Synonyms that are in the dictionary are marked in green. Synonyms that are not in the dictionary are marked in red.
Antonyms that are in the dictionary are marked in green. Antonyms that are not in the dictionary are marked in red.
It seems impossible for us to travel backwards into the past or send signals into our own past: Everything in our universe not only travels no faster than the speed light, but also always in the direction of the future.
Source: https://www.discovermagazine.com/the-sciences/is-there-a-particle-that-can-travel-back-in-time