图示：宇宙早期的类星体

图示：宇宙早期的类星体

ByNASA中文

2022年2月22日 Illustration: An Early Quasar Illustration Credit & License: ESO, M. Kornmesser Explanation: What did the first quasars look like? The nearest quasars are now known to involve supermassive black holes in the centers of active galaxies. Gas and dust that falls toward a quasar glows brightly, sometimes outglowing the entire home galaxy. The quasars that formed in the first billion years of the universe are more mysterious, though. Featured, recent data has enabled an artist’s impression of an early-universe quasar as it might have been: centered on a massive black hole, surrounded by sheets of gas and an accretion disk, and expelling a powerful jet. Quasars are among the most distant objects we see and give humanity unique information about the early and intervening…

爱因斯坦的引力透镜十字架

爱因斯坦的引力透镜十字架

ByNASA中文

2021年10月17日 The Einstein Cross Gravitational Lens Image Credit & License: J. Rhoads (Arizona State U.) et al., WIYN, AURA, NOIRLab, NSF Explanation: Most galaxies have a single nucleus — does this galaxy have four? The strange answer leads astronomers to conclude that the nucleus of the surrounding galaxy is not even visible in this image. The central cloverleaf is rather light emitted from a background quasar. The gravitational field of the visible foreground galaxy breaks light from this distant quasar into four distinct images. The quasar must be properly aligned behind the center of a massive galaxy for a mirage like this to be evident. The general effect is known as gravitational lensing, and this specific case is known as the Einstein Cross. Stranger still,…

仙女座大星系的气晕

仙女座大星系的气晕

ByNASA中文

2020年9月3日 A Halo for Andromeda Digital Illustration Credit: NASA, ESA, J. DePasquale and E. Wheatley (STScI) and Z. Levay Explanation: M31, the Andromeda Galaxy, is the closest large spiral galaxy to our Milky Way. Some 2.5 million light-years distant it shines in Earth’s night sky as a small, faint, elongated cloud just visible to the unaided eye. Invisible to the eye though, its enormous halo of hot ionized gas is represented in purplish hues for this digital illustration of our neighboring galaxy above rocky terrain. Mapped by Hubble Space Telescope observations of the absorption of ultraviolet light against distant quasars, the extent and make-up of Andromeda’s gaseous halo has been recently determined by the AMIGA project. A reservoir of material for future star formation, Andromeda’s…