Swift Tracks Water From Interstellar Comet Borisov

For the first time, NASAs Neil Gehrels Swift Observatory tallied the water lost from an interstellar comet as it approached and rounded the Sun. The object, 2I, Borisov, traveled through the solar system in late 2019. Read more: Comets are frozen clumps of gases mixed with dust, often called dirty snowballs. As a one approaches the Sun, frozen material on its surface warms and converts to gas.