Albert Einstein

Albert Einstein was a German-born scientist who changed the way people understand space, time, and gravity. He lived from 1879 to 1955. He is one of the most famous scientists in history, and his name has become another word for "genius."

Einstein was born in the German city of Ulm. As a boy, he was quiet and slow to start talking. Some teachers thought he was lazy because he hated memorizing facts. But he loved puzzles, music, and questions about how the world worked. When he was five, his father gave him a small compass. The needle always pointed north, no matter which way Einstein turned it. He never forgot the feeling that some hidden force was at work.

After college, Einstein could not find a teaching job. He took work at a patent office in Switzerland, checking new inventions. In his free time, he thought about physics. In 1905, at age 26, he published four scientific papers in a single year. Any one of them would have made him famous. Together, they changed science forever. Today scientists call 1905 his "miracle year."

One of those 1905 papers contained the most famous equation in the world: E = mc². It says that energy (E) and mass (m) are really the same thing, and that a tiny bit of mass can turn into a huge amount of energy. The "c" stands for the speed of light. Light travels about 186,000 miles per second, fast enough to circle Earth seven times in one second. This idea later helped scientists understand how stars shine and how nuclear power works.

In 1915, Einstein finished an even bigger idea called general relativity. It said that gravity is not really a pulling force, the way Isaac Newton had taught. Instead, heavy objects like the Sun bend the space and time around them, the way a bowling ball bends a trampoline. Smaller objects roll along those bends. In 1919, scientists tested his idea during a solar eclipse. Starlight bent around the Sun by exactly the amount Einstein had predicted. He became world famous overnight.

Einstein was Jewish. When the Nazis took power in Germany in 1933, he moved to the United States and never went back. He spent the rest of his life at Princeton University in New Jersey. He also spoke out for peace, civil rights, and the new state of Israel, which once asked him to be its president. He politely said no. He preferred equations to politics.