Selections from the article...
Russian scientists think a space probe should plant a radio beacon on the asteroid Apophis to determine whether it's going to impact Earth, a conference report said Friday.
The report also conjectured that the Russian Phobos-Grunt spacecraft presently scheduled to be launched in 2009 could accomplish that mission with only slight payload changes, but that its launch would have to be delayed until 2012 to make a rendezvous with Apophis.
Such an Apophis impact "could lead to an area equal to France turning into a desert," said Alexander Simonov, one of the authors of the Russian report, in an understatement of the level of global destruction that would be unleashed by a meteor strike of that magnitude.
The report said that even the largest of ground-based radio telescopes cannot discern the orbit of Apophis with the required precision, so one potential solution would be to plant a radio beacon on the asteroid that could permit radio astronomers to determine its orbit within an accuracy of "tens of meters. " That would reveal whether Apophis will hit Earth.
"We propose the Phobos-Grunt spacecraft... as a platform for this mission," the report said. Phobos-Grunt is a planned Russian sample return mission to the Martian moon Phobos. Designed starting in 2001, Phobos-Grunt is currently scheduled for launch in 2009. If the spacecraft's mission is amended to rendezvous with Apophis, the report said its launch should be delayed to May 13, 2012, and the flight is expected to take 330 days.
"Russians offer to track asteroid threat"
Egan Orion
London Inquirer
28 June 2008
Link: London Inquirer Article
29 June 2008
Air & Space/Smithsonian Magazine Article on Human NEO Missions
"The Million Mile Mission: A small band of believers urges NASA to take its next step—onto an asteroid."
Michael Klesius
Air & Space Magazine
01 July 2008
Link: Air & Space/Smithsonian Magazine Article
AFP Tunguska Article
From the article...
A hundred years ago this week, a gigantic explosion ripped open the dawn sky above the swampy taiga forest of western Siberia, leaving a scientific riddle that endures to this day.
A dazzling light pierced the heavens, preceding a shock wave with the power of a thousand atomic bombs which flattened 80 million trees in a swathe of more than 2,000 square kilometres (800 square miles).
Evenki nomads recounted how the blast tossed homes and animals into the air. In Irkutsk, 1,500 kilometres (950 miles) away, seismic sensors registered what was initially deemed to be an earthquake. The fireball was so great that a day later, Londoners could read their newspapers under the night sky.
What caused the so-called Tunguska Event, named after the Podkamennaya Tunguska river near where it happened, has spawned at least a half a dozen theories.
The biggest finger of blame points at a rogue rock whose destiny, after travelling in space for millions of years, was to intersect with Earth at exactly 7:17 am on June 30, 1908.
Even the most ardent defenders of the sudden impact theory acknowledge there are many gaps. They strive to find answers, believing this will strengthen defences against future Tunguska-type threats, which experts say occur with an average frequency from one in 200 years to one in 1,000 years.
"Imagine an unspotted asteroid laying waste to a significant chunk of land... and imagine if that area, unlike Tunguska and a surprising amount of the globe today, were populated," the British science journal Nature commented last week.
If a rock was the culprit, the choices lie between an asteroid -- the rubble that can be jostled out of its orbital belt between Mars and Jupiter and set on collision course with Earth -- and a comet, one of the "icy dirtballs" of frozen, primeval material that loop around the Solar System.
-- 'Why has no one yet found fragments?' --
-------------------------------------------
Comets move at far greater speeds than asteroids, which means they release more kinetic energy pound-for-pound upon impact. A small comet would deliver the same punch as a larger asteroid.
But no fragments of the Tunguska villain have ever been found, despite many searches.
Finding a piece is important, for it will boost our knowledge about the degrees of risk from dangerous Near Earth Objects (NEOs), say Italian researchers Luca Gasperini, Enrico Bonatti and Giuseppe Longo.
When a new asteroid is detected, its orbit can be plotted for scores of years in the future.
Comets are far less numerous than asteroids but are rather more worrying, as they are largely an unknown entity.
Most comets have yet to be spotted because they take decades or even hundreds of years to go around the Sun and pass our home. As a result, any comet on a collision course with Earth could quite literally come out of the dark, leaving us negligible time to respond.
"(I)f the Tunguska event was in fact caused by a comet, it would be a unique occurrence rather than an important case study of a known class of phenomena," Gasperini's team write in this month's issue of Scientific American.
"On the other hand, if an asteroid did explode in the Siberian skies that June morning, why has no-one yet found fragments?"
NEO experts are likewise unsure about the size of the object.
