On this Day in History

On this Day in History in 295: 8th recorded perihelion passage of Halley’s Comet.
 
On this Day in History in 1702: Comet C/1702 H1 approaches within 0.0437 AUs of Earth.
 
On this Day in History in 1902: Marie & Pierre Curie isolate the radioactive element radium chloride.
 
On this Day in History in 1940: The First electron microscope was demonstrated by RCA.

On this Day in History

On this Day in History in 1802: Heinrich Wilhelm Matthäus Olbers discovers 2 Pallas, the second asteroid known to man.

Word of the Day

Word of the Day: Astrobleme
 
Definition: (noun)
 
1) an erosional scar on the earth’s surface, produced by the impact of a cosmic body, as a meteorite or asteroid.
 
Etymology: 1965-70; < astro- + -bleme (< Greek blêma shot, wound)