Does light itself bend spacetime?

In summary, we discussed how light can be accelerated in a gravitational field due to its ability to follow the curves of spacetime. Additionally, it was mentioned that light itself can create a distortion in spacetime and attract other objects due to its energy acting as a source for gravity. However, experiments to confirm this phenomenon have not yet been successfully conducted due to the small energies associated with light in a lab setting.
  • #1
nonequilibrium
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Hello,

I understand light can be accelerated in a gravitational field, because it follows the curves in the spacetimecontinuum. Now I was wondering: does light itself also create a distortion in spacetime and thus attract other things? And are there experiments to confirm this? (E.g. two light beams attracting each other)
 
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  • #2
Yes, since light has energy, it acts as a source for gravity and curves space. Note that this is also required by Newton's 3rd law, which applies to gravitational forces in GR. However, the typical energies associated with light in a lab are still way too small to produce measurable effects. Light on light interactions would be even smaller than, for example the deflection of light due to Earth's gravity.
 

1. What is the concept of bending spacetime?

The concept of bending spacetime is a fundamental principle in Einstein's theory of general relativity. It suggests that massive objects, such as planets and stars, can cause a distortion in the fabric of spacetime, which affects the motion of objects around them.

2. Does light actually bend spacetime?

Yes, according to the theory of general relativity, light itself can cause a curvature in spacetime. This was famously demonstrated during a solar eclipse in 1919 when the light from distant stars was observed to bend around the sun, confirming Einstein's theory.

3. How does light bend spacetime?

Light has energy and momentum, which can exert a gravitational pull on spacetime. The intense gravitational field around massive objects like stars can cause light to follow a curved path as it passes by, bending the fabric of spacetime in its wake.

4. Can light travel in a straight line through curved spacetime?

Yes, light will always travel in a straight line in its local region of spacetime, but its path will appear curved to an outside observer due to the curvature of spacetime caused by massive objects.

5. What are some real-life examples of light bending spacetime?

One of the most well-known examples is the deflection of starlight during a solar eclipse, as mentioned earlier. Other examples include the gravitational lensing effect, where the light from distant galaxies is bent by the gravity of a closer massive object, and the Shapiro delay, where light traveling near a massive object is delayed due to the curvature of spacetime.

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