Estimates, based on the scale of ground destruction, range from three metres (10 feet) to 70 metres (227 feet).
All agree that the object, heated by friction with atmospheric molecules, exploded far above ground -- between several kilometres (miles) and 10 kms (six miles).
But there is fierce debate as to whether any debris hit the ground.
This too is important. When the next Tunguska NEO looms, Earth's guardians will have to choose whether to try to deflect it or blow it up in space, with the risk that objects of a certain size may survive the fiery passage through the atmosphere and hit the planet.
The Italian trio believe the answers lie in a curiously-shaped oval lake, called Lake Cheko, located about 10 kilometres (six miles) from ground zero.
Computer models, they say, suggest it is the impact crater from a metre- (three-feet) -sized fragment that survived the explosion.
They plan a return expedition to Lake Cheko in the hope of reaching a dense object of this size, buried 10 metres (32.5 feet) in the lake's cone-shaped floor, that reflected sonar waves.
But what if neither comet nor asteroid were to blame?
A rival theory is given an airing in this week's New Scientist.
Lake Cheko does not have the typical round shape of an impact crater, and no extraterrestrial material has been found, which means "there's got to be a terrestrial explanation," Wolfgang Kundt, a physicist at Germany's Bonn University told the British weekly.
He believes the Tunguska Event was caused by a massive escape of 10 million tonnes of methane-rich gas deep within Earth's crust. Evidence of a similar apocalyptic release can be found on the Blake Ridge on the seabed off Norway, a "pockmark" of 700 sq. kms (280 sq. miles), Kundt said.
"100 years on, mystery shrouds massive 'cosmic impact' in Russia"
29 June 2008
Link: AFP Article
A hundred years ago this week, a gigantic explosion ripped open the dawn sky above the swampy taiga forest of western Siberia, leaving a scientific riddle that endures to this day.
A dazzling light pierced the heavens, preceding a shock wave with the power of a thousand atomic bombs which flattened 80 million trees in a swathe of more than 2,000 square kilometres (800 square miles).
Evenki nomads recounted how the blast tossed homes and animals into the air. In Irkutsk, 1,500 kilometres (950 miles) away, seismic sensors registered what was initially deemed to be an earthquake. The fireball was so great that a day later, Londoners could read their newspapers under the night sky.
What caused the so-called Tunguska Event, named after the Podkamennaya Tunguska river near where it happened, has spawned at least a half a dozen theories.
The biggest finger of blame points at a rogue rock whose destiny, after travelling in space for millions of years, was to intersect with Earth at exactly 7:17 am on June 30, 1908.
Even the most ardent defenders of the sudden impact theory acknowledge there are many gaps. They strive to find answers, believing this will strengthen defences against future Tunguska-type threats, which experts say occur with an average frequency from one in 200 years to one in 1,000 years.
"Imagine an unspotted asteroid laying waste to a significant chunk of land... and imagine if that area, unlike Tunguska and a surprising amount of the globe today, were populated," the British science journal Nature commented last week.
If a rock was the culprit, the choices lie between an asteroid -- the rubble that can be jostled out of its orbital belt between Mars and Jupiter and set on collision course with Earth -- and a comet, one of the "icy dirtballs" of frozen, primeval material that loop around the Solar System.
-- 'Why has no one yet found fragments?' --
-------------------------------------------
Comets move at far greater speeds than asteroids, which means they release more kinetic energy pound-for-pound upon impact. A small comet would deliver the same punch as a larger asteroid.
But no fragments of the Tunguska villain have ever been found, despite many searches.
Finding a piece is important, for it will boost our knowledge about the degrees of risk from dangerous Near Earth Objects (NEOs), say Italian researchers Luca Gasperini, Enrico Bonatti and Giuseppe Longo.
When a new asteroid is detected, its orbit can be plotted for scores of years in the future.
Comets are far less numerous than asteroids but are rather more worrying, as they are largely an unknown entity.
Most comets have yet to be spotted because they take decades or even hundreds of years to go around the Sun and pass our home. As a result, any comet on a collision course with Earth could quite literally come out of the dark, leaving us negligible time to respond.
"(I)f the Tunguska event was in fact caused by a comet, it would be a unique occurrence rather than an important case study of a known class of phenomena," Gasperini's team write in this month's issue of Scientific American.
"On the other hand, if an asteroid did explode in the Siberian skies that June morning, why has no-one yet found fragments?"
NEO experts are likewise unsure about the size of the object.
Estimates, based on the scale of ground destruction, range from three metres (10 feet) to 70 metres (227 feet).
