What is one thing scientists have learned about the universe by observing supernovas? (Paragraphs 6-8)

Supernovas are often seen in other galaxies. But supernovas are difficult to see in our own Milky Way galaxy because dust blocks our view. In 1604, Johannes Kepler discovered the last observed supernova in the Milky Way. NASA’s Chandra telescope discovered the  

Explanation:

probably because the owner wants to get rid of it