1. Cosmic Cataclysms

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General Astronomy Resources

Articles from 2002 - present

SEE ALSO: Life & Climate Chapter 9, What Happened to the Dinosaurs?

2021-07-15. [] - Exploding stars may have assaulted ancient Earth. Source: By Daniel Clery, Since Magazine. Excerpt: ...Over the past 2 decades, researchers have found hundreds of radioactive atoms, trapped in seafloor minerals, that came from an ancient explosion marking the death of a nearby star. Its fusion fuel exhausted, the star had collapsed, generating a shock wave that blasted away its outer layers in an expanding ball of gas and dust so hot that it briefly glowed as bright as a galaxy—and ultimately showered Earth with those telltale atoms. Erupting from hundreds of light-years away, the flash of x-rays and gamma rays probably did no harm on Earth. But the expanding fireball also accelerated cosmic rays—mostly nuclei of hydrogen and helium—to close to the speed of light. These projectiles arrived stealthily, decades later, ramping up into an invisible fusillade that could have lasted for thousands of years and might have affected the atmosphere—and life. ...A cosmic ray barrage might have boosted mutation rates by eroding Earth’s protective ozone layer and generating showers of secondary, tissue-penetrating particles. Tearing through the atmosphere, the particles would have also created pathways for lightning, perhaps kindling a spate of wildfires. At the same time, atmospheric reactions triggered by the radiation could have led to a rain of nitrogen compounds, which would have fertilized plants, drawing down carbon dioxide. In that way, the celestial event could have cooled the climate and helped initiate the ice ages 2.5 million years ago, at the start of the Pleistocene epoch. ... Adrian Melott, an astronomer at the University of Kansas, Lawrence, who explores how nearby cosmic cataclysms might affect Earth, says it’s time to more carefully probe Earth’s history for ancient supernova strikes. ...a few supernovae go off in the Milky Way every century. By the law of averages, a handful must have exploded very close to Earth—within 30 light-years—during its 4.5-billion-year lifetime, with potentially catastrophic effects.... 

2021-01-27. An Asteroid “Double Disaster” Struck Germany in the Miocene. By Katherine Kornei, Eos/AGU. Excerpt: A Gothic church rises high above the medieval town of Nördlingen, Germany. But unlike most churches, St. George’s is composed of a very special type of rock: suevite, a coarse-grained breccia that’s formed only in powerful impacts. That discovery and other lines of evidence have helped researchers determine that Nördlingen lies within an impact crater. Now, scientists have unearthed evidence that this crater and another one just 40 kilometers away were formed by a “double disaster” of two independent asteroid impacts. ...Our planet is dotted with nearly 200 confirmed impact structures, and a handful of them appear in close pairs. Some researchers have proposed that these apparent double craters are scars created by binary asteroids slamming into Earth at the same time. ...However, scientists have theoretically determined that the binary asteroid scenario is unlikely. That’s because most binary asteroids are orbiting one another too closely to produce two distinct craters.... ...Now, Elmar Buchner, a geologist at the Neu-Ulm University of Applied Sciences in Nue-Ulm, Germany, and his colleagues have investigated the provenance of two impact craters near Stuttgart using observational data. They focused on the 24-kilometer-diameter Ries crater—which encompasses the town of Nördlingen—and the 4-kilometer-diameter Steinheim Basin, which are located roughly 40 kilometers from one another. ...The impact that created the Ries crater must have formed first, the scientists surmised, because blocks of limestone—ejecta from the Ries impact—cap the lower seismite horizon. That’s consistent with previous research suggesting that fossils within the Ries crater are a few hundred thousand years older than fossils found within the Steinheim Basin. This region “witnessed a double disaster in the Middle Miocene,” the team concluded in their paper, which was published last month in Scientific Reports.... [

2019-03-29. 66 million-year-old deathbed linked to dinosaur-killing meteor. By Robert Sanders, Berkeley News, UC Berkeley.

2019-03-29. Fossil Site Reveals Day That Meteor Hit Earth and, Maybe, Wiped Out Dinosaurs. By William J. Broad and Kenneth Chang, The New York Times. 

2019-01-17. Moon’s craters reveal recent spike in outer space impacts on Earth. By Paul Voosen, Science Magazine. 

2018-12-20. Huge Global Tsunami Followed Dinosaur-Killing Asteroid Impact. By Katherine Kornei, Eos/AGU. 

