We can detect volcanoes on alien worlds, say scientists

Last Updated: Wed, Sep 08, 2010 07:10 hrs

Scientists at at the Harvard-Smithsonian Center for Astrophysics have said that it is possible for us to detect volcanoes on alien planets.

"You would need something truly earthshaking, an eruption that dumped a lot of gases into the atmosphere," said Smithsonian astronomer Lisa Kaltenegger.

"Using the James Webb Space Telescope, we could spot an eruption 10 to 100 times the size of Pinatubo for the closest stars," she added.

In a few cases, scientists have been able to detect exoplanet atmospheres for gas giants known as "hot Jupiters." An eruption sends out fumes and various gases, so volcanic activity on a rocky exoplanet might leave a telltale atmospheric signature.

Kaltenegger, Wade Henning and Dimitar Sasselov found that sulphur dioxide from a very large, explosive eruption is potentially measurable because a lot is produced and it is slow to wash out of the air.

The 1991 eruption of Mount Pinatubo in the Philippines spewed about 17 million tons of sulphur dioxide into the stratosphere.

"Once you detected one eruption, you could keep watch for further ones, to learn if frequent eruptions are common on other planets," said Henning.

To look for volcanic sulphur dioxide, astronomers would rely on a technique known as the secondary eclipse, which requires the exoplanet to cross behind its star as seen from Earth.

Alpha Centauri for instance, would offer a best-case scenario for a Sun-like star. A super-Earth orbiting a smaller host star close to our own Sun would show the biggest signal. But any Earth-like planet less than 30 light-years away could show faint signs of volcanism when studied with the James Webb Space Telescope.

This research will be published in The Astrophysical Journal. (ANI)

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