Historical survey of the study of galaxies Early observations and conceptions The dispute over the nature of what were once termed spiral nebulae stands as one of the most significant in the development of astronomy. On this dispute hinged the question of the magnitude of the universe: How this question arose, and how it was resolved, is an important element in the development of our prevailing view of the universe. Up untilspiral nebulae and their related forms had uncertain status.
Since the Andromeda Galaxy is seen close to edge-on, it is difficult to study its spiral structure. Alternative spiral structures have been proposed such as a single spiral arm  or a flocculent  pattern of long, filamentary, and thick spiral arms.
The gas and dust within the galaxy is generally formed into several overlapping rings, with a particularly prominent ring formed at a radius of 32, light-years 2.
Those arms, however, are not continuous and have a segmented structure. This collision stripped more than half the mass from the smaller M32 and created the ring structures in Andromeda.
They are likely to have accreted and assimilated about — low-mass galaxies during the past 12 billion years. Nucleus[ edit ] Hubble image of the Andromeda Galaxy core showing possible double structure.
M31 is known to harbor a dense and compact star cluster at its very center.
In a large telescope it creates a visual impression of a star embedded in the more diffuse surrounding bulge. The nucleus consists of two concentrations separated by 1. The brighter concentration, designated as P1, is offset from the center of the galaxy. The blue source at the center is at the position of the supermassive black hole.
It has been proposed that the observed double nucleus could be explained if P1 is the projection of a disk of stars in an eccentric orbit around the central black hole. P2 also contains a compact disk of hot, spectral-class A stars. The A stars are not evident in redder filters, but in blue and ultraviolet light they dominate the nucleus, causing P2 to appear more prominent than P1.
While this could be partially resolved if P1 had its own black hole to stabilize it, the distribution of stars in P1 does not suggest that there is a black hole at its center. Apparently, by lateno X-rays had been detected from the Andromeda Galaxy.
Robin Barnard et al. The spectrum of the neutron stars is the same as the hypothesized black holes but can be distinguished by their masses. Globular One or G1 has several stellar populations and a structure too massive for an ordinary globular.
As a result, some consider G1 to be the remnant core of a dwarf galaxy that was consumed by Andromeda in the distant past. The new-found clusters contain hundreds of thousands of stars, a similar number of stars that can be found in globular clusters.
What distinguishes them from the globular clusters is that they are much larger—several hundred light-years across—and hundreds of times less dense.
The distances between the stars are, therefore, much greater within the newly discovered extended clusters. The progenitor black hole is located near the galactic center and has about The Andromeda galaxy, our Milky Way's closest neighbor, is the most distant object in the sky that you can see with your unaided eye — but only on a clear night from a location with a very dark sky.
The galaxy is the smallest spiral galaxy in the Local Group and it is believed to be a satellite of the Andromeda Galaxy due to their interactions, velocities, and proximity to one another in the night sky. The Andromeda Galaxy (/ æ n ˈ d r ɒ m ɪ d ə /), also known as Messier 31, M31, or NGC , is a spiral galaxy approximately kiloparsecs ( million light-years) from Earth, and the nearest major galaxy to the Milky Way.
Its name stems from the area of the sky in . The Andromeda galaxy (or M31) is the massive galaxy nearest to us, and it is an excellent laboratory to study the characteristics and the history of great galactic spirals such as our own Milky Way.
Period of western European history between the collapse of the Political system of local government based on the granting of Grant of land given to a vassal from a lord. MA 1 Introduction. Andromeda Galaxy Key Concept: Astronomical Distance Units Light-Travel Time and the Observable Universe Ranking Task: Astronomical Distances and Light-Travel Time Ranking Task: Looking Back in Space and Time Ranking Task: Size and Distance Scales of Levels of Structure in the Universe Chapter 1 Reading Quiz Chapter 1 Visual.