Eric Walker added We Now Have Proof a Supernova Exploded Perilously Close to Earth 2.5 Million Years Ago to Supernovae, 53Mn and 60Fe

Eric Walker added We Now Have Proof a Supernova Exploded Perilously Close to Earth 2.5 Million Years Ago to 53Mn, and added 53Mn to Manganese

Eric Walker added 53Mn and a number of links to Manganese, and added Manganese to Metals and Chemical elements