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Post by Watchman on Dec 13, 2005 18:20:15 GMT -5
It's called Apophis. It's 390m wide. And it could hit Earth in 31 years time
· Scientists call for plans to change asteroid's path · Developing technology could take decades
Alok Jha The Guardian
In Egyptian myth, Apophis was the ancient spirit of evil and destruction, a demon that was determined to plunge the world into eternal darkness. A fitting name, astronomers reasoned, for a menace now hurtling towards Earth from outerspace. Scientists are monitoring the progress of a 390-metre wide asteroid discovered last year that is potentially on a collision course with the planet, and are imploring governments to decide on a strategy for dealing with it.
Nasa has estimated that an impact from Apophis, which has an outside chance of hitting the Earth in 2036, would release more than 100,000 times the energy released in the nuclear blast over Hiroshima. Thousands of square kilometres would be directly affected by the blast but the whole of the Earth would see the effects of the dust released into the atmosphere. And, scientists insist, there is actually very little time left to decide. At a recent meeting of experts in near-Earth objects (NEOs) in London, scientists said it could take decades to design, test and build the required technology to deflect the asteroid. Monica Grady, an expert in meteorites at the Open University, said: "It's a question of when, not if, a near Earth object collides with Earth. Many of the smaller objects break up when they reach the Earth's atmosphere and have no impact. However, a NEO larger than 1km [wide] will collide with Earth every few hundred thousand years and a NEO larger than 6km, which could cause mass extinction, will collide with Earth every hundred million years. We are overdue for a big one."
Apophis had been intermittently tracked since its discovery in June last year but, in December, it started causing serious concern. Projecting the orbit of the asteroid into the future, astronomers had calculated that the odds of it hitting the Earth in 2029 were alarming. As more observations came in, the odds got higher.
Having more than 20 years warning of potential impact might seem plenty of time. But, at last week's meeting, Andrea Carusi, president of the Spaceguard Foundation, said that the time for governments to make decisions on what to do was now, to give scientists time to prepare mitigation missions. At the peak of concern, Apophis asteroid was placed at four out of 10 on the Torino scale - a measure of the threat posed by an NEO where 10 is a certain collision which could cause a global catastrophe. This was the highest of any asteroid in recorded history and it had a 1 in 37 chance of hitting the Earth. The threat of a collision in 2029 was eventually ruled out at the end of last year.
Alan Fitzsimmons, an astronomer from Queen's University Belfast, said: "When it does pass close to us on April 13 2029, the Earth will deflect it and change its orbit. There's a small possibility that if it passes through a particular point in space, the so-called keyhole, ... the Earth's gravity will change things so that when it comes back around again in 2036, it will collide with us." The chance of Apophis passing through the keyhole, a 600-metre patch of space, is 1 in 5,500 based on current information.
There are no shortage of ideas on how to deflect asteroids. The Advanced Concepts Team at the European Space Agency have led the effort in designing a range of satellites and rockets to nudge asteroids on a collision course for Earth into a different orbit.
No technology has been left unconsidered, even potentially dangerous ideas such as nuclear powered spacecraft. "The advantage of nuclear propulsion is a lot of power," said Prof Fitzsimmons. "The negative thing is that ... we haven't done it yet. Whereas with solar electric propulsion, there are several spacecraft now that do use this technology so we're fairly confident it would work."
The favoured method is also potentially the easiest - throwing a spacecraft at an asteroid to change its direction. Esa plans to test this idea with its Don Quixote mission, where two satellites will be sent to an asteroid. One of them, Hidalgo, will collide with the asteroid at high speed while the other, Sancho, will measure the change in the object's orbit. Decisions on the actual design of these probes will be made in the coming months, with launch expected some time in the next decade. One idea that seems to have no support from astronomers is the use of explosives.
Prof Fitzsimmons. "If you explode too close to impact, perhaps you'll get hit by several fragments rather than one, so you spread out the area of damage."
In September, scientists at Strathclyde and Glasgow universities began computer simulations to work out the feasibility of changing the directions of asteroids on a collision course for Earth. In spring next year, there will be another opportunity for radar observations of Apophis that will help astronomers work out possible future orbits of the asteroid more accurately.
If, at that stage, they cannot rule out an impact with Earth in 2036, the next chance to make better observations will not be until 2013. Nasa has argued that a final decision on what to do about Apophis will have to be made at that stage.
