Heart murmur. Heart murmurs are heart sounds produced when blood flows across one of the heart valves that are loud enough to be heard with a stethoscope. There are two types of murmurs. A functional murmur or physiologic murmur is a heart murmur that is primarily due to physiologic conditions outside the heart. Other types of murmurs are due to structural defects in the heart itself.
Voyager 2 passed Neptune in the summer of 1989, the first spacecraft to observe that planet. Passing about 3,000 miles above Neptune's north pole, Voyager 2 made its closest approach to any planet since it left Earth 12 years earlier.
Once probes could reach space, the two countries started sending probes to fly past the moon and other planets. Mariner 2 was the first probe to study another planet. On Dec. 14, 1962, Mariner 2 flew past the planet Venus. It confirmed that Venus is very hot. A different probe, called Mariner 4, was the first probe to snap a picture of a planet.