The idea that time itself could cease to be in billions of years - and everything will grind to a halt - has been set out by Professor José Senovilla, Marc Mars and Raül Vera of the University of the Basque Country, Bilbao, and Univerisity of Salamanca, Spain.
These scientists propose this theory as an explanation for a known phenomenon: distant stars seem to be moving faster. Since images from distant stars come from further back in time these scientists suggest that in the past time ran more rapidly. So things moved more rapidly.
A decade ago, astronomers noticed that distant supernovae - exploding stars on the very fringes of the universe - seemed to be moving faster than those nearer to the centre, suggesting that they were accelerating as they shot through space.
They think their idea makes more sense than hidden dark matter that is at the center of an alternative explanation for how the distant stars appear in telescopes.
My guess is that we are not in the only universe. We need to find a way travel to other universes so we can escape each universe as time in it slows down or all the matter converts to diffuse energy or the universe otherwise gets used up.
Of course, first we need to development rejuvenation treatments that will reverse aging. Once once we accomplish that goal can we have the luxury of worrying about our slowing down or running down universe.
The US West might be facing long massive droughts and the megafire problem now plaguing Southern California might portend even worse problems to come.
Longer term, climate change across the West is leading to hotter days on average and longer fire seasons. Experts say this is likely to yield more megafires like the conflagrations that this week forced evacuations of at least 300,000 resident in California's southland and led President Bush to declare a disaster emergency in seven counties on Tuesday.
Hollywood producers ought to start thinking about a movie script where a megafire threatens to burn all of California. But make a movie better than that one where all an earthquake threatened to dump all of the West Coast into the ocean.
Megafires, also called "siege fires," are the increasingly frequent blazes that burn 500,000 acres or more – 10 times the size of the average forest fire of 20 years ago. One of the current wildfires is the sixth biggest in California ever, in terms of acreage burned, according to state figures and news reports.
Megafires seem like a technologically solvable problem. People living in the American West need to start thinking seriously what to do about these fires. Houses can be built with more flame resistant designs and materials. Zoning and forest management practices can reduce the risks as well. Larger amounts of equipment (e.g. airplanes, water trucks) for delivering large amounts of water and flame retardant chemicals can be stockpiled and methods can be worked out to mobilize the equipment more rapidly. Canyon areas could even have water towers and water pumps for delivering much larger quantities of water onto fires.
Malibu seems especially suitable for some large scale projects to extinguish fires. The Pacific Ocean is right there with plenty of water. What is needed is a way to very rapidly pump huge amounts of sea water up into canyons. What would such a capability cost?
These fires don't just create problems while they are burning. The 240,000 acre Zaca fire burned in the hills behind Santa Barbara for months this summer but was put out in early September. The same Santa Ana winds which have been spreading fires down around LA and San Diego have also been blowing up the ash from extinguished Zaca fire. On some recent days that ash has totally hid the mountains behind Santa Barbara from view. I had no idea that airborne ash from an extinguished fire could reach such thick concentrations and cause such limited visibility over such a wide area. The ash gets in one's eyes and makes the air pollution rating very bad.
The ratio of people evacuated to homes burned is instructive. While 1300 homes have burned so far the estimates for evacuees run from a half million to nearly 1 million.
SAN DIEGO — As a dozen fires raged along the coast of Southern California Tuesday for a third day, San Diego County took the brunt of the wind-whipped fury that forced the evacuation of more than 350,000 houses, encompassing nearly 950,000 people based on average household size, including 10,000 evacuees huddled in QualComm stadium.
The massive size of the evacuations argues for the development of much better methods for controlling fires. The economic disruption hundreds of thousands evacuated costs a lot of lost production. How best to minimize the impact of fires in the future? Anyone have some good ideas?
The New York Times reports on an international collaboration of scientists called the Holocene Impact Working Group which believes asteroids hit the Earth far more often than previously thought and 600 feet high chevrons 3 miles from the ocean in Madagascar are evidence for a massive asteroid 4800 years ago which a caused tsunami wave. (and the article is a good primer on how geologists look at soil samples for evidence of past events)
Scientists in the working group say the evidence for such impacts during the last 10,000 years, known as the Holocene epoch, is strong enough to overturn current estimates of how often the Earth suffers a violent impact on the order of a 10-megaton explosion. Instead of once in 500,000 to one million years, as astronomers now calculate, catastrophic impacts could happen every 1,000 years.
The researchers, who formed the working group after finding one another through an international conference, are based in the United States, Australia, Russia, France and Ireland. They are established experts in geology, geophysics, geomorphology, tsunamis, tree rings, soil science and archaeology, including the structural analysis of myth. Their efforts are just getting under way, but they will present some of their work at the American Geophysical Union meeting in December in San Francisco.
This year the group started using Google Earth, a free source of satellite images, to search around the globe for chevrons, which they interpret as evidence of past giant tsunamis. Scores of such sites have turned up in Australia, Africa, Europe and the United States, including the Hudson River Valley and Long Island.
First of all, isn't it great that Google Earth is speeding research into the asteroid threat? Is it possible for us non-experts to look at Google Earth pages and recognize Chevrons? Can someone collect a set of Google Earth URLs that display chevrons from around the world?
The chevrons these scientists are finding are all pointed at nearby large bodies of water. So all over the world there are signs of past massive waves which have slammed inland at various times in history. But scientists who study near earth asteroids are skeptical because they find too few asteroids to account for the number of chevrons claimed to be from mega-tsunamis due to ocean asteroid hits.
Asteroid detection and deflection research already struck me as woefully underfunded before I read this article. Now the possibility that major asteroids might strike the Earth far more frequently than previously believed makes the urgency of asteroid research even greater.
If someone spots an asteroid tomorrow that is going go hit the Earth 2 days later we'll all spend the following 2 days feeling really really stupid for not doing more to prevent an entirely avoidable threat to our existence. Why not avoid that outcome and find the orbit of every asteroid out there?
On Google Maps check out New Orleans. Note the "Satellite" and "Katrina" buttons which I think are before and after shots for the Hurricane. Check out a zoomed out shot of a larger area.
Anyone else have better sources of aerial views looking down for viewing the effect of the damage on coastlines and rivers?
Update: I think these are Superdome before and after shots. Note that the underlying stuff you are seeing is probably still the roof but without the white covering.
Some European environmentalists like to worry about genetically modified foods. A larger group of people like to worry about global warming. FuturePundit, far more focused on risks to his own life, is worried we don't have the means to produce large numbers of vaccine shots in response to a dangerous flu strain (like the Avian influenza that might currently be spreading in North Korea). Well, these are bush league catastrophe worries. You want to have a heftier and more manly worry? Time to sink your teeth into a massive recurring pattern of extinction that has been happening once every 62 million years for over 500 million years and which is currently overdue!
BERKELEY, CA – A detailed and extensive new analysis of the fossil records of marine animals over the past 542 million years has yielded a stunning surprise. Biodiversity appears to rise and fall in mysterious cycles of 62 million years for which science has no satisfactory explanation. The analysis, performed by researchers with the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California at Berkeley, has withstood thorough testing so that confidence in the results is above 99-percent.
Think about a massive die-off of most of the species on planet Earth that would make environmentalist fears of human-inflicted damage to the environment seem puny in comparison. We are talking about a die-off that would make a first class Hollywood disaster movie. Heck, it could even be made into a series of movies and civilization progressively collapses as our stars fight their way toward the few areas where humans are managing to hang on.
Muller and Rohde have entertained many hypotheses for what might have caused the die-off. But their theorizing is still at the stage of hunches. Either periodic passage of the solar system through molecular clouds or periodic massive volcanic eruptions could be behind the massive die-offs.
Muller and Rohde have been working on this study for nearly two years, and first discovered the 62 million year biodiversity cycle in November, 2003. They spent the next year trying to either knock it down or explain it. Despite examining 14 possible geophysical and astronomical causes of the cycles, no clear explanation emerged. Muller and Rohde each has his own favorite guess.
Muller suspects there is an astrophysical driving mechanism behind the 62 million year periodicity.
“Comets could be perturbed from the Oort cloud by the periodic passage of the solar system through molecular clouds, Galactic arms, or some other structure with strong gravitational influence,” Muller said. “But there is no evidence even suggesting that such a structure exists.”Rohde prefers a geophysical driver, possibly massive volcanic eruptions triggered by the rise of plumes to the earth’s surface. Plumes are upwellings of hot material from near the earth’s core that some scientists believe have the potential to reoccur on a periodic basis.
