... Credit: Stardust@Home Project, Space Science Lab. U. C. Berkeley , NASA Explanation: What caused that hole? ... The interesting part is that something created that dark hole, and it might well be one of the first pieces of matter ever captured from outside our Solar System. ... It is so difficult to find them that the Stardust team has created a downloadable interactive microscope program to allow anyone with a standard computer to help inspect aerogel slices and look for interstellar dust tracks. ...