Kepler 452b is best candidate for life so far
LONDON: A ‘‘superEarth’’ 1400 light years away has emerged as the exoplanet most likely of any known to support alien life.
Kepler 452b, discovered in 2015, lies in its star’s ‘‘habitable’’, or ‘‘Goldilocks’’ zone, where temperatures are not too hot and not too cold to permit liquid surface water.
Almost 4000 exoplanets have been discovered and of these, only about 50 are known to occupy their star’s habitable zone.
However, just one — Kepler 452b — also falls inside what is called the abiogenesis zone. A planet in such a zone is bathed in the right level and type of ultraviolet radiation from its star to kickstart the kind of chemical reactions thought to have given birth to life on Earth.
Scientists at Cambridge University coined the term after conducting laboratory experiments mimicking the creation of life’s building blocks.
A leading theory for the way life began on Earth is that it emerged from chemical reactions involving hydrogen cyanide and hydrogen sulphite, powered by sunlight.
Duplicating earlier work conducted in 2015, the Cambridge researchers created the precur sors of lipids, amino acids and nucleotides — all essential components of living cells.
They then went a step further by comparing the UV light used in the laboratory to that generated by different stars. Generally, the most sunlike stars were found to emit the right sort of light to trigger the formation of life’s building blocks.
Kepler 452, in the constellation of Cygnus, is about 20% brighter than the sun and some two billion years older.
Computer simulations suggest its planet 452b has a thick atmosphere, liquid surface water and active volcanoes. — PA