Questions tagged [faster-than-light]
"Faster-than-light", also known as superluminal velocities, refers to any sort of travel at a speed greater than the speed of light. Prohibited in mainstream physics due to the Special theory of relativity.
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Can gravity make something faster than light? [duplicate]
Scenario,
Let's say we have complete vacuum and nothing in the universe.
If we place 2 bodies at infinite separation and have HUGE masses ($m1, m2 \sim 10^{1000}$ kg or something):
They will attract.
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How does a refractive index of less than one not violate relativity?
If I am not mistaken, this video says that X-rays travel faster in glass than in a vacuum. Special Relativity says that information can not travel faster than the speed of light in a vacuum, so what ...
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Are there cases in quantum field theory's formalism were virtual particles are allowed to exceed the $c$ speed limit?
Virtual particles even today contrary to the overwhelming evidence in my opinion that they have a real effect on normal particles (i.e. Casimir effect, $g-2$ muon Fermilab experiment) are considered ...
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Can a big enough Giant travel many lightyears in just a few seconds? [closed]
We, as humans, given our height and size, view the world from the same general perspective. An ant, on the other hand, will understand the same world in a completely different way, given how limited ...
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FTL Length contraction? [closed]
I found this interesting question in a textbook about special relativity:
A length-contracted object has length $L=\frac{L_0}{\gamma}$. Joe differentiates this with respect to time and finds
$$\frac{\...
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What is innermost unstable circular orbit (IUCO)?
In the paper Tachyon motion in a black hole gravitational field by V. M. Lipunov he writes:
(…) Circular orbits for tachyons begin at the distance of $ 3/2~r_g $, i.e., at the distance of the ...
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Different Escape Velocities of Black Holes?
I am no physics major nor math major to this but merely an amateur cosmology enthusiast, so in my previous inquiries I wasn't able to find anything on the premise that if all black holes obviously ...
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Confusion regarding recessional velocity and Lorentz transformation
Consider that you are receding at a velocity faster than the cosmic speed limit (say, $2c$ with respect to $A$) due to the expansion of our universe. According to me, $A$ is moving at $2c$ and thus ...
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Are there any Alcubierre Style metrics for sub-luminal speed warp drives?
In most literature I have found, research into the Alcubierre Metric, and Warp Drives seems to be highly focused on the plausibility of superluminal travel.
Today I was thinking to myself that maybe ...
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Stuck on thought experiment about light [duplicate]
Say we have a very long fluid pipe with the width of a few astronomical units, and that this pipe is perfectly resistant to sustain the stress of a perfectly incompressible fluid going through it ...
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What force could theoretically redirect the Higgs field? [duplicate]
I’d just like to point out I am by no means a physics expert, or indeed a particularly knowledgable nerd on this subject. I am a minor and a wannabe sci-fi writer who is trying to come up with an idea ...
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Refraction of a Ray of Light [duplicate]
Why can no medium have a refractive index less than 1? Explain with Snell's Laws of Refraction of Light.
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If a photon travelled in the opposite direction of another photon [duplicate]
If a photon travels in the opposite direction as another photon, then what is the speed of the second photon relative to the first. Is it 2 times the speed of light? Also what if two photons travelled ...
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Please give me a single sentence explaining why faster-than-light morse code through entanglement isn't possible? [closed]
Problem with past explanations is they emphasize the need for random choice of measurement angle, but my understanding is that was only necessary in experiments seeking to remove any possible loop-...
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Why Going Faster-Than-Light (FTL) Leads to Time Paradoxes? [duplicate]
In this video: https://www.youtube.com/watch?v=an0M-wcHw5A&lc=UgxqC71gefTRIuVubGt4AaABAg.9jI6ltMIeu59jx2P8cpn_z
In the video the following events happen:
A supernova goes off.
Earth sees the ...
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