Richard Binzel
The MIT astronomer who found the family of small asteroids broken off Vesta and created the Torino scale for impact risk.
Key facts
- Born
- 1958
- Nationality
- American
- Field
- Planetary scientist
Richard P. Binzel is a professor of planetary science at the Massachusetts Institute of Technology. He studies the colours and spectra of asteroids to work out what they are made of and where meteorites come from.
By 1990 scientists knew that the howardite, eucrite and diogenite meteorites matched the spectrum of Vesta, but there was a problem. Vesta lies far from the routes that lead to Earth, so how could pieces of it reach us? In 1993 Binzel and his student Shui Xu measured the spectra of many small asteroids near Vesta. They found a family of small bodies, only a few kilometres across, with the same pyroxene-rich spectra as Vesta, scattered in a stream reaching towards a resonance with Jupiter. These were fragments chipped off Vesta by a great impact, on their way to orbits that cross Earth's.
The Dawn spacecraft later found the source: two huge overlapping impact basins near Vesta's south pole.
Binzel also created the Torino scale, adopted in 1999, a simple scale from 0 to 10 for communicating the risk that a newly found asteroid might hit Earth. Almost every object ever rated has been at level 0, meaning no hazard. He has worked on several NASA missions, including OSIRIS-REx.