Which Weakens More Over Distance: Gravity or Light?

In summary, the conversation discusses the concept of weakening in relation to gravity and light as they propagate through space. The speakers also touch on the idea of a fourth spatial dimension and its potential impact on the behavior of these forces. Ultimately, it is suggested that the existence of a fourth dimension may not be ruled out due to the need for it to explain certain phenomena.
  • #1
sysreset
139
0
Probably a really basic question but it bugs me:

Gravity weakens as it propogates through space. So does light and all electromagnetic signals. Does anyone have an opinion on which of the two weakens proportionately more per unit of distance, and why?
 
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  • #2
There does not seem to me to be any reason to think that they do not "weaken" at the same rate. Basically, the "weakening" is a matter of the same amount being spread out over a larger spherical surface.

Back when I was in high school, my physics teacher had what he called a "butter gun". Basically it was a squirt gun with a pyramidal structure of rods attached. You put the toast between the rods and then squirted butter on it! The point was that, because area is proportional to the square of length, if you put the toast twice as far from the pistol, you could fit 4 pieces of toast where only one would fit before. Since you are firing the same amount of butter over 4 times the area, the thickness of butter is 1/4 as much on each slice of toast. Butter, light, or gravity, it's all 1/r2.
 
  • #3
Odd that both gravity and light travel at c, and both wane proportionate to 1/r^2. Coincidence? I wonder what else gravity and light have in common. Makes me think that gravity and light are just two aspects of one unified phenomenon.
 
  • #4
They occupy exponentially larger volumes of space as distance increases. The relative force falls off proportionately. Energy is always conserved.
 
  • #5
if space were 4 dimensional then they would all follow an inverse cube law.
 
  • #6
granpa said:
if space were 4 dimensional then they would all follow an inverse cube law.

Explain in laymans terms please?
 
  • #7
in x dimensional space long range forces would be expected to follow a 1/(x-1) law
 
  • #8
does that mean that since gravity etc. follows an invers squar law that the existence of a fourth spatial dimension can be ruled out?
 
  • #9
it means that gravity is confined to our 3 dimensions.
 
  • #10
Gravity behaves poorly beyond 3 spatial dimensions.
 
  • #11
how so? poorly in what way?
 
  • #14
Of course if atoms are unstable in more than four dimensions, any discussion of higher order relationships is pointless. More than four dimensions are, however, apparently necessary [on local scales] to accommodate the zoo of exotic particles known to exist. This is a mathematical artifact, but, cannot be ignored.
 

FAQ: Which Weakens More Over Distance: Gravity or Light?

How does gravity propagate?

Gravity propagates through space in the form of gravitational waves. These are ripples or disturbances in the fabric of spacetime that are caused by the acceleration of massive objects.

How does the propagation of gravity differ from that of light?

The propagation of gravity and light differ in several ways. Gravity is a fundamental force that acts on all objects with mass, while light is an electromagnetic wave that only interacts with charged particles. Additionally, gravity propagates through space at the speed of light, but it does not require a medium to travel through, unlike light which requires a medium such as air or a vacuum.

Can gravity and light be affected by each other's propagation?

Yes, gravity and light can affect each other's propagation. For example, the path of light can be bent by the gravitational pull of massive objects, a phenomenon known as gravitational lensing. In turn, the energy and momentum of light can also contribute to the curvature of spacetime and affect the propagation of gravity.

How does the propagation of gravity and light relate to the theory of relativity?

Both the propagation of gravity and light are explained by Einstein's theory of general relativity. This theory states that gravity is not a force between objects, but rather a result of the curvature of spacetime caused by the presence of mass and energy. The speed of light is also a fundamental constant in this theory, and the propagation of light is affected by the curvature of spacetime.

Is the propagation of gravity and light affected by the expansion of the universe?

Yes, the expansion of the universe affects the propagation of both gravity and light. As the universe expands, it also stretches the fabric of spacetime, causing the wavelengths of both gravity and light to be stretched. This phenomenon is known as cosmological redshift and is one of the pieces of evidence used to support the theory of the expanding universe.

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