Special Relativity: Rocket Signal Reception Time and Frequency Shift

In summary, the rocket is traveling at a speed of 0.6c relative to the space station and the nose of the rocket is 200m away from the station according to an observer on the station. The rocket receives a signal at t=200/c and the light emitted from the station is observed at 1000nm in the rocket frame. The space station continuously transmits signals every second according to its own clock. In order for the rocket to receive 500 signals according to its own clock, it would take 1000 seconds. However, in the station frame, the signals are emitted every t'=1s and the time is dilated by a factor of 1.25 for the observer on the rocket. The
  • #1
physiks
101
0

Homework Statement


A rocket of proper length 100m travels at a speed 0.6c relative to a space station, which is on the rocket’s flight path.

I have so far had to work out that:
According to an observer on the space station, the nose of the rocket is a distance of 200m away from the station upon receiving the signal. This occurs at a time t=200/c, and that light of wavelength 500nm emitted from the station is observed at 1000nm in the rocket frame.

The space station continues to transmit signals every second (according to its own clock). At what time has the rocket received 500 signals as measured by its own clock? How many signals according to an observer on the space station have been transmitted during the corresponding time period?

Homework Equations


Length contraction, time dilation, relativistic doppler effect.

The Attempt at a Solution


I'm very confused about this, as it seems to be a simple doppler effect problem to me. I.e the 1 second time period translates to 2 seconds in the rocket frame, and then the rocket has received 500 signals after 1000s in its frame. However this isn't right...
 
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  • #2
according to the ship, the station clock runs slow.
 
  • #3
Simon Bridge said:
according to the ship, the station clock runs slow.

In the station frame, a signal is emitted every t'=1s - this is a proper time. The lorentz factor γ=1.25 here. Therefore somebody on the spaceship sees the signals emitted every γt'=1.25s, i.e the time is dilated. Isn't this true?
 
  • #4
Anybody?
 
  • #5
This problem is overdetermined and inconsistent. The wavelength data is not consistent with the relative speed data. Try using the Relativistic Doppler effect formula.
 
  • #6
dauto said:
This problem is overdetermined and inconsistent. The wavelength data is not consistent with the relative speed data. Try using the Relativistic Doppler effect formula.

Hmm those are previous parts to the question that I have already answered. How is the wavelength inconsistent with the speed data?

λ=λ'√(1+β)/√(1-β)
β=0.6
λ=2λ'
λ=2*500nm
λ=1000nm
 

FAQ: Special Relativity: Rocket Signal Reception Time and Frequency Shift

What is special relativity and why is it important in science?

Special relativity is a theory proposed by Albert Einstein that explains the relationship between space and time. It is important in science because it revolutionized our understanding of the universe and has been confirmed by numerous experiments.

What is the "relativity of simultaneity" in special relativity?

The relativity of simultaneity refers to the idea that two events that appear to occur simultaneously to one observer may appear to occur at different times to another observer, depending on their relative motion. This is a consequence of the speed of light being constant for all observers.

How does special relativity solve the "twin paradox"?

The twin paradox is a thought experiment that involves two twins, one of whom travels at high speeds and returns to Earth younger than the other twin. Special relativity solves this paradox by showing that time dilation, or the slowing down of time at high speeds, occurs for the traveling twin. This explains why the traveling twin would age less than the stationary twin.

Can special relativity be applied to objects moving at speeds close to the speed of light?

Yes, special relativity can be applied to objects moving at any speed, including speeds close to the speed of light. However, at these high speeds, the effects of special relativity become more noticeable, such as time dilation and length contraction.

How does special relativity affect our understanding of causality?

Special relativity states that the concept of absolute simultaneity does not exist, meaning that events that appear to occur simultaneously to one observer may not appear simultaneous to another observer. This challenges our traditional understanding of causality, as cause and effect may appear to occur in different orders for different observers.

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