Earth Flyby Gives Astronomers Close-Up Look at Binary Asteroid

It's an asteroid less than a mile in diameter, with a little “moon” tagging along behind it.

By Hailey Rose McLaughlin
Jun 5, 2019 5:45 PMFeb 22, 2020 3:47 AM
Asteroid 1999 KW4 - ESO
The European Southern Observatory’s Very Large Telescope studied a double asteroid, shown here in an artist’s illustration, during an Earth flyby in May. (Credit: ESO/M. Kornmesser)

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A binary asteroid named 1999 KW4 passed some 32 million miles (5.2 million km) from Earth on May 25, giving astronomers a good look at a space rock that won’t come this close again for nearly two decades. The flyby brought it about 14 times farther away than our Moon, but still close enough for astronomers to study.

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