All agree that the object, heated by friction with atmospheric molecules, exploded far above ground -- between several kilometres (miles) and 10 kms (six miles).
But there is fierce debate as to whether any debris hit the ground.
This too is important. When the next Tunguska NEO looms, Earth's guardians will have to choose whether to try to deflect it or blow it up in space, with the risk that objects of a certain size may survive the fiery passage through the atmosphere and hit the planet.
The Italian trio believe the answers lie in a curiously-shaped oval lake, called Lake Cheko, located about 10 kilometres (six miles) from ground zero.
Computer models, they say, suggest it is the impact crater from a metre- (three-feet) -sized fragment that survived the explosion.
They plan a return expedition to Lake Cheko in the hope of reaching a dense object of this size, buried 10 metres (32.5 feet) in the lake's cone-shaped floor, that reflected sonar waves.
But what if neither comet nor asteroid were to blame?
A rival theory is given an airing in this week's New Scientist.
Lake Cheko does not have the typical round shape of an impact crater, and no extraterrestrial material has been found, which means "there's got to be a terrestrial explanation," Wolfgang Kundt, a physicist at Germany's Bonn University told the British weekly.
He believes the Tunguska Event was caused by a massive escape of 10 million tonnes of methane-rich gas deep within Earth's crust. Evidence of a similar apocalyptic release can be found on the Blake Ridge on the seabed off Norway, a "pockmark" of 700 sq. kms (280 sq. miles), Kundt said.
"100 years on, mystery shrouds massive 'cosmic impact' in Russia"
29 June 2008
Link: AFP Article
Tunguska Article from NASA/JPL
From the article...
100 Years of Space Rock: The Tunguska Impact
June 27, 2008
At around 7:17 on the morning of June 30, 1908, a man based at the trading post at Vanavara in Siberia is sitting on his front porch. In a moment, 40 miles from the center of an immense blast of unknown origin, he will be hurled from his chair and the heat will be so intense he will feel as though his shirt is on fire. The man at the trading post, and others in a largely uninhabited region of Siberia, near the Podkamennaya Tunguska River, are to be accidental eyewitnesses to cosmological history.
"If you want to start a conversation with anyone in the asteroid business all you have to say is Tunguska," said Don Yeomans, manager of the Near-Earth Object Office at NASA's Jet Propulsion Laboratory. "It is the only entry of a large meteoroid we have in the modern era with first-hand accounts."
While the impact occurred in '08, the first scientific expedition to the area would have to wait for 19 years. In 1921, Leonid Kulik, the chief curator for the meteorite collection of the St. Petersburg museum led an expedition to Tunguska. But the harsh conditions of the Siberian outback thwarted his team's attempt to reach the area of the blast. In 1927, a new expedition, again lead by Kulik, reached its goal.
"At first, the locals were reluctant to tell Kulik about the event," said Yeomans. "They believed the blast was a visitation by the god Ogdy, who had cursed the area by smashing trees and killing animals."
While testimonials may have at first been difficult to obtain, there was plenty of evidence lying around. Eight hundred square miles of remote forest had been ripped asunder. Eighty million trees were on their sides, lying in a radial pattern.
"Those trees acted as markers, pointing directly away from the blast's epicenter," said Yeomans. "Later, when the team arrived at ground zero, they found the trees there standing upright -- but their limbs and bark had been stripped away. They looked like a forest of telephone poles."
Such debranching requires fast moving shock waves that break off a tree's branches before the branches can transfer the impact momentum to the tree's stem. Thirty seven years after the Tunguska blast, branchless trees would be found at the site of another massive explosion -- Hiroshima, Japan.
Kulik's expeditions (he traveled to Tunguska on three separate occasions) did finally get some of the locals to talk. One was the man based at the Vanara trading post who witnessed the heat blast as he was launched a few yards. His account:
Suddenly in the north sky… the sky was split in two, and high above the forest the whole northern part of the sky appeared covered with fire… At that moment there was a bang in the sky and a mighty crash… The crash was followed by a noise like stones falling from the sky, or of guns firing. The earth trembled.
The massive explosion packed a wallop. The resulting seismic shockwave registered with sensitive barometers as far away as England. Dense clouds formed over the region at high altitudes which reflected sunlight from beyond the horizon. Night skies glowed, and reports came in that people who lived as far away as Asia could read newspapers outdoors as late as midnight. Locally, hundreds of reindeer, the livelihood of local herders, were killed, but there was no direct evidence that any person perished in the blast.
