Distant Planet Shows How Earth Could Meet Its End

The Hubble Space Telescope has helped make yet another eye-catching discovery of a planet with a halo of hydrogen in its trail. How tail-catching!

The exoplanet is about 33 light years away from Earth but 23 times massive and is about as big as Neptune. Astronomers initially took it to be a fairly small planet but only when they saw it pass before its star, they did realize its massiveness. The exoplanet GJ436b takes just three days to orbit its star.

"When you're searching in the visible region you only see the shadow of a planet whose size is equivalent to four times that of Earth like Nep­tune. But if the sensitive eye is pointed toward the Hubble ultra violet light, the planet is transformed into a veritable monster, far bigger than the star," said David Ehrenreich, the study's lead author.

The cloud that gives the planet a comet like appearance is due to evaporation of hydrogen from the planet's atmosphere. Researchers believe that such exoplanets depict scenarios possible for Earth after four billion years, when the Sun turns into a Red Giant, making life as we know impossible to survive on the planet. Additionally, researchers believe that evaporation could explain the disappearance of atmosphere from planets that got too close their host stars. In GJ436b's case, the planet is no under threat.

"This cloud is very spec­tacular; it's as if, after carrying the planet's atmosphere at a high tempera­ture, causing the hydrogen to evaporate, the radiation of the star was too weak to blow away the cloud that accumulated around the planet," Ehrenreich said.