Signs
In The Sun, The Moon and The Stars
Big Asteroid closes in on Earth
* From: AFP
* November 09, 2011 1:06AM
A BIG asteroid is set to make its closest flyby of Earth in 200
years, but there is no chance of a crash landing when it zips by
our planet, NASA says.
Astronomers have aimed their telescopes to catch a glimpse of the
2005 YU55 asteroid, which will not be visible to the naked eye,
when it makes its closest approach to Earth at 10.28pm (AEDT)
today.
The 400-metre-wide asteroid often travels in the vicinity of the
Earth, Mars and Venus, but "the 2011 encounter with Earth is the
closest it has come for at least the last 200 years", the US space
agency said.
Other asteroids of this size pass by Earth more frequently, though
the last such event happened in 1976 and the next will not happen
again until 2028 when as asteroid called 2001 WN5 will skim about
halfway between the Moon and Earth.
This asteroid is expected to pass a bit further away; about 0.85
times the distance of the Moon to the Earth, or a distance of
325,000 kilometres.
"2005 YU55 is one of the potentially hazardous asteroids that make
close approaches from time to time because their orbits either
approach or intersect the orbit of the Earth," said Robert
McMillan, an associate research scientist at the University of
Arizona.
McMillan discovered the asteroid in 2005 as part of the
university's Spacewatch Project, a solar-system-scanning group of
scientists near Tucson, Arizona.
However, astronomers know from analysing the trajectory of the
asteroid that it will not hit Earth this time.
The asteroid's next closest pass is set to take place in 2094, at
a distance of 269,000 kilometres, according to forecasts.
"The observations will give us a piece of the puzzle, one we don't
get many chances to see," said Don Yeomans of NASA's Jet
Propulsion Laboratory.
"At one time, we thought these were the asteroids that delivered
carbon and other elements to the early Earth, so they are pretty
important."
NASA said radar observations from the Arecibo Planetary Radar
Facility in Puerto Rico have already begun as the asteroid closes
in on its approach.
While the charcoal-coloured, circular asteroid's visit has
scientists excited for the chance to get a closer look, most
Earthlings probably will not notice a thing.
"The gravitational influence of the asteroid will have no
detectable effect on Earth, including tides and tectonic plates,"
NASA said.