Isaac Newton was an English scientist who lived from 1643 to 1727 and made discoveries so important that they changed how we understand the universe. Newton figured out the laws of motion and gravity, explaining why planets orbit the sun, why apples fall from trees, and how force and movement work together. His book Philosophiæ Naturalis Principia Mathematica (often just called Principia) laid the foundation for physics and remained the best explanation of how the universe works for over 200 years.

Newton also helped develop a new type of mathematics called calculus, which helps solve complex problems about how things change over time. He discovered that white light is actually made up of all the colors of the rainbow, and he built the first reflecting telescope, which used mirrors instead of just lenses.

What made Newton remarkable wasn't just his intelligence but his persistence. He could focus intensely on a problem for weeks or months, working through countless calculations until he found the answer. When the Great Plague closed his university in 1665, Newton spent about two years at home making some of his greatest breakthroughs.

Newton showed that careful observation, mathematical thinking, and relentless curiosity could unlock nature's deepest secrets. His work helped show that the same laws governing a falling apple also govern the motion of planets millions of miles away.