Now, NASA climate scientists hunt for alien life

After more than 30 years of studying the Earth, a team at the NASA Goddard Institute for Space Studies (GISS) in New York will adapt its global climate model to simulate conditions on potentially habitable exoplanets.

The effort is part of a broader push to identify Earth-like worlds.

"We have to start thinking about these things as more than planetary objects. All of a sudden, this has become a topic not just for astronomers, but for planetary scientists and now climate scientists," said Anthony Del Genio, climate modeller who is leading the GISS effort.

NASA's space-based Kepler telescope has found more than 1,000 alien planets.

At least five of these planets are similar in size to the Earth and located in the "habitable zone" where liquid water could persist.

The next step would be to detect light passing through exoplanet atmospheres, which could hold clues to conditions on these distant worlds, the scientific journal Nature reported.

Del Genio's group is one of nearly 16 -- ranging from the Earth and planetary scientists to solar physicists and astrophysicists -- that are participating in NASA's new Nexus for Exoplanet System Science (NExSS) programme.

The effort has an initial annual budget of roughly $10-12 million.

"We are bringing together a bunch of different disciplines and they all look at the formation and functioning of planets in different ways," added Mary Voytek who organised NExSS.

NExSS will expand the network of researchers collaborating on exoplanets.

It could also help NASA develop missions to hunt for exoplanets in the 2020s and beyond.

At GISS, Del Genio's team is creating 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.

"In 15 or 20 years, we might get a spectrum of a planet that looks Earth-like, and then everyone will be out with their models trying to model that planet. I would like it to happen quicker -- but we need a big telescope," concluded James Kasting, atmospheric scientist at the Pennsylvania State University.