Canada and the World
Current Events with a Canadian Perspective
Last update
19 November 2010
Asteroid 2009 DD45
Passes Close to Earth
Near-
of space rock that hurtle around our
corner of the Universe sometimes undetected
A large space rock with the catchy name 2009 DD45 made a surprise visit to Earth on March 2, 2009.
As Fox News reported on the day of the fly-
That may sound like a safe distance, but in astronomical terms it’s like two cars missing each other on the highway by the width of a coat of paint.
Astronomers call these things close-
Australian Comet Hunter
DD45 was only spotted three days before its close encounter by Rob McNaught at the Siding Spring Mountain Observatory in New South Wales, Australia.
According to the Australian news website Crikey.com the asteroid “is similar in size to the dead comet shard that exploded with the force of a large hydrogen bomb over a then largely uninhabited region of central Siberia on June 30, 1908.”
This “Tunguska asteroid,” as it’s known, was so small that it didn’t even reach the
ground intact yet its blast wave toppled 60 million trees (left).
But, there are plenty of other rocks out there to worry about.
New Asteroids being Discovered
Most chunks of space rock spend their time buzzing about the Asteroid Belt between the planets Mars and Jupiter. Every so often one of them escapes its orbit and flies off into space.
The National Aeronautics and Space Administration (NASA) has so far counted 4,780 asteroids, comets, and meteorites that are on the loose and could swing by our neighbourhood. There are thought to be many more that haven’t yet been spotted; 2009 DD45 being an example.
Recent NASA Postings
NASA finds new asteroids all the time and, fortunately, they prove to be harmless. Here’s a sample of recent NASA alerts:
- “A newly discovered asteroid, 2010 GA6, will safely fly by Earth” on April 8, 2010.
“At time of closest approach 2010 GA6 will be about 359,000 kilometres away from
Earth -
about 9/10ths the distance to the moon. The asteroid, approximately 22 metres wide;” - “Asteroid 2010 AL30, discovered by the LINEAR survey of MIT’s Lincoln Laboratories on January 10, will make a close approach to the Earth’s surface to within [122,300 km] on January 13;”
- “On October 8, 2009 about 03:00 Greenwich time, an atmospheric fireball blast was observed and recorded over an island region of Indonesia.” This was caused by an asteroid about 10 metres across that exploded in the atmosphere, the aftermath of which was caught on video.
Comfortingly, NASA says “As a rule, the most common types of stony asteroids would not be expected to cause ground damage unless their diameters were about 25 metres… or larger.”
The Asteroid 99942 Apophis
However, there is a big one out there that NASA’s been keeping a wary eye on; it’s called 99942 Apophis. This is an asteroid with a diameter of about 300 metres, big enough to make a nasty mess of anything it bumps into.
Asteroid 99942 Apophis caused a bit of a flap in 2004. It seemed its travels were going to bring it a bit too close to Earth for comfort. In fact, it looked as though there was a 2.7% chance it was going to hit us in 2029.
More observations have been made and the panic level has gone down. Now, NASA’s Near Earth Object Program says there’s a very, very slight chance of a collision in 2036, and an even more remote one for the following year.
Recent observations say there is “no impact risk…However, there will be a historically close approach to the Earth, estimated to be a 1 in 800 year event (on average, for an object of that size).”
Avoiding an Asteroid Collision
A massive asteroid collision, about 65 million years ago, bumped off the dinosaurs. Humans have no intention of falling victim to the same catastrophe.
NASA has plans to send a probe up to meet Apophis in 2014. This will help scientists learn more about the asteroid’s path and, if necessary, nudge it onto a voyage that misses Earth.
There’s no way to avoid the destruction of earthquakes, storms, and other natural disasters that occur on the planet. But, there may be tactics for avoiding some of the dangers of the Universe.
As the people at the Near Earth Object Program point out, “…asteroid impacts are the only major natural hazard that we can effectively protect ourselves against.”
Sources
“Surprise Asteroid Makes Near-
“Sky not Falling, just Passing quite Close.” Ben Sandilands, Crikey.com, March 2, 2009.
© Canada and the World, April 2010
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NASA Photo
Asteroid 253 Mathilde, about 60 km across, is still safely locked in orbit in the Asteroid Belt.
