As the elders tell it, Raven the Creator had turned Earth from a frozen rock into a green garden. But as a reminder of the ice age, he caused every 10th black bear to be white. The formal name is ...

At 8.6 light-years away, Sirius B is the nearest known white dwarf star to Earth. Photograph courtesy NASA/ESA/H. Bond (STScl)/M. Barstow (University of Leicester) Red giants are hot enough to ...