Nothing can exceed the speed of light

In summary: This is called the 'wave-particle duality' and it is central to the workings of quantum mechanics.In summary, Special relativity tells us that information can not be sent faster than the speed of light. This is because a wave-like behavior would occur if information was transmitted.
  • #1
pgcurt
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Special relativity tells us information can not be sent faster than the speed of light. I believe Einstein, but was curious what people thought about the following thought experiment:

The nucleus of an atom has a particular width. With sufficiently advanced technology I could setup a detector that detects motion at the far side of a nucleus. I should be able to “bump” the nucleus from the front side and detect the movement on the back side. One of two things will happen.

1. The detector will instantaneously detect the movement. This would occur if the nucleus is dense and non-elastic. This would reveal an exception to the “cannot transmit information faster than light” rule (albeit at a very small scale).
2. The detector will NOT instantaneously detect the movement. This reveals the dense nucleus itself behaves in a wave like fashion.

I'm an amateur so my question may not even be valid, but I welcome any feedback.
 
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  • #2
The modern view is that a nucleus is really made up of three quarks, so your example doesn't quite work. But we can generalize a bit.

It's possible to view quantum mechanical particles as particles, but it's just as possible to view them as waves. When viewed as waves, the waves propagate at 'c'. (For instance, in QED). When viewed as particles, the quantum mechanical particles do NOT have a size - you need to think of them as being points.

We've actually sidestepped a few tricky issues of interpretation, but these would probably best go in the QM forum. The only coherent interpretation of quantum systems as particles that I'm aware of has the rather odd property that the particles have multiple histories.
 
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  • #3
The one thing you CAN'T do is treat atoms as little spheres with a diameter.
 
  • #4
Without referring to the specific proerties of a nucleus, there is generally no rigid material in relativity, as a matter of principle.
 
  • #5
Pervect, DaveC426913, and Ich have all made good points.

pgcurt said:
The nucleus of an atom has a particular width.

At the subatomic level, things are not so clear-cut.

For simplicity, consider a normal hydrogen atom that has one positively charged proton as its nucleus. This distribution of positive charge doesn't have an edge, it sort of fades away. Getting an extremely accurate handle on the exact form of this fade is a subject of current research.

Also, this charge distribution is not rigid. In fact, quantum theory shows that there is a small but non-zero probability that hydrogen atom's electron will be found inside the proton!

2. The detector will NOT instantaneously detect the movement. This reveals the dense nucleus itself behaves in a wave like fashion.

If instead of a nucleus, a ruler or steel rod is bumped, the resulting disturbance propgates at the speed of sound in the material out of which the object is made. This is always less than the speed of light.
 

1. Why can't anything exceed the speed of light?

The speed of light, denoted by the symbol c, is a fundamental constant in the universe. It is the maximum speed at which all energy, matter, and information can travel. According to Einstein's theory of relativity, as an object approaches the speed of light, its mass increases infinitely and it would require infinite energy to accelerate it any further. This means that it is impossible for anything to exceed the speed of light.

2. How fast is the speed of light compared to other speeds?

The speed of light is approximately 299,792,458 meters per second (m/s), or about 670,616,629 miles per hour (mph). To put this into perspective, the fastest man-made object, the Parker Solar Probe, travels at a speed of about 430,000 mph. This means that the speed of light is more than a million times faster than the fastest man-made object.

3. Can anything travel at the speed of light?

According to our current understanding of physics, only massless particles, such as photons (particles of light), can travel at the speed of light. Anything with mass, even if it is very small, would require an infinite amount of energy to reach the speed of light. This is why we cannot travel at or exceed the speed of light.

4. What happens if something does exceed the speed of light?

It is theoretically impossible for anything to exceed the speed of light, but if it were to happen, it would violate the laws of physics as we know them. This would have major implications for our understanding of the universe and could potentially cause paradoxes and inconsistencies. Therefore, it is believed that the speed of light is an absolute speed limit that cannot be surpassed.

5. Has anything ever been observed to exceed the speed of light?

No, nothing has ever been observed or measured to exceed the speed of light. In fact, many experiments have been conducted to try and find particles or objects that travel faster than light, but all of them have failed. This further supports the idea that the speed of light is an absolute limit in our universe.

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