2018-11-14. International Team, NASA Make Unexpected Discovery Under Greenland Ice. NASA RELEASE 18-099. 

2018-08-08. Dinosaur-Killing Asteroid Impact Made Huge Dead Zones in Oceans. By Lucas Joel, Eos/AGU. 

2017-08-31. Big Space Rock to Pass near Earth on Friday. By Katherine Kornei, Eos/AGU. 

2017-06-25. Could Asteroids Bombard the Earth to Cause a Mass Extinction in 10 Million Years? By Sanna Alwmark, Matthias Meier, Scientific American. 

2017-04-06. Asteroid to Fly Safely Past Earth on April 19. By Jet Propulsion Laboratory News. 

2016-11-17. Updated: Drilling of dinosaur-killing impact crater explains buried circular hills. By Eric Hand, Science.

2016-07-14. Here’s how the world could end—and what we can do about it. By Julia Rosen, Science.

2016-03-29. Jupiter Got Whacked by Yet Another Asteroid/Comet! By Phil Plait, Bad Astronomy.

2016-01-07. NASA Office to Coordinate Asteroid Detection, Hazard Mitigation. NASA Feature.

2015-10-22. NASA Calls for American Industry Ideas on ARM Spacecraft Development. NASA Release 15-213.

2015-10-01. Volcano-asteroid combo may have done in the dinosaurs. By Sid Perkins, Science.

2015-01-13. Asteroid to Fly By Earth Safely on January 26. NASA Jet Propulsion Laboratory.

2014-11-15. New NASA map shows Earth bombarded by asteroids. By Shelby Lin Erdman, CNN.

2014 Feb. Video & animations of asteroid/meteroid impacts.  Produced by Jose Maria Madiedo, University of Huelva, and José Luis Ortiz, Andalusian Astrophysics Institute, on the occasion of the publication in Monthly Notices of the Royal Astronomical Society (MNRAS) of the paper entitled "A large lunar impact blast on 2013 September 11".

2013-02-15. Impact event over the Southern Ural Mountains at 3:20:26 UTC (9:20 AM local time in Chelyabinsk, Russia). Dome-L Planetarians' listserv. The meteor moved from East to West. It was also observed from Tyumen, Ekaterinaburg, and Northern Kazakhstan. Reports that a few fragments have been recovered ~80 km west of Chelyabinsk (near a village called Satka). Based on infrasound reports (9 stations reporting, one as far away as Alaska), the event lasted 32.5 seconds, corresponding to an equivalent yield of 470 kilotons TNT (which, in turn, equates to a size of ~17 meters; which, in turn, equates to a mass of ~10,000 metric tons). Velocity of impact: ~18 km/s (~40,000 mph). Largest reported fireball since Tunguska impact (1908 Jun 30). 1200+ people injured [no reported deaths] mostly from shattered glass. Blast wave damaged 3000+ structures (shallow graze, probably ~20 deg elevation; airburst and subsequent shockwaves from explosion). Why didn't we see it coming? (1) It came at us from 'out of the Sun'.  (2) Small objects like this (just under 20 meters) would likely be fainter than 25th mag--below our capability to detect right now. Compilation of videos:  There is no relation to the close approach of asteroid 2012 DA14 (same day, 15 Feb) as DA14 was on a South-to-North path over the Earth. [To see photos and videos of Asteroid 2012 DA14, visit Universe Today.]

2012-06-25. ‘Nature’s Masons’ Do Double Duty as Storytellers.  By Sean B. Carroll, New York Times.  Excerpt: GUBBIO, Italy — Excerpt: GUBBIO, Italy — …Limestone is composed largely of crystallized calcium carbonate. Some of it comes from the skeletal remains of well-known creatures like corals, but much of the rest comes from less appreciated but truly remarkable organisms called foraminifera, or forams for short. Forams have been called “nature’s masons,” … these single-celled protists construct surprisingly complex, ornate and beautiful shells to protect their bodies. After forams die, their shells settle in ocean sediments…. While tiny relative to ourselves …, forams are extremely large for single-celled organisms, … largest forams can reach a few centimeters. … forams are particularly valuable to geologists and paleontologists in telling us about Earth’s history. The forams in the limestone just outside Gubbio provided the first clues to … an asteroid that struck earth at the end of the Cretaceous period, 65 million years ago…about the size of Mount Everest and traveling at about 50,000 miles an hour when it hit the earth, drilling a 120-mile-wide crater and ejecting so much material into (and even out of) the atmosphere that food chains on land and in the oceans were disrupted for thousands of years. The impact caused one of the greatest mass extinctions in history, from the largest animals to tiny forams. …. Read the full article:

