Earth is composed of four main layers, starting with an inner core at the planet's center, enveloped by the outer core, mantle, and crust. The inner core is a solid sphere made of iron and nickel metals about 759 miles (1,221 kilometers) in radius.
source: nasa
Answer:
1. disk
2.halo
3. globular cluster
4.spiral arm
5. spiral galaxy
6. bulge
Explanation:
1. In Spiral or Lenticular galaxies, the galactic disk is the flat portion that consists of 2 components; the stellar component and the gaseous component. The stellar component consists of the galaxy stars while the gaseous component consists of cool gas and dust.
2. The galactic halo is the first portion of the galaxy to be formed. Formation of halos is caused by increased gravitational effects and the presence of primordial black holes. When baryonic and dark matter merges, halos are formed.
3. A globular cluster is a large compact spherical star cluster, typically of old stars in the outer regions of a galaxy.
4. Spiral arms are region of a large concentration of stars in a spiral galaxy. This large concentration of stars are usually very bright and easily noticeable.
5. The Milky Way galaxy consists of flat, rotating disk containing stars, gas and dust, and a central concentration of stars known as the bulge. The spiral arm that I explained above extends from the center of spiral galaxies. This extension makes it resemble a spiral and thus give spiral galaxies their name.
6. The bulge is a large concentration of stars.
Answer:
The davis's geomorphic cyclic theory raised some of the problems that the davis's concept of the upliftment creates problem so that is why it is unacceptable as it basically described the rapid change in the rate of the upliftment in the very short duration.
And the concept of the correlation in the upliftment and erosion are erroneous as, according to the concept no erosion occurred unless the upliftment process are completed.
