APRIL 26, 1803: A collection of over 3000 meteorites falls and lands near the town of L’Aigle in Normandy, France. Up until then the existence of “stones falling from the sky” had been harshly debated, but the L’Aigle meteorite fall conclusively proved that such events happen, and in effect gave birth to the study of meteorites as a serious science. Meteorites, and the role that the L’Aigle meteorites played in our knowledge about them, are the subjects of this week’s “Special Topics” presentation.
APRIL 27, 1993: Comet Hale-Bopp C/1995 O1 appears on a photographic plate taken at Siding Spring Observatory in New South Wales. It was briefly noticed at the time but then forgotten about, until re-discovered after the comet’s discovery over two years later. The comet’s heliocentric distance was 13.1 AU, a record at the time for an inbound long-period comet. Comet Hale-Bopp is a future “Comet of the Week.”
APRIL 27, 2020: The main-belt asteroid (560) Delila will occult the 7th-magnitude star HD 155789 in Ophiuchus. The predicted path of the occultation crosses northern Chile, southern Bolivia, central Paraguay, southern Brazil, then open waters of the southern Atlantic Ocean and finally southern South Africa.
APRIL 28, 1991: Minor Planet Circulars 18138-9 formally announce the naming of the main-belt asteroid (4151) Alanhale. For obvious reasons, I utilize this asteroid as an example in last week’s “Special Topics” presentation about the designating and naming of asteroids.
APRIL 29, 2020: The Amor-type asteroid (52768) 1998 OR2 will pass 0.042 AU from Earth. For two weeks it should become as bright as 11th magnitude, and radar observations have been scheduled from the Deep Space Network tracking antenna at Goldstone, California.
APRIL 30, 2015: After orbiting Mercury for four years, NASA’s MESSENGER spacecraft is deliberately impacted onto Mercury’s surface. The impact should have created a crater approximately 16 meters in diameter.
MAY 1, 1996: Comet Hyakutake C/1996 B2 passes through perihelion at a heliocentric distance of 0.230 AU. Comet Hyakutake was one of the “Great Comets” of the late 20th Century and is a previous “Comet of the Week.”
MAY 1, 2000: Jeff Larsen with the Spacewatch program in Arizona discovers an asteroid, designated 2000 JW8, that is soon found to be identical to the Amor-type asteroid (719) Albert, which had been “lost” since its discovery in 1911. Albert was the last “lost” numbered asteroid to be found, and passed 0.28 AU from Earth in September 2001; it does not pass close to Earth again until 2078. Albert and other near-Earth asteroids are discussed in a previous “Special Topics” presentation.