Dark matter, the invisible stuff that scientists have determined makes up 85 percent of the mass in the universe, remains one of the biggest mysteries. For one, it can't be directly observed. The only way we know about its existence are its

Before he became Pope Francis, Jorge Mario Bergoglio was known for his staunch charity — but the newly-passed pontiff's own organs will not be donated due to church doctrine. It does not appear that Francis was himself an organ donor, but his