Page 7 of 7

"Alan Harris, a planetary scientist at Space Science Institute in Boulder, Colorado, said he's been following Boslough's work on Tunguska for several years. 'The bottom line is it takes a lot less energy, a small explosion, to create ground damage' such as that at Tunguska, said Harris, who studies the frequency of such impacts to assess hazards. In the future, he said, he'll take Boslough's work into account and revise estimates of damage from impacts by smaller objects."

[NOTE: The point is that there are a great many smaller asteroids undetected in our solar system and the likelihood of Earth being hit by one is high. The Boslough study shows how unprepared we are for the effects of one of these more probable smaller impacts.]

Meteor Crater In Peru

"Streamlined Meteorite Hit Peru Fast and Hard…A meteorite crashed in the southern Peruvian town of Carangas, near the border with Bolivia, September 16, 2007…digging out a deep hole and startling nearby residents, [it] traveled faster and hit harder than would have been expected, researchers reported on Tuesday. The object, which left a 49-foot-wide (15 meter) crater, was made of rock and, in theory, should have disintegrated in the atmosphere long before reaching the Earth's surface, said Peter Schultz, a professor of geological sciences at Brown University in Rhode Island. But the pieces stayed together and were speeding at 15,000 mph (24,000 kph) when they hit. 'Usually only meteorites made of metal make it to the surface intact enough to scoop out a crater…It would make a hole in the ground, like a pit, but not a crater. But this meteorite kept on going at a speed about 40 to 50 times faster than it should have been going,' Schultz said. His team's observations suggest that scientists may need to change theories about the different ways objects can hit planets. 'We have to go back to the drawing board and think again. This just isn't what we expected, it was to the point that many thought this was fake. It was completely inconsistent with our understanding how stony meteorites act,' he said. This could challenge conventional wisdom that all small, stony meteorites disintegrate before striking Earth. 'You just wonder how many other lakes and ponds were created by a stony meteorite, but we just don't know about them because when these things hit the surface they just completely pulverize and then they weather,' said Schultz."

The Atlantic magazine reports: The odds that a potentially devastating space rock will hit Earth this century may be as high as one in 10. So why isn't NASA trying harder to prevent catastrophe?…Only in the past few decades have astronomers begun to search the nearby skies for objects such as asteroids and comets. What they are finding suggests that near-Earth space rocks are more numerous than was once thought, and that their orbits may not be as stable as has been assumed. There is also reason to think that space rocks may not even need to reach Earth's surface to cause cataclysmic damage. Our solar system appears to be a far more dangerous place than was previously believed…These standard assumptions - that remaining space rocks are few, and that encounters with planets were mainly confined to the past - are being upended.

The Kuiper Belt [is] a region of asteroids and comets that starts near the orbit of Neptune…At least 1,000 objects big enough to be seen from Earth have already been located there. These objects are 100 kilometers [62 miles] across or larger…space rocks this size are referred to as "planet killers" because their impact would likely end life on Earth. Investigation of the Kuiper Belt has just begun, but there appear to be substantially more asteroids in this region than in the asteroid belt [between Mars and Jupiter]…

Asteroids are hard to spot - they move rapidly, compared with the rest of the heavens, and even the nearby ones are fainter than other objects in space. In 1980, only 86 near-Earth asteroids and comets were known to exist…as of this writing, it is 5,388…Ten years ago, 244 near-Earth space rocks one kilometer [0.62 miles] across or more - the size that would cause global calamity - were known to exist; now 741 are. Of the recently discovered nearby space objects, NASA has classified 186 as "impact risks." And because most space-rock searches to date have been low-budget affairs, conducted with equipment designed to look deep into the heavens, not at nearby space, the actual number of impact risks is undoubtedly much higher. Extrapolating from recent discoveries, NASA estimates that there are perhaps 20,000 potentially hazardous asteroids and comets in the general vicinity of Earth.

Small asteroids may be more dangerous than we used to think - and may do considerable damage even if they don't reach Earth's surface. If most asteroids and comets explode before reaching the ground, then this is another reason to fear that the conventional thinking seriously underestimates the frequency of space-rock strikes - the small number of craters may be lulling us into complacency…A generation ago, the standard assumption was that a dangerous object would strike Earth perhaps once in a million years. By the mid-1990s, researchers began to say that the threat was greater: perhaps a strike every 300,000 years. William Ailor, an asteroid specialist at The Aerospace Corporation, thought the risk was…a one-in-10 chance per century of a dangerous space-object strike. Given the scientific findings, shouldn't space rocks be one of NASA's priorities? You'd think so, but Dallas Abbott says NASA has shown no interest in her group's work [finding and including ocean floor craters in probability calculations]: "The NASA people don't want to believe me. They won't even listen."

