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.
Neptune might be called the mathematicians' planet. German astronomer Johann Galle discovered it on September 23, 1846. The discovery was made possible, though, by the calculations of mathematicians Urbain Leverrier of France and John Couch Adams of England.