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.
NASA has initiated preliminary studies of missions to either Uranus or Neptune, Jim Green (above), the agency's planetary science director, said Aug. 24. Credit: NASA. LAUREL, MD. â NASA began an early feasibility study for missions to the distant, mostly ignored ice-giants Uranus and Neptune, a senior agency official said here Aug. 24.