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.
<span>A composition of different population of plants and animals is found in the coniferous forest. It is composed of cone-bearing or coniferous trees, some examples are spruces, hemlocks, firs and pines. They are mostly found in an ecosystem that has long winters and modern to high annual rain showers. </span>
The type of sand dune that would most likely form if the sand supply is limited the wind direction is constant and vegetation is sparse would be a barchan dunes. It is a <span>crescent-shaped sand </span>dune<span> produced by the action of wind predominately from one direction.</span>
The Appalachian mountains & the Rocky Mountains :)