"A century later some still debate the cause and come up with different scenarios that could have caused the explosion," said Yeomans. "But the generally agreed upon theory is that on the morning of June 30, 1908, a large space rock, about 120 feet across, entered the atmosphere of Siberia and then detonated in the sky."
It is estimated the asteroid entered Earth's atmosphere traveling at a speed of about 33,500 miles per hour. During its quick plunge, the 220-million-pound space rock heated the air surrounding it to 44,500 degrees Fahrenheit. At 7:17 a.m. (local Siberia time), at a height of about 28,000 feet, the combination of pressure and heat caused the asteroid to fragment and annihilate itself, producing a fireball and releasing energy equivalent to about 185 Hiroshima bombs.
"That is why there is no impact crater," said Yeomans. "The great majority of the asteroid is consumed in the explosion."
Yeomans and his colleagues at JPL's Near-Earth Object Office are tasked with plotting the orbits of present-day comets and asteroids that cross Earth's path, and could be potentially hazardous to our planet.
Yeomans estimates that, on average, a Tunguska-sized asteroid will enter Earth's atmosphere once every 300 years. On this 100th anniversary of the Tunguska event, does that mean we have 200 years of largely meteor-free skies?
"Not necessarily," said Yeomans. "The 300 years between Tunguska-sized events is an average based on our best science. I think about Tunguska all the time from a scientific point of view, but the thought of a another Tunguska does not keep me up at night."
100 Years of Space Rock: The Tunguska Impact
NASA/JPL News Article
June 27, 2008
Link: NASA/JPL Article
26 June 2008
Book: "T. rex" and the Crater of Doom - New Edition Out
A new edition of the 1997 book by geologist Walter Alvarez entitled "T. Rex and the Crater of Doom" has been published. It has been reprinted in June 2008 by Princeton University Press.
From Amazon.com:
One of the great mysteries is what happened to the dinosaurs, and it has taken great detective work to give us an answer. In T. Rex and the Crater of Doom, some brilliant, not to mention determined, scientists roam the world and seek out the clues. What they conclude is that the earth withstood a colossal impact with a meteor (or perhaps a comet) 65 million years ago. The resulting cataclysm destroyed half the life on the planet.
Walter Alvarez, a geologist at the University of California at Berkeley, and one of the four scientists who present this theory on the mystery, tells the story in a clear narrative that contains a wealth of scientific material. The book does require an investment of attention, but the presentation is quite readable, and the story itself is fascinating.
Link: Introduction to Book (at The Loom)
Link: Entire Introduction the Book
Link: Amazon.com
Chesapeake Bay Impact Analysis
From the far reaches of the solar system, a giant asteroid or comet plunged into Earth near what is now the Chesapeake Bay 35 million years ago (shown in this artist's conception). Credit: © The Virginian-Pilot.
From the article...
The true impact of an asteroid or comet crashing near the Chesapeake Bay 35 million years ago has been examined in detail for the first time. The analysis reveals the resilience of life in the aftermath of disaster.
The impact crater, which is buried under 400 to 1,200 feet (120 to 365 meters) of sand, silt and clay, spans twice the length of Manhattan. The sprawling depression helped create what would eventually become Chesapeake Bay. About 10,000 years ago, ice sheets began to melt and once-dry river valleys filled with water. The rivers of the Chesapeake region converged directly over the buried crater, according to the U.S. Geological Survey (USGS).
Gregory Gohn of the USGS and his colleagues analyzed samples from two deep holes drilled into the crater near its center.
"I think what we wanted to do is drill into the central part of the crater and get as long of a section as we could and understand the processes that put them in the order we found them," Gohn told SPACE.com.
Within seconds of the object's touchdown, rocks were flung high into the air. The force of the impact carved a colossal cavity and caused temperatures to skyrocket, turning brittle rocks into taffy. Then, material along the cavity's rim surged downhill into the bowl-shaped depression like an avalanche.
The extreme heat, the researchers say, killed off most life. However, they found abundant microbes living today in the deepest parts of the crater. Some of the ancient bacteria would have survived the impact, the researchers say, because their little hideouts didn't feel the brunt of the heat. The rest of the abundant and newly discovered microbial life is thought to have recolonized the zapped area possibly tens of thousands of years following the impact when temperatures dropped to habitable levels.
"The impact broke up and disaggregated all of these blocks of rock," said researcher Mary Voytek, a microbiologist at the USGS, "and that actually creates space for [the microbes] to colonize and it also creates new routes for water and material to move though, which is always good for bugs."
