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Cake day: June 13th, 2023

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  • Even moving with 10 times the speed of light, you still take “forward time” to move to your end point.

    There’s no such thing as speeds faster than light—the worldlines of objects with such trajectories are called “spacelike” instead of “timelike” for a reason. “Forward” and “backward” time is only defined for events within your light-cone, and trajectories “faster than light” are outside it. Whether events outside your light-cone are in your future or your past are dependent on your current reference frame, which you can change at will by accelerating.

    The thing about “moving with FTL from A to B” is that if B is far away, the event at B simultaneous with your departure from A will be highly dependent on A’s reference frame—a shift in A’s velocity will correspond to a shift in B’s timeline equal to (vx/c2)/√(1-v2/c2) (where v is the change in A’s velocity and x is the distance to B). And things are changing velocities with respect to each other all the time (e.g., for objects on earth due to the planet’s revolution and rotation around the sun), so the point in B’s timeline at which you’d arrive would be constantly swinging backward and forward in time.

    And the same is true for the return trip: a minor change in B’s reference frame can put your arrival back in A’s timeline at a point before your original departure.







  • A mythology is a set of shared stories that define a culture—its values, its productive metaphors, its identity. They may or may not be considered literally true; even when they are, they’re generally understood to have occurred in a place and time distinct from the culture’s current reality.

    But the point of a mythology is the relationship it establishes between community members, while the point of a religion is the relationship it purports to establish between its adherents and the divine.