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. The most prominent stars have been categorised into constellations and asterisms, and many of the brightest stars have proper names.

3 days ago · star, 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 composing the observable universe, only a very small percentage are visible to the naked eye.Many stars occur in pairs, multiple systems, or star clusters.The members of such stellar groups are physically …

May 2, 2025 · Astronomers call stars that are stably undergoing nuclear fusion of hydrogen into helium main sequence star s.This is the longest phase of a star’s life. The star’s luminosity, size, and temperature will slowly change over millions or billions of years during this phase.

Apr 18, 2025 · Stars begin their life cycle in molecular clouds, which are dense regions of gas and dust in space.These clouds contain clumps of material that can collapse under their own gravity to form protostars. The collapse is often triggered by external forces such as shock waves from nearby supernovae.As the cloud collapses, it heats up and forms a rotating disk of material …

Apr 10, 2025 · At the lower end, and to the bitter end, defining a star is tougher than you might expect

3 days ago · 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. Evolutionary effects on these stars are not negligible, even for a middle-aged star …

Jul 3, 2019 · Stars are more than simply objects in the sky. They teach us about the workings of the universe, from the earliest stars to the current ones. People have long used star charts like this one to find their way around the sky at night.

Reconstructed view of the surface of the star Antares in the constellation of Scorpius A star-forming region in the Large Magellanic Cloud. NASA/ESA image The open star cluster Pismis 24 is in the nebula NGC 6357.It has some of the largest stars known. Pismis 24-1 has nearly 300 times the mass of the Sun.It is a multiple system of at least three stars.

Jul 15, 2014 · We're all pretty familiar with stars. We see them on most clear nights as tiny, twinkling pinpricks of light in the sky. Stars are the topic of countless poems, stories, and nursery rhymes alike. But just what is a star, exactly?

A star is a huge sphere of very hot, glowing gas. Stars produce their own light and energy by a process called nuclear fusion. Fusion happens when lighter elements are forced to become heavier elements.