A galaxy is a system of stars, stellar remnants, interstellar gas, dust, and dark matter bound together by gravity. [1] [2] The word is derived from the Greek galaxias (γαλαξίας), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System.Galaxies, averaging an estimated 100 million stars, [3] range in size from dwarfs with less than a thousand stars, [4] to ...

Jan 26, 2025 · Galaxy, any of the systems of stars and interstellar matter that make up the universe. Many such assemblages are so enormous that they contain hundreds of billions of stars. Virtually all galaxies appear to have been formed soon after the universe began, and they pervade all space that is viewable by modern telescopes.

Jan 14, 2025 · A galaxy is a huge collection of gas, dust, and billions of stars and their solar systems, all held together by gravity. We live on a planet called Earth that is part of our solar system. But where is our solar system?

Galaxy is a community-driven web-based analysis platform for life science research.

Oct 22, 2024 · Most galaxies are between 10 billion and 13.6 billion years old. Some are almost as old as the universe itself, which formed around 13.8 billion years ago. Astronomers think the youngest known galaxy formed approximately 500 million years ago. Galaxies can organize into groups of about 100 or fewer members held together by their mutual gravity.

the Galaxy (also the Milky Way) the very large group of stars that contains the solar system (= the sun and all the planets , including Earth , that go around it) 银河系 ， 银河

Jan 28, 2025 · This detailed view of our galactic next-door neighbor, the Andromeda galaxy, contains over 100 million resolved stars and thousands of star clusters. The panorama sweeps from the galaxy's central bulge across lanes of stars and dust to the sparser outer disk.

Jun 1, 2017 · Many people are not clear about the difference between our Solar System, our Milky Way Galaxy, and the Universe. Let’s look at the basics. Our Solar System consists of our star, the Sun, and its orbiting planets (including Earth), along with numerous moons, asteroids, comet material, rocks, and dust.

Oct 22, 2024 · Both the Milky Way and the Andromeda galaxies belong to a subtype known as barred spirals, which make up two-thirds of the group. Barred spirals sport ribbons of stars, gas, and dust that cut across their centers. Scientists think the presence of a bar indicates that a galaxy has reached full maturity. Elliptical Galaxies

The galaxy M101 as seen by NASA's Hubble Space Telescope reveals its beautiful and complex spiral arms. Though spiral galaxies are the most common type of large galaxy, many details of how they form and evolve are still mysterious.