NASA supports some astronomy to search for near-Earth objects, but the agency's efforts have been piecemeal and underfunded, backed by less than a tenth of a percent of the NASA budget. And though altering the course of space objects approaching Earth appears technically feasible, NASA possesses no hardware specifically for this purpose, has nearly nothing in development, and has resisted calls to begin work on protection against space strikes. Instead, NASA is enthusiastically preparing to spend hundreds of billions of taxpayers' dollars on a manned Moon base that has little apparent justification. "What is in the best interest of the country is never even mentioned in current NASA planning," says [Apollo astronaut] Russell Schweickart, who is leading a campaign to raise awareness of the threat posed by space rocks. "Are we going to let a space strike kill millions of people before we get serious about this?" he asks.

In January [at] an internal NASA conference, held at agency headquarters, NASA's core goals were presented. Nothing was said about protecting Earth from space strikes - not even researching what sorts of spacecraft might be used in an approaching-rock emergency. After the presentation, NASA's administrator, Michael Griffin, came into the room. I asked him why there had been no discussion of space rocks. He said, "We don't make up our goals. Congress has not instructed us to provide Earth defense. I administer the policy set by Congress and the White House, and that policy calls for a focus on return to the Moon. We are on the right path. We need to go back to the Moon. We don't need a near-Earth-objects program."

Wouldn't shifting NASA's focus away from wasting money on the Moon and toward something of clear benefit for the entire world - identifying and deflecting dangerous space objects - be a surer route to enhancing national prestige? But NASA's institutional instinct is not to ask, "What can we do in space that makes sense?" Rather, it is to ask, "What can we do in space that requires lots of astronauts?" That finding and stopping space rocks would be an expensive mission with little role for the astronaut corps is, in all likelihood, the principal reason NASA doesn't want to talk about the asteroid threat.

NASA [is] all but ignoring the space-object threat…The B612 Foundation's goal is to get NASA officials, Congress, and ultimately the international community to take the space-rock threat seriously; it advocates testing a means of precise asteroid tracking…Current telescopes cannot track asteroids or comets accurately enough for researchers to be sure of their courses…The Pan-STARRS telescope complex will greatly improve astronomers' ability to find and track space rocks, and it may be joined by the Large Synoptic Survey Telescope [LSST], which would similarly scan the entire sky…[but] even these instruments will not be able to plot the courses of space rocks with absolute precision. NASA has said that an infrared telescope launched into an orbit near Venus could provide detailed information on the exact courses of space rocks. Such a telescope would look outward from the inner solar system toward Earth, detect the slight warmth of asteroids and comets against the cold background of the cosmos, and track their movements with precision. Congress would need to fund a near-Venus telescope, though, and NASA would need to build it - neither of which is happening.

Nukes are a brute-force solution, and because an international treaty bans nuclear warheads in space, any proposal to use them against an asteroid would require complex diplomatic agreements…When it comes to killer comets, you'll just have to lose sleep over the possibility of their approach; there are no proposals for what to do about them. Comets are easy to see when they are near the Sun and glowing, but are difficult to detect at other times…An unknown comet suddenly headed our way would be a nasty surprise. And because many comets change course when the Sun heats their sides and causes their frozen gases to expand, deflecting or destroying them poses technical problems to which there are no ready solutions. The logical first step, then, seems to be to determine how to prevent an asteroid from striking Earth and hope that some future advance, perhaps one building on the asteroid work, proves useful against comets.

Preparations to defend against a space object would take many years. First the necessary hardware must be built - quite possibly a range of space probes and rockets. An asteroid that appeared to pose a serious risk would require extensive study, and a transponder mission could take years to reach it. International debate and consensus would be needed…Suppose Asteroid X appeared to threaten Earth. A mission by, say, the United States to deflect or destroy it might fail, or even backfire, by nudging the rock toward a gravitational keyhole rather than away from it. Asteroid X then hits Costa Rica; is the U.S. to blame? In all likelihood, researchers will be unable to estimate where on Earth a space rock will hit. Effectively, then, everyone would be threatened, another reason nations would need to act cooperatively - and achieving international cooperation could be a greater impediment than designing the technology.