2012-05-16. NASA Survey Counts Potentially Hazardous Asteroid | NASA News Release 12-157. Excerpt: Observations from NASA's Wide-field Infrared Survey Explorer (WISE) have led to the best assessment yet of our solar system's population of potentially hazardous asteroids. The results reveal new information about their total numbers, origins and the possible dangers they may pose. …The project sampled 107 PHAs [potentially hazardous asteroids] to make predictions about the entire population as a whole. Findings indicate there are roughly 4,700 PHAs, plus or minus 1,500, with diameters larger than 330 feet (about 100 meters). So far, an estimated 20 to 30 percent of these objects have been found. While previous estimates of PHAs predicted similar numbers, they were rough approximations. …The new analysis also suggests that about twice as many PHAs as previously thought are likely to reside in "lower-inclination" orbits, which are more aligned with the plane of Earth's orbit. In addition, these lower-inclination objects appear to be somewhat brighter and smaller than the other near-Earth asteroids that spend more time far away from Earth. A possible explanation is that many of the PHAs may have originated from a collision between two asteroids in the main belt lying between Mars and Jupiter. A larger body with a low-inclination orbit may have broken up in the main belt, causing some of the fragments to drift into orbits closer to Earth and eventually become PHAs. For more information about WISE, visit: 

2012-05-07. Asteroid's Impact Still Central to Dinosaurs' Extinction | by JOHN NOBLE WILFORD, The NY Times. Excerpt: For some 30 years, scientists have debated what sealed the fate of the dinosaurs. Was an asteroid impact more or less solely responsible for the catastrophic mass extinction at the end of the Cretaceous geological period, 65 million years ago? Or were the dinosaurs already undergoing a long-term decline, and the asteroid was merely the coup de grâce? So three young researchers, led by Stephen L. Brusatte, a graduate student at Columbia University who is affiliated with the American Museum of Natural History, decided to test this hypothesis with a close examination of the fossil record over the 12 million years leading up to the mass extinction. For the study, the researchers departed from the practice of focusing almost exclusively on raw counts of the number of species over time. Instead, they analyzed changes in the anatomies and body plans of seven large groups of late Cretaceous dinosaurs for insights into their evolutionary trajectory….

2012-04-25. NASA Scientists Find History of Asteroid Impacts in Earth Rocks | by NASA, RELEASE : 12-135. Excerpt: … Research by NASA and international scientists concludes giant asteroids, similar or larger than the one believed to have killed the dinosaurs, hit Earth billions of years ago with more frequency than previously thought. To cause the dinosaur extinction, the killer asteroid that impacted Earth 65 million years ago would have been almost 6 miles (10 kilometers) in diameter. By studying ancient rocks in Australia and using computer models, researchers estimate that approximately 70 asteroids the same size or larger impacted Earth 1.8 to 3.8 billion years ago. During the same period, approximately four similarly-sized objects hit the moon….At least 12 mega-impacts produced spherule beds during the so-called Archean period 2.5 to 3.7 billion years ago, a formative time for life on Earth. Ancient spherule beds are rare finds, rarer than rocks of any other age. Most of the beds have been preserved amid mud deposited on the sea floor below the reach of waves. The impact believed to have killed the dinosaurs was the only known collision over the past half-billion years that made a spherule layer as deep as those of the Archean period. The relative abundance of the beds supports the hypothesis for many giant asteroid impacts during Earth's early history. …To learn about the NLSI, visit:

2012 Jan 23. Death of a Star.  By C. Claiborne Ray, New York Times. Excerpt: Q. As our Sun dies, what will happen to the planets, especially our own? A. In about five billion years, scientists estimate, the Earth will be engulfed and burned up in the expanding radius of the Sun as it evolves. This event will be about a million years after Venus and Mercury “have suffered the same fate,” according to updated calculations published in 2008 in the journal Monthly Notices of the Royal Astronomical Society. …As the Sun ages into a red giant, it will expand, losing mass and cooling somewhat, but remaining very hot. “While solar-mass loss alone would allow the orbital radius of planet Earth to grow sufficiently to avoid this ‘doomsday’ scenario,” the authors of the study conclude, the tidal interaction of the Sun and the closely orbiting planet “will lead to a fatal decrease” in the size of Earth’s orbit….

