A star is a luminous spheroid of plasma held together by self-gravity. [1] The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night; their immense distances from Earth make them appear as fixed points of light.
A star is any massive self-luminous celestial body of gas that shines by radiation derived from its internal energy sources. Of the tens of billions of trillions of stars in the observable universe, only a very small percentage are visible to the naked eye.
These large, swelling stars are known as red giants. But there are different ways a star’s life can end, and its fate depends on how massive the star is.
If you have read How the Sun Works, you already know a lot about the nature of Earth's nearest star. As you read the following pages, you'll find out even more about what you can see in the night sky.Star - Formation, Evolution, Lifecycle: Throughout the Milky Way Galaxy (and even near the Sun itself), astronomers have discovered stars that are well evolved or even approaching extinction, or both, as well as occasional stars that must be very young or still in the process of formation.