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].
Why does a returning boomerang come back?
When most of us think of boomerangs, we imagine somebody throwing a curved stick that eventually turns around and comes right back to the thrower's hand. This device is simply amazing, and a wonderful application of some laws of physics relating to aerodynamic lift and angular momentum.