That theory, a concept first proposed by Albert Einstein and often reiterated by British astrophysicist Stephen Hawking, seeks to find a single set of equations that can explain all the fundamental forces in the universe: gravity, electromagnetism, and the strong and weak interactive forces among subnuclear particles.
There are no astrophysicists from Britain.
( z1 astrophysicist :polarity - :source ( z2 country :name ( z3 name :op "Britain" ) ) )