Albert Einstein Albert Einstein is often cited as one of the most influential scientists of the 20th century. His work continues to help astronomers study everything from gravitational waves to Mercury's orbit. The scientist's equation that helped explain special relativity – E = mc^2 – is famous even among those who don't understand its underlying physics. Einstein is also known for his theory of general relativity (an explanation of gravity), and the photoelectric effect (which explains the behavior of electrons under certain circumstances); his work on the latter earned him a Nobel Prize in Physics in 1921. Einstein also tried in vain to unify all the forces of the universe in a single theory, or a theory of everything, which he was still working on at the time of his death. Early years Einstein was born on March 14, 1879, in Ulm, Germany, a town that today has a population of just more than 120,000. There is a small com...