Kepler finds planet in habital zone, temperature 72f!

[jimmy olsen]

How would one measure the solidity/composition of a planet 600 ly away?

You need to know the planetary radius and mass, we already know how large it is.

To find the mass, you measure the tug of a planet on it's star.


http://en.wikipedia.org/wiki/Doppler_spectroscopy

Jupiter causes the Sun to change velocity by about 13 m/s over a period of 12 years, and the Earth's effect is only 0.1 m/s over a period of 1 year – so long-term observations by instruments with a very high resolution are required.[3][4]

[fhdz]

And then from the mass one is able to guess at the planet's composition?

[jimmy olsen]

If you know the mass and know the size you can figure out the density. Saturn is huge but it's density is so low it would float.

If the density is low it's made of gas, if heavier then mostly water, if heavier still rock.

[fhdz]

If you know the mass and know the size you can figure out the density. Saturn is huge but it's density is so low it would float.

If the density is low it's made of gas, if heavier then mostly water, if heavier still rock.

Yes, I am familiar with density. But that doesn't tell you if there's liquid on it currently. I mean - if it's x heavy, it could be anywhere from all rock to a mix of liquid and heavier rock. I wasn't really talking about high-school level chemistry and physics. I was wondering if there's a way we can actually *tell* something useful about the planet's composition from this far away.

[jimmy olsen]

If you know the mass and know the size you can figure out the density. Saturn is huge but it's density is so low it would float.

If the density is low it's made of gas, if heavier then mostly water, if heavier still rock.

Yes, I am familiar with density. But that doesn't tell you if there's liquid on it currently. I mean - if it's x heavy, it could be anywhere from all rock to a mix of liquid and heavier rock. I wasn't really talking about high-school level chemistry and physics. I was wondering if there's a way we can actually *tell* something useful about the planet's composition from this far away.

Astronomers have done spectral analysis of  the atmospheres of hot jupiters, but I don't think it's yet possible for earth sized planets. It's theoretically possible with better equipment though.

[jimmy olsen]

Nice video explaining the discovery

http://www.youtube.com/watch?feature=player_embedded&v=aDykhzVT15w#!

[Neil]

I'm so ready to colonize

I rather not live on a planet with twice the gravity of Earth.  That's a heart attack waiting to happen.

Depends on the density.

I suppose it could made entirely of plutonium and then it would be poisonous and radioactive in addition to having extremely high gravity.

No, it could never be made entirely of plutonium, and if you understood science, you'd know why.

[Neil]

If you know the mass and know the size you can figure out the density. Saturn is huge but it's density is so low it would float.

If the density is low it's made of gas, if heavier then mostly water, if heavier still rock.

Yes, I am familiar with density. But that doesn't tell you if there's liquid on it currently. I mean - if it's x heavy, it could be anywhere from all rock to a mix of liquid and heavier rock. I wasn't really talking about high-school level chemistry and physics. I was wondering if there's a way we can actually *tell* something useful about the planet's composition from this far away.

Astronomers have done spectral analysis of  the atmospheres of hot jupiters, but I don't think it's yet possible for earth sized planets. It's theoretically possible with better equipment though.

It's not like it's just a matter of better equipment.  What you're talking about is a ridiculously difficult task, not just because of technology, but also because of physics.

[Ideologue]

I'm so ready to colonize

I rather not live on a planet with twice the gravity of Earth.  That's a heart attack waiting to happen.

Depends on the density.

I suppose it could made entirely of plutonium and then it would be poisonous and radioactive in addition to having extremely high gravity.

No, it could never be made entirely of plutonium, and if you understood science, you'd know why.

For real.  Nucleosynthesis-wise, it's like a planet made out of fluorine, except even dumber, and that's before even getting in to its instability.

[Razgovory]

I just thought of something really dense.

[Neil]

For real.  Nucleosynthesis-wise, it's like a planet made out of fluorine, except even dumber, and that's before even getting in to its instability.

I was thinking of the decay.  Even if you started with a whole cloud of plutonium, by the time that the planetary formation process ran through, it would be be mostly decay products.

[jimmy olsen]

If you know the mass and know the size you can figure out the density. Saturn is huge but it's density is so low it would float.

If the density is low it's made of gas, if heavier then mostly water, if heavier still rock.

Yes, I am familiar with density. But that doesn't tell you if there's liquid on it currently. I mean - if it's x heavy, it could be anywhere from all rock to a mix of liquid and heavier rock. I wasn't really talking about high-school level chemistry and physics. I was wondering if there's a way we can actually *tell* something useful about the planet's composition from this far away.

Astronomers have done spectral analysis of  the atmospheres of hot jupiters, but I don't think it's yet possible for earth sized planets. It's theoretically possible with better equipment though.

It's not like it's just a matter of better equipment.  What you're talking about is a ridiculously difficult task, not just because of technology, but also because of physics.

There are space telescopes that are planned which will be capable of that.

[DontSayBanana]

There are space telescopes that are planned which will be capable of that.

Yes, Tim.  The word here is planned.  There is space tourism planned.  There are space elevators planned.  There were plans for missile-destroying laser satellites.  Plans don't necessarily come to fruition.

[jimmy olsen]

There are space telescopes that are planned which will be capable of that.

Yes, Tim.  The word here is planned.  There is space tourism planned.  There are space elevators planned.  There were plans for missile-destroying laser satellites.  Plans don't necessarily come to fruition.

All space telescopes planned and built have successfully fulfilled their mission. There are no technical obstacles to the James Webb Telescope being built.

This is not true true of space elevators, nor ABM satellites.

[DontSayBanana]

All space telescopes planned and built have successfully fulfilled their mission. There are no technical obstacles to the James Webb Telescope being built.

This is not true true of space elevators, nor ABM satellites.

Okay, better analogy: it wasn't technical hurdles that scrapped the Constellation rocket project.

The moral of Constellation is: don't count on technology until funding has been procured, and even then, it's not a lock until post-prototype line production starts.