Muons Decaying on Mt Washington: Expert Answers

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In summary, the conversation discusses the concept of Special Relativity and specifically focuses on the phenomenon of length contraction from the perspective of a muon. The experts explain that this is a result of the differences in measurements between two reference frames in relative motion. The physical space in question is actually spacetime, and the concept of observers and reference frames is important in understanding this phenomenon.
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Length contraction from Muons perspective
Dear Experts,
Currently I am reading up on Special Relativity.
I struggle to understand how from the perspective of the Muon that the distance to the surface of the Earth is contracted and thus more Muons arrive at the surface based detector.
How can this be? To me the physical space is real between the muon and the surface and thus cannot be manipulated. How can this space be „contracted“ so that the muons arrive faster?
I am aware of length and time dilation and is related to observers etc but I am not referring to this. I referring to the muon reference frame...
Any clarity is appreciated! Thanks
 
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It is one and the same thing: in the muon rest frame, the decay time is 2.2 ##\mu##s. So, even at close to the speed of light the length decay distance would only be 660 m (in the Earth frame) without length contraction. In the Earth frame the time dilation factor is the dame as the length contraction factor in the muon frame. It's nicely described on the first pagehttp://www.pas.rochester.edu/~advlab/reports/pelcher_rapach_muon.pdf.
 
  • #3
bugatti79 said:
To me the physical space is real between the muon and the surface and thus cannot be manipulated.

This is a conceptual hurdle to get over. If what you say were true, then there would be no SR. But, as there is SR, your preconceptions must be misplaced.
 
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The "real thing" is spacetime. How you divide that into space and time is a matter of choice, although there's an obvious way to do it for each observer.

Two reference frames in relative motion have different natural choices, so they measure different things and call them both "distance through space". So no-one is manipulating space - the two frames just mean different things when they talk about space.
 
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bugatti79 said:
I am aware of length and time dilation and is related to observers etc but I am not referring to this. I referring to the muon reference frame...
"Observer" is often used as a synonym for "reference frame" in the context of SR, which leads to a lot of confusion.
 
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bugatti79 said:
I am aware of length and time dilation and is related to observers etc but I am not referring to this. I referring to the muon reference frame...

Just have the observer be at rest in the rest frame of the muon.
 

1. What are muons and why do they decay?

Muons are subatomic particles that are similar to electrons, but with a higher mass. They are created in the upper atmosphere when cosmic rays, high-energy particles from outer space, collide with atoms. Muons decay because they are unstable particles and have a short lifespan of only 2.2 microseconds.

2. What is the significance of studying muon decay on Mt Washington?

Mt Washington is the highest peak in the northeastern United States, and its high altitude and remote location make it an ideal place to study muon decay. The high altitude means that there is less air to absorb the muons, allowing more of them to reach the ground and be detected. This makes it a perfect location to conduct experiments and gather data on muon decay rates.

3. How do scientists measure muon decay on Mt Washington?

Scientists use specialized equipment, such as muon detectors, to measure the number of muons that reach the ground on Mt Washington. These detectors are placed at various locations on the mountain and can accurately measure the flux, or flow, of muons. By comparing the flux at different altitudes, scientists can determine the rate of muon decay.

4. What can the study of muon decay on Mt Washington tell us about cosmic rays?

Cosmic rays are high-energy particles that are constantly bombarding the Earth from outer space. By studying muon decay on Mt Washington, scientists can gain a better understanding of the properties and behavior of cosmic rays. This can help us learn more about the origins of these particles and their effects on our planet.

5. How does the weather on Mt Washington affect muon decay?

The weather on Mt Washington can have a significant impact on muon decay rates. For example, during periods of high humidity, the air becomes more dense and can absorb more muons, resulting in a decrease in the number of muons that reach the ground. This makes it important for scientists to take weather conditions into account when conducting experiments and analyzing data on muon decay.

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