On 01/07/2013 03:46 AM, salyavin808 wrote: > 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 – a 'potentially hazardous' asteroid – 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] 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 > <http://www.guardian.co.uk/science/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 > <http://neo.jpl.nasa.gov/news/news146.html> 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 > <http://www.guardian.co.uk/science/2005/dec/07/spaceexploration.research\ >> . > 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 <http://en.wikipedia.org/wiki/Aten_asteroid> . 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 – 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 > <http://www.sciencedirect.com/science/article/pii/S0019103510003179> . > Russia has announced tentative plans to land a tracking beacon on > Apophis sometime after 2020 > <http://rt.com/news/apophis-radio-beacon-mission-908/> , 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 – 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 <http://neo.jpl.nasa.gov/apophis/> . 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 > <http://echo.jpl.nasa.gov/asteroids/Apophis/Apophis_2013_planning.html> > . > > Stuart Clark <http://www.stuartclark.com/> is the author of Voyager: > 101 Wonders Between Earth and the Edge of the Cosmos > <http://www.guardianbookshop.co.uk/BerteShopWeb/viewProduct.do?ISBN=9781\ > 848875432> (Atlantic). > > >
If we weren't so busy warring with each other then we might put together a space force that could easily deflect any such threat. Apparently humans aren't evolved enough for that even if their technology is. Of course then there is always the possibility that some small brained ignorant psychopath might try to take over the space force and start killing earthlings themselves. ------------------------------------ To subscribe, send a message to: fairfieldlife-subscr...@yahoogroups.com Or go to: http://groups.yahoo.com/group/FairfieldLife/ and click 'Join This Group!'Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/FairfieldLife/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/FairfieldLife/join (Yahoo! ID required) <*> To change settings via email: fairfieldlife-dig...@yahoogroups.com fairfieldlife-fullfeatu...@yahoogroups.com <*> To unsubscribe from this group, send an email to: fairfieldlife-unsubscr...@yahoogroups.com <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
