Stars are giant balls of hot gas – mostly hydrogen, with some helium and small amounts of other elements. Every star has its own life cycle, ranging from a few million to trillions of years, and its properties change as it ages.
Many other stars are visible to the naked eye at night; their immense distances from Earth make them appear as fixed points of light. The most prominent stars have been categorised into constellations and asterisms, and many of the brightest stars have proper names.
Stars such as Altair, Alpha Centauri A and B, and Procyon A are called dwarf stars; their dimensions are roughly comparable to those of the Sun. Sirius A and Vega, though much brighter, also are dwarf stars; their higher temperatures yield a larger rate of emission per unit area.
How are stars named? And what happens when they die? These star facts explain the science of the night sky.
What are stars, how do they form and die? Our guide packed with facts about stars and answers to some of the most commonly-asked questions.
Stars are massive, luminous spheres of gas, mainly composed of hydrogen, with smaller amounts of helium and other elements. The lifespan of a star varies widely, generally ranging from several million to several trillion years.
Stars are spherical balls of hot, ionized gas (plasma) held together by their own gravity. Stars are the most fundamental building blocks of our universe.
Stars are huge celestial bodies made mostly of hydrogen and helium that produce light and heat from the churning nuclear forges inside their cores.
Stars are luminous spheres made of plasma – a superheated gas threaded with a magnetic field. They are made mostly of hydrogen, which stars fuse in their cores. That process releases energy, which pushes against the weight of the outer layers of the star and keeps it stable.