"It may be a decision in 2013 whether or not to go ahead with a full-blown mitigation mission, but we need to start planning it before 2013," said Prof Fitzsimmons. In 2029, astronomers will know for sure if Apophis will pose a threat in 2036. If the worst-case scenarios turn out to be true and the Earth is not prepared, it will be too late. "If we wait until 2029, it would seem unlikely that you'd be able to do anything about 2036," said Mr Yates.
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Post by brotherjerm on Dec 13, 2005 23:42:42 GMT -5
Interesting......The Lord very well with return before then!
Glory; Brother Jeremy
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Post by Watchman on Dec 14, 2005 1:05:15 GMT -5
I absolutly believe that Yeshua will return well before 2036- In fact many many people on the earth will not live throught the next year. Abomination of desolation----- 1290 days (Reign of Antichrist)------ 45 day 'Great Tribulation'(Dan 12:11-12)------ Jesus' Return!!!!! (Feast of Trumpets?) ... I liked the story! Notice how man continues to save himself from all these 'threats'? Will he ever turn to God? One way or another all men will bow before the King of kings! The Lord of lords!
That at the name of Jesus every knee should bow, of in heaven, and in earth, and under the earth; Philipp 2:10
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Post by Watchman on May 17, 2006 19:52:18 GMT -5
MICHAEL CABBAGE Knight Ridder Tribune News Service
CAPE CANAVERAL - Mark your calendar for Sunday, April 13, 2036. That's when a 1,000-foot-wide asteroid named Apophis could hit the Earth with enough force to obliterate a small state.
The odds of a collision are 1-in-6,250. But while that's a long shot at the racetrack, the stakes are too high for astronomers to ignore.
For now, Apophis represents the most imminent threat from the worst type of natural disaster known, one reason NASA is spending millions to detect the threat from this and other asteroids.
A direct hit on an urban area could unleash more destruction than Hurricane Katrina, the 2004 Asian tsunami and the 1906 San Francisco earthquake combined. The blast would equal 880 million tons of TNT or 65,000 times the power of the atomic bomb dropped on Hiroshima.
Objects this size are thought to hit Earth about once every 1,000 years, and, according to recent estimates, the risk of dying from a renegade space rock is comparable to the hazards posed by tornadoes and snakebites. Those kind of statistics have moved the once-far-fetched topic of killer asteroids from Hollywood movie sets to the halls of Congress.
"Certainly we had a major credibility problem at the beginning - a giggle factor," said David Morrison, an astrobiologist at NASA's Ames Research Center in Mountain View, Calif. "Now, many people are aware this is something we can actually deal with, mitigate and defend against."
In 1998, lawmakers formally directed NASA to identify by 2008 at least 90 percent of the asteroids more than a kilometer (0.6 mile) wide that orbit the sun and periodically cross Earth's path. That search is now more than three-quarters complete.
Last year, Congress directed the space agency to come up with options for deflecting potential threats. Ideas seriously discussed include lasers on the moon, futuristic "gravity tractors," spacecraft that ram incoming objects and Hollywood's old standby, nuclear weapons.
To help explore possible alternatives, former Apollo astronaut Rusty Schweickart has formed the B612 Foundation. The organization's goal is to be able to significantly alter the orbit of an asteroid in a controlled manner by 2015.
"You can watch all of the golf on television you want, but if you want to go out and break par, it's going to take a lot of playing," Schweickart said. "And you're going to learn a lot that you thought you knew, but you didn't."
Cosmic shooting gallery
Throughout their 4.5 billion-year history, Earth and its neighboring planets have been like sitting ducks in a cosmic shooting gallery.
A glance at our moon shows the scars left by countless collisions with asteroids and comets. In fact, the moon is thought to have been created when part of the early Earth was ripped away in a cosmic impact with an object the size of Mars.
Earth also has scars, but most have been hidden by vegetation or eroded by geologic processes such as rain and wind. About 170 major impact sites, including northern Arizona's 4,000-foot-wide Barringer Crater, have been identified around the globe.
Within the past century, an extraterrestrial chunk of rock about 200 feet wide is thought to have caused a 1908 blast near Tunguska, Siberia, that leveled 60 million trees in an area the size of Rhode Island. Researchers theorize the object exploded four to six miles above the ground with the force of 10 million to 15 million tons of TNT.
Few outside scientific circles took the threat posed by near-Earth objects seriously until 1980. Then, Luis and Walter Alvarez published a study based on geologic evidence that concluded a cataclysmic asteroid or comet impact 65 million years ago caused the mass extinction of two-thirds of all plant and animal life on Earth - including the dinosaurs.
