Example 1.1: What is the solid angle subtended by the moon at any point of the Earth, given
the diameter of the moon is 3474 km and its
distance from the Earth 3.84x108 m.

a high pressure system is a dense air mass that is usually cooler and drier than the surrounding air. a low pressure system is a less dense air mass that is usually wetter and warmer than the surrounding air.

in general, areas that experience high atmospheric pressure also experience fair weather. low pressure systems can cause the formation of clouds and storms. air usually flows from areas of high pressure to areas of low pressure..