How close was Halley’s comet to Earth?
In 837, Halley’s Comet may have passed as close as 0.03 AU (3.2 million miles; 5.1 million kilometres) from Earth, by far its closest approach.
When was the last meteorite hit Earth?
The last such mass extinction led to the demise of the dinosaurs and coincided with a large meteorite impact; this is the Cretaceous–Paleogene extinction event (also known as the K–T or K–Pg extinction event), which occurred 66 million years ago.
How big is Halley’s Comet?
When was Halley’s comet discovered?