Science Astronomers say our galaxy hasn’t seen a supernova in 400 years. Why don’t they count the 1987 supernova?
Science As the Sun set one evening, I observed a sword-like column of light pointing straight up from the horizon. What was it?
Science Astronomers have estimated star diameters from their colors and brightnesses, but modern interferometers can measure them directly. How do the two methods compare?