“My hunch, far from proven,” Rohde said, “is that every 62 million years the earth is releasing a burst of heat in the form of a plume formation event, and that when those plumes reach the surface they result in a major episode of flood volcanism. Such volcanism certainly has the potential to cause extinctions, but, right now there isn't enough geologic evidence to know whether flood basalts or plumes have been recurring at the right frequency.”
We also have a 140 million year cycle to worry about.
Muller and Rohde also found a second, less pronounced diversity cycle of 140 million years.
"The 140 million year cycle is also strong, but we see only four oscillations in our 542 million year record,” Muller said. “This means there is some chance that it could be accidental, rather than driven by some external mechanism."
If it is real, the 140 million year fossil diversity cycle could be tied to a reported 140 million year cycle in Ice Ages. Said Rohde, "It is also possible that this 140 million year fossil diversity cycle is driven by passage through the arms of the Milky Way galaxy".
John Alroy is skeptical of the Muller and Rohde analysis.
John Alroy coordinates the Paleobiology Database at the National Center for Ecological Analysis and Synthesis in Santa Barbara, California. He is skeptical about the accuracy of Rohde and Muller's statistical analysis. He does, however, applaud their exhaustive search for the cycle's cause.
The bad news is if Rohde and Muller are correct then we are overdue for the next big die-off.
Their research has shown that every 62 million years - plus or minus 3m years - creatures are wiped from the planet's surface in massive numbers.
And given that the last great extinction occurred 65m years ago, when dinosaurs and thousands of other creatures abruptly disappeared, the study suggests humanity faces a fairly pressing danger. Even worse, scientists have no idea about its source.
I am hoping that Muller's explanation turns out to be correct. Why? Muller's astrophysical mechanism would be easier to defend against. Suppose this mechanism could be proven to be at work in the waves of extinctions. We could develop a number of methods for deflecting asteroids and comets. The key to such a defense system would be early detection of incoming objects. We would need many great space telescopes constantly scanning the sky looking for an approaching cloud of rocks headed our way. Then space lasers or particle beams could deflect incoming objects or automated nuclear-powered spaceships could be sent out to intercept and nudge them away from a collision with Earth.
Rohde's massive volcanic eruption mechanism would be a lot more difficult to defend against. It is unlikely we could stop a massive eruption. If we knew where the eruption was coming we could move away from it. But we'd be left with the need to find ways to clean up the polluted atmosphere more rapidly in order to prevent a long period of freezing darkness. Perhaps if we knew a massive eruption was coming in advance we could build tens of thousands of nuclear reactors and use their power to run massive air filtration systems on the atmosphere. One year's output of the US economy would pay for the construction of 10,000 $1 billion dollar 1 Gigawatt nuclear reactors. How much air filtration could be done with 10,000 Gigawatts of electric power?
The human race is still at a stage of development where it is vulnerable to natural disasters. We are much more vulnerable than we need to be. Even with our current level of technology we could be doing a lot of fairly cheap stuff to reduce our risks from a few natural threats. For example, a price that is in the range of hundreds of millions of dollars per year we could construct an impressive set of satellite and ground-based stations for detecting 99.9+% of asteroids long before they could threaten Earth. A similar sized expenditure for vaccine technology development would lead to vaccine production techniques that would greatly lower the risks of a big human die-off from natural strains of influenza and probably from some other naturally occurring pathogens as well.
Looking about 50 or 100 years into the future I do not expect either asteroids or naturally occurring pathogens to still have the potential to kill millions of people. Our technologies will be so advanced and our accumulated wealth so great that the cost of defending against both these threats will be so low that the defenses against these threats will be created even without a strong political consensus in support of building the needed defenses. At some point in the 21st century our greater threat of extinction will come from our own technologies in the hands of the most malicious and reckless members of humanity.
It is possible for a massive tsunami to hit the North American West Coast. But the United States has a tsunami warning system that includes deep ocean buoys for tsunami detection and government labs that can send out messages to trigger coastal evacuations.
As the death tolls rises into the tens of thousands in Asia and the number of homeless above one million, OSU experts say many of the same forces that caused this disaster are at work elsewhere on the Pacific Ocean "ring of fire," one of the most active tectonic and volcanic regions of the world.
This clearly includes the West Coast of the U.S. and particularly the Pacific Northwest, which sits near the Cascadia Subduction Zone. Experts believe, in fact, that it was a subduction zone earthquake of magnitude 9 – almost identical in power to the sub-sea earthquake that struck Asia on Monday – that caused a massive tsunami around the year 1700 that caused damage as far away as Japan. And the great Alaska earthquake in 1964 caused waves that swept down the Northwest coast, causing deaths in Oregon and northern California.
...
Robert Yeats, professor emeritus of geosciences at OSU, agrees that the reason for the great loss of life in Sri Lanka, India, and other Asian countries was the lack of a tsunami warning system.
"That much loss of life wouldn't happen here for either a local or distant tsunami because of warning systems operated by the National Oceanic and Atmospheric Administration, with laboratories in Newport and Seattle," Yeats said. "NOAA would record the earthquake on seismographs and issue bulletins about the progress of a tsunami. Deep-ocean buoys off the Aleutian Islands and Cascadia would also record the passage of tsunami waves in the open ocean."
For a tsunami caused by a Cascadia earthquake, people on the coast would have about 15 minutes to get to high ground, Yeats said. Emergency managers of coastal counties have told residents about planning escape routes from a tsunami, and schools in Seaside, Ore. have had tsunami evacuation drills. Some coastal communities also give warnings through a siren for those vacationers who aren't keeping up with the news. Visitors to the coast should look for the blue and white tsunami warning signs on Highway 101 and some beach areas.
Enormously better methods for detecting earthquakes (assuming that it will some day be possible to predict earthquakes within a narrow range of time - a big if) could potentially be more valuable than tsunami warning systems. After all, if a future earthquake that will cause a tsunami could be predicted in advance then the tsunami could be predicted in advance. Then the warning to move to high ground could be announced days, weeks, months, or perhaps even years in advance. Most deaths from tsunamis would then likely come as a result of thrill-seekers doing all sorts of risky things to experience a tsunami. Surfers would try to ride massive waves and voyeurs would try to ride out a tsunami in a tall building or tall tree. Tsunamis would produce less tragedy and more entertainment to be watched via countless numbers of cameras located at every place the waves would wipe out.
Earthquakes and tsunamis are not the only natural disasters in need of better forecasting. Volcano eruption prediction would be of some value. This is especially the case with the most extreme eruptions. If something like the Krakatoa eruption happened today food production would be disrupted. The knowledge that the whole world would experience a temporary cooling for a few years would be used to grow and stockpile more food in advance. Also, volcanic disruptions can kill large numbers of people the immediate vicnity. Plus, island volcanic disruptions can cause tsunamis. So volcanic eruption forecasting is a form of tsunami forecasting.
We also need an asteroid collision detection system. This is doable. It just requires the money to be spent to build more ground and satellite observatories to find all the asteroids. Also, larger asteroids can cause tsunamis. So asteroid detection is another form of tsunami forecasting.
I do not know enough geology to say how much money would have to be spent over how long a period of time to do research to develop useful earthquake or volcanic eruption forecasting capabilities. So I have no advice to offer on geological science policy. However, I think it is a lot easier to argue that not enough is being done to detect large asteroids that are on collision courses with Earth. We have the technology needed to discover asteroids at a much faster rate. So why not delay space exploration initiatives such as the return to the Moon and the trip to Mars and spend that money on asteroid detection satellites and ground observatories? Asteroid study is a valuable way to develop more understanding of the development of solar systems. So the money spent would yield scientific insights and also possibly some day save hundreds of millions or even billions of lives.
Science writer James Oberg reviews the cases where humans have inadvertently caused earthquakes (yes, ways to trigger earthquakes have been discovered accidentally!) and examines the question of whether the damage from large earthquakes could be avoided by causing larger numbers of smaller earthquakes as a way to release tension in faults.
This theory "comes up every few years [but] ... is unfortunately fatally flawed in several ways," according to William Ellsworth, chief scientist of the U.S. Geological Survey's earthquake hazard team.
"First," he said in an e-mail, "it takes 1,000 earthquakes of [magnitude] 6 to release the tectonic forces that go into a [magnitude] 8.” But since those smaller quakes are still serious, it would be better to restrict the force of induced quakes to a magnitude 4 -- which would mean inducing a million smaller earthquakes in order to avoid suffering one giant one.
