Expanding universe and light detection

[UseAsDirected]

Sorry if this question has been reproduced elsewhere.

If the universe expands greater than the speed of light, c, will a light ray from a distant object never reach us? Lawrence Krauss gave a nice presentation and commented about this, but this has thrown my nose out of sorts because I think light will reach us regardless of frame speed, even a frame traveling greater than c oppositely.

Thanks for reading.

-EA

 

[blkqi]

The velocity of a distant object is given by Hubble's law
$$v=H_0 d$$
where v is velocity, d distance, and H is a constant. The distance at which v=c marks the Hubble limit--more or less the event horizon--beyond which we cannot be causally connected. No, light will not reach us.

 

[Entropia]

The answer to this question is quite complex and involves some of the fundamental principles of physics. According to the theory of relativity, nothing can travel faster than the speed of light. This includes objects, matter, and even information. So, if the expansion of the universe is happening at a rate faster than the speed of light, then theoretically, light from a distant object may never reach us.

However, it is important to note that the expansion of the universe is not due to objects moving through space, but rather the space itself is expanding. This means that the speed of light is not being surpassed by the objects in the universe, but rather the space between them is increasing at a rate faster than the speed of light.

In this scenario, it is possible for light from a distant object to eventually reach us, but it may take an extremely long time. Additionally, the light may be significantly redshifted, meaning its wavelength is stretched out, making it difficult to detect.

Furthermore, the concept of time is also affected by the expansion of the universe. As space expands, time also slows down. This means that even if the light from a distant object eventually reaches us, it may have taken so long that the object may no longer exist.

In conclusion, the expansion of the universe and the speed of light are intricately connected, and it is possible for light from a distant object to never reach us if the expansion rate is faster than the speed of light. However, the exact effects of this scenario are still being studied and debated by scientists.