relativity Q (1 Viewer)

[mojako]

Muons travel towards the Earth's surface, but their life is so short, and the distance so great, that few, if any, should reach Earth's surface. Despite this, muons are detected, arriving in large numbers at the surface during cosmic showers. The explanation for this is that:
(A) the muons travel at speeds that can exceed the speed of light.
(B) the muons are travelling at velocity close to the speed of light and therefore the time is dilated relative to an observed on Earth/
(C) the muons are travelling at velocity close to the speed of light and therefore the distance to the surface of Earth seems much shorter to them.
(D) during cosmis showers the cosmic rays penetrate deep into arth's atmosphere producing many muons close to the surface

From my understanding both B and C should be correct. Condition B can be equally said by C.
But the answer says it's B.
Am I wrong or is the question wrong?
Thanks.

 

[FcUk]

Yeh id agree that it could be both answers but im sure theres a reason why c isnt the answer??

 

[helper]

The easiest was of thinking of it is that the observer is on earth, so it is the observer that is seeing the change.

 

[mojako]

but my point is that
B is what the observer on the earth sees.
C is what the muon "sees" (assuming it can see things ). I mean the muon doesn't feel that its time is dilated. It just sees the distance as being shorter...
Similarly the observer on the earth doesn't see the distance as being shorter because the air between the muon and the earth is not moving relative to earth. but he can explain this phenomenon by saying that the time in the muon's frame of reference is dilated...
but isnt it just as correct to explain things from the muon's perspective?

 

[helper]

The observer on earth is doing the detecting. As was said in the question. So it is the observer on earth that is making the observation.