The galaxy is also referred to as the Milky Way and has three distinct parts in its structure. These are the halo, bulge, and disk. To begin with, the Frisbee-shaped and rotating flat section of the Milky Way is known as the disk (Gerhard 129). This part of the galaxy has several spiral arms. The star formation also takes place in the disk part of the galaxy. However, this formation takes quite a long period on the surface of the galaxy. The surface of the disk contains a rather thick component that is sparsely populated. The latter section stretches away from the surface of the Milky Way compared to other parts of the disk.
The central part of the disk is known as the bulge. It is concentrated with stars and also spherical. In other words, the bulge hosts the central part of the Milky Way. It is estimated to be about 24,000 light-years from the solar system (Gerhard 136).
Both the bulge and the disk of the Milky Way are known as the halo. The latter region in the structure of the galaxy is extended and also sparsely populated. Moreover, the region contains several stars. One of the dominant bodies in this section is the globular cluster that comprises large bright star clusters. The halo field stars are also part and parcel of this region (McMillan 2453).
In terms of size, the diameter of the galaxy is estimated to be about 100,000 ly (30 kpc). In regards to thickness, scientists have estimated it to be 1,000 ly (0.3 kpc) (McMillan 2446). Everything is indeed located in the Milky Way or the galaxy system. As already discussed above, the structure of the galaxy is extended and probably, there are still a lot of facts that are yet to be discovered.
How far apart are our stars? There are over one hundred billion stars in the galaxy. Some conservative estimates note that the number could go up to four hundred billion. However, the dwarf stars can assist in detecting the accurate number of stars bearing in mind that these types of stars cannot be detected easily. A thick layer of surrounding gas takes up the space between individual stars in the galaxy (McMillan 2446). There is an average radius that is occupied by the disk of gas between the stars. However, it is quite complex to determine the thickness of the region occupied by the gas.
A recent scientific research study by NASA reported the estimated accurate distance between our stars in the universe. From the findings, one hundred billion cubic meters of light-years contains about 1.4 stars in terms of density. When this measurement is converted in terms of the span between the individual stars, it is found to be 4,150 light-years (Gerhard 133). The Proxima Centauri and the Sun are the two stars that are very close to the planet Earth. The two stars can be used as a comparison in this discussion. They have been found to have a difference of 4.2 light-years (Gerhard 131). It is pertinent to mention that the distance covered by light in a vacuum in any given year on earth is referred to as one light year. Alternatively, it is similar to ten trillion kilometers or six trillion miles.
Works Cited
Gerhard, Ortwin. “Mass distribution in our Galaxy”. Space Science Reviews 100.4 (2002): 129–138. Print.
McMillan, Paul. “Mass models of the Milky Way”. Monthly Notices of the Royal Astronomical Society 414.3 (2011): 2446–2457. Print.