Although the light year is a
commonly used unit, astronomers
prefer a different unit called the parsec (pc). A parsec, equal to 3.26
light years, is defined as the distance at which 1 Astronomical Unit subtends an
angle of 1 second of arc (1/3600 of a degree) When we use the parsec for really
large distances, we often put a prefix in front of it - like kiloparsecs (kpc),
which are equal to 1000 parsecs - or Megaparsecs (Mpc), equal to a million
parsecs.
The Milky Way is about 1,000,000,000,000,000,000 km
(about 100,000 light years or about 30 kpc) across. The Sun does not lie near
the center of our Galaxy. It lies about 8 kpc from the center on what is known
as the Sagittarius arm of the Milky Way.
Explanation:
1- it can quickly mobilize economic resources on a large scale
2-execute massive projects, and create industrial power.
3-It can move so effectively because it overrides individual self-interest and subjugates the welfare of the general population to achieve critical social goals.
Water is the source of life. It is one of the only ways to survive so without water, there is no life.