Dubbed the Great Exterminator, the colossal object was estimated at 7 miles in diameter and created a blast hundreds of millions of times more destructive than a nuclear weapon. Objects that size are thought to hit Earth about every 100 million years.
Spectacular images from the Hubble Space Telescope of Comet Shoemaker-Levy's collision with Jupiter showed 21 comet fragments, some more than a mile wide, producing colossal fireballs that rose above the giant planet's cloud deck.
Informing the public
"I think the most important development for getting this (public awareness) going was the Alvarezes' research that the dinosaurs went extinct as the result of an impact," Morrison said. "We were faced with a real example where an impact had done terrible damage."
In 1998, a year in which the asteroid-disaster flick "Armageddon" was the top-grossing movie worldwide, Congress held hearings that led to the creation of a Near Earth Object Program office at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
That year marked the beginning of the Spaceguard Survey aimed at discovering 90 percent of near-Earth asteroids more than a kilometer wide.
Today, astronomers at five primary U.S. sites work on the survey, which NASA funds with about $4 million annually. Scientists estimate there are 1,100 near-Earth asteroids that are larger than a kilometer wide. With two years to go, they have found 834, or about 76 percent, of the estimated total.
Tracking asteroids
Congress directed NASA in December to look at expanding the search to asteroids larger than 140 meters (460 feet) in diameter and completing the new survey by 2020. Objects that size are capable of destroying a city.
The more often an asteroid or comet is sighted, the more precisely its orbit can be calculated. Researchers hope that radar observations of Apophis taken last weekend by the Arecibo telescope in Puerto Rico could make the odds of a collision even more remote.
"I always use the analogy of a hurricane," said Don Yeomans, manager of the Near Earth Object Program. "When it first forms in the Caribbean, you have no idea where it's going to hit. If you continue to track the hurricane over days and weeks, the future path becomes more predictable."
That uncertainty led former astronaut Schweickart to send a letter to NASA Administrator Michael Griffin last June proposing to land a radio transponder on Apophis to better track its course. For now, the space agency plans to simply monitor the asteroid during passes this year and in 2013.
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Post by Watchman on Nov 5, 2006 18:40:32 GMT -5
Asteroid Can Collide With Earth in 2029 — Russian Scientist
Mos News | November 2, 2006
An asteroid could collide with the Earth in 2029, a Sergey Smirnov, a senior researcher at the Pulkovo Space Observatory, told a press conference in Moscow on Thursday, Interfax news agency reports.
On April 13, 2029 the asteroid Apofiz-99942 will be at its closest distance to the Earth for 200 years, Smirnov said.
The asteroid will pass the Earth at a distance of 30,000 to 40,000 km. “This crosses the geo-stationary orbit, where all the telecommunications and a lot of military satellites are,” he said.
Whatever happens, the Earth will feel the effect of the asteroid, and in the worst case, it will collide with the Earth, and at best it will damage equipment in space in the geo-stationary orbit.
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Post by Watchman on Nov 30, 2006 14:40:00 GMT -5
There’s a chance that the near-Earth asteroid Apophis will inflict widespread devastation in 2036. By DANIEL D. DURDA
Friday, April 13, 2029. An hour after sunset, amateur astronomers across western Europe and northern Africa gaze skyward to watch a third-magnitude “star” drift ever so slowly westward through Cancer. It’s not an artificial satellite but a 320-meter (1,050-foot) pile of rock called Apophis. Its barely perceptible, nearly degree-per-minute motion against the stars belies its grazing flight through the realm of our geostationary satellites.
Although not a threat in 2029, a quarter-century earlier Apophis raised the eyebrows of astronomers worldwide and the awareness of many nonscientists to the global ramifications of the near-Earth-asteroid impact hazard.
Today, in 2006, it’s not the 2029 close pass itself that merits our concern but the potential for an Earth impact just seven years later. That possibility has astronomers and policymakers alike grappling for an appropriate international response to a rare but very real global threat.
A Christmas Story
During the Christmas 2004 holiday, a couple dozen of us who study the near-Earth-object impact hazard received an e-mail stating that the next day, the two world centers for asteroid impact predictions (at the Jet Propulsion Laboratory in California and the University of Pisa in Italy) were going to announce the first-ever forecast of a possible impact with a Torino Scale value of two. Roy Tucker (Goodricke-Pigott Observatory), along with David Tholen and Fabrizio Bernardi (University of Hawaii), discovered the asteroid, provisionally designated 2004 MN4, while testing new equipment at Kitt Peak in June 2004 (S&T: April 2005). But then it was lost. It was observed again on December 18, and astronomers realized that it was the same object seen in June.
