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 …

May 2, 2025 · A star’s gas provides its fuel, and its mass determines how rapidly it runs through its supply, with lower-mass stars burning longer, dimmer, and cooler than very massive stars.

Jan 20, 2026 · 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, …

Where Do Stars Come From? Every star forms in a huge cloud of gas and dust. Over time, gravity causes the cloud to contract, drawing the gas closer and closer together. As more gas accumulates …

Mar 20, 2019 · 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.

Jan 4, 2021 · It's easy enough to say what a star is: one of those bright pointy things that twinkle in the night sky. But the actual definition of a star is as rich and colorful as the stars themselves.

The amount of material in a star (its mass) is so huge that a nuclear reaction called nuclear fusion goes on inside it. This reaction changes hydrogen to helium and gives off heat.

Somewhat related to star clusters are stellar associations, which consist of loose groups of physically similar stars that have insufficient mass as a group to remain together as an organization. This is a …

Dec 18, 2025 · The universe’s stars range in brightness, size, color, and behavior. Some types change into others very quickly, while others stay relatively unchanged over

Sep 28, 2023 · To unravel the birth and early evolution of stars and planets, we need to be able to peer into the hearts of dense and dusty cloud cores where star formation begins.