Chemical element named mendelevium in honor of D.I. Mendeleev, the first to arrange the elements in a periodic manner. Most recently, the synthesis of element 118 (since named oganesson) was reported in October 2006, and the synthesis of element 117 (tennessine) was reported in April 2010. Ten materials familiar to various prehistoric cultures are now known to be chemical elements: Carbon, copper, gold, iron, lead, mercury, silver, sulfur, tin, and zinc. Three additional materials now accepted as elements, arsenic, antimony, and bismuth, were recognized as distinct substances prior to 1500 AD. Phosphorus, cobalt, and platinum were isolated before 1750. Most of the
SN 2014J ± 0.3 megaparsecs), SN 2014J was one of the closest supernovae seen for decades. It was the closest type Ia supernova since SN 1972E, and the closest supernova of any type since 2004. Some sources initially stated that SN 2014J was the closest supernova of any type since SN 1987A, but this claim is erroneous. The last supernova that was unambiguously closer to Earth than SN 2014J was SN 2004dj, a type II-P supernova in the galaxy NGC 2403, 8 million light-years from Earth. SN 1993J was a type IIb supernova at almost the same distance as SN 2014J, because