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.
Percival Lowell: Search for Planet X. The story of Pluto's discovery begins with Percival Lowell, the founder of Lowell Observatory in Flagstaff, Arizona. Lowell was obsessed with the notion of a trans-Neptunian planet, which he believed could be detected from the effect it would have on Neptune's orbit.