Why might institutions of authority tend to reject new ideas developed by scientists and other thinkers

The reason why authorities might reject new scientific discoveries is mainly because these challenge the status quo, and in this status quo they are the ones which hold the power.

For example, this happened with old European absolut monarchies when the era of the Enlighment started. The principles of social contract, suffrage or division of powers developed by Enlightment thinkers were opposite to the religious dogmas that supported the Ancient Regime.

think kush in nubia is not as well

beowulf is considered an epic poem because it describes the actions of a great warrior.

beowulf is taken into account an epos. in this poem, the main character may be a hero who travels nice distances to prove his strength at not possible odds against supernatural demons and beasts. in the poem, beowulf was a young warrior and he leaves his country to hrothgar, as hrothgar was in a great trouble.