So a catastrophic event like this could actually be a boon to microbes, at least in the long-run, Voytek said. The impact breaks up compacted rock to create nooks and crannies for bacteria to reside in, and it also brings in a fresh supply of food.
"It's somewhat analogous to whale falls," when a whale carcass eventually settles on the sea floor, Voytek said. "All of a sudden it's a restaurant for these bugs."
Understanding the biological effects of this asteroid impact will shed light on the potential for life deep underground during Earth's Archaean period, 3.8 billion to 2.5 billion years ago, when impacts were more frequent than today. The results also have implications for predicting life in the deep biosphere on Mars.
"If we're going to find life [on Mars], everyone agrees a good place to look is in the subsurface," Voytek said.
The project, which is detailed in the June 27 issue of the journal Science, was funded by the USGS, NASA, the National Science Foundation, the Austrian Science Foundation and DOSECC Inc.
"Life Survived Catastrophic Space Rock Impact"
Jeanna Bryner
Space.com
26 June 2008
Link: Space.com article
-----
ABSTRACT FROM SCIENCE
Science 27 June 2008:
Vol. 320. no. 5884, pp. 1740 - 1745
DOI: 10.1126/science.1158708
Deep Drilling into the Chesapeake Bay Impact Structure
G. S. Gohn,1* C. Koeberl,2 K. G. Miller,3 W. U. Reimold,4 J. V. Browning,3 C. S. Cockell,5 J. W. Horton, Jr.,1 T. Kenkmann,4 A. A. Kulpecz,3 D. S. Powars,1 W. E. Sanford,1 M. A. Voytek1
Samples from a 1.76-kilometer-deep corehole drilled near the center of the late Eocene Chesapeake Bay impact structure (Virginia, USA) reveal its geologic, hydrologic, and biologic history. We conducted stratigraphic and petrologic analyses of the cores to elucidate the timing and results of impact-melt creation and distribution, transient-cavity collapse, and ocean-water resurge. Comparison of post-impact sedimentary sequences inside and outside the structure indicates that compaction of the crater fill influenced long-term sedimentation patterns in the mid-Atlantic region. Salty connate water of the target remains in the crater fill today, where it poses a potential threat to the regional groundwater resource. Observed depth variations in microbial abundance indicate a complex history of impact-related thermal sterilization and habitat modification, and subsequent post-impact repopulation.
1 U.S. Geological Survey, Reston, VA 20192, USA.
2 Department of Lithospheric Research, Center for Earth Sciences, University of Vienna, Althanstrasse 14, Vienna A-1090, Austria.
3 Department of Geological Sciences, Rutgers University, 610 Taylor Road, Piscataway, NJ08854, USA.
4 Museum of Natural History (Mineralogy), Humboldt-University Berlin, Invalidenstrasse 43, Berlin 10115, Germany.
5 Centre for Earth, Planetary, Space, and Astronomical Research, Open University, Milton Keynes MK7 6AA, UK.
Link: Science Abstract
Additional Articles on Canadian NEO Search Small Satellite: NEOSSat
Additional articles on Canadian NEO search satellite, NEOSSat. From the articles...
On Thursday, the Canadian Space Agency and Defence Research Development Canada announced they are preparing to launch the Near Earth Object Surveillance Satellite, or NEOSSat, a suitcase-sized telescope capable of spotting asteroids and tracking high-altitude satellites and space debris.
NEOSSat follows on the success of the MOST (Microvariability and Oscillations of STars) telescope, the 60 kg star-watching satellite that was launched in 2003 and operates on a shoestring budget.
Like its predecessor, NEOSSat is tiny, with a mass of 65 kilograms and a telescope with a 15 centimetre aperture, smaller than most amateur astronomers' telescopes.
And like MOST, it will be cheap too, costing $12 million to build, launch and operate.
Scheduled to launch into space in 2010, NEOSSat will have two main science tasks: the NESS (Near Earth Space Surveillance) asteroid search program and the HEOSS (High Earth Orbit Space Surveillance) program, which will track satellites and other objects floating in high orbit around Earth.
The satellite, funded by the Canadian Space Agency and Defence Research & Development Canada and built by Mississauga-based Dynacon Inc., will also to keep an eye on satellites and floating debris orbiting the Earth.
Although NEOSSat's 15-centimetre telescope is smaller than most amateur astronomers', its location approximately 700 kilometres above Earth's atmosphere will give it a huge advantage in searching the blackness of space for faint signs of moving asteroids. Twisting and turning hundreds of times each day, orbiting from pole to pole every 50 minutes, and generating power from the Sun, NEOSSat will send dozens of images to the ground each time it passes over Canada. Due to the ultra-low sky background provided by the vacuum of space, NEOSSat will be able to detect asteroids delivering as few as 50 photons of light in a 100-second exposure.
