An asteroid that recently passed by Earth
is about twice as large as originally estimated, and it would have had
serious global consequences if it had impacted Earth. Asteroid 2012 LZ1
was only discovered on June 10, 2012 by Rob McNaught at the Siding
Spring Observatory in Australia.
This Near Earth Object was thought to
be fairly large, 502 meters (1,650 feet) wide, and quite bright. But
astronomers using the planetary radar system at Arecibo Observatory were
able to better determine the asteroid’s size, rotation rate and shape
and found it to be about 1 kilometer (0.6 miles) wide and actually quite
dark.
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| Asteroid 2012 LZ1 as seen by the Haleakala-Faulkes Telescope North
on June 13, 2012. Credit: Nick Howes, Ernesto Guido & Giovanni
Sostero.
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Scientists consider a kilometer-wide asteroid is at the size
threshold that could set off an extinction-level event if it were to hit
Earth.
“This object turned out to be quite a bit bigger than we expected, said
Dr. Ellen Howell from Arecibo, “which shows how important radar
observations can be, because we’re still learning a lot about the
population of asteroids.”
2012 LZ1 sneaked by our planet at about 5.3 million km (3.35 million)
miles away, or about 14 times the distance between Earth and the Moon
on June 14, and it won’t be back in Earth’s vicinity again until June
12th, 2053, and then will be about 3 times as distant.