# BlackHole

Senior Members

167

2. ## 0.999999999c

In 2003 they announced that the speed of gravity is c but i think there was experimental bias. The issue is not completely solved yet.
3. ## 0.999999999c

The speed of gravity is also a problem. According to special relativity no useful information can be transmited faster than light but it appears gravity can.
4. ## Bothers me

True, all physical theories are our interpretation of nature. The problem is with Schroedinger's equation. It is not relativistic, reducing to Newtonian mechanics rather than relativistic mechanics in the correspondence limit.

6. ## I've always thought the universe was pure white light in the beginning.

I'm not sure whether our present understanding of electromagnetism is correct. I'll have to work on Maxwell equations. According to the BBT, 70% of the universal energy density is in the form of dark energy but no one knows what it is.

9. ## The equivalence principle

Depends what you mean by "evidence". In cosmology all observations make use of prior assumptions. I might be able to give mathematical evidence that gravity is not space curvature.
10. ## The equivalence principle

Dr. Swansont, do you agree with me that gravity is not a geometric phenomenon?
11. ## The equivalence principle

I might be totally wrong here but i think curvature is not the source of gravitation. It's something with the quantum vacuum.
12. ## The equivalence principle

I know it's a half-baked assumption but i think gravity is a force.

14. ## Gravity Question

I'm not sure that the equivalence principle holds true in all reference frames. From the equivalence principle we get the stress-energy tensor which states that energy gravitates.
15. ## Gravity Question

Since the earth's center is also the center of mass, gravitation in the center should be zero (the forces cancell out). However i believe gravity has something to do with the vacuum. If light (or any electromagnetic radiation) is not effected by gravitation then all we need is a vacuum theory.
16. ## Gravity Question

In QFT there was an experiment which demonstrated that two parallel laser beams do not interact which made me think that light doesn't really gravitate. On the other hand, two anti-parallel laser beams do interact (for some reason). Maybe the answer lies in a vacuum theory, but others prefer dark energy, strings and so on.
17. ## Movement requires energy

Do you mean a fourth spatial dimension or a temporal dimension? I imagine space-time as an abstract 4-dimensional sphere but motion takes place only through the three spatial dimensions. Kind regards
18. ## Movement requires energy

Time dilation is the result of mass-energy conservation. When mass is accelerated toward light speed, physical processes slow down due to mass-energy conservation. Therefore clocks run slower.
19. ## The equivalence principle

The EEP assumes the complete physical equivalence of a gravitational field and a corresponding acceleration of the reference system. I know this principle is supported by many experiments. But recently i read an unknown article which seems to contradict the equivalence principle. I don't know how seriously to take it. You can read the entire book here.

21. ## Absolute zero-velocity measured in Sagnac Effect

I'm no expert but i think relativity applies only to inertial reference frames. In the case of an accelerating reference frame, special relativity does not apply.

23. ## The earth's core is hollow? (Big bang and bubbles III)

Of course nuclear fusion reactions takes place. In the sun's core, four protons or hydrogen nuclei fuse together to form one alpha particle or helium nucleus. The alpha particle is about 7% less massive than the four protons.
24. ## Absolute zero-velocity measured in Sagnac Effect

The rotating ring is an accelerated frame of reference, while the constancy of the speed of light © applies only in inertial frames of reference (uniform motion).
25. ## The earth's core is hollow? (Big bang and bubbles III)

Planetry cores are definitely not hallow (a vacuum). Actually it's a very dense place. It's where nuclear fusion takes place. Nuclear fusion is a process in which two nuclei join, forming a larger nucleus and releasing or absorbing energy.
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