Space scientists have designed the technology to spot planets like Earth around other stars, they have revealed. For the first time, Nasa have demonstrated that a telescope in space could take a snapshot of our own twin outside the solar system.

Previous planets found around nearby stars have been giant gas balls like Jupiter rather than rocky worlds like Earth. We can now even identify what is in their atmospheres.

The problem with snapping other Earths is that the dim glow of the planet is drowned out by the glare of its own parent sun.

But scientists have come up with a system of special masks and mirrors that would hide the starlight but leave the planet in view. It is essentially a sophisticated form of the coronograph used to block out the Sun.

The challenge is like looking for a firefly next to a searchlight. But scientists from Nasa’s Jet Propulsion Laboratory in California say their technology could enable a space telescope to photograph a distant planet 10 billion times fainter than its star.

John Trauger, who presented a paper in the science journal Nature this week, said:
“Our experiment demonstrates the suppression of glare extremely close to a star, clearing a field dark enough to allow us to see an Earth twin. This is at least a thousand times better than anything demonstrated previously.”

Picture: A computer simulation of a masked star, represented by the asterisk, and three planets.

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