Link: CBC News Article
Link: ScienceDaily Article
Link: NEOSSAT Home page
On Thursday, the Canadian Space Agency and Defence Research Development Canada announced they are preparing to launch the Near Earth Object Surveillance Satellite, or NEOSSat, a suitcase-sized telescope capable of spotting asteroids and tracking high-altitude satellites and space debris.
NEOSSat follows on the success of the MOST (Microvariability and Oscillations of STars) telescope, the 60 kg star-watching satellite that was launched in 2003 and operates on a shoestring budget.
Like its predecessor, NEOSSat is tiny, with a mass of 65 kilograms and a telescope with a 15 centimetre aperture, smaller than most amateur astronomers' telescopes.
And like MOST, it will be cheap too, costing $12 million to build, launch and operate.
Scheduled to launch into space in 2010, NEOSSat will have two main science tasks: the NESS (Near Earth Space Surveillance) asteroid search program and the HEOSS (High Earth Orbit Space Surveillance) program, which will track satellites and other objects floating in high orbit around Earth.
The satellite, funded by the Canadian Space Agency and Defence Research & Development Canada and built by Mississauga-based Dynacon Inc., will also to keep an eye on satellites and floating debris orbiting the Earth.
Although NEOSSat's 15-centimetre telescope is smaller than most amateur astronomers', its location approximately 700 kilometres above Earth's atmosphere will give it a huge advantage in searching the blackness of space for faint signs of moving asteroids. Twisting and turning hundreds of times each day, orbiting from pole to pole every 50 minutes, and generating power from the Sun, NEOSSat will send dozens of images to the ground each time it passes over Canada. Due to the ultra-low sky background provided by the vacuum of space, NEOSSat will be able to detect asteroids delivering as few as 50 photons of light in a 100-second exposure.
Link: CBC News Article
Link: ScienceDaily Article
Link: NEOSSAT Home page
Russia's Academy of Sciences hosts forum on Tunguska phenomenon
Upcoming conference in Russia on the occasion of the 100th anniversary of the Tunguska explosion, selections from the article...
Russia's Academy of Sciences is hosting an international conference marking the 100th anniversary of the mysterious event which occurred on June 30, 1908 near the river Podkamennaya Tunguska, and has defied explanation up to date.
Boris Shustov, director of RAN's Institute of Astronomy and head of the expert group on asteroid-comet danger (ACO) under the Council for Outer Space, told Itar-Tass that "they often use the word "meteorite" when talking about this event; but it is the wrong term."
"In the course of the conference, the participants will discuss the Tunguska phenomenon proper and the asteroid-comet danger. They are our colleagues from the United States, Great Britain, and Germany, and we’re expecting extensive discussions of this theme. It has been proposed to bring forward a package of documents for consideration by the UN in 2009 which would regulate countries' conduct in connection with the asteroid-comet danger. ACO is a global threat," Shustov underlined.
Director of the center for planetary defense of the Earth from asteroids Anatoly Zaitsev said two lessons have to be learnt form the Tunguska Phenomenon.
"Firstly, it showed the Earth's vulnerability in the event of "asteroid attack." Secondly, it was a sort of warning: nations should consolidate their efforts as fast as possible in the cause to protect the planet from asteroids.
The international conference will last until June 28. Among its organizers are the Russian Academy of Sciences (RAN), the Moscow State University (MGU), the RAN committee on meteorites, and the MGU's Sternberg state astronomical institute.
Link: ITAR-TASS Story: "RAN hosts forum on Tunguska phenomenon" (26 June 2008)
Link: International Conference "100 years since Tunguska phenomenon: Past, present and future" - Conference Website
Link: International Conference "100 years since Tunguska phenomenon: Past, present and future" - Conference Abstracts (PDF)
Russia's Academy of Sciences is hosting an international conference marking the 100th anniversary of the mysterious event which occurred on June 30, 1908 near the river Podkamennaya Tunguska, and has defied explanation up to date.
Boris Shustov, director of RAN's Institute of Astronomy and head of the expert group on asteroid-comet danger (ACO) under the Council for Outer Space, told Itar-Tass that "they often use the word "meteorite" when talking about this event; but it is the wrong term."
