Hubble telescope takes a 'close' look at 'Super Earth' GJ1214b and discovers - clouds!

IT'S an alien planet 40-light-years away. Now Hubble has spent more time staring at it than any other. What it found is pushing the boundaries of exploration.
Jamie SeidelNews Corp Australia Network

An artist's interpretation of a cloudy GJ1214b-like exoplanet. Picture: Space Telescope Scienc...

IT'S an alien planet 'just' 40-light-years away. Now Hubble has spent more time staring at it than any other. What it found is pushing back the boundaries of exploration.

The planet - known as GJ1214b - is known as a "super-Earth" because of its large size and close orbits to their stars.

Very little is known about them. We know they're big. We know they're heavy. We know they're common.

We know there is nothing like them in our own solar system.

Now a team of astronomers have focused space telescope Hubble's eye on one of the closest known examples - and found clouds.

Earlier "looks" at GJ1214b produced several possible options for the planet's atmosphere.

It could have been almost entirely made of water vapour. Or it could have some kind of high-altitude cloud that blocked any observation of what lies beneath.

Hubble gazed at the infinitesimally small pinprick of light for a total of 96 hours over a period of 11 months.

"We really pushed the limits of what is possible with Hubble to make this measurement," the University of Chicago's Laura Kreidberg said. "This advance lays the foundation for characterising other Earths with similar techniques."


GJ 1214b was chosen because it whizzes around its parent star every 38 hours, giving scientists an opportunity to study its atmosphere as starlight filters through it.

Using light from the near-infra-red light spectrum, the researchers found what they believe is definitive evidence of high-altitude clouds blanketing the planet.

How GJ 1214b and GJ436b stack-up against Earth and Neptune.

How GJ 1214b and GJ436b stack-up against Earth and Neptune.Source:Supplied

These clouds conceal what's going on beneath.

Astronomers still don't know what these clouds are made of.


The clouds could be made out of potassium chloride or zinc sulfide at the scorching temperatures of 230C found on GJ 1214b.

Exactly what the clouds are will not likely be known until after the launch of NASA's next major space telescope, the 6.5m James Webb Space Telescope later this decade.

A second team of researchers examined what is categorised as a "Warm Neptune". Only 36-light-years away, GJ436b is much closer to its star than Neptune is to our sun.

The spectra Hubble found was featureless; revealing no chemical fingerprints whatsoever.

Heather Knutson of the California Institute of Technology in Pasadena said: "Either this planet has a high cloud layer obscuring the view, or it has a cloud-free atmosphere that is deficient in hydrogen, which would make it very unlike Neptune.


Both studies appear in the January 2 issue of the journal Nature.