The mysteries of the icy cloud around our Solar System

摘要

For a few weeks in the summer of 2020,if you had been looking up on a clear night,there is a chance you might have spotted a rare visitor to our part of the Solar System.Through binoculars,it had the shape of a classic comet-a bright nucleus and long tail formed by ice being blasted into gas by the heat from the Sun.It could even be seen by the naked eye in the Northern Hemisphere during early July.