Astronomers discover extreme planet which rains rocks, has lava seas and 3,000 mph winds

Telegraph reporters
·3 min read
The planet planet has 60 mile deep lava seas - Reuters
The planet planet has 60 mile deep lava seas - Reuters

Astronomers have discovered the most inhospitable planet ever that rains rocks, with 60 mile deep lava seas and winds of more than 3,000 mph.

The Earth size planet has winds four times the speed of sound with temperatures of about 3,000 degrees Centigrade on one side - hot enough to vaporise rock.

But they plunge to below minus 200C on the other - cold enough to freeze nitrogen.

The bizarre exoplanet also harbours a vast ocean of magma - more than 60 miles deep.

Named K2-141b, it lies around 200 light years away - and is one of the "most extreme" ever found.

Studying it is shedding fresh light on the evolution of Earth.

Lead author Giang Nguyen, a PhD student at York University, Toronto, said: "The study is the first to make predictions about weather conditions on K2-141b."

The fiery, hot world has a surface, ocean and atmosphere all made up of the same ingredients - rocks. There are seas of molten lava.

The planet described in Monthly Notices of the Royal Astronomical Society was detected two years ago by the Kepler Space Telescope.

Computer simulations have now predicted the weather.

The inhospitable conditions forecasted may permanently change the surface and atmosphere over time.

An analysis of the light patterns show two-thirds of K2-141b faces endless daylight. On Earth, both hemispheres receive the sun's rays equally.

The exoplanet belongs to a subset of rocky planets that orbit very close to their star, explained the researchers.

This proximity keeps it gravitationally locked in place with the same side always facing it - ultimately creating a thin atmosphere in some areas.

Co author Professor Nicolas Cowan, of McGill University, Montreal, said: "Our finding likely means the atmosphere extends a little beyond the shore of the magma ocean, making it easier to spot with space telescopes."

Remarkably, the vaporised atmosphere mimics Earth's - only with rocks instead of water.

The extreme heat leads to them undergoing precipitation - as if they were particles of water.

Just like the water cycle on Earth where it evaporates, rises into the atmosphere, condenses, and falls back as rain, so too does the sodium, silicon monoxide and silicon dioxide on K2-141b.

On Earth, rain flows back into the oceans, where it will once more evaporate and the water cycle is repeated.

On K2-141b, the mineral vapour formed by evaporated rock is swept to the frigid night side by supersonic winds and rocks "rain" back down into a magma ocean.

The resulting currents flow back to the hot day side of the exoplanet, where rock evaporates once more.

Still, the cycle on K2-141b is not as stable as the one on Earth, say the scientists.

The return flow of the magma ocean to the day side is slow.

As a result, they predict that the mineral composition will change over time - eventually altering the very surface and atmosphere of K2-141b.

Prof Cowan said: "All rocky planets­, including Earth, started off as molten worlds but then rapidly cooled and solidified. Lava planets give us a rare glimpse at this stage of planetary evolution."

The next step will be to test if these predictions are correct, say the scientists. The team now has data from the Spitzer Space Telescope that should give them a first glimpse at the day-side and night-side temperatures of the exoplanet.

With the James Webb Space Telescope launching in 2021, they will also be able to verify whether the atmosphere behaves as predicted.

Added Mr Nguyen: "Next-generation space telescopes such as the James Webb will be able to detect it from hundreds of light years away."