This red supergiant star [V838] monocerotis is located about 20,000 light-years from Earth. A burst of light in a huge dust cloud caused light echos that were seen for three years. Credit: NASA, ESA and H.E. Bond [STScI].
Quadratic Equation Roots
At some point during our math schooling, most of us were required to memorize the quadratic solutions equation. It was confusing, because we never knew what it was really about. Here's your chance to see where that messy equation comes from.