What mysteries lie in the Oort Cloud at the edge of our solar system?

The answer

The Oort Cloud is a theoretical spherical shell of icy objects extending from roughly 2,000 to 100,000 astronomical units from the Sun - nearly halfway to the nearest star, Proxima Centauri. Proposed by Dutch astronomer Jan Oort in 1950, it is believed to contain trillions of cometary nuclei with a total mass of roughly five Earth masses. Long-period comets like Hale-Bopp and NEOWISE originate from the Oort Cloud, perturbed inward by passing stars or the galactic tide. No spacecraft has reached it - Voyager 1, the most distant human object, will take about 300 years to reach the inner boundary and 30,000 years to cross it. The Oort Cloud may preserve pristine material from the solar system's formation 4.6 billion years ago. Its existence has never been directly confirmed, as individual objects are too distant and dim for current telescopes to detect.