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Question: Is faster than light travel possible? Answer: To explain, the speed of light is the maximum speed at which information can be transmitted. It is not

Question: Is faster than light travel possible? Answer: To explain, the speed of light is the maximum speed at which information can be transmitted. It is not the maximum speed at which objects can travel. Objects can travel faster than light.

consumer451 4y ago
As I barely understand it, objects are not prevented from travelling faster than light by general relativity. Objects are prevented from acceleration to and beyond the speed of light. Disclaimer: I learned this on YouTube.
- malfist 4y ago
  More that objects themselves can't travel faster than the speed of light, but nothing limits non-objects. Spacetime may expand at whatever speed it would like to, including faster than the speed of light. Imagine if you are on a sheet of stretchy fabric, that represents spacetime. If you stretch the sheet from corner to corner at and even rate, things at the edge travel faster away from the things in the center of the sheet. They themselves are not traveling, spacetime is expanding around them.
  - consumer451 4y ago
    Thanks, I think I get the spacetime part. I was not very clear previously. Here is the transcript of the YT video I was referring to: > Next, Einstein also showed that if you have any particle which moves slower than the speed of light, then you cannot accelerate it to faster than the speed of light. You cannot do that because it would take an infinite amount of energy. And this is why you often hear that the speed of light is an upper limit. > However, there is nothing in Einstein’s theory that forbids a particle to move faster than light. You just don’t know how to accelerate anything to such a speed. So really Einstein did not rule out faster than light motion, he just said, no idea how to get there. However, there is a problem with particles that go faster than light, which is that for some observers they look like they go backwards in time. Really, that’s what the mathematics says. https://backreaction.blogspot.com/2020/05/is-faster-than-light-travel-possible.html https://backreaction.blogspot.com/2020/05/is-faster-than-lig... (Sabine Hossenfelder, Theoretical Physicist, Research Fellow at the Frankfurt Institute for Advanced Studies)
dekhn 4y ago
There's https://en.wikipedia.org/wiki/Cherenkov_radiation https://en.wikipedia.org/wiki/Cherenkov_radiation but I don't really consider that "objects can travel faster than light" in the general sense.
fy20 4y ago
> The key idea behind the propulsion system is that it is designed to focus all the emitted photons in the direction of travel of the spacecraft. This is accomplished by using a sphere with a reflective coating that has a diameter of 1000 km. As we will see, the spacecraft would have to emit 10^27 photons per second. To achieve this enormous rate of photon emission, we will need to use a very large number of solar-powered lasers. https://galactica.org/?max_new_tokens=800&prompt=Lecture+notes+on+the+first+faster+than+light+spacecraft https://galactica.org/?max_new_tokens=800&prompt=Lecture+not...

consumer451 4y ago

As I barely understand it, objects are not prevented from travelling faster than light by general relativity. Objects are prevented from acceleration to and beyond the speed of light. Disclaimer: I learned this on YouTube.

malfist 4y ago
More that objects themselves can't travel faster than the speed of light, but nothing limits non-objects. Spacetime may expand at whatever speed it would like to, including faster than the speed of light. Imagine if you are on a sheet of stretchy fabric, that represents spacetime. If you stretch the sheet from corner to corner at and even rate, things at the edge travel faster away from the things in the center of the sheet. They themselves are not traveling, spacetime is expanding around them.
- consumer451 4y ago
  Thanks, I think I get the spacetime part. I was not very clear previously. Here is the transcript of the YT video I was referring to: > Next, Einstein also showed that if you have any particle which moves slower than the speed of light, then you cannot accelerate it to faster than the speed of light. You cannot do that because it would take an infinite amount of energy. And this is why you often hear that the speed of light is an upper limit. > However, there is nothing in Einstein’s theory that forbids a particle to move faster than light. You just don’t know how to accelerate anything to such a speed. So really Einstein did not rule out faster than light motion, he just said, no idea how to get there. However, there is a problem with particles that go faster than light, which is that for some observers they look like they go backwards in time. Really, that’s what the mathematics says. https://backreaction.blogspot.com/2020/05/is-faster-than-light-travel-possible.html https://backreaction.blogspot.com/2020/05/is-faster-than-lig... (Sabine Hossenfelder, Theoretical Physicist, Research Fellow at the Frankfurt Institute for Advanced Studies)

dekhn 4y ago

There's https://en.wikipedia.org/wiki/Cherenkov_radiation https://en.wikipedia.org/wiki/Cherenkov_radiation but I don't really consider that "objects can travel faster than light" in the general sense.

fy20 4y ago

> The key idea behind the propulsion system is that it is designed to focus all the emitted photons in the direction of travel of the spacecraft. This is accomplished by using a sphere with a reflective coating that has a diameter of 1000 km. As we will see, the spacecraft would have to emit 10^27 photons per second. To achieve this enormous rate of photon emission, we will need to use a very large number of solar-powered lasers. https://galactica.org/?max_new_tokens=800&prompt=Lecture+notes+on+the+first+faster+than+light+spacecraft https://galactica.org/?max_new_tokens=800&prompt=Lecture+not...