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Wed 18 Dec, 2013 09:37 pm
If the escape velocity for the moon is about 2.38 km/s(1.5 mi/s.), then what do you think is the escape velocity for one atom or molecule?
@redballoon,
Is this homework?
I will give you the answer anyway because it is cool. The mass cancels out of the equation for escape velocity. It is the same value for microscopic objects as it is for very big objects.
@maxdancona,
In other words, how much speed is needed to escape the gravitational force(mass) of an atom or molecule? Any guesses?
@redballoon,
I think he said if you find the answer for a great big rock, you'll have the answer of an atom.
Not that max can't speak for himself, of course.
@roger,
Makes no sense to me. So, a rock as big as Jupiter would have the same escape velocity as an atom?
@redballoon,
Redundant question. Pretty sure Niels Bohr disproved the possibility of thinking of thinking of electrons as having mass affected by gravity. What do you imagine would launch from an atom?
Gravity is meaningless at that scale. By definition gravity is a long scale effect.
@hingehead,
I don't think gravity is meaningless at atomic level because all mass has gravity, so my question is still waiting for an answer.
Any guesses?
No need to "guess". The escape velocity from a body in metres per second is given by the square root of (2GM)/r where M is the mass of the atom, G is the gravitational constant(6.67x10^-11) and r is the radius of the body. However at the scale being discussed, other forces e.g. electric are significant.
@contrex,
contrex wrote:
other forces
The strong and weak forces and the electromagnetic forces would be stronger than the gravitational force of the atom; also exactly what kind of "object" were you imagining reaching an atom's escape velocity? Where would it go?
@contrex,
Not only that but what would the atom escape from?
Let's say, if an atom of H2O escapes the mollecule, do the other two atoms stay?
@redballoon,
You not thinking it doesn't make it so.
This is from the intro of the Wikipedia entry for unified field theory
Quote:According to the current understanding of physics, forces are not transmitted directly between objects, but instead are described by intermediary entities called fields. All four of the known fundamental forces are mediated by fields, which in the Standard Model of particle physics result from exchange of gauge bosons. Specifically the four interactions to be unified are:
Strong interaction: the interaction responsible for holding quarks together to form neutrons and protons, and holding neutrons and protons together to form nuclei. The exchange particle that mediates this force is the gluon.
Electromagnetic interaction: the familiar interaction that acts on electrically charged particles. The photon is the exchange particle for this force.
Weak interaction: a repulsive short-range interaction responsible for some forms of radioactivity, that acts on electrons, neutrinos, and quarks. It is governed by the W and Z bosons.
Gravitational interaction: a long-range attractive interaction that acts on all particles. The postulated exchange particle has been named the graviton.
Modern unified field theory attempts to bring these four interactions together into a single framework.
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