In 2003, Mars was closer and brighter in our sky than in nearly 60,000 years. In 2018, Mars will be at its brightest since then! Start watching Mars now.
At a very steady rate, unstable carbon-14 gradually decays to carbon-12. The ratio of these carbon isotopes reveals the ages of some of Earth's oldest inhabitants.
Stefan Nilsson took this photo last Sunday. He told us, “I try to shoot this tree once every year during this season ... The tree is on the beach where I live in Åhus, in the southeast part of Sweden.”