Those independent observations over many months enabled astronomers to calculate an orbit precise enough to reveal a roughly 1-in-200 chance of the asteroid hitting Earth on Friday the 13 (of all days!) of April 2029, with a force of thousands of megatons. Many of us in the impact-hazard community never expected to face a threat of this magnitude.
Determining the asteroid’s size was an urgent issue, since one factor in a Torino Scale ranking is the severity of a potential impact. Initial uncertainties of 2004 MN4’s diameter allowed it to be anywhere between 200 meters and 1.5 kilometers. The impact of a 200-meter asteroid could devastate a major metropolitan area or spawn a terrible tsunami, but a 1.5-kilometer object could cause global catastrophe by destroying the ozone layer and perhaps throwing enough dust into the atmosphere to trigger worldwide climate effects.
Over the next few days, professional and amateur astronomers around the world observed the asteroid and fed the positions to the Minor Planet Center. The JPL and Pisa groups used these new observations to update their orbit calculations and impact predictions. The calculated impact odds rose to 1 in 170 on December 23, 1 in 60 on December 24, 1 in 40 on Christmas Day, and 1 in 37 on December 27. The potential impact had reached 4 on the Torino Scale. Usually, when more observations of an asteroid are made, the odds of impact go down. But this was going in the opposite direction!
Although there was growing media interest in this evolving story, it didn’t make the big headlines the way some previous, far-less-likely impact warnings had. Journalists go on vacation, too, during the holidays. And on December 26 a tsunami devastated Southeast Asia and media attention was rightly focused on that tragic event.
A Close Shave
By December 27 it looked like the odds of impact were going to climb to about 1 in 20. Fortunately, an extensive search turned up several images of 2004 MN4 taken back on March 15 by the 0.9-meter Spacewatch telescope on Kitt Peak. Spacewatch’s automated image-scanning software initially missed the asteroid because it was right at the system’s magnitude limit. The odds of finding the object in old images were only about 10 percent. It is interesting to ponder how we would have reacted had the odds of a substantial impact hung in there at 1 in 20 for several weeks or months.
With these newfound images, astronomers realized on December 28th that 2004 MN4 would surely miss Earth on April 13, 2029. Further calculations showed that it would miss by a comfortable distance, about five Earth diameters.
In addition, ground-based near-infrared spectra acquired in early January 2005 by Andrew Rivkin (Applied Physics Laboratory) and Richard Binzel (MIT) suggested that the asteroid’s composition was like that of a common, ordinary chondritic meteorite. This observation allowed us to estimate its albedo (reflectivity), which in turn yielded a diameter of about 320 meters. In late January 2005, the Arecibo radio telescope (the world’s largest, in Puerto Rico) was able to ping the asteroid, now named Apophis (the Greek name for the Egyptian god Apep, “the Destroyer”), with radar. With the radar data included in a new orbit determination, it turned out that some of the optically determined positions were in error. The asteroid is going to miss us by only half the distance calculated back on December 28 (S&T: May 2005). It will, in fact, pass within the orbits of our geosynchronous satellites and will sail across the European skies as a bright, 3rd-magnitude star, traversing some 40 degrees in only one hour during its closest approach.
Something this big should pass this close to Earth only once every 1,500 years or so, yet Apophis will buzz us only a quarter century after its discovery. Are we missing something? Could our estimates of the impact rate be that far off?
Such concerns aside, Apophis provides a wonderful scientific opportunity. During its very close 2029 pass, gravitational tides will likely alter its spin and may even subtly change its shape, although they won’t be strong enough to tear the asteroid apart the way Jupiter ripped Comet Shoemaker-Levy 9 into a string of pearls.
Knowing years ahead that this asteroid will make a close approach gives us a chance to discern its internal structure. Is Apophis a solid shard of rock, or is it a rubble pile barely held together by its own feeble gravity? As Earth’s tidal forces stretch and pull the asteroid, its interior will probably creak and pop with asteroidquakes. The echoes of these tremors will reveal boundaries between any significant internal structural components. Nature will be doing the energetically difficult part of an active seismic experiment for us -- we need only implant a series of sensors and passively listen.
Not Out of the Woods Yet
As Apophis slingshots past Earth, gravitational forces will also bend its trajectory by about 28 degrees. The size and period of its orbit will increase, and Apophis will spend more time outside Earth’s orbit than it does now. But the details of the new trajectory depend on exactly where the asteroid makes its closest approach. And here lies the danger posed by this little mountain of rock.
