| dethalternate | Date: Sunday, 10-January-2016, 5:44 PM | Message # 1 |
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WASHINGTON: Globular star clusters that hold a million stars in a ball only about 100 light years across could be extraordinarily good places to look for space-faring civilizations, say scientists, including one from India.
"A globular cluster might be the first place in which intelligent life is identified in our galaxy," said lead author Rosanne DiStefano, from the Harvard-Smithsonian Centre for Astrophysics (CfA) in US.
Our Milky Way galaxy hosts about 150 globular clusters, most of them orbiting in the galactic outskirts. They formed about 10 billion years ago on average, researchers said. Some scientists have argued that this makes globular cluster stars less likely to host planets. In fact, only one planet has been found in a globular cluster to date.
However, DiStefano and Alak Ray from Tata Institute of Fundamental Research in Mumbai, argue that this view is too pessimistic. Exoplanets have been found around stars only one-tenth as metal-rich as our Sun. While Jupiter-sized planets are found preferentially around stars containing higher levels of heavy elements, research finds that smaller, Earth-sized planets show no such preference.
Another concern is that a globular cluster's crowded environment would threaten any planets that do form. A neighbouring star could wander too close and gravitationally disrupt a planetary system, flinging worlds into icy interstellar space.
However, a star's habitable zone — the distance at which a planet would be warm enough for liquid water — varies depending on the star.
Read more/full article/source - http://timesofindia.indiatimes.com/home....617.cms
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