The New Horizons spacecraft flew by Pluto at 7:49 a.m. EDT on July 14, 2015. Astronomy writer Christopher Crockett wrote several updates from mission control at the Johns Hopkins University Applied Physics Lab in Laurel, Md., from July 12-15, and reviewed some of the mission's major milestones from the last several months. Check our Mission to Pluto editor’s pick for the latest on New Horizons...
More than 1,800 years ago, the Greek physician Galen came up with a model for how the human body works. Blood, which he called the "natural spirit," originated in the liver and traveled to all parts of the body through the veins. In the left side of the heart, some of the blood mixed with air from the lungs to make "vital spirit," which flowed to all parts of the body through the arteries....