All Questions
7
questions
1
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3
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66
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Besides traveling at the speed of light, how can we be sure that it is possible to have energy and momentum without mass?
How can we be sure that it is possible to have energy and momentum without mass? If something were to continually lose energy, would it not also lose a corresponding amount of mass? I understand that ...
10
votes
4
answers
3k
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Can massless particles travel slower than the speed of light in vacuum?
We know an object with positive mass cannot be accelerated to the speed of light because this would require an infinite amount of energy. My question is:
Is there anything in the universe that can ...
3
votes
1
answer
138
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Does the speed of light in our definitions take vacuum energy into consideration?
We know that the speed of light decreases as it goes through a medium, and we also know that there is a certain vacuum energy that creates a sea of particles coming in and out of existence, which, ...
- 199
1
vote
2
answers
1k
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When electrons move at high speeds, why is their mass LARGER than their rest mass? Why isn't it the opposite? [duplicate]
When an electron moves at a high speed, it has a large kinetic energy.
I know that E = mc^2 and so if an electron was travelling at a high speed, wouldn't the mass decrease in order to increase the ...
- 220
2
votes
2
answers
545
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Travel at the speed of light
Is it me who have a poor understanding, or does all matter have to become 'pure energy' in order to achieve speed-of-light speed?
If so, does that mean that no material can achieve the speed of light ...
- 175
7
votes
4
answers
4k
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Can you create mass with $E=mc^2$?
If you use the equation $E=mc^2$ could you make matter by dividing the $c^2$? I'm sorry if this is a really stupid sounding question or if it shouldn't be asked here.
- 191
30
votes
3
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19k
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Does $E = mc^2$ apply to photons?
Photons are massless, but if $m = 0$ and $E=mc^2$, then $E = 0c^2 = 0$. This would say that photons have no energy, which is not true.
However, given the formula $E = ℎf$, a photon does have energy ...
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