Like many astronomy instructors this past autumn, I have been forced to teach my classes online. That means re-creating PowerPoint presentations,  inasmuch as communicating visually on a small screen is different from doing so on a large one. In the process I came to see an old acquaintance in a new way.

Tycho’s supernova (left) imaged by the Chandra X-Ray Observatory. (Courtesy of NASA/CXC/RIKEN & GSFC/T. Sato et al.) SARS-CoV-2 virus (right) from a 3D computer simulation. (Courtesy of Fusion Medical Animation.)

Tycho’s supernova (left) imaged by the Chandra X-Ray Observatory. (Courtesy of NASA/CXC/RIKEN & GSFC/T. Sato et al.) SARS-CoV-2 virus (right) from a 3D computer simulation. (Courtesy of Fusion Medical Animation.)

Close modal

The remnant of Tycho’s supernova, SN 1572, appears in the left image, taken by the Chandra X-Ray Observatory. On the right is a computer model, derived from an electron microscopy image, of SARS-CoV-2. NASA puts the supernova remnant at 45 light-years in diameter; the virus is 0.1 µm across, according to the National Institutes of Health. So the objects differ in size by a factor of 4 × 1024.

Yet the two share aspects in common. Both are young with respect to the Milky Way, and both evoke dread in those nearby.