Unofficial: Cosmic

The High Bay 1 clean room within the Spacecraft Assembly Facility at JPL is seen in this image taken on Nov. 12, 2019. The Mars 2020 rover is visible just above the center. Credits: NASA/JPL-Caltech Built-in 1961, the Spacecraft Assembly Facility at NASA's Jet Propulsion Laboratory in Pasadena, California, is the cradle of robotic space exploration.   The first probes launched to the Moon, Mars, and Venus were assembled here. So were all of NASA's Mars rovers, Galileo and Cassini (the first orbiters to Jupiter and Saturn), and the twin Voyager spacecraft that are scouting the farthest reaches of the solar system. A new rover, Mars 2020, is going through final testing in this facility before being shipped in February to Cape Canaveral, Florida, where it will launch this summer. The Spacecraft Assembly Facility's construction marks when JPL transitioned from missiles to space exploration, according to JPL historian Erik Conway. "It's where a...

John Michell and dark stars. During 1783, Geologist John Michell wrote a letter to Henry Cavendish outlining the expected properties of dark stars, published by The Royal Society in their 1784 volume. Michell calculated that when the escape velocity at the surface of a star was equal to or greater than the speed of light, the generated light would be gravitationally trapped so that the star would not be visible to a distant astronomer.  "If the semi-diameter of a sphere of the same density as the Sun was to exceed that of the Sun is the proportion of 500 to 1, a body falling from an infinite height towards it would have acquired at its surface greater velocity than that of light, and consequently supposing light to be attracted by the same force in proportion to its vis inertia( A want of power in a body to move itself when at rest or to come to rest when in motion. ), with other bodies, all light emitted from such a body would be made to return towards it by its own pro...