"In the course of the conference, the participants will discuss the Tunguska phenomenon proper and the asteroid-comet danger. They are our colleagues from the United States, Great Britain, and Germany, and we’re expecting extensive discussions of this theme. It has been proposed to bring forward a package of documents for consideration by the UN in 2009 which would regulate countries' conduct in connection with the asteroid-comet danger. ACO is a global threat," Shustov underlined.
Director of the center for planetary defense of the Earth from asteroids Anatoly Zaitsev said two lessons have to be learnt form the Tunguska Phenomenon.
"Firstly, it showed the Earth's vulnerability in the event of "asteroid attack." Secondly, it was a sort of warning: nations should consolidate their efforts as fast as possible in the cause to protect the planet from asteroids.
The international conference will last until June 28. Among its organizers are the Russian Academy of Sciences (RAN), the Moscow State University (MGU), the RAN committee on meteorites, and the MGU's Sternberg state astronomical institute.
Link: ITAR-TASS Story: "RAN hosts forum on Tunguska phenomenon" (26 June 2008)
Link: International Conference "100 years since Tunguska phenomenon: Past, present and future" - Conference Website
Link: International Conference "100 years since Tunguska phenomenon: Past, present and future" - Conference Abstracts (PDF)
25 June 2008
Dave Morrison: NEO News (06/25/08) Burger Bar that Saved the World
Dave Morrison's NEO News comments on the recent series of Articles in Nature (including one article in particular). Here is the NEO News (06/25/08) Burger Bar that Saved the World issue...
NEO News (06/25/08) Burger Bar that Saved the World
Nature is publishing a special edition this week on the 100th anniversary of the Tunguska impact. The first part to be released is this historical summary assembled by David Chandler from a series of separate interviews. The text is below, but I especially call your attention to the enclosed pdf file with the illustrations. The introductory "burger bar" cartoon is really funny (something we don't often say about NEOs).
Most of the history recounted here strikes me as accurate, except perhaps the statements that Gene Shoemaker resisted the idea that there was an impact hazard up until the discovery of Comet Shoemaker-Levy 9. My own experience over the preceding decade was that Gene understood the issues as well as any of us and fully supported the recommendations of the Spaceguard Survey workshop, a report to which Gene made important contributions. The split in the early 1990s was between the nuclear weapons labs and the astronomers, not among us astronomers. I credit Pete Worden's organization of the Erice NEO workshop, and Tom Gehrels for the Tucson Hazards meeting (both held in early 1993), for closing much of that rift between these two scientific communities.
David Morrison
NEO News (now in its fourteenth year of distribution) is an informal compilation of news and opinion dealing with Near Earth Objects (NEOs) and their impacts. These opinions are the responsibility of the individual authors and do not represent the positions of NASA, Ames Research Center, the International Astronomical Union, or any other organization. To subscribe (or unsubscribe) contact dmorrison@arc.nasa.gov. For additional information, please see the website http://impact.arc.nasa.gov. If anyone wishes to copy or redistribute original material from these notes, fully or in part, please include this disclaimer.
NEO News (06/25/08) Burger Bar that Saved the World
Nature is publishing a special edition this week on the 100th anniversary of the Tunguska impact. The first part to be released is this historical summary assembled by David Chandler from a series of separate interviews. The text is below, but I especially call your attention to the enclosed pdf file with the illustrations. The introductory "burger bar" cartoon is really funny (something we don't often say about NEOs).
Most of the history recounted here strikes me as accurate, except perhaps the statements that Gene Shoemaker resisted the idea that there was an impact hazard up until the discovery of Comet Shoemaker-Levy 9. My own experience over the preceding decade was that Gene understood the issues as well as any of us and fully supported the recommendations of the Spaceguard Survey workshop, a report to which Gene made important contributions. The split in the early 1990s was between the nuclear weapons labs and the astronomers, not among us astronomers. I credit Pete Worden's organization of the Erice NEO workshop, and Tom Gehrels for the Tucson Hazards meeting (both held in early 1993), for closing much of that rift between these two scientific communities.
David Morrison
NEO News (now in its fourteenth year of distribution) is an informal compilation of news and opinion dealing with Near Earth Objects (NEOs) and their impacts. These opinions are the responsibility of the individual authors and do not represent the positions of NASA, Ames Research Center, the International Astronomical Union, or any other organization. To subscribe (or unsubscribe) contact dmorrison@arc.nasa.gov. For additional information, please see the website http://impact.arc.nasa.gov. If anyone wishes to copy or redistribute original material from these notes, fully or in part, please include this disclaimer.
