Other disklike galaxies, with no overall spiral form, are classified as irregulars. These galaxies also have large amounts of gas, dust, and young stars, but no arrangement of a spiral form. They are usually located near larger galaxies, and their appearance is probably the result of a tidal encounter with the more massive galaxy. Some extremely peculiar galaxies are located in close groups of two or three, and their tidal interactions have caused distortions of spiral arms, producing warped disks and long streamer tails. Ring galaxies, for example, form when a small galaxy collides with the center of a spiral galaxy. An intense ring of stars forms at the outer edges of the new, combined galaxy. Quasars are objects that appear stellar or almost stellar, but their enormous redshifts identify them as objects at very large distances. They are probably closely related to radio galaxies.
- irregular [iˈreɡjulə] n. 不规则的物体
- tidal [ˈtaidl] adj. 潮汐的
- encounter [inˈkauntə] n. 相遇
- peculiar [piˈkju:ljə] adj. 罕见的
- interaction [ˌɪntərˈækʃən] n. 相互作用
- distortion [disˈtɔ:ʃən] n. 扭曲变形
- warped [wɔ:p - d] adj. 弯曲的
- streamer tail [ˈstri:mə - teil] n. 带状的尾巴
- collide [kəˈlaid] v. 碰撞
- edge [edʒ] n. 边缘
- quasar [ˈkweizɑ:] n. 类星体
- stellar [ˈstelə] adj.恒星的
- redshift [ˈred - ʃift] n. 红移