Whoever takes office will decide whether the nation commits to spending hundreds of billions of dollars on a motel on the Moon, or invests in space projects of tangible benefit…readying the world for protection against a space-object strike. Congress ought to look more sensibly at space priorities. Because it controls federal funding, Congress holds the trump cards…The House and Senate ought to demand that the space program have as its first priority returning benefits to taxpayers. It's hard to imagine how taxpayers could benefit from a Moon base. It's easy to imagine them benefiting from an effort to protect our world from the ultimate calamity.

NewScientist.com reports: The U.S. Air Force recently brought together scientists, military officers and emergency-response officials for the first time to assess the nation's ability to cope [with asteroid threat] should it come to pass. The exercise, which took place in December 2008, exposed the chilling dangers asteroids pose. Not only is there no plan for what to do when an asteroid hits, but our early-warning systems are woefully inadequate. "As a taxpayer, I would appreciate my Air Force taking a look at something that would be certainly as bad as nuclear terrorism in a city, and potentially a civilisation-ending event," says meeting organiser Peter Garreston

The latest space rock to put the frighteners on us was…first spotted it just 20 hours before impact - at a distance of 500,000 kilometres - and astronomers say we were lucky to get any warning at all…we are nearly blind to objects big enough to do serious harm. We have barely begun to track down the millions of skyscraper-sized asteroids zipping around Earth's neighbourhood, any one of which could unleash as much destructive power as a nuclear bomb on impact…Asteroid impacts are not as rare as you might think…The chance of a [1908 Tunguska-size] impact is about 1 in 500 each year. Put another way, that's a 10 per cent chance of an impact in the next 50 years.

"Fifty-meter asteroids scare me to death," says Timothy Spahr, director of the Minor Planet Center in Cambridge, Massachusetts. "I could easily see a 50-metre object hitting in three days causing absolute pandemonium. I'm picturing people panicking and driving the wrong way on the freeway, screaming 'Oh my god, it's going to kill us!'"…With so little warning there would be no hope of preventing an impact…a 50-metre asteroid would weigh hundreds of thousands of tonnes, requiring an enormous push to change its trajectory appreciably - so much so that detonating a nuke near it in space would not provide a sufficient impulse so late in the game to cause a miss. To deflect an asteroid sufficiently, force would need to be applied years in advance…Realistically, the nuclear option would not be on the table in the first place: the nuclear-tipped missiles sitting patiently in silos around the world are not designed to track and home in on an asteroid or even survive for more than a few minutes in space. Instead, we would simply have to brace ourselves for the impact.

To prevent panic and disorganised movement, it is crucial for authorities to develop an evacuation plan and communicate it to the public as soon as possible.

The 2008 U.S. Air Force exercise could barely scratch the surface of the incoming-asteroid problem. Not surprisingly, it discovered that should the nightmare come true, there is no plan for how to coordinate the activities of NASA, emergency planners, the US military and other parts of government. Further planning exercises are needed. Our chance of having any prior warning at all for an approaching 30-metre asteroid is no better than 25 to 35 per cent with existing sky surveillance, calculates astronomer Alan Harris of the Space Science Institute in Boulder, Colorado. The Sun washes out half of the sky with daylight, blinding us to 50 per cent of threatening objects. Even glare from the Moon can hide unwelcome incoming guests. What's more, two of the world's three leading asteroid surveys are based in Arizona…The region tends to cloud over between July and September…[and there's] a gap in the NASA-funded surveys, which are limited to watching the skies of the northern hemisphere…An asteroid flying out of nowhere and exploding over a sensitive region like the Middle East could be misinterpreted as a nuclear attack ..

Plans are afoot to construct the 8.4-metre Large Synoptic Survey Telescope in Chile by 2015, though the project is still raising funds…But even so, every ground-based lookout suffers from interference from the Sun and Moon. A dedicated space telescope would fix this problem, but such a mission could cost more than a billion dollars…"It does warrant some priority in the list of things that we ought to be worried about," warns Lindley Johnson at NASA headquarters, who oversees the agency's work on near-Earth objects. "From what we know today it could happen next week." Designing and building new spacecraft typically takes a few years. With current rocket technology, it would probably take several additional years to reach a threatening asteroid. And since the explosion would need to occur years ahead of the predicted impact in order to make the asteroid miss Earth, we'd need decades of lead time if we hoped to deflect Armageddon. A confounding factor is that nukes in space are forbidden by the Outer Space Treaty of 1967, signed by the US, Russia, and other nuclear powers.

