Look up at the night sky. You’ll see thousands of twinkling lights. Each one is a star, a massive ball of hot gas that glows from nuclear fusion deep inside. Stars power our universe. They light up galaxies and forge elements for planets and life. Our Sun is one such star, a middle-aged example that … Read more
Imagine lying under a clear night sky. You gaze up at those twinkling lights and wonder, why do stars shine so steadily? Those distant specks aren’t magic; they’re powered by nuclear fusion deep in their cores. Stars produce light because intense gravity crushes hydrogen atoms together. This proton-proton chain fuses four protons into one helium … Read more
Picture a star like our Sun swelling to swallow planets, or another one ripping apart in a blast brighter than a billion suns. Stars seem eternal, but they all die someday. What happens when a star dies depends on its size. Small ones fade quietly over trillions of years. Sun-like stars puff out glowing shells … Read more
Look up at a clear night sky. Those faint fuzzy patches aren’t clouds. They mark entire cities of stars, each a galaxy packed with millions to trillions of stars, gas, dust, and dark matter. Gravity binds them into vast systems that stretch thousands to millions of light-years across. Our home, the Milky Way, fits this … Read more
Picture this: our galaxy packs in 100 to 400 billion stars. That’s more than all the grains of sand on every beach on Earth. Yet Earth sits in a quiet neighborhood called the Orion Arm. This spot lies about 26,800 light-years from the galactic center. You might wonder why this matters. It gives us context … Read more