Galaxy | Definition, Formation, Types, Properties, & Facts | Britannica
6 天之前 · 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. …
Astronomy | Definition, History, Discoveries, & Facts | Britannica
2024年11月17日 · Astronomy, science that encompasses the study of all extraterrestrial objects and phenomena. Since the late 19th century, astronomy has expanded to include …
Galaxy - Elliptical, Spiral, Irregular | Britannica
3 天之前 · In Hubble’s scheme, which is based on the optical appearance of galaxy images on photographic plates, galaxies are divided into three general classes: ellipticals, spirals, and …
Astronomy Portal | Britannica
Astronomy, science that encompasses the study of all extraterrestrial objects and phenomena. Until the invention of the telescope and the discovery of the laws of motion and gravity in the …
Astronomy - Solar System, Planets, Stars | Britannica
2024年11月17日 · Astronomy - Solar System, Planets, Stars: The solar system took shape 4.57 billion years ago, when it condensed within a large cloud of gas and dust. Gravitational …
Galaxy - Evolution, Quasars, Structure | Britannica
3 天之前 · Galaxy - Evolution, Quasars, Structure: The study of the origin and evolution of galaxies and the quasar phenomenon has only just begun.
Space exploration | History, Definition, & Facts | Britannica
2024年11月4日 · From modest beginnings, space science has expanded under government support to include multibillion-dollar exploratory missions in the solar system. Examples of …
Edwin Hubble | Biography, Discoveries, Education, & Facts
2024年11月16日 · Edwin Hubble, American astronomer who played a crucial role in establishing the field of extragalactic astronomy and is generally regarded as the leading observational …
Science | Definition, Disciplines, & Facts | Britannica
2024年11月16日 · science, any system of knowledge that is concerned with the physical world and its phenomena and that entails unbiased observations and systematic experimentation. In …
Supercluster | Astronomy, Galaxies & Clusters | Britannica
Supercluster, a group of galaxy clusters typically consisting of 3 to 10 clusters and spanning as many as 200,000,000 light-years. They are the largest structures in the universe. In 1932 …