> It is about 2.7 times the Earth's diameter, but weighs almost seven times as much.
2.7^3 = 20 times the volume. But only 7 times the mass. So its density would be only 35% of Earth's density. Earth's density is 5.5g/cm^3. That makes this planet's density 1.9g/cm^3, which looks about right for an object that is partially rock and partially water.
But this ain't a waterworld, it's a steamworld. Imagine the greenhouse effect from all that water vapor!
Does the density & mass calculation affect what the surface gravity would be? If the planet is more massive than Earth, but less dense, would someone standing on the surface experience a greater weight than we do here?
Gravity depends on m/r^2 where m is the mass of the planet and r its radius. Compared to Earth's, m = 7 m_earth and r = 2.7 r_earth, which gives you a gravity 0.96 times the gravity on Earth.
Remarkably similar... But I wonder, if the temperature is 200 degrees, there must be a massive pressure, in order to have liquid water. Where does the pressure come from? Heavy atmosphere?
Pressure is nothing other than gravity pulling down everything that lies above you. So if you go deep enough, there will be enough gas above you to create enough pressure to make water liquid, or even solid.
I wonder whether it will be possible to build a floating city somewhere in the middle of that massive atmosphere. Air conditioning will probably take up the majority of the city's energy consumption, but hey, if you've got water, you can get oxygen, and if you've got boiling water, you can make electricity. Actually, it might be easier to live on this planet than to live on Venus (450C, all CO2).
Boiling water doesn't give you electricity. A temperature gradient gives you electricity. Having a hot, steamy planet won't help you if the air is just as hot as the water.
It would be pretty freaking awesome, although I wonder if the cost of building and maintaining such a station could be recouped from fees and sponsorship.
Moon station: Undisturbed astronomical observation (minimize earth's interference, take advantage of moon's almost non existent atmosphere)? A robotic station on the other side of the moon with a transmission station on our side?
1) Building out sufficient solar power collectors to solve the Earth's energy problems forever.
2) Manufacturing medicines, alloys, and materials that can only be produced in micro-gravity.
3) Protecting humanity against social breakdown and/or extinction in case of massive asteroid strike / global pandemic / etc.
4) Because every dollar that has been spent on space development in the US has put $7 back into the economy by way of spinoffs, technical advances, etc.
If bullet number 4 is correct, it sounds like a good idea. I would have to see proof that bullets 2 and 4 are correct in order for me to agree though.
3) is far fetched and would be catastrophic regardless, and 1) may not be viable because the 15 days of the month where the far side of the moon is facing the sun, it isn't facing the earth. If placed on the other side, 50% of the month, earth would be blocking out the sun on the moon's surface, and the other 50% of the month, the near side of the moon wouldn't be facing the sun.
I tend to think of it from an economic standpoint. It takes a great deal of economic capital to put things into space. Until space is returning a reciprocal amount of value to earth then the equations don't match up. Humans love warring, clicking links the internet, eating, fucking, and arguing instead. Intellectuals and idealists still have to abide by economics. Convince a large swath of the populace that a moon base is a good idea via some means of propaganda or figure out how to extract real tangible value from space. What's on the moon that is immediately valuable? That's the ticket right there.
Upon coming to this conclusion, I have found that I've just straight up given up on space. Someday some species may colonize another planet. I just don't think it'll be the homo sapiens, at least not while I'm around. Leave it up to the foundation of the long now. They're the ones I have any semblance of hope in. At least they've got the right mindset.
"What's on the moon that is immediately valuable? That's the ticket right there."
There's an old joke that, if we'd found oil on the moon, we'd have colonized it in a heartbeat.
Putting aside the absurdity of finding large stores of organic material on the moon, the point is still valid. People usually need an economically viable return on investment before funding such big outlays. It's actually pretty remarkable that our government funded manned space exploration to the extent that it did. And, absent the space race with Russia -- and its military motives -- I wonder if it ever would have.
At the end of the day, I'm perhaps a tiny bit more optimistic than you are about the future of space exploration. But let me reemphasize "tiny." I don't think anything dramatic is going to happen in our lifetimes. And, cynically, I don't think anything short of a tangible ecological disaster of epic proportions, or a second militarized space race with, say, China, is going to get us off our butts.
It's telling that even Star Trek, that most optimistic of sci-fi series, didn't set the dawn of serious space exploration until after a World War 3.
