Why were the rings of uranus not observed directly from telescopes on the ground on earth? how were they discovered?

Explained below.

Explanation:

Uranus rings is made up of jet black, coal-like particles in small bands, making them difficult  to perceive from Earth.This indicates that they are probably composed of a mixture of the ice and a dark material. The nature of  material is dismal, but it might be some organic compounds greatly darkened by the charged particle irradiation from the Uranian magnetosphere. Rings were discovered by using a infrared telescope throughout  the occultation of a star as Uranus passed in front of it. The light from the star dimmed many times before it was obstructed by the disk of Uranus and subsequently, showing the presence of various distinct rings.

(75°f − 32) × 5/9 = 23.889°c

colorectal cancer may also develop from areas of abnormal cells in the lining of the colon or rectum. this area of abnormal cells is called dysplasia and is more commonly seen in people with certain inflammatory diseases of the bowel such as crohn's disease or ulcerative colitis.