Kepler finds "Mars-size" exoplanets

[Jarvitä]

NASA's Kepler Mission Finds Three Smallest Exoplanets

Astronomers using data from NASA's Kepler mission have discovered the three smallest planets yet detected orbiting a star beyond our sun. The planets orbit a single star, called KOI-961, and are 0.78, 0.73 and 0.57 times the radius of Earth. The smallest is about the size of Mars.

All three planets are thought to be rocky like Earth, but orbit close to their star. That makes them too hot to be in the habitable zone, which is the region where liquid water could exist. Of the more than 700 planets confirmed to orbit other stars -- called exoplanets -- only a handful are known to be rocky.

"Astronomers are just beginning to confirm thousands of planet candidates uncovered by Kepler so far," said Doug Hudgins, Kepler program scientist at NASA Headquarters in Washington." Finding one as small as Mars is amazing, and hints that there may be a bounty of rocky planets all around us."

http://www.nasa.gov/mission_pages/kepler/news/smallest-exoplanets.html

I wonder how much longer Kepler will continue to revolutionize our understanding of how solar systems work on a weekly basis. Remember how we used to think our neighbourhood was littered with super-Earths and hot Jupiters?

 

[NovaSilisko]

2012 is looking to be a great year for exoplanets already!

 

[jedidia]

So now they're discovering smaller than earth bodies around a star 130 lightyears distant with a luminosity significantly smaller than the sun's. I'm impressed!

Another thing that impresses me, according to reports, they're too close to be in the habitable zone. For a star of that luminosity, that means they're practically hugging it! We didn't exactly expect to find planets that close to a star. Exciting times indeed!

 

[squeaky024]

Did they find any Earth sized exoplanets in the habitable zone? I know theres planets that are much larger in the zone but are there any that we could actually walk on without getting crushed?

 

[T.Neo]

I know theres planets that are much larger in the zone but are there any that we could actually walk on without getting crushed?

The issue isn't 'getting crushed', humans could (more or less) survive the sort of gravitational forces on said planets, though walking would be pretty tough, it'd probably be tiresome/painful or cause other problems.

The issue is planets of that size (we're talking... 5-7 Earth masses, perhaps) are so big that they're global "world-oceans"- i.e. covered in a layer of water on the orders of hundreds of kilometers thick. Or worse, they're miniature gas giants.

 

[squeaky024]

It must be a pain getting out of said planet too, it's hard enough getting into orbit here on Earth.

 

[NovaSilisko]

It must be a pain getting out of said planet too, it's hard enough getting into orbit here on Earth.

Without significant advances in propulsion tech, anything landing on those planets better be prepared to stay a while.

Then again, by the time we CAN reach them, that'll probably be a non-issue.

 

[SiberianTiger]

I wonder how much longer Kepler will continue to revolutionize our understanding of how solar systems work on a weekly basis. Remember how we used to think our neighbourhood was littered with super-Earths and hot Jupiters?

Thus far, it's confirming the general image of the Universe I had in my 10. A sentient mushrooms' planet is ought to be out there, somewhere. :lol:

 

[jedidia]

I know theres planets that are much larger in the zone but are there any that we could actually walk on without getting crushed?

Contrary to general misconception, Large planets must not necessarily have very high surface gravity, since gravity diminishes squarely proportional to the radius. I.e. the density is the major factor for surface acceleration, not the mass in itself.

It is very well possible that a super earth ends up with less than 1.5 G surface acceleration (and unlikely that it ends up with more than two).

 

[fsci123]

The issue isn't 'getting crushed', humans could (more or less) survive the sort of gravitational forces on said planets, though walking would be pretty tough, it'd probably be tiresome/painful or cause other problems.

The issue is planets of that size (we're talking... 5-7 Earth masses, perhaps) are so big that they're global "world-oceans"- i.e. covered in a layer of water on the orders of hundreds of kilometers thick. Or worse, they're miniature gas giants.

Isnt it true that such water worlds may have gravitational forces around 0.8-1.3g but still have relatively high mass?

 

[n72.75]

Isnt it true that such water worlds may have gravitational forces around 0.8-1.3g but still have relatively high mass?

Where did you hear that? I'm not saying it's wrong; just, where did you hear it?

Thus far, it's confirming the general image of the Universe I had in my 10. A sentient mushrooms' planet is ought to be out there, somewhere. :lol:

I loved that book.

 

[T.Neo]

Isnt it true that such water worlds may have gravitational forces around 0.8-1.3g but still have relatively high mass?

Surface gravity depends both on mass and density.