New type of exoplanet found: Waterworld

[wautd]

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Scientists have discovered a new type of alien planet — a steamy waterworld that is larger than Earth but smaller than Uranus.

The standard-bearer for this new class of exoplanet is called GJ 1214b, which astronomers first discovered in December 2009. New observations by NASA's Hubble Space Telescope suggest that GJ 1214b is a watery world enshrouded by a thick, steamy atmosphere.

"GJ 1214b is like no planet we know of," study lead author Zachory Berta of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., said in a statement. "A huge fraction of its mass is made up of water."

Adding to the diversity
To date, astronomers have discovered more than 700 planets beyond our solar system, with about 2,300 more "candidates" awaiting confirmation by follow-up observations.

These alien planets are a diverse bunch. Astronomers have found one planet as light and airy as Styrofoam, for example, and another as dense as iron. They've discovered several alien worlds that orbit two suns, like Luke Skywalker's home planet of Tatooine in the "Star Wars" films. [The Strangest Alien Planets]

But GJ 1214b, which is located 40 light-years from Earth in the constellation Ophiuchus (The Serpent Bearer), is something new altogether, researchers said.

This so-called "super-Earth" is about 2.7 times Earth’s diameter and weighs nearly seven times as much as our home planet. It orbits a red-dwarf star at a distance of 1.2 million miles (2 million kilometres), giving it an estimated surface temperature of 446 degrees Fahrenheit (230 degrees Celsius) — too hot to host life as we know it.

Scientists first reported in 2010 that GJ 1214b's atmosphere is likely composed primarily of water, but their findings were not definitive. Berta and his team used Hubble's Wide Field Camera 3 to help dispel the doubts.

Hubble watched as GJ 1214b crossed in front of its host star, and the scientists were able to determine the composition of the planet's atmosphere based on how it filtered the starlight.

"We’re using Hubble to measure the infrared color of sunset on this world," Berta said. "The Hubble measurements really tip the balance in favor of a steamy atmosphere."

Berta and his colleagues report their results online in the Astrophysical Journal.

A watery world
Since astronomers know GJ 1214b's mass and size, they're able to calculate its density, which turns out to be just 2 grams per cubic centimeter (g/cc). Earth's density is 5.5 g/cc, while that of water is 1 g/cc.

GJ 1214b thus appears to have much more water than Earth does, and much less rock. The alien planet's interior structure is likely quite different from that of our world.

"The high temperatures and high pressures would form exotic materials like 'hot ice' or 'superfluid water,' substances that are completely alien to our everyday experience," Berta said.

GJ 1214b probably formed farther out from its star, where water ice was plentiful, and then migrated in to its current location long ago. In the process, it would have experienced more Earth-like temperatures, but how long this benign phase lasted is unknown, researchers said.

Because GJ 1214b is so close to Earth, it's a prime candidate for study by future instruments. NASA's James Webb Space Telescope, which is slated to launch in 2018, may be able to get an even better look at the planet's atmosphere, researchers said.

[Molyneux]

Damn shame that it looks too hot to support life, but still, interesting find. Wonder if it would be possible to have a similar world with a bit less heat?

[Alerik the Fortunate]

Well, it might be moveable or cooled with orbital shades some day. Though it seems like the gravity well would be something of a headache to escape from.

[Malagar]

Damn shame that it looks too hot to support life, but still, interesting find. Wonder if it would be possible to have a similar world with a bit less heat?

Giving that the article said that it was originally formed in the outer edges of the system and slowly drifted inwards, passing the habitable zone along the way. Yes it should be very possible.

[Guardsman Bass]

Damn shame that it looks too hot to support life, but still, interesting find. Wonder if it would be possible to have a similar world with a bit less heat?

Giving that the article said that it was originally formed in the outer edges of the system and slowly drifted inwards, passing the habitable zone along the way. Yes it should be very possible.

It sounds like a proto-gas giant core that fell inwards before it could accumulate a hydrogen atmosphere.

[Sky Captain]

Is this really new discovery? For some reason I was under impression that water worlds are quite common among exoplanets.

[cosmicalstorm]

It seems there must be billions of planets in our galaxy alone. And they seem to be very different to each other. At this point in time I'm quite sure we'd find a galaxy boiling with at least primordial lifeforms if we could look. Really does make the great silence even more disturbing.

[Irbis]

Out of curiosity... I always wondered how a planet made exclusively out of water would look like. Would core still be "liquid" (for given meaning of this word) at enormous pressure or would it crystallize into something? Could such a planet have a magnetosphere? If not, could life evolve shielded from radiation by top layer of the water? If so, could it ever leave water, or would it remain bound by it?

[Sky Captain]

I think problem with water worlds might be the lack of other chemicals required to buld living organisms. If oceans are hundreds of km deep and down below water becomes solid from extreme pressure then how life could possibly form? It is thought that life on Earth originated in shallow ponds rich with dissolved minerals or near hydrothermal wents on ocean floor. None of those would exist on water world.

[Irbis]

Space resupply?

After all, every planet is hit by thousands of meteoroids everyday, many of which contain organic matter. 15.000 tons yearly for Earth, for example, and our system is relatively old and clean. Or, the star is within nebula of organic compounds, and the planet just scoops them along the way. Maybe meteoroids could create approximation of hydrothermal went environment?

Alternatively, if core of the planet is hotter, we could imagine rising currents carrying everything not heavy enough to be trapped to the top while clear (filtered?), colder water sinks? With virtually whole surface being a potential hydrothermal went? No idea how feasible it would be, though.

Or maybe life would begin in atmosphere, and colonize water from above? Scientists seriously consider existence of life on gas giants, which don't have surface either, so... Though, again, I'm not astrobiologist, I'd love to read what someone who actually researched the topic has to say...

[madd0ct0r]

"The high temperatures and high pressures would form exotic materials like 'hot ice' or 'superfluid water,' substances that are completely alien to our everyday experience," Berta said.

hmmm.

Water 'Drop' Planet has been found by Scientists. "Unique amongst the cataloged planets so far, this is the first planet with a thick water atmosphere that we've identified. However, the low gravity and iron core suggest it is unlikely to sustain life, at least as we know it" said renowned scientist Grebblethr'oxaxx. "The planet is much too far from the sun for the initial Galilet formations to take place, with any chance molecules literally boiling away and freezing at the same time. What water has been identified probably exists in the unusual state of 'Hard liquid' a supercooled version of water which is actually denser then hypercooled water (Water rock) but not as dense as our own 'deep water.' With such low gravity, pressure and temperatures it's hard to see how life could get started at all.

Gee Guyz, have you seen the news? Pity about that planet. I guess we could float a solar lens in the atmosphere, or turn the moon into a big reflector dish or something. No, i don't think nukes are a good idea.

[Lord Relvenous]

What the hell are the second two quotes from?

[madd0ct0r]

from a little planet 40 light-years from Earth in the constellation Ophiuchus.

I\'ve been monitoring communications