Exploring the Mystery of Light Speed: Nearest Star vs. Farthest Galaxy

  • Thread starter Jim Beam
  • Start date
  • Tags
    Light
In summary, the speed of light remains constant regardless of the source, but the time it takes for light to reach us varies depending on the distance of the source. In the frame of reference of light, it would appear that light is everywhere at the same time. However, since we do not live in this frame of reference, this explanation is not practical.
  • #1
Jim Beam
15
0
So, if the speed of light appears to reach the observer at the same time no matter the observers velocity, then does that mean that light from the nearest star reaches us just as quickly as light from the farthest galaxy?
 
Physics news on Phys.org
  • #2
Jim Beam said:
So, if the speed of light appears to reach the observer at the same time no matter the observers velocity, then does that mean that light from the nearest star reaches us just as quickly as light from the farthest galaxy?

I think you may have misread or misunderstood something. Light doesn't take the same amount of TIME regardless of the source. It has the same SPEED, regardless of the source. The constancy of the speed of light is one of the fundamental postulate of Special Relativity, NOT the constancy of the TIME that light travels.

This correction should answer your question above.

Zz.
 
  • #3
ZapperZ is right, light is emmited from a source, no matter what its inetrial frame is, at c. But if one source if further from the other, the closer sources light will reach us first. Now if you were in the frame of reference of the light, then it would all reach us at the same time, since at the speed of light, d becomes 0, and time becomes 0, so you can say that light is everywhere in the universe at the same time. But we do not live or can see the frame of reference of light, so using this explination is rather useless.
 

1. How is the speed of light measured?

The speed of light is measured using a unit called meters per second (m/s) or kilometers per second (km/s). It is typically measured by using a device called a laser interferometer, which measures the time it takes for light to travel a certain distance.

2. What is the speed of light in a vacuum?

The speed of light in a vacuum is approximately 299,792,458 meters per second or 186,282 miles per second. This is considered to be the maximum speed at which anything in the universe can travel.

3. How far is the nearest star from Earth?

The nearest star to Earth is Proxima Centauri, which is located approximately 4.2 light years away. This means that it takes light 4.2 years to travel from Proxima Centauri to Earth.

4. How far is the farthest galaxy from Earth?

The farthest galaxy from Earth is GN-z11, which is located approximately 13.4 billion light years away. This means that it takes light 13.4 billion years to travel from GN-z11 to Earth.

5. Does anything in the universe travel faster than the speed of light?

No, according to Einstein's theory of relativity, nothing can travel faster than the speed of light. This is considered to be a fundamental law of the universe and has been supported by numerous experiments and observations.

Similar threads

  • Astronomy and Astrophysics
Replies
9
Views
1K
Replies
14
Views
1K
Replies
6
Views
483
Replies
4
Views
723
Replies
6
Views
715
  • Special and General Relativity
Replies
33
Views
2K
  • Special and General Relativity
Replies
19
Views
838
Replies
57
Views
3K
  • Introductory Physics Homework Help
Replies
6
Views
620
Back
Top