Final answer:
The rings of Uranus were discovered during an occultation when astronomers observed a distant star's light dimming as Uranus passed in front of it. Later, the Voyager spacecraft captured close-up images of these narrow and dark rings.
Step-by-step explanation:
The rings of Uranus were discovered during an event called an occultation, which occurs when one astronomical object passes in front of another from our perspective. In 1977, as Uranus passed in front of a distant star, astronomers noticed that the star's light dimmed multiple times before being occulted by Uranus, suggesting the presence of rings. These rings are composed of narrow ribbons of dark material, difficult to observe from Earth due to their color and size. The discovery was comparable to counting the number of cars in a train at night by watching a light blink as each car passes in front of it. The Voyager spacecraft later provided detailed images and studies of Uranus' rings when it flew past the planet in 1986.