what does mass have to do with radius? the radius of a ton of feathers has no more mass than a ton of bricks. that's like multiplying bricks times feathers to get gravity.
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Scientists find most Earth-like planet yet
- Thread starter GnrlyMrly
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Sigh ... the gravitational force of any object X at any distance is proportional to its mass and inversely proportional to the square of the distance.
Force on 1kg at surface of Earth = GMe/Re^2 (G = gravitional constant, Me = mass of earth, Re = radius of earth)
Force on 1kg at surface of Planet = Gx5Me/(1.5xRe)^2 = 5/(1.5^2)xGMe/Re^2 = 5/(1.5^2) x force on 1kg on Earth.
Gravitional force on surface of planet = 2.2g.
QED.
(Edit: and before you jump in again, kg is a measurement of mass which is constant whatever the force of gravity is. It's weight that would differ and weight != mass)
Edit 2:
I hope you're just pulling his leg.
Actually it's a problem of mass and energy, as they are interchangable (E=mc^2). As acceleration and velocity increase, so does mass, as you're constantly putting more energy into it. More mass means more energy needed to apply more acceleration. Long story short, to attain a velocity of c requires an infinite amount of energy. You can get closer and closer to c, but barring the discovery of warp drive, you'll never get completely there.
actually, i've solved the problem of going faster than the speed of light.
when you pass the speed of light, time travel becomes possible.
the error everyone seems to be making is the energy required to exceed 186,000 miles per second. the expenditure of energy becomes prohibitive.
there is a much better way to do it!
slow down light. we already know how to do that. now, we just need to put a spaceship in the slowed light stream and we can travel that 90k years in no time at all.
there's always more than one way to skin a cat.
book coming soon!
If you can pull an accelleration of a full g all the way (Well, half way and a full g decel, cos there's no point getting there travelling at 20 trillion m/s) you can get there in 8.8 years. Not bad, eh? Of course the problem is getting the fuel to do it. Fusion might work, but Antimatter would be optimal.
New life goal...
Oh, and about the problem of moving faster than the speed of light. True, you can't, but when you travel at very high speeds, time dialation / length contraction (Which are really the same thing, just from different points of view) means that the person doing the acceleration can get to somewhere 20.4 light years away in less than 9 years. It will take more like 25 years (plus 20.4 year light speed communication time) for someone on Earth to see them get there.
New life goal...
Oh, and about the problem of moving faster than the speed of light. True, you can't, but when you travel at very high speeds, time dialation / length contraction (Which are really the same thing, just from different points of view) means that the person doing the acceleration can get to somewhere 20.4 light years away in less than 9 years. It will take more like 25 years (plus 20.4 year light speed communication time) for someone on Earth to see them get there.
I wondered about that. The $450bn spent so far on Iraq would probably have gotten us quite a bit closer to nuclear fusion.
Although they'd probably immediately use it to power weapons
You may already know this, but nuclear fusion powered weapons already exist. They are called thermonukes. ie. normal nuke sets off nuclear fusion chain reaction making bigger explosion. First one was set off over Bikini Atoll a very long time ago???
Hence the bit in brackets. I took account of that. If you didn't need to slow down, the time taken would be a LOT less.
No, because that would imply you would be going faster than the speed of light The planet is 20.5 light years away ... that's the minimum time anything would take to get there.
I'm sorry, but it is YOU who is mistaken.
The concept of not being able to break the speed of light only applies for stationary observers.
If you travel at high speed, length contraction means the distance you have to travel will be shorter. This means that it IS possible to reach this planet in less than 9 years.
Different observers see different things. A stationary observer would see the spacecraft taking over 20.4 years to get to the planet.
Trust me... I'm a future Rocket Scientist : ) I do know what I'm talking about, but if you insist on arguing, I'm happy to oblige ; )
Well, yes, but no, no and no.
Clocks on fast moving things run slower then clocks that don't. ie. Atomic clock on 747 and flown around the world when compared to atomic clock left on ground showed a discrepancy too large to be an error. Also, particles created in the upper atmosphere by cosmic rays should never survive long enough to make it to the ground, but they are frequently detected here, because of time dilation / length contraction.
I believe the movie Contact featured wormholes, and so the person wasn't actually moving... So, bad analogy.
No, I'm not going to argue. Your original unedited comment made no mention of time dilation.
Since I'm never going to go above 30,000 feet, I look at from my point of view. It's all relative.
OK, I suppose that's true, but I did edit my post to add the extra bit immediately after posting.
And if you replied immediately after I submitted my unedited post, it took you, what... 25 minutes to write two lines???