Space telescopes may soon start detecting air-breathing aliens in exoplanets

May 18th, 2009 - 6:19 pm ICT by ANI  

London, May 18 (ANI): The day is not far when it would be possible to see signs of life on planets far away from our own solar system-thanks to space telescopes that could soon be able to detect “biosignatures” in the light from planets orbiting other stars.

Talking at an astrobiology meeting, scientists revealed that it could be possible to get clues of life on such exoplanets via tiny fraction of the parent star’s light that interacts with the planet on its journey towards Earth.

Already, the Hubble and Spitzer space telescopes have detected gases such as carbon dioxide and water vapour in the atmospheres of a handful of gas-giant exoplanets while they pass in front of their parent stars.

But these instruments are not sensitive enough to detect evidence of life - so-called biosignatures - in the spectrum of rocky Earth-like planets.

One of the most important biosignature is oxygen and it was announced that NASA’s infrared James Webb Space Telescope (JWST) could distinguish signs of oxygen present in the atmospheres of Earth-like planets around the nearest stars.

Another promising device is NASA’s proposed Terrestrial Planet Finder, which could launch in the 2020s and would be powerful enough to spot oxygen-rich planets in systems much farther from Earth (even when they are not passing in front of their parent stars) by seeing light reflected from the planet’s surface.

However, oxygen alone does not prove that life is present, especially on a planet close to its parent star.

Another possible biosignature might be found in the light reflected off living matter like cyanobacteria, reports New Scientist magazine.

The red and blue light reflected from an alien world could be used to create maps of its oceans, which could at least indicate the planet is habitable.

In an experiment led by Nicholas Cowan of the University of Washington in Seattle, researchers made maps by using the measurements by NASA’s Deep Impact spacecraft, which showed Earth’s apparent colour varying over time.

When more water is on the side facing the probe, the planet appears bluer, while a large landmass looks redder-which helped the researchers to construct a crude map of how land and water are distributed on our planet.

The researchers said that a telescope like NASA’s proposed Terrestrial Planet Finder could do the same for Earth-like exoplanets.

The findings were presented at a symposium on the search for life beyond Earth held last week in Baltimore, Maryland. (ANI)

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