http://www.eso.org/public/outreach/press-rel/pr-2009/pr-15-09.html
Gliese 581 c and d are large exoplanets orbiting a star a mere 20 light years from earth, both weigh in at about 8 earth masses and are believed to have formed as icy giants in the outer solar system and drifted in. At the time of their discovery in 2007 it was believed that 581 d was frozen solid, and c was on the very very inner edge of the habitable zone in terms of temperature. Further investigation revealed that the likely greenhouse effect caused by its enormous mass would make any life like that on earth nearly impossible as most of the planet would be superheated steam.
However yesterday Gliese 581 e was discovered, with a mass of only 1.9 earths it is almost definately a rocky planet, perfect for life but it is far too close to the star.\
Don't despair however those who hope for an alien fishing trip, the new updated Data now places Gliese 581 d perfectly in the habitable zone. Its 'most likely' structure is a single giant endless ocean of liquid water, about 78 KM deep before it freezes. Surface gravity would be near identical to earth due to the lower density, and all in all with just a few methods for generating convection currents rising from the deep ocean to throw stuff back into the upper ocean it would be perfect for life.
So, what do we all think? Even if Gliese itself turns out to be a dud, this means we have found earth size planets and planets in the habiable zone of their stars even in the presence of near solar giant planets. This means there are likely hundreds of trillions of these planets, more common than grains of sand on the beach. On the drakes equation we very rapidly move from life being rare and far away, to life being uniform and everywhere!
edit - In other good news, the Bebo social networking site has already sent them some spam email, back in 2008 when it looked that c might just be habitable.
http://www.bebo.com/amessagefromearth
Posts
/facepalm
Kagera: at my top speed it would take 3000 trillion years.
I am not sure about spaceships though.
Billions of years? I didn't think our propulsion technology was that advanced yet given that we don't even have any interplanetary spaceships
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edit: thats like walking to the waffle house down the road
Shogun Streams Vidya
20 light years is 189,085,099,110,000 km...
About 592,122 years, though I might have counted it wrong?
Seriously though, I think it's already a time to send a trip to Mars to find the ruins of an dead alien race so we can harness their amazing technology and get off this rock already.
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http://lexiconmegatherium.tumblr.com/
Such a cool name though.
I ain't just a plain centaur...I'm the ALPHA Centaur!
Seriously though, we need to start inventing antimatter and fusion reactors already.
It wouldn't be entirely ocean, it would just be covered by it so much that land masses wouldn't be visible. I mean look at Earth, 71% of our surface is covered by water, it isn't such a huge stretch to imagine that there are planets out there that have shaved off those few dozen remaining percentage points.
Also, Europa:
http://en.wikipedia.org/wiki/Europa_(moon)
I mean even Mars right now has enough water to coat the whole planet in about 20 m of water.
I'd wager that if we honestly devoted resources to it, we could drop a few orders of magnitude off that number inside a decade. We just haven't put any effort into increasing space-speeds in forever, since all we do these days is putter 30 year old superplanes around the exosphere.
Well, could we add the speed of the earths orbit (29.7km/s) to the ship's velocity assuming it is in approximately the same horizontal plane as our solar system. Unless there is something about orbit's I'm failing at.
also, our sun and the destination star could easily be moving away or towards each other at 40km/s, which could mean we get there twice as fast or never.
Edit: according to this we are moving at 268.2km/s around the center of the galaxy, so a nearby stay (20light years) is probably also orbiting the center of the galaxy at about the same speed as us seeing as how the milky way is 100,000 light years across. so yeah, forget the +/- 40km/s, doesn't work that way for nearby stars, my bad.
http://www.cosmosmagazine.com/news/2455/milky-way-spins-faster-has-more-mass-thought
I can't wait when we get to Mars, though. That should happen during my lifetime as well.
Pfft, getting there is boring.
Setting up a colony would be cool.
... It's only now that I realize how big space is.
20 lightyears, is just a peas in the pod when you talk about space, honestly. If there is a planet supporting life this close from us, we would be REALLY lucky.
Artist's impression of Gliese 581e...I'd say that the sunrises would be kind of depressing.
We could have Orion drive propulsion, it'd fast as shit! Too bad the cold war happened and "nukes in space" got such a tacky feel to it
Actually, you don't need a core at all. Current theories suggest a core is likely, but once you get up to a few earth masses you could just plop a big thing of pure H2O right there and it would be just as stable as earth is. More in fact, rocky planets have an upper limit on their size, liquid and gaseous planets do not.
On this planet its not very big by liquid giant standards so it doesn't need a rocky core at all. Water doesn't usually freeze under pressure (think fish in a pond in winter, anything but H2O in there and it freezes from the bottom up rather than the top down) however under sufficient pressure it does freeze under compression. So go down 78 km and the water on this planet is crushed into ice.
The big thing about this being habitable would be the need for something down there to get stuff back up into the high ocean where there would be lots of solar energy. Otherwise all there would be was water, no carbon and metals which life needs. Once you have sub-ocean ice volcanoes, or gigantic planet spanning super currents to get things mixing into the high ocean then you could get all kinds of stuff on the surface over time. Even huge mats of floating seaweed, which could allow land animals to evolve.
Its tidally locked though, so it would be an odd place. Hopefully this might mean a constant churning balance between the hot sun side and the colder dark side which would encourage nutrients to not simply fall to the bottom.
Orion drive is certainly good in the solar system, unfortunately extra solar probes are always going to be slow.
Even if we could build a ship with 90% of its mass being fuel, and that fuel being matter and anti matter and we could build a pusher plate design with zero reflectivity which could radiate heat fast enough to allow us to achieve an average speed of 66% of top speed (1/3 accelerate, 1/3 cruise, 1/3 brake) it would still take 82 years to get there. Orion drives work in the interstellar medium, but only just.
It'd be the ultimate case of "well, our generation doesn't have to worry about it..."
There are two real ways to explore the wider galaxy—find some way to cheat, through whatever contrivance of engineering, and get there faster than would seem possible now, or live for a really, really long time.
This is 82 years from Earth's point of view right?
So?
Edit: Good point though, if we got to say 30% of light speed, how long would it seem like to people on-ship?
...and only kicks in when you hit relativistic speeds. At the point where you have meaningful time dilation, the travel time drops down to ~25 years or so even without dilation.
Of course, it's entirely possible that we'll find life elsewhere within our own solar system before too long anyway.
Still requires you to get to around 99.99% of the speed of light before it's usable, which is beyond the capabilities of any known or projected propulsion system. I guess maybe a really insane battery of lasers near Sol pushing on a solar sail might work, but that'd take an engineering program of a truly enormous scale. It's also technically possible that you could achieve this with antimatter, I guess, but I wouldn't bet on it.
Or someone else finds us.
Personally, I'm hoping we find a race of MASSIVE space whales under that ice in Europa. Like the size of cities. Something so huge and alien that mankind hasn't been able to imagine it before.