If an alien lands on your front lawn and extends an appendage as a gesture of greeting, before you get friendly, toss it an eightball. If the appendage explodes, then the alien was probably made of antimatter. If not, then you can proceed to take it to your leader.
Neil deGrasse TysonI'm fascinated by the deaths of stars and the havoc they wreak on their environments.
Neil deGrasse Tyson