SpaceX’s Starship flies during its fifth flight test, in Boca Chica, Texas, U.S., October 13, 2024.
| Photo Credit: Reuters

Questions:

1. The path an object traces as it moves through the four dimensions of spacetime is called its X. When X forms a closed loop in spacetime, the object can be said to be able to return to its past, i.e. time-travel. Name X.

2. As long as a communication signal travels at or under the speed of light, the receiver will receive it after the transmitter has sent it. But if the signal exceeds the speed of light, the receiver can receive it before it has been transmitted. What is the name for the hypothetical device capable of doing the latter?

3. Name the physicist who shared the physics Nobel Prize in 2022 for an experiment he conducted in 1988. The experiment helped prove that if quantum physics is complete and non-deterministic, reality is also nonlocal, i.e. admitting action at a distance.

4. The grandfather paradox of time travel holds that if you travel to the past and kill your grandfather, your own existence shouldn’t have been possible. Name the paradox that uses this argument to ask whether free will could be real in a world with time travel.

5. Name the interpretation of quantum mechanics advanced by Hugh Everett that resolves the grandfather paradox by claiming that once you’ve killed your grandfather, you move into a new future different from the one before.

Visual:

Name this sports car first manufactured in 1981. It became famous when the Back to the Future films (1985-1990) used it as a time machine.

Answers:

1. World line

2. Tachyonic antitelephone

3. Anton Zeilinger

4. Newcomb’s paradox

5. Many-worlds interpretation

Visual: DeLorean