Posted on 06/20/2002 8:43:49 AM PDT by cogitator
Asteroid gives Earth closest shave in years
PARIS (AFP) Jun 20, 2002 A football-pitch-sized asteroid capable of razing a major city came within a whisker of hitting the Earth on June 14, but was only spotted three days later, scientists said Thursday.
Asteroid 2002 MN, estimated at up to 120 metres (yards) long, hurtled by the Earth at a distance of 120,000 kilometers (75,000 miles), well within the orbit of the Moon and just a hair's breadth in galactic terms.
It is the closest recorded near-miss by any asteroid, with the exception of a 10-metre (33-feet) rock, 1994 XM1, which approached within 105,000 kilometers (65,000) miles on December 9, 1994, they said.
"2002 MN is a lightweight among asteroids and incapable of causing damage on a global scale, such as the object associated with the extinction of the dinosaurs," the Near Earth Object (NEO) Information Centre of Britain's National Space Centre said in a press release.
"However, if it had hit the Earth, 2002 MN may have caused local devastation similar to that which occurred in Tunguska, Siberia in 1908, when 2,000 square kilometres (800 square miles) of forest were flattened," it said.
Spokesman Kevin Yates told AFP that the asteroid was only spotted on June 17 -- three days after its flyby.
Had it collided with the Earth, "the most likely thing is that it would have detonated in the atmosphere, creating a blast wave," he said.
"You're talking in the region of 10 megatonnes -- quite a lot of energy to be released in any one place," he said.
The risk of the Earth being hit by an asteroid or comet is very remote, and most objects never come so close as 2002 MN.
NASA's Near-Earth Object (NEO) Program website confirmed the incident and said 2002 MN was spotted by the Lincoln Near Earth Asteroid Research (LINEAR), a project funded by the US Air Force and NASA and located in New Mexico.
The website of the US magazine Sky et Telescope voiced alarm at the near miss.
"What is most shocking is just how close it came to Earth," it said.
"Though the exact details of an impact scenario depend on the rock's composition, had it hit the Earth, the event would have been 'Tunguska-like', with a force rivalling the largest H-bombs."
US and other astronomers are working hard to map large asteroids, greater than a kilometer (five-eighths of a mile) across, that could inflict lasting climate change.
One such monster is believed to have wacked into the Earth 65 million years ago in what is modern-day Mexico, kicking up dust and debris that swathed the planet, unleashing a prolonged winter that ended the long reign of the dinosaurs.
But many specialists are worried that little sustained effort is being made to spot smaller space wanderers, which could still unleash the energy of an arsenal of nuclear bombs if they collided with our home.
In addition, the search for dangerously asteroids is overwhelmingly conducted by telescopes in the northern hemisphere. A rock approaching from the southern hemisphere could go undetected.
Astronomers spot asteroids thanks to the light they reflect from the Sun, which means that smaller ones are frequently only discovered when they are very close to the Earth and become visible.
If one of these were on a collision course, that would leave no time to launch a rocket or missiles to try to deflect or destroy it, or even prepare cities for a potential disaster.
Asteroids are often described as the rubble left over from the building of the Solar System.
They orbit the Sun, but the paths are never eternal, for the trajectories can be deflected by gravitational pull whenever the asteroid passes by a planet or goes around the star itself.
The latest calculations of 2002 MN suggest it has an orbit of 894.9 days and is unlikely ever to be any future threat to the Earth, said Yates.
The next close flyby will be in 2061 but the distance will be much greater than in the June 14 episode, he said.
Asteroids are a very remote yet real peril, because they move at such speeds that they unleash terrific energy on impact.
The Tunguska event was caused by an object estimated to be 60 metresfeet) long. It exploded in the atmosphere with the force of 600 times the Hiroshima bomb.
Asteroid 1950 DA is calculated as the highest probability of impact with the Earth for any near Earth asteroid to date: about one in 300. This will be in March 2800. If it hits, this is bad news. Very, very bad news, particularly if we haven't figured out how to destroy it first.
Yeah, but in ant terms it's like a light year.
Ah, but they were claiming we were running into the mainstream, and all of those satellite were in Great Jeopardy!!!!!
As it turned out, nothing really happened except that these so-called experts got to run off with full boodle-bags.
While there is a nugget of truth at the center of the asteroid scare, I'm an admitted cynic on things like this. Too many managers are susceptible to the wiles of gurus, and they'll chase them to this or that trend until it becomes obvious that another trend is more demanding of their attention.
And the "experts" seem to be comprised of smart guys who know both math and marketing.
Beg pardon..I thought that they were all Perfect A$$....s!
I'm not a gamblin' man but I'm willing to stake good money on Humankind's ingenuity prevailing over the next 798 years.
Despite the threat to satellites, I was hoping we were going to run into the mainstream too. Meteor storms are very rare and quite amazing to observers.
According to the astronomers that have studied the Leonids, there is a very narrow band of relatively thick particle concentration. The experts attempted to predict when the Earth would encounter that band, if it did. Because the band is in orbit around the Sun, it is subject to perturbation from gravity (i.e., Jupiter) and even the solar wind, because we are talking about very small particles. But the experts don't know exactly where the band is, and it can't be observed from Earth.
So we missed the center of the band. We apparently came close; the show I saw last November was the best heavy meteror shower I've ever seen, and my light conditions weren't good. But it wasn't a meteor storm. The estimated rate of Leonids during the 1966 storm was around 144,000 an hour. The best that observers saw last November was 1500- 2000 an hour.
This is one picture (a 10-minute exposure) of the '66 Leonids.
I'm not ignoring the possibility of asteroidal devastation, mind you. But having seen the specialist-driven hoo-raw about not one, but two Leonids meteor showers ("satellites will be destroyed!!!!"), I'm mighty cynical about guys like this.
Money spent looking out for asteroids, our potential doom, is better than spending $500 million on African AIDS cases.
And if we DO have such a device by then, we could simply transport the asteroids directly out of the path using the combined oomph of our mighty, mighty laundry transporters!
There are already such careers underway in Europe, especially England. They have, of course, failed to spot most of the asteroids that have whizzed by close until 3 days after the event.
In any case, spotting asteroids won't do any good at all unless there is a program to actually do something about such asteroids. That is the problem: there is no action plan. Put anti-asteroid hardware in space and don't wait until the last minute.
"Will these primitive savages want to take a chance that it's NOT an act of God, especially after "He" hits 'em with four of five big asteroids over a period of a few years in response to their outragously sinful and murderous ways? I doubt it. Don't mess with God".
Because this type of assinide comment does not help any thing and in fact does more harm than good.
These things happen far more than people realize, meteors explode in the atmosphere on a regular basis.
If you are not familiar with the Tunguska blast in 1908 you should realize that such an event would wipe out any major metropolitan area. And it would be assumed that it was a nuclear blast.
The evidence would not bear this out, but by then it would most likely be too late, some sort of retaliation would have taken place.
Unless you believe that a politician could resist the enormous pressure to retaliate. Who is retaliated against wouldn't be a matter of prime importance.
Why do we always get this type of thing sensationalized? Why would a piece of rock "explode" as opposed to simply burning furiously until impact, at which point it would be much smaller? Just wondering.
I am very familiar with it. However, I don't believe it would be mistaken for a nuclear attack to the point where retaliation would be in order. Monitoring of possible missile launches and incoming atmospheric anomalies such as a meteor is sufficient these days for us to determine exactly what hit us.
It depends mainly upon the composition of the rock.
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