2011 July 1. Last Dinosaur Before Mass Extinction Discovered. EarthSky. Excerpt: A team of scientists has discovered the newest dinosaur preserved in the fossil record before the catastrophic meteor impact 65 million years ago, which many scientists believe caused their extinction. The finding indicates that dinosaurs did not go extinct prior to the impact and provides further evidence of the impact as cause of extinction. Results of the study appear online July 13, 2011 in the journal Biology Letters....

2011 Feb 2. NASA RELEASE 11-029: NASA's Neowise Completes Scan For Asteroids And Comets. Excerpt: WASHINGTON -- NASA's NEOWISE mission has completed its survey of small bodies, asteroids and comets, in our solar system. The mission's discoveries of previously unknown objects include 20 comets, more than 33,000 asteroids in the main belt between Mars and Jupiter, and 134 near-Earth objects (NEOs)...asteroids and comets with orbits that come within 28 million miles of Earth's path around the sun. NEOWISE is an enhancement of the Wide-field Infrared Survey Explorer, or WISE, mission that launched in December 2009. WISE scanned the entire celestial sky in infrared light about 1.5 times. It captured more than 2.7 million images of objects in space, ranging from faraway galaxies to asteroids and comets close to Earth. In early October 2010, after completing its prime science mission, the spacecraft ran out of frozen coolant that keeps its instrumentation cold. However, two of its four infrared cameras remained operational. These two channels were still useful for asteroid hunting, so NASA extended the NEOWISE portion of the WISE mission by four months, with the primary purpose of hunting for more asteroids and comets, and to finish one complete scan of the main asteroid belt.
 ...In addition to discovering new asteroids and comets, NEOWISE also confirmed the presence of objects in the main belt that already had been detected. In just one year, it observed about 153,000 rocky bodies out of approximately 500,000 known objects. Those include the 33,000 that NEOWISE discovered. ...The first batch of observations from the WISE mission will be available to the public and astronomical community in April…. For more information about WISE, visit: [Mission website -]

2010 September. Stars on Radio. By Kathleen M. Wong, Science Matters @ Berkeley. Excerpt: The radio sky to modern astronomers is much like the West was to Lewis and Clark. “It’s all very sparsely explored at this point,” says Geoffrey Bower. A Berkeley professor of astronomy, Bower is conducting systematic radio wavelength surveys of the heavens. Such comprehensive viewing goals, made possible by modern increases in data storage and processing abilities, were identified this August as among the highest priorities in astronomy by the National Academy of Sciences.
During his surveys, Bower expects to uncover not only new phenomena, but invent better ways to decipher the physics and structure of the universe.
...Bower has found one such tool by analyzing neutron stars. These ultra-dense collapsed stars can emit brief but astoundingly powerful bursts of radio wavelength energy…. Bower hopes to use these fleeting flashes to illuminate the spaces between galaxies.
...Bower’s radio surveys have already turned up another promising space exploration technique: astrometric planet hunting. …Radio measurements, they realized, yield measurements of a star’s position so precise that they could reveal the back-and-forth wobble caused by the orbit of a large planet. Bower is now using this method to search for extrasolar planets.

2010 August 23. Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies. By Committee to Review Near-Earth Object Surveys and Hazard Mitigation Strategies; National Research Council. Excerpt: The United States spends approximately $4 million each year searching for near-Earth objects (NEOs). The objective is to detect those that may collide with Earth. The majority of this funding supports the operation of several observatories that scan the sky searching for NEOs. This, however, is insufficient in detecting the majority of NEOs that may present a tangible threat to humanity....
...Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies identifies the need for detection of objects as small as 30 to 50 meters as these can be highly destructive...
...Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies is a useful guide for scientists, astronomers, policy makers and engineers.

