Question about neutron stars and light speed

[Fallingstar1971]

Ok, First, I am no genius..........

With that said, here is my question......

1. Lets start with a neutron star. One that is 99.9% ready to collapse into a black hole. All it needs is that .1 %
2. Now, lets accelerate said neutron star to a signifigant portion of light speed. (A near miss with a black hole may do it)
3. Now, with the mass increase, does it collapse? If it slowed back down to its original velocity what would happen then? Would it "loose" that mass and evaporate? Or turn into something else?
4. Or maybe this happens? ............

Lets say Neutron star has a mass of .9, and to make a black hole you need a mass of 1.

So Neutron Star accelerates and gains that .1, but perhaps the rules change at such speeds? It is possible that the mass increase "bumps" all the other requirements higher so that you will always be .1 away from collaspe, no matter the speed(the faster you go, the farther the adjustment?) It just seems to me, that with any math Ive done, you cant adjust one number of an equation without effecting the rest of the equation. If relativity "bends" one rule does it not have to bend ALL rules?

Someone at my work asked me this, and I was stumped for an answer. Any ideas?

Star

 

[dragon04]

The mass of the neutron star remains .9 Its rest mass doesn't increase with acceleration.

Best way I can explain it? You're in a plane. You weigh 100kg. Plane accelerates into a dive and you pull 5g. Your inertial mass is an apparent 500kg, and you "feel" that, but your body is still its 100kg like it was at rest on your couch.

 

[Saiph]

you're falling victim to a common misconception. The mass increase due to speed isn't the same as regular mass. It's a hold over from how mass is defined classically (i.e. by newton).

Mass, classically, is merely the measure of how much a body resists changes in motion, a measure of it's inertia. The greater the mass, the harder it is to accelerate. Mass IS Inertia, in the classical sense the terms are equivalent and interchangeable. This is why it's said that an objects mass increases with speed, as the object becomes harder and harder to accelerate.

However there are actually TWO kinds of mass. There is the rest mass, the mass of an object inherent in the object when you are in the same stationary frame of reference. This mass will always be there. Then there is the inertial mass, the actual measure of an objects inertia due to motion. The sum of these two parts will tell you how hard it is to accelerate an object.

In the Neutron Stars own reference frame it has only it's rest mass, as it cannot move relative to itself. As such, it won't experience any increase in mass...and won't be tipped over the edge into a BH.

Interestingly enough though, the outside observer (who watches it zip by ata .999C) will measure it as more dense than a typical neutron star due to length contraction and mass increase. This may mean that any submarines traveling at relativistic speeds through the ocean...sink....makes my head hurt

 

[origin]

Good question! This is the type of question that is clear and concise and leads to a better understanding of the underlying physics.

 

[xsaturnaliax]

Ok, as far as the nuetron star losing its material and it 'floating' off into outer space, I don't think that would happen because a nuetron star is one of the densest (actual word?) objects in the universe. Its made of course entirely of nuetrinos, hence the name 'Nuetron star.' If it sped up anymore, I have no idea what would happen if it sped up, even in the slightest amount.

 

[DrRocket]

Ok, First, I am no genius..........

With that said, here is my question......

1. Lets start with a neutron star. One that is 99.9% ready to collapse into a black hole. All it needs is that .1 %
2. Now, lets accelerate said neutron star to a signifigant portion of light speed. (A near miss with a black hole may do it)
3. Now, with the mass increase, does it collapse? If it slowed back down to its original velocity what would happen then? Would it "loose" that mass and evaporate? Or turn into something else?
4. Or maybe this happens? ............

Lets say Neutron star has a mass of .9, and to make a black hole you need a mass of 1.

So Neutron Star accelerates and gains that .1, but perhaps the rules change at such speeds? It is possible that the mass increase "bumps" all the other requirements higher so that you will always be .1 away from collaspe, no matter the speed(the faster you go, the farther the adjustment?) It just seems to me, that with any math Ive done, you cant adjust one number of an equation without effecting the rest of the equation. If relativity "bends" one rule does it not have to bend ALL rules?

Someone at my work asked me this, and I was stumped for an answer. Any ideas?

Star

The thing to do is to answer this question in the most convenient reference frame. Remember that the answer is independent of the reference frame even when you think there is a difference, creating an apparent paradox.

Here the simplest reference frame is that of the neutron star. In that reference frame there is no effect from the velocity that you hypothesize, so it does not collapse.

 

[metastring]

Answer of dragon04 is correct in special relativity only.
In general relativity - I'm not sure about it...

Answer of Saiph disbelieves the strong equivalence principle.

A stronger version of the equivalence principle, known as the Einstein equivalence principle or the strong equivalence principle, lies at the heart of the general theory of relativity. Einstein's equivalence principle states that within sufficiently small regions of space-time, it is impossible to distinguish between a uniform acceleration and a uniform gravitational field. Thus, the theory postulates that inertial and gravitational masses are fundamentally the same thing.

Answer of DrRocket escaping from essence of question.
Is interesting what senses observer from reference frame of neutron star?
I should say not - in itself...
(More interesting is observation near enough to collapsing neutron star.)
This consequence is interest at the most:
It is possible object, which state of it is black hole for one of observer and same state is NOT black hole for the other one...
(This uncertainty is déjà vu for me )
Negation of black holes is easily digestible, but paradox above isn't disproof.
What's about discrepant causality relationship between surface of neutron star / BH and two regions:
distant BH-observer,
distant not BH-observer from reference frame of neutron star?
Does not exist configuration of events and regions, which is contradiction in terms?

Ultimate answer...?

http://en.wikipedia.org/wiki/Mass_in_general_relativity#Questions.2C_answers.2C_and_simple_examples_of_mass_in_general_relativity[/url]":1c4hwy9i]
Can an object move so fast that it turns into a black hole?

No. An object that is not a black hole in its rest frame will not be a black hole in any other frame. One of the characteristics of a black hole is that a black hole has an event horizon, which light cannot escape. If light can escape from an object to infinity in the object's rest frame, it can also escape to infinity in a frame in which the object is moving. The path that the light takes will be aberrated by the motion of the object, but the light will still escape to infinity.