There are several regions of space only a few hundred meters across that Apophis could pass through during its 2029 encounter that would bring it back to the same place exactly seven, eight or 27 years later. The problem is that Earth will be back at that same place, too, and at the same time. So passage through one of these resonant-return “keyholes” allows for the possibility that Apophis could slam into our planet on April 13 of 2036, 2037 or 2056.
At the moment, the error ellipse, or region of uncertainty, around Apophis’s 2029 close approach has us keeping a close eye on the 640-meter-wide keyhole that would put it on a collision course for April 13, 2036. We need more observations to reduce the uncertainty, but unfortunately Apophis will be very difficult to see optically between about 2007 and 2011. This faint body spends most of its time inside Earth’s orbit, closer to the Sun, where it remains hidden in twilight. In May 2006 Arecibo was just able to detect Apophis and nail its position. The orbital refinement shrank the error ellipse and displaced it somewhat away from the 2036 keyhole. With these and more recent optical observations, the chance that the asteroid might pass through that keyhole and impact Earth in 2036 is currently rated at about 1 in 48,000, down by a factor of eight from earlier predictions.
That’s moving comfortably in the right direction, but it looks like we won’t be able to say anything more definitive about Apophis’s impact probability in 2036 until the early 2010s, when it next comes close to Earth and can again be observed by both optical telescopes and radar. By that time there is a 47,999-in-48,000 chance that the 2036 impact probability will drop to zero.
But if the 2036 keyhole is still within the even smaller error ellipse, we would probably send a spacecraft to place a radio transponder on the asteroid. In response to a request to NASA administrator Michael Griffin in 2005 to begin work on a transponder mission now, the agency conducted a very thorough analysis and determined that such a mission could be accomplished after the next good radar opportunity in 2013. The transponder’s clear radio blips would allow us to track Apophis’s motion more precisely than with passive radar observations alone. Those data will presumably show once and for all that the asteroid will not pass through the 2036 keyhole.
But then again, what should we do if by the early 2020s it still looks like Apophis has a significant chance of passing through the 2036 keyhole during its 2029 close pass? This possibility raises an important question: When does an object become threatening enough that action should be taken to deflect it? And since no national or international organization has been tasked with protecting Earth from impacts, who should make that decision, who should take action, who will pay for it, and who will be liable if something goes wrong with a deflection mission? A committee chaired by Apollo 9 astronaut Rusty Schweickart is working with the United Nations to address these issues.
Gravity Tractor to the Rescue!
Researchers have proposed numerous techniques for deflecting a threatening asteroid onto a new trajectory. Large inflatable mirrors could focus sunlight onto the asteroid, or powerful lasers could zap its surface, vaporizing rocks. The comet-like jetting would slowly thrust the asteroid into a slightly different orbit, causing it to miss Earth.
Alternatively, scientists could slam something big into the asteroid, Deep Impact–style, to divert it or even break it up. A problem with this approach (and with nuclear weapons) is that you don’t have much control over what happens to the asteroid after the impact, and you could end up with several large fragments. If some of them remain on an impact trajectory, you’ve made the problem even worse.
It’s a good idea to have multiple tools at your disposal. A technique that might work well for one combination of lead time and object type might not work for another. One of our problems is that we don’t really know the surface properties and internal structures of small asteroids. Observations of near-Earth asteroids, and laboratory studies of meteorites, suggest that their mechanical properties might range from solid nickel-iron to very porous, low-density rocky aggregates (S&T: September 2006). How do you blast, grab ahold of, or work near the surface of a small body that has essentially zero gravity if you don’t know whether its surface characteristics are akin to solid metal, powdery regolith, or something in-between?
NASA astronauts Edward Lu and Stanley Love have devised an elegant solution to this problem: Park a spacecraft in close proximity to the asteroid, cant its highly efficient solar- or nuclear-powered ion thrusters to the side so their plumes don’t hit the object, and hover beside it for several months or more with long, continuous thrusting. Due to the spacecraft’s gravitational attraction on the asteroid, the vehicle effectively tows the rock along with it using gravity as the tow-line.
If we launched a tugboat to Apophis before the 2029 close approach, we would only need to move the asteroid a few hundred meters to miss a keyhole, rather than several thousand kilometers to miss the entire planet. The tiny change in the asteroid’s orbit could be accomplished with only a 1-ton solar-electric-propulsion spacecraft similar to NASA’s low-cost Deep Space 1 mission.
