High speed black holes

[triskaidekaphile]

From what I understand so far, objects cannot accelerate to the speed of light since it would require an infinite amount of energy and would increase the objects mass relative to a "motionless" observer. The object would become more massive as it tries to accelerate. If this is so then would the accelerating object become so massive that it would become a black hole, while in reference to itself nothing changes?

 

Another way to look at it is: if there was an extremely dense white dwarf star that is on the verge of black hole density and/or mass, and you started moving relative to it, to a considerable speed, but much less then before, then would we see the white dwarf transition to being a black hole due to relative motion?

 

I apologize if this is another case of an incomplete grasp of relativity, I'm young and am still learning. Thanks in advance for any replies.

[MigL]

No, relativistic mass increase, time dilation and length foreshortening are frame dependant effects.

[triskaidekaphile]

So it can only appear to become a black hole?

[ACG52]

So it can only appear to become a black hole?

 

 

It doesn't become a black hole, and it doesn't appear to be a black hole.

 

Relativistic mass, which is an outdated and misleading concept, does not contribute to gravity.

[triskaidekaphile]

So is it the relative kinetic energy that contributes to gravity?

[IM Egdall]

In spacetime physics, momenergy is the source of gravity (spacetime curvature). It is made up of rest mass, energy, and momentum. See link:

 

http://www8.hp.com/u...Display=drivers

 

 

Mywebsite: http://marksmodernphysics.com/

Edited September 18, 2012 by IM Egdall

[ACG52]

So is it the relative kinetic energy that contributes to gravity?

 

 

No. Relative energy does not contribute to gravity. The thing is, it's relative. If I were in a ship moving alongside of you, your relative kinetic energy would be zero. This would lead to a frame dependent gravitational field.

 

It's rest mass which contributes to gravity.

[triskaidekaphile]

Thank you all for your replies. I now have some more material to mull over, and I guess I need to stop reading oversimplified explanations and instead focus on the mathematical specifics.