Apophis asteroid: Large space rock flies past Earth

Esa’s Herschel Space Observatory captured Apophis in its
field of view in the far-infrared light in January 2013
A 300m-wide asteroid is making a close pass to the
Earth.
Apophis – named after the Egyptian demon of destruction and
darkness – has been put on a watch list by scientists.
They have calculated that in 2036 there is a very small chance
it could collide with our planet.
However, its current fly-by is at a safe distance of about 14
million km – but this is close enough for astronomers to study
the space rock and assess its future risk.
Apophis will not be visible with the naked eye, but space
enthusiasts can watch it online via the Slooh space camera’s
website.

Collision course?
The large rocky mass was first discovered in 2004. At the
time, it raised alarm when scientists calculated that it had a
one-in-45 chance of smashing into the Earth in 2029.
Later revisions, lifted this threat; instead on the Friday 13
April 2029, it will make a close pass at a distance of about
30,000km.
However, astronomers say there is still a one-in-200,000
chance that it could strike Earth in 2036.
Professor Alan Fitzsimmons, an astronomer at Queen’s
University Belfast, UK, said: “In 2029, it will pass so close to
us that Earth’s gravity will change its orbit.
“Most of the potential orbits it will end up on will mean we are
safe for the next 100 years. But there is a small region of
space – something we call a keyhole – and if it passes through
that keyhole in 2029, it will come back and hit us on 13 April
in 2036.”
If this happened, it would strike the Earth with 100 times the
energy in our largest nuclear bombs, said Prof Fitzsimmons.

Future hazards
Astronomers are using the current close encounter as an
opportunity to study the asteroid, so they can improve their
calculations to predict its future path.
Prof Fitzsimmons said: “While [the asteroid] is relatively close
to the Earth, astronomers can ping it with radar. Radar
measurements are incredibly accurate: we get the distance to
the asteroid very, very precisely, and we can also get its
velocity relative to us. And these two things let us pin its orbit
down very precisely. ”
Researchers are becoming increasingly interested in
potentially hazardous asteroids.
So far they have counted more than 9,000 near-Earth
asteroids, and they spot another 800 new space rocks on
average each year.
Prof Fitzsimmons said learning more about them was vital.
“At some point, we are going to find an asteroid big enough
that it could cause damage at ground level if we let it hit,” he
explained.
“So we should find these objects, we should track them, work
out where they are going – and if they stand a chance of
hitting us, do something about it.”

Source : BBC

Posted from WordPress for BlackBerry.

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