The dub ( diastolic sound) occurs when part of the heart relaxes and the aortic and pulmonary valves close. A heart murmur is an extra sound, such as a whooshing, caused by irregular blood flow through the heart valves. Heart murmurs can be heard through a stethoscope and are often detected during routine physical examinations. If your heart murmur is related to more serious problems, your doctor may refer you to a cardiologist (heart specialist).
On July 20, 1969, Apollo 11 astronaut Neil Armstrong became the first man to walk on the moon. Armstrong is pictured here, shortly after collecting a sample of lunar dust and rocks. At his feet is the handle for the sample collection tool.
Student Features. Thirty-five years ago astronaut Neil Armstrong did something no one had ever done before. On July 20, 1969, he set foot on the moon. People around the world watched and listened as Neil slowly climbed down the ladder of the lunar lander.