This creative gravity-tractor concept solves the problem of not knowing the asteroid’s surface properties, internal structure or spin state. Since you don’t have to land on the body or otherwise interact with its surface or interior, the gravity tractor provides a robust deflection technique that is also controllable. It can change the asteroid’s orbital speed in any direction required to efficiently move the impact error ellipse off Earth. Scientists can continually monitor the progress throughout the deflection mission and take corrective action if necessary. Large rocks do fall from the sky very rarely, but when they do, they can cause significant loss of life. Can we rationally evaluate the asteroid impact threat and undertake a national or international program to deal with it that is of sensible magnitude? Some feel that the appropriate response for dealing with this extremely rare threat is to do nothing. But you might think that since we have the knowledge and the technology at our disposal, we might as well not take the chance of going the way of the dinosaurs.
Daniel D. Durda is a senior research scientist at the Southwest Research Institute in Boulder, Colo., where he studies the collisional evolution of asteroids and the effects of their impacts on Earth. He is president of the B612 Foundation (www.b612foundation.org), a group of scientists working to mitigate the impact threat.
© 2006 Sky Publishing Corp.
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Post by Watchman on Jan 10, 2007 15:49:13 GMT -5
Friday the 13th Might Be Pretty Frightening After All—in 2029
If scientists and astronomers have it calculated correctly, Friday, April 13, 2029, could be a very unlucky day for Earth if the asteroid Apophis continues on its path toward Earth.
By Linda Orlando
Apophis was the name of the ancient Egyptian god of darkness and destruction. So there is no more appropriate moniker astronomers could have chosen to assign to a 25-million-ton, 820-ft. wide asteroid that is expected to slice across the orbit of the moon and hurtle toward Earth at more than 28,000 miles per hour on Friday the 13th of April, 2029, at 4:36 a.m. Greenwich Mean Time.
Scientists are 99.7% certain that Apophis, a huge pockmarked rock that carries the energy of 65,000 Hiroshima bombs, will pass the Earth at a distance of only 18,800 to 20,800 miles. That distance is shorter than a round-trip flight from Melbourne, Australia, to New York City, and well inside the orbits of many of the geosynchronous communications satellites that are now circling the Earth. Just after dusk on April 13, people in Europe, Africa, and parts of Asia will be able to see what looks like a star slowly making its way westward through the sky. Apophis will be the first asteroid in human history to be clearly visible to the naked eye.
The asteroid will be packing enough power to wipe out a small country or churn up an 800-ft. high tsunami. Current projections show the asteroid’s impact occurring somewhere along a 30-mile-wide path stretching from Russia across the Pacific Ocean into Central America and then across the Atlantic. Although San Jose, Costa Rica, Nicaragua, and Venezuela are all potential targets for total destruction, scientists believe the most likely target to be several thousand miles off the West Coast of the United States, where the impact would create a 5-mile wide crater in the ocean floor. The impact would trigger tsunamis that could pound the coast of California with 50-foot waves.
Scientists believe that if Apophis passes the Earth at a distance of exactly 18,893 miles, it will go through a "gravitational keyhole," where the Earth’s gravity could pull Apophis off track just enough to cause it to enter an orbit that is seven-sixths as long as the Earth’s orbit. If that happens, then exactly seven years later, as Apophis comes back around, the planet would be dead center in the path of the behemoth. Fortunately, current tracking estimates put the odds of that happening at about 45,000 to 1.
However, former astronaut Rusty Schweickart, now 71, who served on the Apollo 9 mission in 1969, feels that even a tiny risk cannot be ignored. Through his B612 Foundation, which he co-founded in 2001, Schweickart has been urging NASA to start now making preparations to do something about the asteroid. "We need to act," he said. "If we blow this, it’ll be criminal."
Despite Hollywood’s imaginative cinematic escapades, current technology does not provide any way for Apophis to be deflected by some 5000 miles to miss the Earth in 2036, if it does go through the gravitational keyhole and comes back around with our planet in its crosshairs. Not even Bruce Willis and his crew of roughnecks would be able to do a thing about it. Unless some revolutionary new technology emerges, there would be little scientists could do other than plotting the precise impact point and begin evacuating people.
In 2005, Schweickart began urging NASA administrator Michael Griffin to start planning a mission to land a radio transponder on Apophis, in an effort to track the asteroid’s path to confirm that it will not hit the gravitational keyhole. If that data shows that the path will bring it into the keyhole, there would still be time to do something about it and launch a deflection mission. Using current technology, we could nudge it slightly off course by hitting it with a simple 1-ton "kinetic energy impactor" spacecraft. An alternative solution would be to use a "gravity tractor" spacecraft to hover above the asteroid and gently pull it slightly off course using its own gravity.