A space station on the moon would require an international effort between many nations willing to fund such an idea. Issues within our own nation and around the world are still too prominent before we begin to significantly make an impact on space travels and exploration.
Have they started doing commercial launches? Last time I checked they were still testing the rockets... But yeah, it's much cheaper and hopefully it'll get cheaper in the future. Still not seeing the price go down to sub-$1000/kg anytime soon, though...
It never ceases to amaze me what information we can glean about things so far away from us.
Zach Berta in the article is my friend, so it's neat to see this article here on HN. :-) When the article was accepted for publication we all watched Waterworld and he gave a high level overview of the research to me (as a non-astrophysicist).
How I understood it is: When the orbiting planet crosses between its star and us, it blocks some of the light, and the decrease in brightness can be used to calculate the diameter of the planet. In addition, the planet orbiting the star makes it wobble a bit, and from that you can calculate its mass. These two things limit the possibilities of the planet's composition, and a watergiant is the most likely scenario. In the papers on the Arxiv[1], it looks like there's finer grained observations than those, though, so maybe that was just what caused them to give it a closer look.
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[ 3.6 ms ] story [ 63.5 ms ] thread2.7^3 = 20 times the volume. But only 7 times the mass. So its density would be only 35% of Earth's density. Earth's density is 5.5g/cm^3. That makes this planet's density 1.9g/cm^3, which looks about right for an object that is partially rock and partially water.
But this ain't a waterworld, it's a steamworld. Imagine the greenhouse effect from all that water vapor!
http://en.wikipedia.org/wiki/GJ_1214_b
I wonder whether it will be possible to build a floating city somewhere in the middle of that massive atmosphere. Air conditioning will probably take up the majority of the city's energy consumption, but hey, if you've got water, you can get oxygen, and if you've got boiling water, you can make electricity. Actually, it might be easier to live on this planet than to live on Venus (450C, all CO2).
2) Manufacturing medicines, alloys, and materials that can only be produced in micro-gravity.
3) Protecting humanity against social breakdown and/or extinction in case of massive asteroid strike / global pandemic / etc.
4) Because every dollar that has been spent on space development in the US has put $7 back into the economy by way of spinoffs, technical advances, etc.
3) is far fetched and would be catastrophic regardless, and 1) may not be viable because the 15 days of the month where the far side of the moon is facing the sun, it isn't facing the earth. If placed on the other side, 50% of the month, earth would be blocking out the sun on the moon's surface, and the other 50% of the month, the near side of the moon wouldn't be facing the sun.
Upon coming to this conclusion, I have found that I've just straight up given up on space. Someday some species may colonize another planet. I just don't think it'll be the homo sapiens, at least not while I'm around. Leave it up to the foundation of the long now. They're the ones I have any semblance of hope in. At least they've got the right mindset.
There's an old joke that, if we'd found oil on the moon, we'd have colonized it in a heartbeat.
Putting aside the absurdity of finding large stores of organic material on the moon, the point is still valid. People usually need an economically viable return on investment before funding such big outlays. It's actually pretty remarkable that our government funded manned space exploration to the extent that it did. And, absent the space race with Russia -- and its military motives -- I wonder if it ever would have.
At the end of the day, I'm perhaps a tiny bit more optimistic than you are about the future of space exploration. But let me reemphasize "tiny." I don't think anything dramatic is going to happen in our lifetimes. And, cynically, I don't think anything short of a tangible ecological disaster of epic proportions, or a second militarized space race with, say, China, is going to get us off our butts.
It's telling that even Star Trek, that most optimistic of sci-fi series, didn't set the dawn of serious space exploration until after a World War 3.
Source: http://www.spacex.com/falcon9.php
Zach Berta in the article is my friend, so it's neat to see this article here on HN. :-) When the article was accepted for publication we all watched Waterworld and he gave a high level overview of the research to me (as a non-astrophysicist).
How I understood it is: When the orbiting planet crosses between its star and us, it blocks some of the light, and the decrease in brightness can be used to calculate the diameter of the planet. In addition, the planet orbiting the star makes it wobble a bit, and from that you can calculate its mass. These two things limit the possibilities of the planet's composition, and a watergiant is the most likely scenario. In the papers on the Arxiv[1], it looks like there's finer grained observations than those, though, so maybe that was just what caused them to give it a closer look.
[1] http://arxiv.org/find/all/1/all:+AND+berta+gj1214b/0/1/0/all...