4 ms·

Is this actually a problem? By the time the person travelling in the car and the stationary person synchronise their information enough to communicate won’t the

Is this actually a problem? By the time the person travelling in the car and the stationary person synchronise their information enough to communicate won’t their frames of reference also sync up? Like if I’m moving and I see something before you, won’t you see it as well before or at the same time I can tell you I saw it?

irthomasthomas 6y ago
From the wiki... "Notice that neither observer can actually "see" what is happening in Andromeda, because light from Andromeda (and the hypothetical alien fleet) will take 2.5 million years to reach Earth. The argument is not about what can be "seen"; it is purely about what events different observers consider to occur in the present moment."
- sudhirj 6y ago
  But the entire point of relativity is that there’s no such thing as a joint “present moment” between more than observer. The only meaningful construct is your own present moment, about which information radiates outward at the maximum speed of information transfer in space-time (speed of light/gravity). Information reaches other observers based on their trajectory and position in space time. No such thing as the universal now.
  - irthomasthomas 6y ago
    Which circles right back to the paradox. The moving persons reference frame has aliens still debating an invasion, and the stationary persons reference frame has the aliens already on their way. How can there be any room for free will in the deliberations of the alien government, if the timelines of both observers are equally valid? The article on relativity of simultaneity has much more detail on the subject https://en.wikipedia.org/wiki/Relativity_of_simultaneity https://en.wikipedia.org/wiki/Relativity_of_simultaneity
    - 8note 6y ago
      For there to be a paradox, the observers would have to find out about it sooner than it would take light to communicate the result. Otherwise, the earliest time that the aliens can find out if they're going to invade or not is when they make the decision. Sure, the observers can find out, and try to tell each other and the aliens, but since it takes at least a round trip of light from the aliens to the observers, the observers always find out after the aliens have made up their minds. If the aliens find out that they make the decision when they make the decision, it seems to me at least that they actually made the decision rather than having it be predestined

irthomasthomas 6y ago

From the wiki... "Notice that neither observer can actually "see" what is happening in Andromeda, because light from Andromeda (and the hypothetical alien fleet) will take 2.5 million years to reach Earth. The argument is not about what can be "seen"; it is purely about what events different observers consider to occur in the present moment."

sudhirj 6y ago
But the entire point of relativity is that there’s no such thing as a joint “present moment” between more than observer. The only meaningful construct is your own present moment, about which information radiates outward at the maximum speed of information transfer in space-time (speed of light/gravity). Information reaches other observers based on their trajectory and position in space time. No such thing as the universal now.
- irthomasthomas 6y ago
  Which circles right back to the paradox. The moving persons reference frame has aliens still debating an invasion, and the stationary persons reference frame has the aliens already on their way. How can there be any room for free will in the deliberations of the alien government, if the timelines of both observers are equally valid? The article on relativity of simultaneity has much more detail on the subject https://en.wikipedia.org/wiki/Relativity_of_simultaneity https://en.wikipedia.org/wiki/Relativity_of_simultaneity
  - 8note 6y ago
    For there to be a paradox, the observers would have to find out about it sooner than it would take light to communicate the result. Otherwise, the earliest time that the aliens can find out if they're going to invade or not is when they make the decision. Sure, the observers can find out, and try to tell each other and the aliens, but since it takes at least a round trip of light from the aliens to the observers, the observers always find out after the aliens have made up their minds. If the aliens find out that they make the decision when they make the decision, it seems to me at least that they actually made the decision rather than having it be predestined