Register to reply

Are you sure that objects which moves enought fast are not black holes?

by Born2Perform
Tags: black, enought, holes, moves, objects
Share this thread:
Born2Perform
#1
Jul3-06, 07:48 PM
P: 80
In order that any mass creates a gravitational field, if those objects do not become black holes, this means that relativistic mass does not create a grav field.

How can a mass increasing not produce a deeper space warp? That is the mass does not increase with speed?
Apologies my english.
Phys.Org News Partner Science news on Phys.org
Experts defend operational earthquake forecasting, counter critiques
EU urged to convert TV frequencies to mobile broadband
Sierra Nevada freshwater runoff could drop 26 percent by 2100
pervect
#2
Jul3-06, 09:04 PM
Emeritus
Sci Advisor
P: 7,635
Quote Quote by Born2Perform
In order that any mass creates a gravitational field, if those objects do not become black holes, this means that relativistic mass does not create a grav field.

How can a mass increasing not produce a deeper space warp? That is the mass does not increase with speed?
Apologies my english.
Yes.

See the sci.physics.faq If you go too fast, do you become a black hole?

Whether an object is a black hole or not is a global property of the object. Therfore if an object is not a black hole in it's rest frame, it is not not a black hole if you whiz by it at a high velocity.

The gravitational field of an object can change when its velocity changes. This can most easily be seen by means of the tidal force.

If you move at "right angles" to an object, the tidal force you experience will be greater than if you were standing still.

Interestingly enough, however, if you move directly towards or away from a massive object, the tidal force you experience will not change (it will be the same as if you were not moving).

You can find the later fact in MTW's "Gravitation" (page numbers on request).

This demonstrates that velocity can change "gravity". It also helps illustrate how the gravity from a moving object is not symmetrical. It is stronger "to the sides" than it is in front or in back. This is similar in general behavior (though not in exact detail) to how the electric field from an electric charge acts.

What's important as far as an object being a black hole or not is whether or not light can escape from it. That does not change when the velocities object changes.
MeJennifer
#3
Jul4-06, 12:05 AM
P: 2,043
Quote Quote by pervect
What's important as far as an object being a black hole or not is whether or not light can escape from it. That does not change when the velocities object changes.
Hmmmm, is that correct?
Does not something happen to the visibility of particles leaving or entering an object during a change in velocity?

pervect
#4
Jul4-06, 01:18 AM
Emeritus
Sci Advisor
P: 7,635
Are you sure that objects which moves enought fast are not black holes?

Consider the rest frame of the object. Light leaves it and escapes to infinty.

Now consider the object in a moving frame. Light abberrates, but it still escapes to infinity.

For an object to be a black hole, light must be trapped by the object.


Register to reply

Related Discussions
Massive objects moving too fast Special & General Relativity 57
Why the black objects absorb more light and heat from the other color objects? General Physics 27
Do we observe fast moving objects in the universe? General Physics 12
Re: White Holes are time-reversed black holes? General Physics 0