أرسل هذا في رسالة قصيرة: De Sitter and Schwarzschild-de Sitter according to Schwarzschild and de Sitter

  _____      ___      _____     _____    _    _   
 / ____||   / _ \\   / ____||  |  ___|| | \  / || 
/ //---`'  | / \ || / //---`'  | ||__   |  \/  || 
\ \\___    | \_/ || \ \\___    | ||__   | .  . || 
 \_____||   \___//   \_____||  |_____|| |_|\/|_|| 
  `----`    `---`     `----`   `-----`  `-`  `-`