Miscellany
In 1783 an English rector named John Michell wrote to the physicist Henry Cavendish of his belief in the possibility of “dark stars,” entities so dense and with such a strong gravitational pull that they could prevent light from escaping them and render them invisible. The Royal Society published his theory the following year, but it would be nearly two hundred years before the term black hole was used to refer to such a phenomenon.
Miscellany
In 1978 NASA scientists Donald J. Kessler and Burton G. Cour-Palais predicted that the number of artificial satellites in low earth orbit might reach such density as to spark a cascade of collisions. The resulting debris belt would eventually make some orbits nearly impassable. “Under certain conditions,” they wrote, “the belt could begin to form within this century and could be a significant problem during the next century.”
Miscellany
Astronomers theorizing the existence of small moons orbiting larger moons have proposed calling them “moonmoons.” The planet Kepler-1625b, which has a Neptune-sized moon distantly orbiting it, was cited as “sort of the best-case scenario for a moonmoon.”
