All Questions
9
questions
1
vote
2
answers
130
views
Does infinite time dilation increase a photons energy to collapse to a black hole, and does it do the same for matter?
As I understand the mass of an object doesn't increase in a gravitational field according to general relativity. It just follows a geodesic, its worldline.
Now imagine a small marble falling straight ...
- 95
2
votes
4
answers
405
views
Mass-energy equivalence and gravitational potential energy
If mass and energy are equivalent, and if gravitational potential energy is energy, why doesn't an object have more mass when it is at a higher altitude? Does the mass-energy equivalence work for ...
- 181
0
votes
1
answer
57
views
What qualifies as “Energy” in the Einsteinian sense of the word?
As an absolute beginner to special relativity (and all the 1900s Einstein stuff), I find it hard to grasp the real meaning of the term energy used in the popular equations. I’ve heard it is possible ...
- 33
6
votes
2
answers
523
views
Can I use the expansion of the universe to create or destroy energy?
Imagine I have a setup like this:
(The objects are not attached to each other. The red objects are much heaver than the black one, and the setup is balanced.)
This setup has a non-zero ...
- 241
3
votes
2
answers
644
views
If gravity is not a force, how come it can produce potential energy?
From my poor understanding of Einstein's theory of relativity, gravity is not a force but the consequence of mass curving the space-time continuum. As such, the moon revolving around the earth is ...
- 307
1
vote
1
answer
213
views
When an object is in free fall from rest at an infinite radius, is its potential energy proportional to its clock rate?
The total energy $E$ of an object in free fall from rest at an infinite radius is known to be
$$
E = m c^2
$$
As the object falls, its energy doesn't change since the object is merely moving freely ...
- 43
1
vote
1
answer
81
views
Where is the potential mass-energy located?
In general relativity, energy, including potential energy, creates mass. That accounts for things like the mass defect in atomic nuclei. But that potential mass-energy must also generate a ...
1
vote
3
answers
693
views
Negative potential energy of gravity
Does the negative potential energy in the gravitational field have to be considered in calculating the total mass of the system in question (because of $E=mc^2$)?
If so it seems to me that the ...
- 481
4
votes
3
answers
1k
views
storing energy (as mass)
When chemical energy is released mass is reduced, if only by a negligible amount. Presumably that's true for all energy. And presumably that works in reverse as well: storing energy involves an ...
- 375