Speed of Light: Expert Answers to Your Questions

  • Thread starter Thread starter BDfarsi
  • Start date Start date
  • Tags Tags
    Light Speed
BDfarsi
Messages
3
Reaction score
0
hello scientists!
Im new user. so I don't know manythings about physics.

one more thing:I don't know english well.

I just have a question about "Speed of light".
Whats the real speed of it?
300,000 k/h Or 300,000,000.001 m/h?

whats the rule of it?

The light's speed is the same as the gravity's speed?

What are your answers?
 
Last edited:
Physics news on Phys.org
BDfarsi said:
I just have a question about "Speed of light".
Whats the real speed of it?
300,000 k/h Or 300,000,000.001 k/h?
The speed of light is 299,792,458 m/s. (≈ 300,000 km per second, not per hour.)

See: http://en.wikipedia.org/wiki/Speed_of_light"
 
Last edited by a moderator:
thanks alot.
I think its very important in our equation and i didnt know it!it was too bad!

another question:
The light's speed is the same as the gravity's speed?

I think gravity has a real speed and It can't be faster than light. so why the black holes can suction the light?

thanks for your help!
 
BDfarsi said:
another question:
The light's speed is the same as the gravity's speed?
Yes. A disturbance in the gravitational field is believed to travel at the speed of light.

I think gravity has a real speed and It can't be faster than light. so why the black holes can suction the light?
Spacetime around a black hole is so distorted it curves back onto itself. (I'm sure there are folks here who will give you a much more detailed answer, if you need one.)
 
Its so good!

So I can not interpret.
I think even the distance (eg time) in a black hole is not defined and strange.
Let alone the speed!

A very small object, which is related to quantum mechanics and high crime s that gets laws of relativity. These two are not compatible! Is there a link between them?
 

Thread 'Describing the Big Bang'

I started reading a National Geographic article related to the Big Bang. It starts these statements: Gazing up at the stars at night, it’s easy to imagine that space goes on forever. But cosmologists know that the universe actually has limits. First, their best models indicate that space and time had a beginning, a subatomic point called a singularity. This point of intense heat and density rapidly ballooned outward. My first reaction was that this is a layman's approximation to...
View full post »
Thread 'Dirac's integral for the energy-momentum of the gravitational field'

Thread 'Dirac's integral for the energy-momentum of the gravitational field'

See Dirac's brief treatment of the energy-momentum pseudo-tensor in the attached picture. Dirac is presumably integrating eq. (31.2) over the 4D "hypercylinder" defined by ##T_1 \le x^0 \le T_2## and ##\mathbf{|x|} \le R##, where ##R## is sufficiently large to include all the matter-energy fields in the system. Then \begin{align} 0 &= \int_V \left[ ({t_\mu}^\nu + T_\mu^\nu)\sqrt{-g}\, \right]_{,\nu} d^4 x = \int_{\partial V} ({t_\mu}^\nu + T_\mu^\nu)\sqrt{-g} \, dS_\nu \nonumber\\ &= \left(...
View full post »

Thread 'A sufficient condition for integrability of equation ##\nabla g=0##'

In Philippe G. Ciarlet's book 'An introduction to differential geometry', He gives the integrability conditions of the differential equations like this: $$ \partial_{i} F_{lj}=L^p_{ij} F_{lp},\,\,\,F_{ij}(x_0)=F^0_{ij}. $$ The integrability conditions for the existence of a global solution ##F_{lj}## is: $$ R^i_{jkl}\equiv\partial_k L^i_{jl}-\partial_l L^i_{jk}+L^h_{jl} L^i_{hk}-L^h_{jk} L^i_{hl}=0 $$ Then from the equation: $$\nabla_b e_a= \Gamma^c_{ab} e_c$$ Using cartesian basis ## e_I...
View full post »

Similar threads

B Let me ask a thing about the Speed of Light
Replies
6
Views
1K
B Why is it impossible to go faster than the speed of light?
Replies
21
Views
3K
I Why is Rømer's light speed measurement not one-way?
Replies
42
Views
3K
B Speed of light and this Accelerating Rocket scenario
Replies
45
Views
5K
I Has anyone measured the speed of light in one direction?
Replies
45
Views
6K
B Why does it require an infinite amount of energy to reach the speed of light?
3
Replies
130
Views
13K
B Thought Experiment : Try and get Alice to "0%" the Speed of light
Replies
15
Views
2K
B Does Force Travel Faster Than Light?
Replies
8
Views
3K
B Speed of Light: Questions Answered
Replies
8
Views
1K
I Is Erik's Paradox Challenging Our Understanding of Gravity and Light Speed?
Replies
18
Views
2K

Hot Threads

Recent Insights

Back
Top