Extragalactic astronomy is a branch of astronomy that studies objects outside our galaxy [1] .
The first extragalactic objects discovered are Cepheids , discovered in the 1920s in spiral nebulae ( galaxies ) by Edwin Hubble , when it became clear that such distant objects as galaxies are very far away. Before the Second World War , galaxy research was conducted only in the visible range. Technological development made it possible to observe extragalactic objects in all areas of the electromagnetic spectrum. Due to this, and increasing the sensitivity of modern telescopes and tools in addition to stars and nebulae, galaxies and new phenomena, such as active galactic nuclei , gas and dust in the interstellar medium of galaxies and, finally, cosmic background radiation.
The usual measure of extragalactic distances is megaparsec, abbreviated as Mpc, corresponding to a distance of 1 million parsec , or 3262 thousand light-years. The galaxies closest to us, Magellanic clouds lie at a distance of about 0.05 Mpc.
See also
- Galaxy
- Quasar
- Cosmology
- Interstellar medium
- Parsec
- Constellation