Donald Brownlee
The astronomer who first collected dust from comets and asteroids in the stratosphere, and who led NASA's Stardust mission to a comet.
Key facts
- Born
- 1943
- Nationality
- American
- Field
- Astronomer
Donald E. Brownlee is a professor of astronomy at the University of Washington in Seattle. In the 1970s he found a way to collect tiny particles of space dust before they reached the ground. Sticky collectors were carried on high-flying aircraft about 20 kilometres up, where the air is thin and Earth dust is rare.
The particles they caught, often only a few thousandths of a millimetre across, included fluffy clusters of minerals and carbon unlike anything in meteorites. Many came from comets. They are now called interplanetary dust particles, and some scientists still call them Brownlee particles.
Brownlee was principal investigator of Stardust, the first mission to bring back material from a comet. Launched in 1999, it flew through the dust around Comet Wild 2 in 2004, catching grains in a block of aerogel, an extremely light glassy foam. The capsule landed in Utah in January 2006. To scientists' surprise, many grains had formed at high temperature near the young Sun, showing that material was mixed out to the cold edge of the Solar System where comets formed.
Brownlee has also written popular books on the planets and on how rare complex life might be in the universe.