Nature Magazine has Special on Cosmic Impacts: Various Articles
Nature Magazine has several articles in a special section on impacts. Articles include the following:
All craters great and small (picture gallery)
From a 5-millimetre dent on a satellite to a 3-kilometre pit in the surface of Mars, the scars of impact events can be seen at every scale. We present a gallery of some particularly appealing ones from Earth and beyond.
Tunguska at 100
The most dramatic cosmic impact in recent history has gathered up almost as many weird explanations as it knocked down trees, writes Duncan Steel.
25 June 2008
The hole at the bottom of the Moon
A giant crater on the lunar farside holds the key to a catastrophic bombardment that reshaped the Moon, Earth and other planets. Eric Hand reports.
25 June 2008
The burger bar that saved the world
Fewer people are searching for near-Earth asteroids, astronomer David Morrison said in the 1990s, than work a shift in a small McDonalds. But that group — a little larger now — has over the past two decades discovered a host of happily harmless rocks, and in doing so reduced the risk of an unknown asteroid blighting civilization. David Chandler puts together the story in the words of those who watched, and those who watched the watchers.
25 June 2008
COMMENTARY: What Spaceguard did
A survey of large objects near Earth has shown that there is little risk of a cataclysmic impact in the next century. Alan Harris asks if such cataloguing efforts should continue.
25 June 2008
In retrospect: Lucifer's Hammer
Oliver Morton recalls how the first major science fiction novel to depict an impact event conjured the thrill and the horror of natural cataclysm — and even inspired some researchers.
25 June 2008
Message from the heavens
Discerning the meaning behind Maurizio Cattelan's violent, provocative and now highly valuable sculpture of Pope John Paul II felled by a meteorite raises many questions for viewers, explains Martin Kemp.
25 June 2008
Forming the martian great divide
Early in its history, Mars suffered a convulsion that left a lasting geological and topographical scar. The latest work adds to evidence that the cause was external — a massive impact.
25 June 2008
The Borealis basin and the martian crustal dichotomy
Jeffery C. Andrews-Hanna et al.
25 June 2008
Mega-impact formation of the Mars hemispheric dichotomy
Margarita M. Marinova et al.
25 June 2008
Implications of an impact origin for the Martian hemispheric Dichotomy
Francis Nimmo et al.
25 June 2008
Link: Nature Magazine - Cosmic Impacts
All craters great and small (picture gallery)
From a 5-millimetre dent on a satellite to a 3-kilometre pit in the surface of Mars, the scars of impact events can be seen at every scale. We present a gallery of some particularly appealing ones from Earth and beyond.
Tunguska at 100
The most dramatic cosmic impact in recent history has gathered up almost as many weird explanations as it knocked down trees, writes Duncan Steel.
25 June 2008
The hole at the bottom of the Moon
A giant crater on the lunar farside holds the key to a catastrophic bombardment that reshaped the Moon, Earth and other planets. Eric Hand reports.
25 June 2008
The burger bar that saved the world
Fewer people are searching for near-Earth asteroids, astronomer David Morrison said in the 1990s, than work a shift in a small McDonalds. But that group — a little larger now — has over the past two decades discovered a host of happily harmless rocks, and in doing so reduced the risk of an unknown asteroid blighting civilization. David Chandler puts together the story in the words of those who watched, and those who watched the watchers.
25 June 2008
COMMENTARY: What Spaceguard did
A survey of large objects near Earth has shown that there is little risk of a cataclysmic impact in the next century. Alan Harris asks if such cataloguing efforts should continue.
25 June 2008
In retrospect: Lucifer's Hammer
Oliver Morton recalls how the first major science fiction novel to depict an impact event conjured the thrill and the horror of natural cataclysm — and even inspired some researchers.
25 June 2008
Message from the heavens
Discerning the meaning behind Maurizio Cattelan's violent, provocative and now highly valuable sculpture of Pope John Paul II felled by a meteorite raises many questions for viewers, explains Martin Kemp.
25 June 2008
Forming the martian great divide
Early in its history, Mars suffered a convulsion that left a lasting geological and topographical scar. The latest work adds to evidence that the cause was external — a massive impact.
25 June 2008
The Borealis basin and the martian crustal dichotomy
Jeffery C. Andrews-Hanna et al.
25 June 2008
Mega-impact formation of the Mars hemispheric dichotomy
Margarita M. Marinova et al.
25 June 2008
Implications of an impact origin for the Martian hemispheric Dichotomy
Francis Nimmo et al.
25 June 2008
Link: Nature Magazine - Cosmic Impacts
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