Evidence of Special Relativity

In summary: The displacement of charges in the dielectric is zero, and the electric field due to the charges is also zero."
  • #1
webb202
12
2
I know that the example of time dilation and length contraction due to Special Relativity is usually given as the mountain top / sea level decays of muons created by cosmic rays but what is the evidence for mass change?
 
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  • #2
Actually mass change is not one of the things that SR predicts, its just something that some textbooks on relativity introduce and I don't know why they do that because they never use it.
Its only that linear momentum and kinetic energy are different for different inertial observers which is like Newtonian mechanics just the transformation is different.
 
  • #4
webb202 said:
...what is the evidence for mass change
When designing particle accelerators the designers need to take the relativistic mass increase into account. See the outreach page at the Large Hadron Collider at
http://lhc-machine-outreach.web.cern.ch/lhc-machine-outreach/lhc-machine-outreach-faq.htm
Basically the relativistic mass of a particle increases with velocity and tends to infinity as the velocity approaches the speed of light.

UCSB Science Line sq test
http://scienceline.ucsb.edu/getkey.php?key=1571
Now if you were traveling along with the object, even at the speed of light, it would appear to have its ordinary, rest mass. It's only to the outside world that it appears to have a greater mass. In other words, it's only if the object is moving *relative to you* that you see a difference--which is why we call it relativity. If you're moving along with the object, we say that you are in the object's reference frame. A stationary observer has a different reference frame.

Of course, it may be possible that special relativity is wrong, and something else happens at extremely high velocities. But big particle accelerators like at Stanford and in Switzerland use special relativity every day, and it's been perfectly correct even for the fastest particles we can accelerate.
See also
http://en.wikipedia.org/wiki/Cyclotron
http://en.wikipedia.org/wiki/Particle_accelerator
http://hyperphysics.phy-astr.gsu.edu/hbase/particles/cyclo.html
http://galileoandeinstein.physics.virginia.edu/lectures/mass_increase.html

Shyan said:
Actually mass change is not one of the things that SR predicts, its just something that some textbooks on relativity introduce and I don't know why they do that because they never use it.
Where did you get the idea that they never use it? Just look above. I've also seen many other examples of it. For example; A simple relativistic paradox about electrostatic energy, Wolfgang Rindler, Jack Denur, Am. J. Phys., 56 (9), September 1988, page 795.
 
  • #5
Shyan said:
Actually mass change is not one of the things that SR predicts, its just something that some textbooks on relativity introduce and I don't know why they do that because they never use it.
Its only that linear momentum and kinetic energy are different for different inertial observers which is like Newtonian mechanics just the transformation is different.

Correct me if I'm wrong, but I though mass change had been derived in the late 1800s. The example I seem to remember is change in mass when the energy in a spring changes.
 
  • #6
Devils said:
Correct me if I'm wrong, but I though mass change had been derived in the late 1800s. The example I seem to remember is change in mass when the energy in a spring changes.

Thomson, Joseph John (1893), Notes on recent researches in electricity and magnetism on Internet Archive, Oxford: Clarendon Press
http://www.archive.org/details/notesonrecentres00thom

[p. 21] "When in the limit v = c, the increase in mass is infinite, thus a charged sphere moving with the velocity of light behaves as if its mass were infinite, its velocity therefore will remain constant, in other words it is impossible to increase the velocity of a charged body moving through the dielectric beyond that of light."
 
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What is Special Relativity?

Special Relativity is a theory proposed by Albert Einstein in 1905 that explains the relationship between space and time. It states that the laws of physics are the same for all inertial observers, regardless of their relative motion.

What is the evidence for Special Relativity?

There are several pieces of evidence that support Special Relativity, including the Michelson-Morley experiment, which showed that the speed of light is constant in all inertial frames of reference. Other evidence includes time dilation, length contraction, and the observation of particle accelerators.

Why is the speed of light considered a universal constant in Special Relativity?

In Special Relativity, the speed of light is considered a universal constant because it is the same for all observers, regardless of their relative motion. This is in contrast to other physical quantities, such as velocity or acceleration, which can vary depending on the frame of reference.

How does Special Relativity impact our understanding of time and space?

Special Relativity revolutionized our understanding of time and space by showing that they are not absolute concepts, but rather are relative to the observer's frame of reference. It also introduced the concept of spacetime, where space and time are interconnected and cannot be considered separately.

Is Special Relativity still relevant today?

Yes, Special Relativity is still a fundamental theory in modern physics and is used in many practical applications. It is essential for understanding phenomena like GPS systems, particle accelerators, and the behavior of objects traveling at high speeds. It is also a crucial component of Einstein's more comprehensive theory of General Relativity.

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