Nearby "Super Earth" May Have Oceans, Thick Atmosphere

http://news.nationalgeographic.com/news/2009/12/091216-new-super-earth-oceans-atmosphere.html

by mattjaynes • 17 years ago

36 29 17 years ago

news.nationalgeographic.com

luchak2• 17 years ago

"Based on its density, scientists think GJ 1214b is made up of about three-quarters liquid water with a solid core of iron and nickel and an atmosphere of hydrogen and helium—not unlike Earth."

what

This is either terrible writing or terrible science (on the author's part, not the scientists', I would imagine). About 70% of the Earth's surface is water, but only a fraction of a percent of Earth's mass is water. (http://bit.ly/7Gfk8V, total water volume from http://en.wikipedia.org/wiki/Water#Water_on_Earth). And the Earth's atmosphere is definitely not primarily hydrogen and helium.

jpwagner• 17 years ago

in theory, that sounds a lot more like Earth than any other known celestial body.

now, whether or not it's all accurate, we'll find out eventually.

luchak2• 17 years ago

I'm not so sure, given the article as written. Comparing Earth and Jupiter:

1. made up of about three-quarters liquid water

False for both. Possibly true for Earth if you're talking about surface area, but that's a pretty generous interpretation of the article as written.

2. with a solid core of iron and nickel

Likely true for both. ("At the center of [Jupiter's] rocky core is probably a metallic ball of iron and nickel, just like Earth's core." http://www.spacedaily.com/reports/Jupiter_Has_Large_Rocky_Co...)

3. an atmosphere of hydrogen and helium

True for Jupiter, not for Earth.

That's 2 of 3 for Jupiter, 1 of 3 for Earth (or 2 of 3 for Earth if you're being generous). Mars sounds a lot more like Earth than GJ 1214b does, based on the article.

GJ 1214b might be more like Earth than any other known exoplanet, but given the murky reporting it's hard to tell.

hugh_7• 17 years ago

Actually it'd be more like a small Neptune/Uranus than a large Earth. Those two planets are made up mostly of a water/ammonia/methane mixture with a solid core and a H/He outer atmosphere.

http://en.wikipedia.org/wiki/Neptune#Composition_and_structu...

eru• 17 years ago

Mars and Venus are more similar to Earth than this.

bioweek4• 17 years ago

How do they know what it's made of? How do they even know the density?

boredguy8• 17 years ago

The gist: spectrum analysis of light that passes through the planet's atmosphere from the system's sun compared to light that doesn't pass through the planet's atmosphere. They look at what light bands the planet's atmosphere absorbed. (IANA astrophysicist, learn more at http://en.wikipedia.org/wiki/Absorption_spectrum )

adamfeldman• 17 years ago

They do spectroscopy - http://en.wikipedia.org/wiki/Spectroscopy

lssndrdn• 17 years ago

To find out what it's made of, they are thinking of using spectroscopy.

To find out the density, it's mass over volume. They infer the mass by the planet's distance from its star and by its orbiting speed, and they get the volume by the amount of light it takes away from the star when it pases in front of it.

lutorm2• 17 years ago

hugh_ is right. It's a mass/volume calculation.

ryanwaggoner• 17 years ago

OT, but can we send a damn probe to Europa already? I want to know if there's liquid oceans there, and if so, do they harbor life? It's in our freaking solar system, for crying out loud!

rms• 17 years ago

Sounds like it will get there eventually. http://www.washingtonpost.com/wp-dyn/content/article/2009/02...

lutorm2• 17 years ago

That article is weird. They already sent a probe to Titan: http://en.wikipedia.org/wiki/Huygens_probe

Maybe it doesn't count if NASA doesn't build it?

robobenjie• 17 years ago

Using Gmm/r^2 we find that it should have almost exactly the same gavitaional pull as earth at the surface (89% g). That's neat. Means we could have a boat with a sealed cabin at the right pressure and sail around the ocean with basically normal gravity.

delano• 17 years ago

We could walk too!

jcruz• 17 years ago

Link to original article in Nature: http://dx.doi.org/10.1038/nature08679 (for those who have access)

nkassis• 17 years ago

$32? Really? For 1 article? I guess they really want you to subscribe at $199 a year. Ridiculous pricing.

Nearby "Super Earth" May Have Oceans, Thick Atmosphere

Related Stories