Scientists need to focus on pale red dots to find Earth-like planets

June 30th, 2009 - 1:57 pm ICT by ANI  

Sydney, June 30 (ANI): A team of astronomers from Spain and the US has suggested that scientists looking for Earth-like planets in distant solar systems might find it more productive to focus on pale red dots, rather than blue ones.

According to a report by ABC Science, the astronomers observed the lunar eclipse of August 2008 from a simulated alien perspective.

They discovered that several biologically relevant molecules, such as oxygen, water, carbon dioxide and methane, show up stronger than expected in longer, redder wavelengths of light.

“The Earth is often referred to as the pale blue dot, but in transmission, the pale blue dot becomes the pale red dot,” said Enric Palle of Spain’s Instituto de Astrofisica de Canarias and colleagues.

The team used optical and near-infrared spectrographs attached to telescopes at the El Roque de los Muchachos observatory in the Canary Islands to observe the light reflected from the moon during the eclipse.

With the Sun positioned behind Earth and the planet’s shadow falling on the Moon, the light reflecting off the lunar surface back to Earth first passed through the planet’s atmosphere.

“The effect is similar to the geometry observed when an extrasolar planet passes in front of its parent star,” said Palle.

When a planet transits a star, part of the starlight passes through the planet’s atmosphere where it interacts with the various atoms and molecules.

Breaking down the light into its component wavelengths then gives scientists insight into the planet’s composition.

Scientists have discovered more than 350 planets orbiting stars beyond the solar system, including at least 58 that transit their parent stars, relative to the perspective of Earth.

“We have a much better idea about what to do to find planets similar to our own where life may be thriving,” said Associate Professor Eduardo Martin of the University of Central Florida in Orlando.

The spectra of Earth during the eclipse also revealed the presence of the planet’s ionosphere, the layer of ionised gas that sits atop of the atmosphere.

Scientists found a telltale sign of ionised calcium atoms, the sixth most abundant element on Earth.

Future investigations could reveal additional ionised elements, such as magnesium, which would appear in shorter wavelengths. (ANI)

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