The immediate cause of sudden cardiac arrest is usually an abnormality in your heart rhythm (arrhythmia), the result of a problem with your heart's electrical system.
Version for printing. The first planet to be discovered was Uranus by William and Caroline Herschel on 13 March 1781. It was discovered by the fact that it showed a disk when viewed through even a fairly low powered telescope. The only other planets which have been discovered are Neptune and Pluto.
Who discovered Pluto? Pluto was discovered in 1930 by Clyde Tombaugh. Astronomers noticed that the orbits of Neptune and Uranus were being affected by the gravity of an unknown object in the Solar System. Clyde Tombaugh carefully studied images of the night sky, and after a lot of hard work he finally discovered Pluto.