“Multiply that number by any reasonable estimate of what it would cost to induce one of them, and you are looking at costs far in excess of the expected losses” of the big quake, Ellsworth said.
An additional problem with trying to initiate a small earthquake is that it might trigger an even larger quake.
Even if we accept Ellsworth's arguments there may still be some benefit (leaving aside the military angle) to be had from the ability to trigger earthquakes. How? Trigger the really big earthquakes as a way to make the timing of the most dangerous earthquakes more predictable.
Think about earthquakes from the standpoint of both human lives lost and economic disruption. If earthquake prediction methods could advance to the point where, say, an 8+ Richter scale earthquake could be known to be coming to Los Angeles in 5 years there would be considerable value in being able to make that earthquake happen on a particular weekend. People could stay out of the weakest buildings, away from the bridges most likely to collapse, and otherwise away from anything that might kill them. Also equipment and goods could be protected from construction. Supermarkets alone could save a great deal of money just by taking glass containers off of shelves and putting cardboard around the bottles before a scheduled quake.
Rescue and repair workers could be on duty with vacations cancelled and extra workers brought in from other areas. Workers could be geared up with lots of extra equipment ordered in advance to fix electric power lines and other key structures that would fail in an earthquake. Freeways could be empty. No dangerous chemical rail cargoes would be passing through populated areas when a big quake hit. No jumbo jet would set down on a pitching tarmac and suffer a landing gear collapse. Weak water reservoirs could have their water levels lowered in advance. People could have extra bottled water and flashlights with fresh batteries and sleep outside in tents or cars. Tourists could stay away. Though perhaps thrill-seekers would show up to experience a quake that tourism would surge.
The ability to schedule earthquakes would allow them to be scheduled for the most convenient time of year. My guess is that the ideal time for an earthquake would be in the early summer (say mid June in the Northern Hemisphere) before temperatures get too hot. Then the days would be long and electricity (which may be knocked out in many areas) would be less needed for lighting and it would be easier to spend extended periods of time outdoors. In Southern California mid June would also be well away from the rainy season. So extra time spent outside would be easier to manage. In many different ways civilization could be braced for a really big quake scheduled to occur at some point over a fairly short range of time.
To make the scheduled triggering of large quakes a net benefit requires the ability to narrow the range of time expectations for the next earthquake down to a period of time close enough in the future that people would be willing to accept the inevitability of the quake. There is no point in inflicting an earthquake on ourselves now if the quake otherwise wasn't going to happen in 20 years. 20 years from now many buildings that would be wrecked by an earthquake today will either be reinforced or torn down. We will have better roads, better emergency response capabilities, and the like. Costs delayed will be costs avoided altogether in many cases.
In order to make earthquake triggering worthwhile another crucial capability needed would be the ability to trigger a quake to occur over a fairly short period of time. No one wants to be told that some time in the next 6 months an 8.0 quake is coming. Disrupting our lives for 6 months would be far too costly.
Note that precise prediction of the time of natural earthquakes would provide the same benefits as precise prediction of the time of human-triggered earthquakes but without the political and legal problems that come from human-triggered earthquakes. I have no idea whether geological scientists will ever achieve the ability to predict fairly exact times of natural earthquakes or of human-triggered earthquakes. My guess is that any such precision of prediction or of control lies decades into the future.
Bill Napier, Chandra Wickramasinghe, and his daughter, Cardiff University student Janaki Wickramasinghe have proposed that there may be hundreds of comets in Sun's orbit that are so dark that optical methods will fail to detect them before they collide with Earth.
Napier worked with Chandra Wickramasinghe, an astronomer at Cardiff University in Wales, to explain the comets' invisibility. Wickramasinghe has suggested that Sedna, the most distant body identified in our Solar System, could have an orbiting twin that is dark, fluffy and made of tarry carbon compounds (see "Sedna 'has invisible moon'").
As Sedna may be a member of the Oort cloud, Napier thinks that other members of the cloud could be equally dark. Once ejected, the tarry comets would simply suck up visible light, he says, remaining cloaked in darkness. "Photons go in, but they don't come out."
Infrared telescopes may be able to detect dark comets.
Because dark matter emits little light it will be invisible to optical telescopes, but it might emit infrared radiation and be able to be picked up by infra- red telescopes.
As yet no such object has definitely been found in the solar system. But Prof Wickramasinghe believes that if there is one, there may well be hundreds, lurking beyond the outer planets of Neptune and Pluto.
Such comets may require defenses that can deflect them within fairly short distances from Earth.
Here we demonstrate that the surfaces of inactive comets, if composed of loose, fluffy organic material like cometary meteoroids, develop reflectivities that are vanishingly small in visible light. The near-Earth objects may therefore be dominated by a population of fast, multi-kilometre bodies too dark to be seen with current near-Earth object surveys. Deflection strategies that assume decades or centuries of warning before impact are inapplicable to this hazard.
If it was my decision to make I'd divert NASA money from either manned programs or space probe programs toward the detection of objects in the Sun's orbit that are dangerous enough to kill a lot of humans and toward the development of methods for diverting such objects away from collision courses with Earth. What would be going through your mind if you just heard on the radio a report that we were all going to die tomorrow due to a massive asteroid or comet just discovered to be on a collision course for Earth? I'd be thinking that we were total fools and idiots for failing to develop defenses against such a threat.
Susanne Lehner, Associate Professor in the Division of Applied Marine Physics at the University of Miami and Wolfgang Rosenthal of the GKSS Forschungszentrum GmbH research centre, in Geesthacht Germany used synthetic aperture radar data of the oceans collected by two European Space Agency satellites to find that huge 25+ meter high waves are far more common than previously thought.
Once dismissed as a nautical myth, freakish ocean waves that rise as tall as ten-storey apartment blocks have been accepted as a leading cause of large ship sinkings. Results from ESA's ERS satellites helped establish the widespread existence of these 'rogue' waves and are now being used to study their origins.
Severe weather has sunk more than 200 supertankers and container ships exceeding 200 metres in length during the last two decades. Rogue waves are believed to be the major cause in many such cases.
Mariners who survived similar encounters have had remarkable stories to tell. In February 1995 the cruiser liner Queen Elizabeth II met a 29-metre high rogue wave during a hurricane in the North Atlantic that Captain Ronald Warwick described as "a great wall of water… it looked as if we were going into the White Cliffs of Dover."
In a three period looking at a small fraction of the ocean surface these scientists found 10 waves that were at least 25 meters (over 82 feet) high. So these waves are like 7 story buildings or even higher.
Previously many scientists thought waves of such heights were extremely rare.
Objective radar evidence from this and other platforms – radar data from the North Sea's Goma oilfield recorded 466 rogue wave encounters in 12 years - helped convert previously sceptical scientists, whose statistics showed such large deviations from the surrounding sea state should occur only once every 10000 years.
The fact that rogue waves actually take place relatively frequently had major safety and economic implications, since current ships and offshore platforms are built to withstand maximum wave heights of only 15 metres.
This brings up an interesting question: Is the risk of dying in a trans-Atlantic or trans-Pacific crossing greater on a cruise liner or in a jumbo jet? I had assumed up until now that the risk was greater on an airplane. Now I'm not so sure. Anyone know if there are reliable numbers that can be used for calculating risks for ocean cruise ship crossings?
Aircraft and ships will become safer with time. One obvious strategy to adopt with ships is to develop technologies for spotting waves so that a ship's course can be altered to avoid them. Also, ships can be designed to be able to survive encounters with 30 or even 40 or 50 meter waves. But right now what is the safest way to travel?
Once it becomes possible to reverse aging and keep one's body in a permanently youthful state many people are going to become far more interested in reducing risks of accidental death. A risk that may seem low for an 80 year lifespan will seem much larger for an 800 or 8000 year lifespan. So the relative risks of driving, flying, and travelling on ships or trains is going to become a topic of much wider spread interest. Since the purpose of this web log is to think about issues that will be of increasing importance in the future it is not too early to start thinking about what is the safest way to cross oceans.
The European Space Agency has approved a mission proposal to collide a space probe with an asteroid in order to study techniques to deflect any large asteroid found to be on a collision course with Earth.
On 9 July 2004, the Near-Earth Object Mission Advisory Panel recommended that ESA place a high priority on developing a mission to actually move an asteroid. The conclusion was based on the panel’s consideration of six near-Earth object mission studies submitted to the Agency in February 2003.
