What did Albert Einstein invent? Discoveries that made him famous and changed the world.

Albert Einstein’s name is synonymous with “genius,” and his wild hair is a trope of its own for mad scientists and professors in popular culture.

Einstein’s discoveries led to modern-day inventions like paper towels, solar power, stock market forecasts and laser pointers, but his theory of general relativity is often regarded as his most significant contribution.

Here’s a look at the life and work of Einstein, who is considered one of the most influential physicists of the 20th century.

What did Albert Einstein invent?

Einstein published four notable papers during his “Miracle Year” in 1905 while he was working at a Swiss patent office:

In his first paper, Einstein applied German physicist Max Planck’s quantum theory to light to explain the photoelectric effect. He went on to win the Nobel Prize for this work in 1921.

His second paper used the Brownian motion, or the motion of tiny particles suspended in liquid, to share the first experimental proof of the existence of atoms, according to Britannica.

His third paper, “On the Electrodynamics of Moving Bodies,” offered Einstein’s special theory of relativity. His fourth paper led to the development of the most well-recognized equation in science: E = mc².

E=mc2 says, basically, mass and energy are the same physical entity. This equation, and his other theories, helped in the development of the atomic bomb, though Einstein was never asked to participate in the American-led atomic weapon effort called the Manhattan Project.

In 1915, he published his general theory of relativity, the first theory of gravity since the publication of "Principia", by Sir Isaac Newton in 1687. Newton’s work established gravity both as a concept and a universal law, stating that gravity is a constant force that tugs on objects. The tug will be stronger if the object has more mass, and weaker if you increase the distance between two objects.

Einstein’s theory, which he discovered while the director of the Kaiser Wilhelm Institute for Physics at the University of Berlin, tackled the explanation of gravity. His theory of general relativity says that gravity is a natural consequence of a mass’ existence in space – that mass can bend space and time. Newton didn’t believe objects affected space, the American Museum of Natural History writes, but Einstein did, and had even distinguished a fourth dimension known as space-time in his 1905 special theory of relativity.

Einstein also predicted the existence of gravitational waves in his theory of relativity. Instead of viewing gravity as a constant, immediate force, Einstein proposed a large change in mass would cause space to squeeze and stretch by a small amount.

Einstein’s last work, which remained unfinished when he died, was on unified field theory, which uses a single theoretical framework to describe fundamental forces and the relationships between elementary particles, according to Britannica.

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When did Albert Einstein die?

Einstein died at the age of 76 on April 18, 1955, of an abdominal aortic aneurysm. According to AMNH, Einstein denied surgery for the burst blood vessel, saying “I want to go when I want to go. It is tasteless to prolong life artificially. I have done my share; it is time to go. I will do it elegantly.”

What was Albert Einstein’s IQ?

There’s no definitive answer or evidence Einstein had his IQ tested, but his IQ is estimated to be around 160. Theoretical physicist Stephen Hawking’s IQ is estimated to be the same, but the two physicists are far from the highest IQs recorded despite popular acclaim.

The average IQ score in the U.S. is 98.

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This article originally appeared on USA TODAY: What did Albert Einstein invent? Here's what made him famous.