COMMENTS POSTED TO THE ABOVE ARTICLE AT NewScientist.com:

No Atmosphere = No Shockwave

The idea that the solution to asteroid collisions is to "blast them to smithereens" comes from Hollywood movies. The reality is more complicated. Blasting an asteroid to smithereens is not as easy as one might think, and not necessarily productive. The effects of nuclear weapons in [space] vacuum are significantly different to the effects in atmosphere. Contrary to what one might see in Hollywood movies, asteroids would not disintegrate into harmless lights when a nuclear weapon detonates nearby…the major effect of the detonation will be surface ablation…by applying a few centimeters per second of velocity change [the rock] early enough, you can make the object miss the Earth [but] this requires several years of lead time, and requires accurately tracking the orbits of far more objects than we do at present. But by the time an object is three days away, there's nothing you can do to prevent impact. - Pistachio T Wildebeest

Nuking an asteroid is not a good idea for several reasons. A nuke would not explode in space like it does in the atmosphere. A nuclear bomb is so destructive on earth because of the effects it has on the local atmosphere: shockwaves are created due to heating and sudden large expansion of a small mass into a ball of plasma caused by fission/fusion. In space all you would have is heating from radiation, infrared gamma, etc.…and there would be no atmospheric shockwave. The mass of 2 tons of plasma spreading in all directions is going to have neglible effect on a 500,000 ton ball of spinning metal. This is why nukes are put inside asteroids in Hollywood films, with the idea of splitting them open. Detonating a nuke next to an asteroid will be of limited use…it would be relatively ineffective to detonate a nuke outside the body, unless done several years/billions of miles from the Earth, as the surface evaporation from an unfocused nuclear blast of a few tons of metal would have limited force to push the asteroid seriously off course.

Putting a nuke inside an asteroid is also not a good idea. Apart from the technical challenge to actually drill a meter-plus wide hole of up to 50/100 meters depth into a large spinning mass of unknown density at unimaginable distances from Earth, you have 2 scenarios: 1) loose rubble is blown apart by a massive nuke, creating a shotgun effect, the danger of capturing this shrapnel in low Earth orbit, making it is impossible to [launch anything] into space due to space debris trapped around the Earth…each object destroyed, like space ships or satellites, is itself turned into more space debris. That situation would take hundreds of years to solve, all we can do is wait for the debris density to decrease naturally. 2) Throwing current nuclear weapon technology at asteroids and comets is bad science. A suitable nuclear device for this situation, to blow AWAY a dangerous solar body, would have to be able to seriously melt glaciers, with a thickness of a mile or more, from the outside [which means] the energy of an erupting volcano. Our largest nukes can't even scratch huge lumps of ice. - mogg

Nukes are sitting on top of ICBMs, which are suborbital delivery platforms. You might be able to organise for some of them to go off near an object as it entered the atmosphere, but if you think you can lob an MIRV at something that's as far away as the Moon or further with a Polaris or an Atlas, look up the velocity needed for a balistic shot, the velocity needed for orbital insertion, and the escape velocity. THEN let's talk about throwing nukes around. - Mike Thompson

The nuke option is very messy, very uncertain. - Hobart

The deflection methods we know about seem futile with objects in this size range, unless we have years of early warning. Nuking such objects would also be futile. Applying a steady thrust orthogonal to its path e.g. with ion propulsion would change the orbit, but would be difficult to control, especially at the distances needed to deflect the object enough to miss Earth. And any errors could even aid the object and move it into a potentially more deadly trajectory. We clearly have a lot more to learn about such objects, and the research needs to be increased, not cut back. - Paul

The near-Earth orbit program is currently budgeted at $4.1 million per year for FY 2006 through FY 2012. Global military expenditures are over $1.460.000 million per year! we spend 4.1 to protect life on Earth and 1.460.000 to exterminate life on Earth! I call this STUPID. - Emo

Governments seem so eager to play God in so many things. It is unforgivable that they do not have a coherent plan for these scenarios. - Scott Quint

- NewScientist.com - Sept. 23, 2009

Space.com reports: "A small asteroid will buzz the Earth late Friday EDT, flying just inside the orbit of the Moon…The space rock, named 2009 TM8, was just discovered Thursday by the Catalina Sky Survey in Arizona. It will get within 216,000 miles (348,000 km) of Earth…'There're about 7 million of these objects in near-Earth space; we have discovered only a small fraction of them,' said Don Yeomans of the Jet Propulsion Laboratory."

COMMENTS POSTED TO THE ABOVE ARTICLE AT Space.com:

They discovered on Thursday that it would pass by on Friday, 24 hours notice for a potential 4kt event if the orbit was slightly off, makes me feel safer already. - CSStein

The space rock was just discovered Thursday? There is no early warning system, to be sure. - Toaster34

- Space.com - Oct. 16, 2009

Wired.com reports: Asteroid-deflection efforts will have to start years before a prospective impact and will have to be essentially international. "Whether or not the international community, within or outside the United Nations, can rise to the demands of such a challenge in advance of an impact," says [Apollo astronaut] Rusty Schweickart, "is problematic."