Of the six studies, three were space-based observatories for detecting NEOs and three were rendezvous missions. All addressed the growing realisation of the threat posed by Near-Earth Objects (NEOs) and proposed ways of detecting NEOs or discovering more about them from a close distance.
A panel of six experts, known as the Near-Earth Object Mission Advisory Panel (NEOMAP) assessed the proposals. Alan Harris, German Aerospace Centre (DLR), Berlin, and Chairman of NEOMAP, says, “The task has been very difficult because the goalposts have changed. When the studies were commissioned, the discovery business was in no way as advanced as it is now. Today, a number of organisations are building large telescopes on Earth that promise to find a very large percentage of the NEO population at even smaller sizes than visible today.”
As a result, the panel decided that ESA should leave detection to ground-based telescopes for the time being, until the share of the remaining population not visible from the ground becomes better known. The need for a space-based observatory will then be re-assessed. The panel placed its highest priority on rendezvous missions, and in particular, the Don Quijote mission concept. “If you think about the chain of events between detecting a hazardous object and doing something about it, there is one area in which we have no experience at all and that is in directly interacting with an asteroid, trying to alter its orbit,” explains Harris.
The Don Quijote mission concept will do this by using two spacecraft, Sancho and Hidalgo. Both are launched at the same time but Sancho takes a faster route. When it arrives at the target asteroid it will begin a seven-month campaign of observation and physical characterisation during which it will land penetrators and seismometers on the asteroid’s surface to understand its internal structure.
Sancho will then watch as Hidalgo arrives and smashes into the asteroid at very high speed. This will provide information about the behaviour of the internal structure of the asteroid during an impact event as well as excavating some of the interior for Sancho to observe. After the impact, Sancho and telescopes from Earth will monitor the asteroid to see how its orbit and rotation have been affected.
The FuturePundit reaction? Finally a space agency is trying to do something in space that may yield a huge benefit to the human race. We could all die from an asteroid impact and yet little is done to develop defenses against this potential threat. Meanwhile billions are spent every year on the Space Shuttle and International Space Station with little return in scientific knowledge, technological advance, or improved safety for humans down here on Earth. An asteroid detection and deflection system capable of preventing all major asteroid threats to human life offers a far greater potential benefit for humanity than the vast bulk of the programs funded by government space agencies.
A small change in an asteroid's path could prevent a collision with Earth.
"It is just to test a technique: can we change their orbits by running a kinetic energy impactor?" said Matt Genge, an asteroid expert at Imperial College, London.
"Can we change its orbit by less than a centimetre per second? If we ever find an asteroid that is on collision course with Earth, at some point in the future, whether it is 10 orbits away, or 20 orbits away, just giving it a small nudge will make it miss the Earth."
In the proposed mission one space probe would watch while another probe slammed into an asteroid.
Sancho would arrive first and orbit the asteroid for several months. It would deploy some penetrating probes to form a seismic network on the asteroid to examine its structure before and after its sister craft's smashing arrival.
Hidalgo would crash into the asteroid at about 22,370 mph (10 kilometers per second).
NASA's Deep Impact mission to Comet Tempel 1 to slam into it on July 4, 2005 (creating fireworks that will be visible from Earth btw) bears some similarity to the ESA mission But while the Deep Impact mission will slam into Tempel 1 at a very simlar speed it does not appear aimed at gathering information about how to do asteroid deflection.
And how. The 770-pound (350-kilogram) probe will hit the comet at 22,300 miles (35, 885 kilometers) per hour and penetrate 16 to 32 feet (5 to 10 meters). Much, but not all of the probe will be vaporized.
Still, it seems likely that the Deep Impact mission will yield information useful for doing asteroid deflection.
For more on the subject of asteroid defenses see my previous post We Should Develop Defenses Against Large Asteroids.
Civilization could be disrupted by a collapse and reversal of Earth's magnetic field.
The collapse of the Earth's magnetic field, which both guards the planet and guides many of its creatures, appears to have started in earnest about 150 years ago. The field's strength has waned 10 to 15 percent, and the deterioration has accelerated of late, increasing debate over whether it portends a reversal of the lines of magnetic force that normally envelop the Earth.
During a reversal, the main field weakens, almost vanishes, then reappears with opposite polarity. Afterward, compass needles that normally point north would point south, and during the thousands of years of transition, much in the heavens and Earth would go askew.
A reversal could knock out power grids, hurt astronauts and satellites, widen atmospheric ozone holes, send polar auroras flashing to the equator and confuse birds, fish and migratory animals that rely on the steadiness of the magnetic field as a navigation aid. But experts said the repercussions would fall short of catastrophic, despite a few proclamations of doom and sketchy evidence of past links between field reversals and species extinctions.
Note that with sufficient planning a lot of the electrical effects could be ameliorated by better shielding and back-ups. Even satellites could be built to be better shielded. But maintaining a human presence in low Earth orbit would become a much riskier proposition.
Suppose the flip comes to pass. Should we respond by creating new maps that show the Southern Hemisphere on top?
Consider just one practical problem: If we continue to call the "North" the "North" then all compasses will be wrong. But if we make new compasses then they will have to be labelled as "Post-Collapse" compasses or else someone could use a compass, not know it was built before or after the collapse, and go off in the wrong direction. Likely the period of collapsed magnetic field would last so long before the field popped up firmly again that the use of compasses will have long been abandoned before their labelling becomes an issue.
Animals that have evolved to navigate by the magnetic field might be driven extinct.
When baby loggerhead turtles embark on an 8,000-mile trek around the Atlantic, they use invisible magnetic clues to check their bearings. So do salmon and whales, honeybees and homing pigeons, frogs and Zambian mole rats, scientists have found.
But within a hundred years we may well know all the species that have genetic adaptations to magnetic fields. We could use future advances in biotechnology to easily do genetic engineering to the most threatened of these species to adapt them to the change in magnetic fields. Therefore mass extinctions may be avoidable unless the collapse of the magnetic field causes holes in the ozone layer that cause extinctions via increases in UV radiation. Though even in that scenario we could save some of the species either by genetically engineering them to be more resistant to high UV or by doing climate engineering to create UV shields.
The flip of the magnetic poles may not happen for hundreds of thousands of years. But there may already be people alive today who will live to see the magnetic field collapse. Anyone who is still alive when Engineered Negligible Senescence (rejuvenation therapies that will make us young again) is achieved could conceivably live long enough to witness the magnetic field collapse. There may well already be people alive today who will live long enough to be around when rejuvenation becomes commonplace. Therefore some readers of this post may live through the future collapse of Earth's magnetic field.
The European Space Agency is going to launch a "Swing" cluster of 3 satellites in 2009 to collect enough data to perhaps allow magnetic field forecasting in a fashion analogous to weather and climate forecasting.
The objective of the Swarm mission is to provide the best ever survey of the geomagnetic field and its temporal evolution, in order to gain new insights into the Earth system by improving our understanding of the Earth’s interior and climate. The mission is scheduled for launch in 2009. After release from a single launcher, a side-by-side flying lower pair of satellites at an initial altitude of 450 km and a single higher satellite at 530 km will form the Swarm constellation.
High-precision and high-resolution measurements of the strength, direction and variation of the magnetic field, complemented by precise navigation, accelerometer and electric field measurements, will provide the necessary observations that are required to separate and model various sources of the geomagnetic field. This results in a unique “view” inside the Earth from space to study the composition and processes in the interior.
My guess is that we will be so technologically advanced by the time a magnetic field collapse becomes severe that we will be able to easily compensate for its effects. Climate engineering, UV shields over human habitats, genetic engineering of other species, and heavy shielding of electronics will be among the methods we use to protect human civilization and other species.
My recent few days absence here was due to attendance at a recent Liberty Fund conference on liberty, biological determinism and Steven Pinker's The Blank Slate: The Modern Denial of Human Nature. The conference was also attended by bloggers Alex Tabarrok and Tyler Cowen of Marginal Revolution, the mentally nimble and facially expressive (really, his speedily changing mental state is visible for all to see) Daniel Drezner (see Dan's own description of the conference's highlights), the towering intellectual figure Megan McArdle and heck-of-a-nice-guy art dealer and historian David Nishimura.
