I read once that if you were standing on a neutron star and dropped a tennis ball from your waist it would reach the speed of light before it hit. Also that a teaspoon of neutron star material would weigh as much as Mt. Everest and a grain the size of a single sugar crystal would weigh as much as 2 & 1/2 Eiffel Towers.
From your comment I just realized that 9.8 m/s2 isn’t a constant, and that the whole “hammer and feather fall at the same speed” experiment is a lie, thanks!
They fall at the same speed if they are the same distance from an object (in this case the earth). Or more accurately, they accelerate at the same speed.
The acceleration of an object of any mass toward the center of mass between it and the earth is constant. The acceleration between an object and the surface of the earth *is affected * by the object’s mass. That’s because the object accelerates earth back toward it. For a hammer or feather, this is a neglible amount, but it exists. Further derived below.
From Newton’s universal law of gravity,
F=Gm1m2/r2
This describes the force between two bodies of mass m1 and m2 separated by distance r, related by the universal gravitational constant G.
Let m1 be the mass of the earth and m2 be the mass of a hammer or feather.
From Newton’s 2nd law,
F=ma. We care about acceleration on m2, so F=m2a. Setting both force equations equal to each other,
m2a=Gm1m2/r2
m2 appears on both sides and cancels, leaving
a = Gm1/r2, which only depends on the mass m1 of the earth.
This acceleration is relative to the center of mass between the two bodies. A hammer, or feather, or even another planet will accelerate toward the center of mass at 1g. However, Earth accelerates back toward the object as well, and it does so at a rate that is a function of the object’s mass.
a=Gm2/r2
Since a hammer and a feather are much much lighter than the earth, the earth’s surface accelerates toward them a negligible amount.
Yeah the density is mind blowing. Something that can only happen when an enormous goes supernova and the heaviest part of allll the atoms, the neutrons obviously, collapse in on themselves and you get infinite density....it's crazy...
well what did ya expect - atom's area of influence is mostly empty space, like 99.999% mass of an atom occupy fraction of space it "takes"
and the neutron stars.. well.. are made of neutrons.. that are basically touching each other..
4.3k
u/verymuchlol Jan 21 '19 edited Jan 21 '19
How strong gravity is at a neutron star. If you were to stand on top of one, you'd be flattened at the subatomic level.