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.
The Solar Parker Probe will be the first spacecraft to fly into the low solar corona. It will determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate energetic particles.