2024年10月22日 · 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. Stars form in large clouds of gas and dust called molecular clouds.

4 天之前 · Stellarium Web is a planetarium running in your web browser. It shows a realistic star map, just like what you see with the naked eye, binoculars or a telescope.

2024年10月22日 · Scientists call a star that is fusing hydrogen to helium in its core a main sequence star. Main sequence stars make up around 90% of the universe’s stellar population. They range in luminosity, color, and size – from a tenth to 200 times the Sun’s mass – and live for millions to billions of years.

2022年9月26日 · Stars are giant, luminous spheres of plasma. There are billions of them — including our own sun — in the Milky Way galaxy. And there are billions of galaxies in the universe. So far, we have...

2025年1月21日 · 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.

2023年4月19日 · Learn about stars from NASA's High Energy Astrophysics Science Archive Center.

2021年1月12日 · After a long and historic period of exploring the four giant planets in our solar system, the Voyagers became the first probes ever to reach interstellar space. In that vast, previously unexplored region, the probes are tasting space outside the protective bubble of particles and magnetic fields created by our Sun.

2024年9月21日 · 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.

6 天之前 · Smaller stars like our sun end their lives by ejecting their outer layers of gas into space over the course of about 10,000 years, leaving behind the star’s hot core — a white dwarf. Radiation from the white dwarf causes the gas to glow, creating a unique and beautiful formation called a planetary nebula.

2022年1月28日 · First off, a decent enough astrophysical definition of a star is: any object that is sufficiently massive that it can ignite the fusion of elements in its core due to the gravitational pressures...