"Today's society is unable to raise a defense in time to stop the Rock…Hendrix presents a picture of disaster resulting from our inability to organize world resources in time to stop the rock from coming at us." - Rock Prophecy book, 1999

Nuclear weapons have been explicitly outlawed in space since the Partial Test Ban Treaty was negotiated in 1963. Sending a nuclear weapon into space to hit an asteroid would require modifying the treaty, which could have unforeseen negative repercussions…and difficult international negotiation. [Schweickar's organization] propose to bump or tow an asteroid "in a controlled manner" so that it misses Earth. The only problem is that such a process would take time and as the asteroid's trajectory changed, it would be "pointed" at different places along a horizontal plane on Earth called the "risk corridor." That's a major geopolitical problem, Schweickart said, because it requires temporarily increasing the risk to one population. Who gets to decide which way the asteroid is dragged away from an impact with Earth? The United Nations? The United States? Russia? Some independent body of astronomers and space agencies?

Earlier this year, the Association of Space Explorers presented a report to the U.N. Committee on the Peaceful Uses of Outer Space recommending that some international decision-making bodies be created to evaluate and respond to near-Earth object hazards. The U.N. committee could bring some options before the General Assembly by 2012, although Schweickart has some doubts that people are politically prepared to deal with the tough decisions that humanity could face to deflect an asteroid. "You're going to have to make that decision when the probability is less than one, 10 or 20 years ahead of time," he said. "That's not easy for anyone, let alone the United Nations."

COMMENTS POSTED TO THE ABOVE ARTICLE AT Wired.com:

If the rock is heading toward the USA, I'm voting that we talk about your treaty later and nuke the thing. - IraMeanwell

I see a big problem with any of these plans…it's all theoretical! Who knows if any plan we have will actually work? - careydw

We need to come up with a cheap, widely deployable drone ship that we could post at various points throughout the solar system, and activate when an object is near. That way we have a shotgun chance at destroying it rather than a single bullet chance. Funding for this would never survive the political process. - NotAfraidOfRobots

If an asteroid hits the Earth with size enough to take out a nation, it won't really matter where it hits, the fallout and other effects would doom the rest of the world. If we add to the test ban treaty something that says, "It's okay to use nuclear arms in space, as long as you're using them to deflect asteroids that threaten Earth," you end up with nations using that as an excuse to test their arms in space. It will become very difficult for the scientific community to convince hard headed diplomats to take TIMELY action. - robcull

Bureaucrats to save the Earth? We are so screwed! - Zombowski

The chances of us finding it before it hits us are infinitesimally small, we scan very little of the observable sky. Even if found, the speed of the moving object would require that it is found years before it's projected collision with Earth to allow for accurate calculations and preparedness to occur, so people could mount a counter offensive against the threat. A highly porous object can't be just blown out of the way of Earth's orbit, as it will cause to the object to fracture into multiple moving objects, or even absorb the majority of the blast, causing little effect at all. We have absolutely no way at this point in time to stop an object that's, lets hypothetically say, 900 kilometers in diameter and moving at 60,000 miles per second. Not gonna happen. - BrantonPlaster

AFP - Dec. 30, 2009

Is there documented proof of humans that moved a space object that large? If not, any science supporting the possibility is a theory, considered a "maybe" if it has not or cannot be proven by scientific method. Show me documentation that shows that humans have experimented with moving a space object of that size. I love the arrogance of the human race. Are we really that big-headed that we honestly think that if an asteroid were on a collision course with Earth that we would be ABLE TO STOP IT? People really are arrogant. An asteroid that big is probably, what? A few BILLION TONS. Yeah, dream on that we can do ANYTHING to stop an Earth-killer asteroid from hitting us. Dream big people. Dream big. - Unr3a1

- Wired.com - Dec. 16, 2009

Russian scientists will soon meet in secret to work on a plan for saving Earth from a possible catastrophic collision with a giant asteroid in 26 years, the head of Russia's space agency said on Wednesday. "We will soon hold a closed meeting of our collegium, the science-technical council to look at what can be done" to prevent the asteroid Apophis from slamming into the planet in 2036, Anatoly Perminov told Voice of Russia Radio, "better to spend a few hundred million dollars to create a system for preventing a collision."

.