1. Y

    I Interstellar travel without propulsion and time dilation

    I hope this is the right forum for this question. Imagine alien tech allows them to travel 1 million light years to Earth instantaneously. No thrust, vector, propulsion was involved. They didn't have to approach the speed of light, with its attendant increase in mass. Having arrived at earth, in...
  2. T

    I Quantum entanglement, wave-function collapse

    I have 2 questions i would really like to find an answer to: if we have a quantum pair, we can determine whether 2 quanta are entangled or not assuming that we have access to the information of both of them. so if we have a quantum "trio" instead of a quantum pair, does the information about 2...
  3. T

    I Do laws of physics apply below the event horizon?

    Do laws of physics apply below the event horizon? It appears as if black holes had such gravity as to have an escapr velocity higher than c, which means that things are pulled inwards at higher speeds than the speed of light. Or am I overlooking something?
  4. Stephanus

    B Can we travel faster than the speed of light?

    Dear PF Forum, Before I get a NO answer, I'd like to ask a few question. https://en.wikipedia.org/wiki/Hubble%27s_law#Observed_values As of 13th July, 2016 Hubble flow is 67.6 km/s per mega parsec. Or 67km/s per 31 trillion * 1 million km or per 3.26 million light year. Say a galaxy 11.68 giga...
  5. F

    A Experiment design FTL particle though magnetic field

    Hi. I was browsing Wikipedia on a topic, went to magnetic bearings, etc etc...ended up on synchrotron radiation then the phrase about how a moving or accelerat/ing/ed particle passing through a magnetic field generates electromagnetic radiation. Then I has a revelation. How to get a particle...
  6. EnumaElish

    Are aliens FTL humans?

    What do you think of the following scenario*? Aliens are future humans who discovered faster than light travel. They propagated throughout the universe. In so doing they travelled back in time, to our time, or even earlier times. *I read this in a popular space opera novel. It may have been...
  7. Stephanus

    B FTL signal and causality

    Dear PF Forum, I've tried to googled how causality can happen by FTL communcation (I use communication, because if it "travels", I'm having trouble calculating ##\gamma## imaginer). But from all examples that I've found it can violate causality if one of the party is moving relative to the...
  8. entropy1

    Non-locality: (FTL) 'influence' at all?

    I have a basic question about the concept of non-locality in QM. I'll explain as I understand it (correct me if I'm missing the essence): The so called 'non-local' property of two entangled photons (for instance), suggests that the measurement of one of the pair 'communicates' with the other...
  9. T

    Using space time for FTL communications

    I think we all know what an Alcubierre drive is, well this is similar in principle. Is it possible to conduct faster than light communication through the acceleration of a bubble of space time? is it even possible to do this without a ship, and just send it out as a warp bubble from a point like...
  10. entropy1

    Bell-state entanglement swapping and retrocausality

    I thought there were already some posts about this, but I can't find them.:frown: In this article of Anton Zeilinger et al. they perform an experiment which suggests FTL or retrocausal influence. Alice and Bob both produce their own polarisation-entangled photon pair, both send one photon of...