For now, NASA has decided to wait and see what’s going to happen. According to an analysis by Steven Chesley of the Near Earth Object program at the Jet Propulsion Laboratory in Pasadena, CA, there is no cause for alarm yet. Apophis will be swinging by the Earth in 2013, when it will be in perfect position to be tracked by the 1000-ft. diameter radio telescope in Arecibo, Puerto Rico. The data obtained during that pass could rule out the asteroid hitting the keyhole in 2029. But if it isn’t able to rule out the possibility, there will still be enough time to launch a deflection mission. Schweickart estimates that such a mission could take as long as 12 years to complete. But for now, most scientists are content to wait until we get a better idea of exactly what the risks are.
"There’s no rush right now," says Chesley. "But if it’s still serious by 2014, we need to start designing real missions."
By Buzzle Staff and Agencies Published: 1/8/2007
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Post by Watchman on Jan 22, 2007 19:09:43 GMT -5
. Sunday, 21 January 2007 By Jonathan Leake in London
NASA is drawing up a shortlist of ideas, to be unveiled early next year, for diverting a 40 million tonne asteroid on course to pass dangerously close to Earth.
Fears that the planet may be in danger from being struck by asteroids were heightened by the discovery of one orbiting the sun that, on its present path, will pass within 35,405km - a hair's breadth in astronomical terms - in April 2029.
NASA's plan is to engineer a minor shift in the asteroid's trajectory that would make it miss Earth by a wider margin on this and all subsequent passes.
Under one possible plan, a robotic craft would be sent to the asteroid to attempt to alter its course. One option might be to install a propulsion system on the surface to nudge it onto a new course.
The schemes will be presented and discussed at the annual meeting of the American Association for the Advancement of Science.
The studies follow the discovery of hundreds of small asteroids orbiting the sun that repeatedly cross Earth's orbit, raising the possibility of a devastating collision.
The one causing most concern is a rock of more than 304m called Apophis, the Greek name for the Egyptian god Apep, known as "the destroyer". It will come so close to Earth it will pass under many satellites and may destroy some.
Astronomers fear that although 2029 should pass without incident, coming so close to Earth might change Apophis's 323-day orbit around the sun - during which it crosses the planet's path twice - creating an even bigger risk in the future. A second close encounter is predicted for 2036.
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Post by Watchman on Jan 24, 2007 13:07:02 GMT -5
Another Asteroid Collision With Earth: It's Just a Matter of Time
Ex-Astronaut Looks at Ways to Prevent Catastrophe By GINA SUNSERI
Jan. 24, 2007— - What are the odds an asteroid or meteoroid will hit the Earth again? Pretty good, according to some scientists.
There are millions of these "rocks" out there, and about 200,000 to 400,000 of them get close enough to be classified as celestial objects that could come within range of our home planet.
But it only takes one, as anyone who has studied the dinosaurs will tell you. Many scientists believe an asteroid impact led to the extinction of the dinosaurs 65 million years ago.
Apollo 9 astronaut Russell Schweickart believes it is simply a matter of time before another asteroid targets Earth.
"It could be 20 years, or a hundred years, or a thousand years," he said.
Schweickart is one of the founders of the B612 Foundation, which studies how to alter the orbit of an asteroid to prevent it from hitting Earth. "It's a very infrequent occurrence -- an asteroid impacting the Earth -- but when it happens, it will be devastating."
Schweickart says he's frustrated because he believes this project should be led by an international organization. He contends there is no way to predict when or where an asteroid will hit the Earth, so no single government should be held responsible for asteroid avoidance.
He wants to see the United Nations set up an agency mandated to prevent an asteroid from colliding with the Earth and has planned a series of meetings around the world to develop a comprehensive plan. Schweickart anticipates a project that would cost several hundred million dollars, a burden for any single country, but something much more practical as a combined effort.
How would you keep an asteroid form hitting the Earth? Schweickart outlined a three-step program.
Early Warning. You need to know it's coming by searching for it. NASA currently has a budget of $4.1 million to look for asteroids.
Take Action. Develop the ability to deflect an asteroid. Some technology is available now, but propulsion that doesn't exist yet will be required -- nuclear reactors that could power ion-propulsion systems for interplanetary spacecraft.
