Nearest Sol-Like Star May Host Habitable Planet Pages PREV 1 2 grigjd3 albino boo: grigjd3: albino boo:According to the law of gravity, the attractive force between two bodies is proportional to the product of their masses and inversely proportional to the square of the distance. If density was a factor then 1kg of feathers would fall slower than 1kg of iron. You have no clue what you are talking about. The force of gravity is F = GM1m2/r^2. That is the force is equal to a number times the mass of one object times the mass of the second object divided by the square of the distance between the two *centers* of mass. If the planet is larger, the *center* of mass of the planet is further from the *surface* of the planet, thus reducing the force of gravity - thus in this case, the density of the planet is particularly important to the surface gravity. And by the way, your analogy isn't referring to the density of the planet but the density of the object you are dropping - in other words, you're completely misquoting the equivalence principle. Do you mind pointing out where there term for density is in F = GM1m2/r^2. desnity(planet) = 4*PI*M1/(3*r^3) => M1 = 3*density(planet)*r^3/(4*PI) => F = G*m2*3*density(planet)*r/(4*PI) That would do it exactly. EDIT Sorry, algebra mistake (I'm a bit tired right now): density(planet) = M1/Volume Volume = (4*PI*r^3)/3 => => F = G*m2*4*PI*density(planet)*r/(3*PI) That would do it exactly. dmase Vuliev: Mark D. Stroyer:So many great gritty sci-fi futures are opening up as legitimate possibilities! But...FIVE TIMES the mass? Oi. That'll take some acclimating. Doesn't necessarily mean that that planet is five times as dense. More likely, it's just really big. I'm not sure about that because if the planet was as dense as earth yet 5 times as big I think that would mean it would basically "implode" on itself, unless it was a very gassy planet which I believe they would be able to tell right off the bat. Though I'm not structural meteorologist/geologist and I'm just guessing. As for someone else who said the chemical bonds wouldn't be able to form under those conditions I'd point back to another article the escapist had saying they found living single cell organisms in a heavily toxic lake, where the cells where actually using... arsenic I believe to fuel the cell. The first planet we find with complex diverse molecules will probably rewrite the book on Organic chemistry and evolution. If not then I think there is absolutely no chance of finding another planet with living organisms ever beyond earth. Vuliev dmase:I'm not sure about that because if the planet was as dense as earth yet 5 times as big I think that would mean it would basically "implode" on itself, unless it was a very gassy planet which I believe they would be able to tell right off the bat. Though I'm not structural meteorologist/geologist and I'm just guessing. Not five times as big, no. Twice, I guess? I dunno. DRTJR When are we going to be able to boldly go were no man has gone before. CrazyGirl17 Neat! Now if only there was a faster way to get there and see if there are any alien life forms... survivor686 Excellent. All we need now is for NASA to finish that warp drive and thus will begin our glorious expansion. Seriously if I was NASA I'd be singing these news from the mountain tops when it comes time for funding. WiseBass The error margin is 2.0 Earth-masses, so it could actually be anywhere from 2.29 to 6.29 times the mass of Earth - or even higher, since these are lower limits. Assuming that they're there and not just issues with the signal, it's pretty good news*. Hopefully it's closer to the bottom of that range (2-4 times Earth mass), because then I'd feel more confident that it's a rocky planet and not a failed-gas-giant-core turned water-planet. I don't think Kepler can find its radius, so our best bet is to try and direct-image it from Earth with planet-side telescopes (which used to be virtually impossible, but adaptive optics is good news). One thing has me a little concerned - Steve Vogt. He was involved in that Gliese 581g debacle, where the team kept on insisting that the planet was there despite repeated independent verifications that showed that it was a mistake. * Especially since it would be a potentially earth-like planet around a sun-like star, and not a "MEarth" (a potentially habitable planet around a red dwarf). bananafishtoday More importantly, the star has five planets. Now that we know Tau Ceti V is a real thing, someone needs to get to work building Shodan. albino boo:According to the law of gravity, the attractive force between two bodies is proportional to the product of their masses and inversely proportional to the square of the distance. If density was a factor then 1kg of feathers would fall slower than 1kg of iron. The relevant distance is the distance to the center. You can treat symmetrical spheres as if all their mass is concentrated at the center (shell theorem, proved by Newton.) Planets are close enough to this shape for most purposes. So larger planets of the same mass will have weaker gravity on the surface because you're further away from the center. Frezzato This just in: A planet within the hospitable zone of a planetary system has been discovered, just 12 light years away. We've already received radio transmissions and by the Horns of Gloxnar, they sure do love their pornography. Icehearted If Star Trek and Mass Effect have shown us anything it's that the only important part of seeking out new life on strange new worlds is whether or not we can mate with them. WaitWHAT Tau Ceti? Really? Does nobody remember what happened last time we went there? Pages PREV 1 2