What is the escape velocity of a neutron star?

Answer 1

The gravitational force that a black hole has on another object depends on the following:

1. The mass of the black hole

2. The mass of the object

3. The distance between the centres of the black hole and the object (r)

Using Newton's Law of Universal Gravitation, this force can be calculated using the following equation:

F=G*[(m1*m2)/(r2)]

where:

F = force

G = universal gravitational constant = 6.674

Answer 2

That naturally depends on the mass content of the individual black hole.

At a distance 'D' (meters) from the black hole, the acceleration of gravity
due to its mass is:

A = g M / D2

where

g = universal gravitational constant
M = the mass of the black hole (kg)

Answer 3

I found a reference value of 5,200 km/sec for the case of Sirius B, but I didn't take the trouble to do the calculations. However, obviously the escape velocity depends on the exact mass of the white dwarf. Note that a white dwarf with a larger mass will have a smaller diameter (due to the increased gravitation); both the larger mass and the smaller diameter will contribute to a larger escape velocity.

Answer 4

Specifically for a black hole the range of gravitational influence is calculated by the "Shwarzchild Radius" and surprisingly the radius is quite small for even the biggest blackhole, If a blackhole had the mass of the earth, then the Shwarzchild radius would only be a centimeter! Meaning you would have to come with in a centimeter of the blackhole to get sucked in.

Answer 5

Yes. Well, we THINK so; we cannot observe anything inside a black hole, and our mathematical understanding of physics breaks down within the "singularity" around a black hole. Literally, the mathematical equations that appear to work in "normal" space break down and give nonsense answers when applied to what we believe are the conditions near a black hole.

Someday, we'll probably figure out what's happening there - but for now, we're just happy that there are no black holes anywhere nearby. At least, not that we know of!

Answer 6

The gravitational force that a black hole has on another object depends on the following:

1. The mass of the black hole

2. The mass of the object

3. The distance between the centres of the black hole and the object (r)

Using Newton's Law of Universal Gravitation, this force can be calculated using the following equation:

F=G*[(m1*m2)/(r2)]

where:

F = force

G = universal gravitational constant = 6.674×10−11 N m2 kg−2

m1 = mass of the first object

m2 = mass of the second object

r = distance between the centres of the objects

If, however, you wish to calculate the surface gravity of a black hole - which refers to the gravitational acceleration that's experienced at its surface (i.e. the event horizon) - then a different equation is used:

k = c4/[4Gm]

Where:

k = surface gravity

c = speed of light in a vacuum = 3x108m/s

G = universal gravitational constant = 6.674×10−11 N m2 kg−2

m = mass of the black hole

Answer 7

A white hole is the theoretical time reversal of a black hole.

Stephen Hawking implied that black holes and white holes are the same object and one could surmise from this, that they are the same thing and would thus have the same amount of gravity.

See related link and question for more information

Answer 8

About a third, or half, the speed of light. The exact escape velocity really depends on the mass and diameter of the neutron star. Note that a more massive neutron star would be smaller, due to the increase in gravitation. If a certain limit is reached, the neutron star becomes a black hole. Before that limit is reached, pressumably the escape velocity could reach any value up to (almost) the speed of light.

Matter falling upon the dark hole reaches such a large speed (the escape velocity), that it is utterly destroyed; individual atoms don't remain whole, but rather, become part of the neutron soup of the neutron star.

Answer 9

F= (G x(m1x m2))/r2 The force a black hole has on another object is equal to a constant multiplied by the masses involved, divided by the distance squared. So 2 small objects very close can has the same gravitational pull as 2 huge objects billions of miles apart. The force the black hole has relates to it's size (mass) and the mass of the object being measured against, and the distance between them. The pull of a black hole at a distance is no different than that of a regular star, it's when you get very close that things happen differently.

Answer 10

It is more appropriate to talk about the mass of a black hole. Read here if you don't know the difference: http://en.wikipedia.org/wiki/Mass_versus_weight. To talk about the weight means that you measure the attraction of the black hole against some other object - and that will vary, depending on the distance and mass of the other object.

The mass of a black hole, then, can vary between a few times the mass of the Sun (stellar black holes), passing through intermediate-mass black holes (a few thousand of times the mass of the Sun, believed to exist in some star clusters), up to the galactic (or "supermassive") black holes, in the centers of galaxies, that have a mass of millions, or even billions, of times the mass of our Sun.

It is also suspected - but not yet confirmed - that during the Big Bang, miniature black holes may have been created, small enough that they might evaporate any time soon.