One very gratifying moment at the Liberty Fund conference came when Ph.D. academic economists Alex and Tyler both emphatically agreed with me that spending on the search for asteroids that might strike the Earth is a woefully underfunded public good. Well, that leads to the topic for this post. One big asteroid hit could ruin your whole day and even end your life along with the lives of hundreds of millions or billions of others. I don't want to wake up some day and hear a news report that we all have about 3 days to live because of a just-discovered asteroid that is about to kill us all that can not be stopped because we didn't prepare in advance.
Former NASA astronaut Russell L. "Rusty" Schweickart is currently Chairman of the B612 Foundation which is dedicated to the development of anti-asteroid defenses to protect planet Earth from Near Earth Asteroids (NEAs). The U.S. Senate Subcommittee on Science, Technology, and Space held hearings on April 7, 2004 about Near Earth Objects (NEO) which included discussion of what should be done about asteroids that may strike planet Earth. Schweickart recently testified before those hearings presenting arguments on the feasibility and desirability of developing a system for diverting any large asteroid found to be on a collision course with Earth.
It became immediately clear to us that the combination of advanced propulsion technologies and small space qualified nuclear reactors, both operating in prototype form already, would be powerful enough, with reasonable future development, to deflect most threatening asteroids away from a collision with the Earth, given a decade or more of advance warning.
Nevertheless we saw two immediate problems.
First we lack the specific knowledge of the characteristics of NEAs necessary to design anything approaching a reliable operational system. We could readily show that the technology would exist within a few years to get to and land on an asteroid. We also determined that after arriving at the asteroid we would have enough propulsive energy available to successfully deflect the asteroid from an Earth impact a decade or so later. What was missing however was knowledge about the structure and characteristics of asteroids detailed enough to enable successful and secure attachment to it.
Second we recognized that before we would be able to gather such detailed information about NEAs there would likely be many public announcements about near misses and possible future impacts with asteroids which would alarm the general public and generate a growing demand for action. We felt strongly that there needed to be some legitimate answer to the inevitable question which will be put to public officials and decision makers, "and what are you doing about this?"
These two considerations led us to the conclusion that the most responsible course of action would be to mount a demonstration mission to a NEA (one of our choosing) which would accomplish two essential tasks; 1) gather critical information on the nature of asteroid structure and surface characteristics, and 2) while there, push on the asteroid enough to slightly change its orbit thereby clearly demonstrating to the public that humanity now has the technology to protect the Earth from this hazard in the future.
We furthermore determined that this demonstration mission could be done with currently emerging capabilities within 10-12 years.
We therefore adopted the goal of "altering the orbit of an asteroid, in a controlled manner, by 2015".
Astronaut Edward Lu, President of the B612 Foundation also testified at the Senate hearings arguing for
Recent developments have now given us the potential to defend the Earth against these natural disasters. To develop this capability we have proposed a spacecraft mission to significantly alter the orbit of an asteroid in a controlled manner by 2015.
Why move an asteroid? There is a 10 percent chance that during our lifetimes there will be a 60 meter asteroid that impacts Earth with energy 10 megatons (roughly equivalent to 700 simultaneous Hiroshima sized bombs). There is even a very remote one in 50,000 chance that you and I and everyone we know, along with most of humanity and human civilization, will perish together with the impact of a much larger kilometer or more sized asteroid. We now have the potential to change these odds.
There are many unknowns surrounding how to go about deflecting an asteroid, but the surest way to learn about both asteroids themselves as well as the mechanics of moving them is to actually try a demonstration mission. The first attempt to deflect an asteroid should not be when it counts for real, because there are no doubt many surprises in store as we learn how to manipulate asteroids.
Why by 2015? The time to test, learn, and experiment is now. A number of recent developments in space nuclear power and high efficiency propulsion have made this goal feasible. The goal of 2015 is challenging, but doable, and will serve to focus the development efforts.
How big of an asteroid are we proposing to move? The demonstration asteroid should be large enough to represent a real risk, and the technology used should be scaleable in the future to larger asteroids. We are suggesting picking an asteroid of about 200 meters. A 200 meter asteroid is capable of penetrating the atmosphere and striking the ground with an energy of 600 megatons. Should it land in the ocean (as is likely), it will create an enormous tsunami that could destroy coastal cities. Asteroids of about 150 meters and larger are thought to be comprised of loose conglomerations of pieces, or rubble piles, while smaller asteroids are often single large rocks. The techniques we test on a 200 meter asteroid should therefore also be applicable to larger asteroids.
Lu argues that the nuclear propulsion system proposed for the Jupiter Icy Moons Orbiter spacecraft should be used to move an asteroid.
How can this be accomplished? This mission is well beyond the capability of conventional chemically powered spacecraft. We are proposing a nuclear powered spacecraft using high efficiency propulsion (ion or plasma engines). Such propulsion packages are currently already under development at NASA as part of the Prometheus Project. In fact, the power and thrust requirements are very similar to the Jupiter Icy Moons Orbiter spacecraft, currently planned for launch around 2012. The B612 spacecraft would fly to, rendezvous with, and attach to a suitably chosen target asteroid (there are many candidate asteroids which are known to be nowhere near a collision course with Earth). By continuously thrusting, the spacecraft would slowly alter the velocity of the asteroid by a fraction of a cm/sec – enough to be clearly measurable from Earth.
I have previously argued that the development of nuclear ion propulsion for the JIMO mission is an excellent idea. Well, development of a space nuclear propulsion system for any number of missions is a great idea because it then allows the propulsion system to be used on something that may some day save millions or perhaps even billions of lives. The development of a space nuclear propulsion system ought to be greatly accelerated so that we have a method to protect us against asteroids as soon as possible.
Encouragingly the Bush Administration has allocated $3 billion over the next 5 years for Project Prometheus. NASA has more on Prometheus.
Aside from still moving too slowly to develop technologies to use against an asteroid that is on a collision course there is still one big problem with NASA's current strategy: the amount of money going into finding asteroids on a collision course with Earth is still chump change.
NASA spends a modest $3.5 million per year as part of the Spaceguard Survey search for large asteroids, the sort that could cause global damage, including a global "winter" that might last years and could kill off some species and possibly threaten civilization.
The current mission of the NASA Near-Earth Object Program is focused on finding only the bigger asteroids and not even all of them.
NASA’s Near-Earth Object Program Office will focus on the goal of locating at least 90 percent of the estimated 2,000 asteroids and comets that approach the Earth and are larger than about 2/3-mile (about 1 kilometer) in diameter, by the end of the next decade.
“These are objects that are difficult to detect because of their relatively small size, but are large enough to cause global effects if one hit the Earth,” said Dr. Donald K. Yeomans of JPL, who will head the new program office. “Finding a majority of this population will require the efforts of researchers at several NASA centers, at universities and at observatories across the country, and will require the participation by the international astronomy community as well.”
A panel of experts working at NASA's request has recommended a bold new search for potentially dangerous asteroids, including smaller objects that could cause regional damage in an Earth impact.
The price tag: At least $236 million.
The United States is spending hundreds of billions in Iraq for unclear benefit. The US government spends billions on many other undertakings of questionable benefit. In the space program both the Space Shuttle and the International Space Station come to mind as programs with dubious benefits and huge price tags. By contrast, we know that somewhere out there multiple asteroids are on collision paths with planet Earth and some are large enough to kill millions or billions of lives. Efforts to discover them and plot their orbits will both help to protect human lives and further the advance of space science. Efforts to develop technologies to deflect asteroids will both protect human lives and increase our capabilities to do things in space for other purposes. The effort to discover and plot the future trajectories of all asteroids ought to be increased by a couple of orders of magnitude and considerable funding should be allocated to the development of spacecraft capable of deflecting asteroid paths.
Update: Tyler Cowen draws my attention to a previous report he linked to from the Volokh Conspiracy about an effort to provide monetary incentives for private individuals and groups to discover asteroids.
"Amateur astronomers could receive awards of $3,000 for discovering and tracking near-Earth asteroids under legislation approved by the House of Representatives on Wednesday.
"Given the vast number of asteroids and comets that inhabits Earth's neighborhood, greater efforts for tracking and monitoring these objects are critical," said Rep. Dana Rohrabacher, sponsor of the legislation that passed 404-1.
Rohrabacher's legislation is H.R. 912, the Charles "Pete" Conrad Astronomy Awards Act.
H.R. 912, the Charles "Pete" Conrad Astronomy Awards Act, named for the third man to walk on the moon, establishes awards to encourage amateur astronomers to discover and track near-earth asteroids. The bill directs the NASA Administrator to make awards, of $3,000 each, based on the recommendations of the Smithsonian Minor Planet Center. Earth has experienced several near misses with asteroids that would have proven catastrophic, and the scientific community relies heavily on amateur astronomers to discover and track these objects.