Make a Decision. Some agency has to decide to do this and fund it. This isn't about ducking a bullet going past your head; this is about seeing what is coming your way decades ahead and believing in the laws of gravity.
Edward T. Lu is a NASA astronaut who has developed a plan of action for deflecting an asteroid. He and fellow astronaut Stan Love have come up with the concept of a space tug. A space tug is a rocket that would launch to the same orbit as an asteroid threatening to hit the Earth and alter the asteroid's orbit by pushing in the direction of its orbital motion.
Lu told ABC News, "You don't have to change much -- one hundred thousandth of a mile an hour is enough, 10 years ahead of time, to cause an asteroid to miss the rendezvous with Earth."
NASA is taking some steps to learn more about asteroids. Chris McKay is a planetary scientist with the Ames Research Center as well as the deputy lead scientist for the Constellation Program -- the project to go back to the moon and on to Mars. Orion is the vehicle that will carry the astronauts, launched with an Ares rocket. McKay is exploring ways to use Orion for other missions, like sending a crew to land on an asteroid.
"It is exciting to think about rendezvousing with an asteroid and bringing back samples," McKay said. "What we could learn about the origins of the Earth is mind-boggling."
While McKay is excited about the possibility of landing on an asteroid, he says there is currently no mandate to start deflecting asteroids. "Right now, there is nothing out there that we know of with our name on it, but if we did find something, this mission could give the knowledge to deter a disaster."
An ounce of prevention is the mantra for scientists concerned about asteroids smacking into us. Both Schweickart and McKay use the failure of the levees in New Orleans after Hurricane Katrina as an example of poor planning on all levels of government.
Is getting hit by an asteroid something to lose sleep over? Probably not, said Schweickart. But he said that people should be more concerned about the government's role in watching for an asteroid.
NASA's Near Earth Object Observation Program is responsible for tracking any near-Earth asteroids larger than a kilometer in size. NASA is not responsible for preventing an asteroid that it tracks from hitting the Earth. No agency has that mandate right now.
And the lack of a plan, said Schweickart, is something that causes him to lose sleep.
Copyright © 2007 ABC News Internet Ventures
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Post by Watchman on Feb 22, 2007 11:13:52 GMT -5
The United Nations will shortly be asked to take on a new and unfamiliar mission - to save the Earth, not from drought, war or disease, but from the cataclysm that could occur following a direct hit by an asteroid. A group of former astronauts and cosmonauts is warning that at least one asteroid already identified in outer space is on a path that could indeed see it colliding with our planet in 2036. They say work should begin now on considering a strategy to protect humankind from this and other asteroids. Specifically, members of the Association of Space Explorers are planning a series of meetings over the next two years, to be attended by diplomats, astronomers, astronauts and engineers, to draft an international treaty on address the threat. It will be presented to the UN for adoption in 2009. "You have to act when things look like they are going to happen - if you wait until you know for certain, it's too late," Dr Russell Schweickart, an Apollo 9 astronaut, told a conference of the American Association for the Advancement of Science in San Francisco. "We believe there needs to be a decision process spelled out and adopted by the United Nations." The United States Congress recently instructed Nasa to increase its efforts to identify asteroids that could pose a threat to Earth. As of now, the agency is monitoring the paths of 127 so-called near-Earth objects (NEO) that have the possibility of striking the planet. Among prominent figures who have been asked to participate in drafting a UN treaty are Lord Rees, the English Astronomer Royal as well as Roger Bonnet, the ex-director of science at the European Space Agency and the former British ambassador the UN, Sir Crispin Tickell. Underscoring the peril, an asteroid named Apophis risks passing very close to Earth on 13 April, 2036. Astronomers warn that as of now, there is a 1 in 45,000 chance of a direct hit. Its impact would be enough to wipe out a country as large as England. Debate over how best to deflect any asteroid headed to our planet echoes the science-fiction scripts of Hollywood films like 'Armageddon', which precisely told the story of an asteroid and the derring-do of astronauts sent on a mission to destroy it before it reached Earth's atmosphere. Dr Edward Lu told the conference that notions of smashing asteroids before they reach Earth are risky. "There is a random element to them," he said. "Things like hitting them with a bomb or flying a spacecraft into them - you just do not know what the results of that are going to be." Scientists now favour deploying so-called 'Gravity Tractors', small spacecrafts that would travel close to a speeding asteroid and, with their own gravitational pull, try to drag it onto a different path. www.mrt.com.mk/en/index.php?option=com_content&task=view&id=2246&Itemid=33
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