Phantastic Photons: Rate of Light Emission & Laser Images

  • Thread starter Thread starter Wonderballs
  • Start date Start date
  • Tags Tags
    Photons
Wonderballs
Messages
31
Reaction score
0
Are photons released from a lightsource at a particular rate? I am pondering this because i got the idea if a laser pointer were attached to a rotating cylinder and rotated at the speed of light (impossible I know) I wonder what the image the laser beam would produce on the wall?
 
Physics news on Phys.org
"Rotated at the speed of light" doesn't have any meaning. If you really mean that it should be rotated so a spot on the wall moves faster than the speed of light, this is certainly possible.

Anyway, the rate at which photons are produced is what gives the light its intensity.
 
Thank you
 

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 Can an Object Exceed the Speed of Light?
Replies
12
Views
2K
B Laser Pointer at Speed of Light: Does It Point Ahead?
Replies
3
Views
2K
Matter breaking the speed of light? [Nope]
Replies
43
Views
5K
B Experience Travel on a Photon: Hitch-Hiker's Guide to the Universe
Replies
7
Views
2K
A How produce twin photons in practice?
Replies
3
Views
1K
I Cat Chasing Red Dot Faster Than c: Results & Analysis
Replies
13
Views
2K
B Light Speed In Forward and Backward Directions
2
Replies
51
Views
4K
I Is it feasible to measure one way speed of light this way?
2
Replies
52
Views
5K
I Laser and hair - scattering or destructive interference?
Replies
4
Views
2K

Hot Threads

Recent Insights

Back
Top