--- In FairfieldLife@yahoogroups.com, Share Long wrote: > > Thanks salya, I enjoyed this article a lot. Even when I realized I'll be 80 > when it happens. Yikes! (-:
Don't worry Share, there are plenty out there we don't know about that might surprise us long before that. Here's hoping, em...you know what I mean... ________________________________ > From: salyavin808 > To: FairfieldLife@yahoogroups.com > Sent: Monday, January 7, 2013 5:46 AM > Subject: [FairfieldLife] The real armageddon.... > > >  > > > I can say with a high degree of confidence that this is how the world ends, > maybe not with this particular asteroid, this particular time but someday. > For a start, it's happened before - a good many times and with a great deal > of mass extinction. Sure, every time a big one hits there's one less big one > *to* hit but just in my life there have been several instances of previously > unknown asteroids crossing between the Earth and Moon. In 1989 one that, had > it been travelling one millionth of a mile an hour slower, would have hit in > the middle of the atlantic and set off every volcano and earthquake faultline > on earth, not to mention swamping Europe, Africa and the America's with the > resulting tsunami. > > Hardly a rare occurrence then but something to loose sleep over? Not for me > but just think, there were three in the last century that struck land, one in > Siberia, one in Arabia and one in south America. No known casualties but > there was massive destruction in each case. Millions of felled trees in > Tunguska, a desert melted into glass in Arabia. I often wonder what would > have happened at the height of the cold war if, say, New York or Moscow had > been suddenly vapourised by an incoming comet. Would the powers that be been > able to stop themselves retaliating against the mistaken foe? Most of these > things are unknown before they flash by close enough to part our hair, > cosmically speaking, without us being aware of their existence - except this > one. Anyway, it's all just something to help keep life in perspective.... > > > > Apophis â" a 'potentially hazardous' asteroid â" flies by Earth on Wednesday > Asteroid Apophis arrives this week for a close pass of Earth. This isn't the > end of the world but a new beginning for research into potentially hazardous > asteroids > A computer-generated image of a near-Earth asteroid. Astronomers will get a > close-up view of Apophis on Wednesday. Photograph: Planetary Resources/EPA > Apophis hit the headlines in December 2004. Six months after its discovery, > astronomers had accrued enough images to calculate a reasonable orbit for the > 300-metre chunk of space rock. What they saw was shocking. > There was a roughly 1 in 300 chance of the asteroid hitting Earth during > April 2029. Nasa issued a press release spurring astronomers around the > world to take more observations in order to refine the orbit. Far from > dropping, however, the chances of an impact on (you've guessed it) Friday 13 > April 2029 actually rose. > By Christmas Day 2004, the chance of the 2029 impact was 1 in 45 and things > were looking serious. Then, on 27 December astronomers had a stroke of luck. > Looking back through previous images, they found one from March on which the > asteroid had been captured but had gone unnoticed. This significantly > improved the orbital calculation and the chances of the 2029 impact dropped > to essentially zero. However, the small chance of an impact in 2036 opened up > and remains open today. > While there is no cause for alarm, similarly there is no room for complacency > either. Apophis remains on the list of Potentially Hazardous Asteroids > compiled by the International Astronomical Union's Minor Planet Center. > Although most asteroids are found in the belt of space between Mars and > Jupiter, not all of them reside there. Apophis belongs to a group known as > theAten family. These do not belong to the asteroid belt and spend most of > their time inside the orbit of the Earth, placing them between our planet and > the sun. > That makes them particularly dangerous because they spend the majority of > their orbit close to the sun, whose overwhelming glare obscures them to > telescopes on Earth â" rather like a second world war fighter ace > approaching out of the sun. > Having crossed outside Earth's orbit, Apophis will appear briefly in the > night-time sky. Wednesday 9 January will afford astronomers the rare > opportunity to bring a battery of telescopes to bear: from optical telescopes > to radio telescopes to the European Space Agency's Infrared Space Observatory > Herschel. Two of the biggest unknowns that remain to be established are the > asteroid's mass and the way it is spinning. Both of these affect the > asteroid's orbit and without them, precise calculations cannot be made. > Another unknown is the way sunlight affects the asteroid's orbit, either > through heating the asteroid or the pressure of sunlight itself. Russia has > announced tentative plans to land a tracking beacon on Apophis sometime > after 2020, so that its orbit can be much more precisely followed from Earth. > Wednesday's pass is only really close by astronomical standards, taking place > at around 14.5 million kilometres above Earth's surface. The moon's orbit is > 385,000 km. The 2029 close pass is another matter entirely, however. > On Friday 13 April 2029, Apophis will slip past the Earth just 30,000km above > our heads â" less that one-tenth the distance of the moon and closer even > than the communication satellites that encircle the Earth at 36,000km. It > will appear as a moderate bright moving object, visible from the > mid-Atlantic. Depending upon its composition, astronomers could watch the > Earth's gravity pull the asteroid out of shape, offering an unprecedented > insight into its composition. > So, although Apophis poses no immediate danger, we are almost certain to hear > a lot more about it over the coming years and decades. Apart from all the > science we can learn, its orbit's proximity to Earth's makes it a potential > target for future robotic and even manned missions. > Stuart Clark is the author of Voyager: 101 Wonders Between Earth and the > Edge of the Cosmos (Atlantic). >
