Quote by Stephen Hawking, A Brief History
There could be whole antiworlds and antipeople made out of antiparticles. However, if you ever meet your antiself, don't shake hands! You would both vanish in a great flash of light.
Summary
This quote suggests the existence of parallel universes composed of anti-worlds and anti-people made from anti-particles. It warns against the peril of encountering one's own anti-self, as the interaction could result in the annihilation of both individuals, symbolized by a brilliant burst of light. This concept alludes to the theory of antimatter, where oppositely charged particles can annihilate each other upon contact, showcasing the potentially dangerous consequences of encountering a physical counterpart from an anti-universe.