This image shows the Sun, Moon and Earth (not to scale) together with the ‘Earthshine’. Earthshine is caused by sunlight reflecting off the Earth first to the Moon and then back again to Earth(Credit: Enric Palle, Instituto de Astrofisica de Canarias, Spain).
The odds of finding extra-terrestrial life on Earth-like planets outside our own Solar System have suddenly improved.
This is thanks to the pioneering work of a team of astronomers including Dr Stefano Bagnulo based at Armagh Observatory.
The international team have devised a way to filter out the bright light coming from a nearby Star which blocked the view of astronomers when they were trying to look at a planet that might have life.
They team also came up with a definitive way to test for the presence of life on other planets – by looking at Earth from space.
This was achieved using the Moon as a large mirror to look back at Earth. Scientists know that light from the Earth bounces off part of the Moon’s surface and is reflected back to Earth, as ‘Earthshine’.
The signatures of life on Earth, in terms of composition of gases, can be determined by looking in detail at the information in Earthshine.
The scientists found that a unique ratio of gases are present in the Earth’s atmosphere that can only be explained by the action of living organisms. If life didn’t exist here, the gases would interact, and different ratios would be observed.
So if something similar is observed on another planet, it can only mean one thing: Life exists there. This can be determined with certainty without the need to physically travel to that planet.
This could be the method by which life is first discovered on another planet in coming years!
LISTEN: Interview with Dr Stefano Bagnulo
Broadcast on Science Spinning on 103.2 Dublin City FM on 15.03.2012