There is a US Senate equivalent of that bill as S. 1855 for the 108th Congress. However, it is sitting in the Senate Committee on Commerce, Science, and Transportation. This bill deserves more attention.
Tyler also links to a Gregg Easterbrook Easterblogg post on how the threat from asteroids is, statistically speaking, roughly the same as that posed by commercial airliner risks.
Should humanity simply assume its luck will hold? Many don't think so. As Nathan Myhrvold, the chief technology officer at Microsoft, has written, "Most estimates of the mortality risk posed by asteroid impacts put it at about the same risk as flying in a commercial airliner. However, you have to remember that this is like the entire human race riding the plane."
Here is a potentially huge threat that could be protected against at a cost that probably ranges in the billions or at most a few tens of billions of dollars. In the process of developing the knowledge and technology needed to protect against it we will both gain scientific knowledge about the solar system and will gain technologies that are useful for doing other things up in space. Contrast the cost and benefit of doing this with the cost of the International Space Station which has costs for US taxpayers alone that many estimate to be as high as $100 billion if not more (also see here and here for more estimates in the $100 billion range). The ISS accomplishes very little in terms of science produced. An asteroid protection program might literally save all our lives. The risk is high enough to justify expenditures to protect us.
A UCLA team claims it can predict earthquakes months in advance falling within a several month period.
Earthquakes can be predicted months in advance
Major earthquakes can be predicted months in advance, argues UCLA seismologist and mathematical geophysicist Vladimir Keilis-Borok.
"Earthquake prediction is called the Holy Grail of earthquake science, and has been considered impossible by many scientists," said Keilis-Borok, a professor in residence in UCLA's Institute of Geophysics and Planetary Physics and department of earth and space sciences. "It is not impossible."
"We have made a major breakthrough, discovering the possibility of making predictions months ahead of time, instead of years, as in previously known methods," Keilis-Borok said. "This discovery was not generated by an instant inspiration, but culminates 20 years of multinational, interdisciplinary collaboration by a team of scientists from Russia, the United States, Western Europe, Japan and Canada."
The team includes experts in pattern recognition, geodynamics, seismology, chaos theory, statistical physics and public safety. They have developed algorithms to detect precursory earthquake patterns.
In June of 2003, this team predicted an earthquake of magnitude 6.4 or higher would strike within nine months in a 310-mile region of Central California whose southern part includes San Simeon, where a magnitude 6.5 earthquake struck on Dec. 22.
In July of 2003, the team predicted an earthquake in Japan of magnitude 7 or higher by Dec. 28, 2003, in a region that includes Hokkaido. A magnitude 8.1 earthquake struck Hokkaido on Sept. 25, 2003.
Previously, the team made "intermediate-term" predictions, years in advance. The 1994 Northridge earthquake struck 21 days after an 18-month period when the team predicted that an earthquake of magnitude 6.6 or more would strike within 120 miles from the epicenter of the 1992 Landers earthquake — an area that includes Northridge. The magnitude 6.8 Northridge earthquake caused some $30 billion in damage. The 1989 magnitude 7.1 Loma Prieta earthquake fulfilled a five-year forecast the team issued in 1986.
Keilis-Borok's team now predicts an earthquake of at least magnitude 6.4 by Sept. 5, 2004, in a region that includes the southeastern portion of the Mojave Desert, and an area south of it.
If this technique continues to return correct answers how will Los Angeles or Bay Area residents respond if they are eventually told that a really big quake is coming their way?
Kellis-Borok apparently took on earthquake prediction to give him something worthwhile to do in his old age. Incredible.
Still, not all seismologists are convinced. "Application of nonlinear dynamics and chaos theory is often counter-intuitive," Keilis-Borok said, "so acceptance by some research teams will take time. Other teams, however, accepted it easily."
Keilis-Borok, 82, has been working on earthquake prediction for more than 20 years. A mathematical geophysicist, he was the leading seismologist in Russia for decades, said his UCLA colleague John Vidale, who calls Keilis-Borok the world's leading scientist in the art of earthquake prediction. Keilis-Borok is a member of the National Academy of Sciences, and the American Academy of Arts and Sciences, as well as the Russian Academy of Sciences, and the European, Austrian and Pontifical academies of science. He founded Moscow's International Institute of Earthquake Prediction Theory and Mathematical Geophysics, and joined UCLA's faculty in 1999.
His research team has started experiments in advance prediction of destructive earthquakes in Southern California, Central California, Japan, Israel and neighboring countries, and plans to expand prediction to other regions.
Parenthetically, this report demonstrates the potential of life extension. Kellis-Borok's mind is probably aging more slowly than the average mind. Imagine what top scientists would accomplish if the aging of their minds could be delayed or avoided.
While there is a few decade cycle of hurricane frequency there does not appear to be a longer term trend toward more or stronger hurricanes.
"It does confirm there are cycles of activity, rather than long-term trends towards more or stronger storms," says Landsea. That database also reveals that states such as Georgia that were largely spared during the 20th century remain at risk.
The problem we face now is that the cycle is moving into the higher frequency period. This comes after a lot of population growth in coastal regions. So the economic and human cost is going to be much greater in the coming higher hurricane activity period.
Blaine Harden has an interesting article in the Washington Post about the dangers posed by a volcanic eruption of Mount Rainier in Washington State.
"A monumental threat," said William E. Scott, scientist in charge of the Cascades Volcano Observatory, a USGS center that monitors volcanoes from California to Alaska.
...
About 150,000 people now live atop lahars that have rioted down the slopes of Mount Rainier over the past 5,000 years. The lahars ran all the way to what are now the ports of Tacoma and Seattle, distances, respectively, of 50 and 75 miles.
No volcano in the lower 48 states packs so much risk so close to so many people, Scott said. Mount St. Helens, which erupted in 1980 and killed 57 people, is more active than Rainier, but it is not near large population centers.
Based on the historical pattern Rainier is expected to erupt some time in the next 500 years. The population is growing around the volcano. A really large eruption could send flows running all the way to Seattle.
Thanks to Joe Katzman for the heads-up.
The chances of asteroid 1950 DA hitting Earth in the year 2880 are only 0.3 percent. We really need to achieve Engineered Negligible Senescence so that we can still be around to worry about it when it gets here. If the human race still exists in 2880 (a big if) we should be able to deflect it from its path by then.
SANTA CRUZ, CA--If an asteroid crashes into the Earth, it is likely to splash down somewhere in the oceans that cover 70 percent of the planet's surface. Huge tsunami waves, spreading out from the impact site like the ripples from a rock tossed into a pond, would inundate heavily populated coastal areas. A computer simulation of an asteroid impact tsunami developed by scientists at the University of California, Santa Cruz, shows waves as high as 400 feet sweeping onto the Atlantic Coast of the United States.
The researchers based their simulation on a real asteroid known to be on course for a close encounter with Earth eight centuries from now. Steven Ward, a researcher at the Institute of Geophysics and Planetary Physics at UCSC, and Erik Asphaug, an associate professor of Earth sciences, report their findings in the June issue of the Geophysical Journal International.
March 16, 2880, is the day the asteroid known as 1950 DA, a huge rock two-thirds of a mile in diameter, is due to swing so close to Earth it could slam into the Atlantic Ocean at 38,000 miles per hour. The probability of a direct hit is pretty small, but over the long timescales of Earth's history, asteroids this size and larger have periodically hammered the planet, sometimes with calamitous effects. The so-called K/T impact, for example, ended the age of the dinosaurs 65 million years ago.
"From a geologic perspective, events like this have happened many times in the past. Asteroids the size of 1950 DA have probably struck the Earth about 600 times since the age of the dinosaurs," Ward said.
Ward and Asphaug's study is part of a general effort to conduct a rational assessment of asteroid impact hazards. Asphaug, who organized a NASA-sponsored scientific workshop on asteroids last year, noted that asteroid risks are interesting because the probabilities are so small while the potential consequences are enormous. Furthermore, the laws of orbital mechanics make it possible for scientists to predict an impact if they are able to detect the asteroid in advance.
"It's like knowing the exact time when Mount Shasta will erupt," Asphaug said. "The way to deal with any natural hazard is to improve our knowledge base, so we can turn the kind of human fear that gets played on in the movies into something that we have a handle on."
