Research on emotion has shown that emotion has a guiding influence on people's lives. what is the purpose of sadness?

Sadness serves many constructive purposes in our lives though apparently it seems like a paradox. Research has shown that people when sad or feeling blue have had experienced better memory comparing to the times they were happy, so it serves as a support to boost human memory. Secondly in one study scientists found out that sadness helped the subject to make better judgment of the people and social cues than those who were happy. Sadness serves as a motivating force as well.

On a personal note, in my point of view sadness is the main factor behind all the human progress today, if man was not sad he had never developed so much today, take the sad part of man’s life out and his personal growth halts.

giant impact theory - the moon was formed from the collision between earth and another mars-sized body.

colliding planetesimals hypothesis - the moon was formed from the same cloud of material as earth.

capture hypothesis - the moon was locked into orbit by earths gravity as it was passing by it.

accretion hypothesis - the moon was formed from collisions and combining of planetesimals.

i think this is right, if not and you know better let me know.

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