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.
This date in science: Definitive discovery of Neptuneâs rings. A few days before the NASA spacecraft Voyager 2 skimmed by Neptune in 1989, it acquired images of a faint, continuous ring system encircling the planet. August 22, 1989. NASAâs Voyager 2 spacecraft swept past the planet Neptune on August 25, 1989.