Although the probability of an impact from 1950 DA is only about 0.3 percent, it is the only asteroid yet detected that scientists cannot entirely dismiss as a threat. A team of scientists led by researchers at NASA's Jet Propulsion Laboratory reported on the probability of 1950 DA crossing paths with the Earth in the April 5, 2002, issue of the journal Science.
"It's a low threat, actually a bit lower than the threat of being hit by an as-yet-undiscovered asteroid in the same size range over the same period of time, but it provided a good representative scenario for us to analyze," Asphaug said.
For the simulation, the researchers chose an impact site consistent with the orientation of the Earth at the time of the predicted encounter: in the Atlantic Ocean about 360 miles from the U.S. coast. Ward summarized the results as follows:
The 60,000-megaton blast of the impact vaporizes the asteroid and blows a cavity in the ocean 11 miles across and all the way down to the seafloor, which is about 3 miles deep at that point. The blast even excavates some of the seafloor. Water then rushes back in to fill the cavity, and a ring of waves spreads out in all directions. The impact creates tsunami waves of all frequencies and wavelengths, with a peak wavelength about the same as the diameter of the cavity. Because lower-frequency waves travel faster than waves with higher frequencies, the initial impulse spreads out into a series of waves.
"In the movies they show one big wave, but you actually end up with dozens of waves. The first ones to arrive are pretty small, and they gradually increase in height, arriving at intervals of 3 or 4 minutes," Ward said.
The waves propagate all through the Atlantic Ocean and the Caribbean. The waves decay as they travel, so coastal areas closest to the impact get hit by the largest waves. Two hours after impact, 400-foot waves reach beaches from Cape Cod to Cape Hatteras, and by four hours after impact the entire East Coast has experienced waves at least 200 feet high, Ward said. It takes 8 hours for the waves to reach Europe, where they come ashore at heights of about 30 to 50 feet.
Computer simulations not only give scientists a better handle on the potential hazards of asteroid impacts, they can also help researchers interpret the geologic evidence of past events, Ward said. Geologists have found evidence of past asteroid impact tsunamis in the form of inland sediment deposits and disturbed sediment layers in the seafloor that correlate with craters, meteorite fragments, and other impact evidence. An important feature of Ward's simulation is that it enabled him to calculate the speed of the water flows created by the tsunami at the bottom of the ocean--more than 3 feet per second out to distances of several hundred miles from the impact.
"That's like a raging river, so as these waves cross the ocean they're going to stir up the seafloor, eroding sediments on the slopes of seamounts, and we may be able to identify more places where this has happened," Ward said.
He added that the waves may also destabilize undersea slopes, causing landslides that could trigger secondary tsunamis. Ward has also done computer simulations of tsunamis generated by submarine landslides. He showed, for example, that the collapse of an unstable volcanic slope in the Canary Islands could send a massive tsunami toward the U.S. East Coast.
A tsunami warning system has been established for the Pacific Ocean involving an international effort to evaluate earthquakes for their potential to generate tsunamis. Ward said that asteroid impact tsunamis could also be incorporated into such a system.
"Tsunamis travel fast, but the ocean is very big, so even if a small or moderate-sized asteroid comes out of nowhere you could still have several hours of advance warning before the tsunami reaches land," he said. "We have a pretty good handle on the size of the waves that would be generated if we can estimate the size of the asteroid."Planetary scientists, meanwhile, are getting a better handle on the risks of asteroid impacts. A NASA-led campaign to detect large asteroids in near-Earth orbits is about half way toward its goal of detecting 90 percent of those larger than 1 kilometer in diameter (the size of 1950 DA) by 2008.
"Until we detect all the big ones and can predict their orbits, we could be struck without warning," said Asphaug. "With the ongoing search campaigns, we'll probably be able to sound the 'all clear' by 2030 for 90 percent of the impacts that could trigger a global catastrophe."
Rogue comets visiting the inner solar system for the first time, however, may never be detected very long in advance. Smaller asteroids that can still cause major tsunami damage may also go undetected.
"Those are risks we may just have to live with," Asphaug said.
See static images of the wave spread or see it as a movie.
A far better expenditure of the money currently going toward the Space Shuttle and International Space Station would be for the development of much better systems for identifying all asteroids that might strike the Earth. Such a system should be powerful enough to be able to identify comets that are going to enter the inner solar system for the first time. Both ground-based and satellite observatories should be funded at much higher levels to be able to identify well in advance every object that might hit Earth.
Objects such as comets whose orbital paths around the Sun that are highly elliptical and extend out beyond Jupiter are going to be harder to identify in advance. However, a very advanced tracking system ought to at least be capable of spotting such objects several months in advance. Fortunately such objects are far more rare than the asteroids that are in the asteroid belt and in closer orbits to the Sun.
Tired of the war? Not sufficiently scared by the spread of SARS? Want something different, more dramatic, and larger scale to worry about? How about the running down of the nuclear reactor supposedly at the Earth's core?
Geophysicist J. Marvin Herndon argues that the core of the Earth is really a 5 mile (or 8 kilometer) uranium ball that operates as a natural nuclear reactor. He says some day the reactor will exhaust its supply of radioactive material and that when it does the Earth's magnetic field will collapse with disastrous consequences.
SAN DIEGO, March 27 (UPI) -- New government laboratory test results are fueling a controversial contention that a giant natural nuclear reactor at the center of the Earth powers the planet's life-protecting magnetic field -- but it might be running out of gas, scientists told United Press International.
Herndon happens also to have served as a technical consultant for the new disaster movie "The Core" which is based on the idea that the Earth's core will stop spinning.
J. Marvin Herndon of Transdyne Corp. in San Diego, who worked as an advisor to Paramount Pictures in the creation of the new science thriller, maintains that a nuclear "georeactor" provides most of the heat in the Earth's spinning core
Unfortunately its probably impossible for real life terranauts to travel down to the Earth's core and fix it if the core starts running out of nuclear fuel.
A new research paper published in the Proceedings of the National Academy of Sciences provides supporting evidence for the theory.
Computer simulations of a nuclear reactor in the Earth's core, conducted at the prestigious Oak Ridge National Laboratory, reveal evidence, in the form of helium fission products, which indicates that the end of the georeactor lifetime may be approaching.
Most geophysicists do not believe Herndon's theory.
Dr. Fred Vine laid the foundations for many of Herndon's theories in the 1970s. Vine, however, believes that the Earth's core stops spinning every 400,000 years.
The August 2002 issue of Discover has a fairly lengthy write-up of Herndon's theory.
In Herndon's view, these polarity flip-flops make no sense if the magnetic field is powered, as traditionalists contend, by heat from the crystallization of molten iron and nickel from the fluid core or from the decay of isolated radioactive isotopes. "Those are both gradual, one-way processes," he says. But if the field's energy results from a mass of uranium and plutonium acting like a natural nuclear reactor, Herndon says, such variations in the field's strength would be almost mandatory.
In this theory the energy comes from the splitting of Uranium U235 atoms and is the same process as occurs in nuclear power plants..
"It's a self-sustaining critical reaction," said nuclear engineer Daniel F. Hollenbach of Oak Ridge National Laboratory, a longtime collaborator of Herndon's until the two parted ways last year. "Depending on how much it fissions, that's the power."
There are a few separate issues here. One is whether the Earth's core is a large nuclear reactor that drives the Earth's magnetic field. There is no consensus among geophysicists that this is the case. Herndon is definitely in a small minority with his theory. However, there is also the widely accepted theory that every few hundred thousand years the Earth's core stops spinning, the magnetic field collapses, and then the core starts spinning again and the magnetic field reverses. So a magnetic field collapse could still happen as part of the process of periodic magnetic field collapse even if Herndon's theory is wrong.
This leads to the important question: Could the Earth's magnetic field reverse today? The British Geological Survey weighs in on the odds of the possibility.
Measurements have been made of the Earth's magnetic field more or less continuously since about 1840. Some measurements even go back to the 1500s, for example at Greenwich in London. If we look at the trend in the strength of the magnetic field over this time (for example the so-called 'dipole moment' shown in the graph below) we can see a downward trend. Indeed projecting this forward in time would suggest zero dipole moment in about 1500-1600 years time. This is one reason why some people believe the field may be in the early stages of a reversal. We also know from studies of the magnetisation of minerals in ancient clay pots that the Earth's magnetic field was approximately twice as strong in Roman times as it is now.
