Washington: Nasa scientists have joined the hunt for extraterrestrial life and will adapt a global climate model to simulate conditions on potentially habitable exoplanets.
The effort by Nasa Goddard Institute for Space Studies (GISS) is part of a broader push to identify Earth-like worlds.
Nasa's space-based Kepler telescope has pinpointed more than 1,000 alien planets by observing the brief interruption of starlight that signals a planet passing in front of its parent star.
At least five of these planets are similar in size to Earth and located in the 'habitable zone', where liquid water could persist.
"We have to start thinking about these things as more than planetary objects," said Anthony Del Genio, a climate modeller who is leading the GISS effort.
"All of a sudden, this has become a topic not just for astronomers, but for planetary scientists and now climate scientists," Del Genio said.
Del Genio's group is one of around 16 - ranging from Earth and planetary scientists to solar physicists and astrophysicists - that are participating in Nasa's new Nexus for Exoplanet System Science (NExSS) programme, 'Nature.com' reported.
"We are bringing together a bunch of different disciplines, and they all look at the formation and functioning of planets in different ways," said Mary Voytek, who directs Nasa's astrobiology programme and organised NExSS.
NExSS will expand the network of researchers collaborating on exoplanets, she said.
That should help scientists to make sense of existing data and observations from the James Webb Space Telescope and the Transiting Exoplanet Survey Satellite, which are both scheduled for launch in 2018.
It could also help Nasa develop missions to hunt for exoplanets in the 2020s and beyond.
At GISS, Del Genio's team has started repurposing the institution's workhorse Earth-system climate model.
The researchers are trying to locate simple parameters that are fixed for Earth, such as 24-hour days and 365-day orbits, in order to create an exoplanet model that can be adjusted for different planetary systems.
Initial simulations will focus on the Earth's ancient past and the evolution of Venus and Mars. Although neither can support life today, each may have had liquid surface water at some time.
The team's ultimate goal is to explore the concept of a habitable zone by mixing and matching some of the key factors that determine whether a planet can support life.
By feeding these parameters into the exoplanet model, the group will create a database of 'hypothetical atmospheres' with spectra that could be visible to astronomers.
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