “super Earths,” or planets with masses between one and 10 times that of Earth, orbiting stars that are relatively nearby. The astronomers define “neighboring” as about 30 light-years away.

The astronomers surveyed a carefully chosen sample of 102 red dwarfs using the European Southern Observatory’s 3.6-metre telescope at La Silla, Chile.

More massive planets, with masses 100 times to 1000 times that of Earth – similar to Saturn and Jupiter – were found to be rare around red dwarfs.

However, massive planets similar to Jupiter and Saturn were rare around red dwarfs. Less than 12 per cent of the stars were expected to have such ”gas giants”.

But the rocky worlds that spinning around red dwarfs are not necessarily good places for alien forms of life.

Reds dwarfs are much cooler than the sun,that is why any planets with liquid water will need to be orbiting much closer to the star than the Earth is from the Sun. That may mean they are bathed in damaging X-ray and ultraviolet radiation.

Dr Stephane Udry, from Geneva Observatory, who is also a member of the international team, said: “The habitable zone around a red dwarf, where the temperature is suitable for liquid water to exist on the surface, is much closer to the star than the Earth is to the sun.

”But red dwarfs are known to be subject to stellar eruptions or flares, which may bathe the planet in X-rays or ultraviolet radiation, and which may make life there less likely.”

Scientists are going to take a closer look at some of the Earth-like planets as they pass in front of nearby red dwarfs. That should yield information about their atmospheres and help in the search for possible signs of life.

The research will be published in the journal Astronomy & Astrophysics.

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