Saving the planet from space rocks with radar
Bowler Hat Science from Matthew R Francis
I have only one new publication scheduled this month, but it’s a big one: a feature article for AGU Eos about using radar to help defend Earth from hazardous asteroids. Read the whole thing here.
Saving the Planet with Radar Astronomy
Once the largest telescope in the world, Arecibo kept watch for dangerous asteroids using radar. With it gone, the world is preparing the next generation of radar observatories.
The giant radio telescope at the Arecibo Observatory was destroyed twice: the first time deliberately to save the planet, the second time as a result of natural disasters—making it harder to save Earth in the future.
Although the first “destruction” was a special effect in the 1995 James Bond movie GoldenEye, the world’s most powerful telescope for studying near-Earth asteroids was, in real life, damaged beyond repair by multiple storms before finally collapsing in December 2020. For more than 50 years, the Arecibo Telescope (often referred to simply as “Arecibo” when there’s no confusion with the observatory as a whole) was the largest in the world: a radio dish 305 meters (1,000 feet) in diameter set into a natural karst depression in Puerto Rico. It played a part in studies of Earth’s ionosphere, attempts to detect signs of—and send messages to—potential alien civilizations, the characterization of pulsars, and many astronomical discoveries.
The greatest loss posed by Arecibo’s collapse, however, may be the ability to identify potentially hazardous asteroids and comets using radar to track their orbits and other properties. Our solar system contains more than 2,000 known possibly dangerous near-Earth objects (NEOs). The vast majority don’t pose a danger to us for the next century or more, but at the same time, the danger from an asteroid impact is large enough that we want as much warning as possible—just ask the dinosaurs. Radar astronomy is a key part of the field known as planetary defense for that reason.
Tales from the Peaceable Kingdom
I didn’t include a cat picture last time, so here’s an action shot of both my cats (Callisto [top] and Nebula [bottom]) in a typical view:
Bowlerhattishly thine,
Matthew
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