What is a primary source?

A primary source is an original document such as diaries, speeches, manuscripts, letters, interviews, records, eyewitness accounts, autobiographies. Empirical scholarly works such as research articles, clinical reports, case studies, dissertation

Explanation:

as we probably am aware that our atmosphere or air have various levels, each level has different gasses, and each gas has another porousness. at the point when the light originates from lower porousness to higher penetrability, it alters its course. with the goal that implies that when the light originates from the moon to the earth, it alters it's course a lot more occasions. it essentially implies that the state of the light piece of the moon is changed on the earth.

not copied too! hope this !

joke:

h o h o hope you have a merry christmas!