Spiral Galaxy : Basic Info

Ya…

Spiral galaxies (Spiral Galaxy) has a lot of gas, dust and hot, bright stars, the formation of spiral structure of flat galaxies. The spiral galaxy is a spiral structure extragalactic in Hubble ’s galaxy classification using the S stands for. The spiral shape of the spiral galaxy was first found in 1845 observations Canes galaxy M51.
Distorted spiral galaxy ( ESO 510-G13 ) is the result of collision with another galaxy, another galaxy was completely absorbed, this process usually takes millions of years　　In the modern theory of the formation of our Milky Way, the earliest (It is understood that astronomers Els
, Followed by the presentation of papers Olin, Eggen, Donald dba Lynden-Bell, and Allan Sandage [1]) described in a separate (relative) speed after the collision, the galactic halo along with the disk of the galaxy was born. In 1978, another version (It is understood that the SZ, the author Leonard Searle and Robert Zinn [2]) described a gradual process, the first is the collapse of the smaller units collapse out, and then merged into a large part.

The more modern idea is that after the destruction of dwarf galaxies and globular clusters in the galactic halo may be used to surround the Milky Way rotation of debris, then the galactic halo is the old part of recycled updated with the new celestial place.

In recent years, the main idea is to focus on the merger events in galaxy evolution to allow the simulation of the evolution of galaxies do better in the rapid progress of computer technical and observation techniques improve the experience of many distant galaxies merge events data and information. Discovered in 1994, our satellite galaxy, the Sagittarius dwarf spheroidal (SagDEG), being the Galaxy gradually torn and swallowed , this event is quite common in large galaxies. Magellanic Clouds, our satellite galaxy, and no doubt will suffer the same as the Sagittarius dwarf spheroidal fate. Merger events out of satellite galaxies may explain the M31 ( Andromeda Galaxy ) appears to have dual core of the problem.The orbit of the 　　Sagittarius dwarf spheroidal galaxy around our Galaxy Department almost perpendicular to the galactic disk, he is now crossing the disk, each crossing when the star will be stripped into the galactic halo of our galaxy , and finally, the Sagittarius dwarf spheroidal will remain at the core. Nevertheless, the remainder of his quality is still a huge globular clusters like Centaurus ω cluster and G1, but it looks quite different, because a lot of mysterious dark matter appear, so that its lower surface density, but become globular clusters, the mysterious dark matter content may be few.