Even so, the current strength of the magnetic field is as high as it has been in the last 50,000 years, even if it is nearly 800,000 years since the last reversal. Also, bearing in mind what we said about 'excursions' above, and knowing what we do about the properties of mathematical models of the magnetic field, it is far from clear we can easily extrapolate to 1500 years hence.
The British Geological Survey does not see a big threat to human life if an Earth's magnetic field reversal should start happening in earnest today.
Is there any danger to life?
Almost certainly not. The Earth's magnetic field is contained within a region of space, known as the magnetosphere, by the action of the solar wind. The magnetosphere deflects many, but not all, of the high-energy particles that flow from the Sun in the solar wind and from other sources in the galaxy. Sometimes the Sun is particularly active, for example when there are many sunspots, and it may send clouds of high-energy particles in the direction of the Earth. During such solar 'flares' and 'coronal mass ejections', astronauts in Earth orbit may need extra shelter to avoid higher doses of radiation. Therefore we know that the Earth's magnetic field offers only some, rather than complete, resistance to particle radiation from space. Indeed high-energy particles can actually be accelerated within the magnetosphere.
At the Earth's surface, the atmosphere acts as an extra blanket to stop all but the most energetic of the solar and galactic radiation. In the absence of a magnetic field, the atmosphere would still stop most of the radiation. Indeed the atmosphere shields us from high-energy radiation as effectively as a concrete layer some 13 feet thick.
Human beings have been on the Earth for a number of million years, during which there have been many reversals, and there is no obvious correlation between human development and reversals. Similarly, reversal patterns do not match patterns in species extinction during geological history.
The fact that Earth's atmosphere provides as much protection from radiation as 13 feet of concrete has interesting ramifications for space exploration and planet colonization. The ability to create a thick atmosphere on Mars would be enormously valuable not just for allowing people to go out and breath the atmosphere. It also greatly reduce the amount of radiation Mars colonists would be exposed to.
You can read more about Herndon's nuclear core theory and its ramifications on the NuclearPlanet website.
What have we done to anger the Sun God? Helios is getting hotter every decade.
Since the late 1970s, the amount of solar radiation the sun emits, during times of quiet sunspot activity, has increased by nearly .05 percent per decade, according to a NASA funded study.
"This trend is important because, if sustained over many decades, it could cause significant climate change," said Richard Willson, a researcher affiliated with NASA's Goddard Institute for Space Studies and Columbia University's Earth Institute, New York. He is the lead author of the study recently published in Geophysical Research Letters.
"Historical records of solar activity indicate that solar radiation has been increasing since the late 19th century. If a trend, comparable to the one found in this study, persisted throughout the 20th century, it would have provided a significant component of the global warming the Intergovernmental Panel on Climate Change reports to have occurred over the past 100 years," he said.
NASA's Earth Science Enterprise funded this research as part of its mission to understand and protect our home planet by studying the primary causes of climate variability, including trends in solar radiation that may be a factor in global climate change.
The solar cycle occurs approximately every 11 years when the sun undergoes a period of increased magnetic and sunspot activity called the "solar maximum," followed by a quiet period called the "solar minimum."
Although the inferred increase of solar irradiance in 24 years, about 0.1 percent, is not enough to cause notable climate change, the trend would be important if maintained for a century or more. Satellite observations of total solar irradiance have obtained a long enough record (over 24 years) to begin looking for this effect.
Total Solar Irradiance (TSI) is the radiant energy received by the Earth from the sun, over all wavelengths, outside the atmosphere. TSI interaction with the Earth's atmosphere,oceans and landmasses is the biggest factor determining our climate. To put it into perspective, decreases in TSI of 0.2 percent occur during the weeklong passage of large sunspot groups across our side of the sun. These changes are relatively insignificant compared to the sun's total output of energy, yet equivalent to all the energy that mankind uses in a year. According to Willson, small variations, like the one found in this study, if sustained over many decades, could have significant climate effects.
Perhaps we have gradually been angering the god Helios (a.k.a. Sol Invictus, Mithra, Ra, Dazhbog, and assorted other names for Sun and Light gods. Perhaps Helios is getting hotter under the collar as his anger builds.
Of course our prehistoric ancestors might intentionally have set out to do something that would gradually increase anger of Helios and to make him hot under the proverbial collar because they were freezing their buns in the Ice Age. Helios, being a God, may not react in the same time frame in which ephemeral mortals respond.
The idea that asteroids as small as 100 meters across pose a serious threat to humanity because they create great, destructive ocean waves, or tsunamis, every few hundred years was suggested in 1993 at a UA-hosted asteroids hazards meeting in Tucson.
At that meeting, a distinguished Leiden Observatory astrophysicist named J. Mayo Greenberg, who since has died, countered that people living below sea level in the Netherlands for the past millennium had not experienced such tsunamis every 250 years as the theory predicted, Melosh noted.
But scientists at the time either didn't follow up or they didn't listen, Melosh added.
While on sabbatical in Amsterdam in 1996, Melosh checked with Dutch geologists who had drilled to basement rock in the Rhine River delta, a geologic record of the past 10,000 years. That record shows only one large tsunami at 7,000 years ago, the Dutch scientists said, but it coincides perfectly in time to a giant landslide off the coast of Norway and is not the result of an asteroid-ocean impact.
In addition, Melosh was highly skeptical of estimates that project small asteroids will generate waves that grow to a thousand meters or higher in a 4,000-meter deep ocean.
Concerned that such doubtful information was -- and is -- being used to justify proposed science projects, Melosh has argued that the hazard of small asteroid-ocean impacts is greatly exaggerated.
Melosh mentioned it at a seminar he gave at the Scripps Institution of Oceanography a few years ago, which is where he met tsunami expert William Van Dorn.
Van Dorn, who lives in San Diego, had been commissioned in 1968 by the U.S. Office of Naval Research to summarize several decades of research into the hazard posed by waves generated by nuclear explosions. The research included 1965-66 experiments that measured wave run-up from blasts of up to 10,000 pounds of TNT in Mono Lake, Calif.
The experiments indeed proved that wave run-up from explosion waves produced either by bombs or bolides (meteors) is much smaller relative to run-up of tsunami waves, Van Dorn said in the report. "As most of the energy is dissipated before the waves reach the shoreline, it is evident that no catastrophe of damage by flooding can result from explosion waves as initially feared," he concluded.
The discovery that explosion waves or large impact-generated waves will break on the outer continental shelf and produce little onshore damage is a phenomenon known in the defense community as the "Van Dorn effect."
But Van Dorn was not authorized to release his 173-page report when he and Melosh met in 1995.
However, sub-kilometer asteroids can still cause a lot of damage.
The asteroid that exploded over the Tunguska River in 1908 is estimated to have been 160- to 180-feet in diameter. And a similar sized asteroid is believed to have exploded over Khazakstan in the late 1940s.
The 1908 Tunguska Siberia asteroid was fairly small and yet devastated a large area when it exploded.
A notorious example occurred in 1908 when an asteroid in this size range is believed to have exploded above the uninhabited Tunguska region of Siberia, leveling trees for some 800 square miles (2,000 square kilometers) around. Astronomers have for a decade or so said so-called Tunguska events probably occur about once every hundred years, leading some to speculate that we're about due for another.
So the take-home lesson is that you can still worry about getting killed by smaller asteriods that could hit closer to where you are. You just can't expect to be killed by a sub-kilometer asteroid that hits the ocean thousands of miles away from land.
Something called phantom energy is as yet unproven to exist but if it does then the universe will eventually accelerate its expansion and even atoms will be pulled apart.
"Until now we thought the Universe would either re-collapse to a big crunch or expand forever to a state of infinite dilution," says Robert Caldwell of Dartmouth College, New Hampshire. "Now we've come up with a third possibility - the 'big rip'."
Its slated for 22 billion years from now so we can relax for now.
The question Caldwell and his colleagues posed is, what would happen if the rate of acceleration increased?
Their answer is that the eventual, phenomenal pace would overwhelm the normal, trusted effects of gravity right down to the local level. Even the nuclear forces that bind things in the subatomic world will cease to be effective.
We have more pressing problems that need to be solved first. For instance, in a mere 1 billion years increased light output from the Sun will make Earth too hot for human life. Therefore, we will need to move Earth. Some may already be living on Mars and will welcome the increased sunlight. But Mars is smaller and will be too crowded to hold everyone.
Of course by then the human race may either be wiped out by nanogoo or by robots.