2010 August 20. New Worlds, New Horizons in Astronomy and Astrophysics. By Committee for a Decadal Survey of Astronomy and Astrophysics; National Research Council Excerpt: The field of astronomy and astrophysics is making new connections to physics, chemistry, biology, and computer science....
...New Worlds, New Horizons in Astronomy and Astrophysics outlines a plan for ground- and space- based astronomy and astrophysics for the decade of the 2010's...
...The book recommends beginning construction on survey telescopes in space and on the ground to investigate the nature of dark energy, as well as the next generation of large ground-based giant optical telescopes and a new class of space-based gravitational observatory to observe the merging of distant black holes and precisely test theories of gravity. New Worlds, New Horizons in Astronomy and Astrophysics recommends a balanced and executable program that will support research surrounding the most profound questions about the cosmos...
...The discoveries ahead will facilitate the search for habitable planets, shed light on dark energy and dark matter, and aid our understanding of the history of the universe and how the earliest stars and galaxies formed.

2010 March 9. Alvarez Theory on Dinosaur Die-Out Upheld: Experts Find Asteroid Guilty of Killing the Dinosaurs. By Lynn Yarris, Lawrence Berkeley National Laboratory. Excerpt: In the March 5, 2010 edition of the journal Science, an international panel of 41 experts in geology, paleontology and other related fields, after an exhaustive review of the data, declared an end to a 30 year controversy over what triggered the extinction of the dinosaurs – an asteroid or volcanoes. The panel ruled in favor of the asteroid, a theory first put forth in 1980 by one of Berkeley Lab’s greatest scientists, the late Nobel laureate Luis Alvarez, and his son Walter, a geologist with UC Berkeley....

2009 October 26. Asteroid blast reveals holes in Earth's defences. By David Shiga, NewScientist. Excerpt: As the US government ponders a strategy to deal with threatening asteroids, a dramatic explosion over Indonesia has underscored how blind we still are to hurtling space rocks.
On 8 October an asteroid detonated high in the atmosphere above South Sulawesi, Indonesia, releasing about as much energy as 50,000 tons of TNT, according to a NASA estimate released on Friday. That's about three times more powerful than the atomic bomb that levelled Hiroshima, making it one of the largest asteroid explosions ever observed.
However, the blast caused no damage on the ground because of the high altitude, 15 to 20 kilometres above Earth's surface, says astronomer Peter Brown of the University of Western Ontario (UWO), Canada.
...The amount of energy released suggests the object was about 10 metres across, the researchers say. Such objects are thought to hit Earth about once per decade.
No telescope spotted the asteroid ahead of its impact. That is not surprising, given that only a tiny fraction of asteroids smaller than 100 metres across have been catalogued, says Tim Spahr, director of the Minor Planet Center in Cambridge, Massachusetts. Yet objects as small as 20 or 30 metres across may be capable of doing damage on the ground, he says....

2009 Oct 7. NASA RELEASE: 09-232, NASA REFINES ASTEROID APOPHIS' PATH TOWARD EARTH. Excerpt: PASADENA, Calif. -- Using updated information, NASA scientists have recalculated the path of a large asteroid. The refined path indicates a significantly reduced likelihood of a hazardous encounter with Earth in 2036.
The Apophis asteroid is approximately the size of two-and-a-half football fields. The new data were documented by near-Earth object scientists Steve Chesley and Paul Chodas at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
"Apophis has been one of those celestial bodies that has captured the public's interest since it was discovered in 2004," said Chesley. "Updated computational techniques and newly available data indicate the probability of an Earth encounter on April 13, 2036, for Apophis has dropped from one-in-45,000 to about four-in-a million."
...Initially, Apophis was thought to have a 2.7 percent chance of impacting Earth in 2029. Additional observations of the asteriod ruled out any possibility of an impact in 2029. However, the asteroid is expected to make a record-setting -- but harmless -- close approach to Earth on Friday, April 13, 2029, when it comes no closer than 18,300 miles above Earth's surface.
...NASA detects and tracks asteroids and comets passing close to Earth using both ground and space-based telescopes. The Near Earth-Object Observations Program, commonly called "Spaceguard," discovers these objects, characterizes a subset of them and plots their orbits to determine if any could be potentially hazardous to our planet. For more information about asteroids and near-Earth objects, visit:

2009 October 2. After Asteroid Strike, a Fast Rebound for Some. By Henry Fountain, The NY Times. Excerpt: The asteroid that struck the planet 65 million years ago was very bad for the dinosaurs, as everyone knows, but it wasn’t too good for smaller things, either. Even algae and other primary producers in the ocean were affected, probably because atmospheric debris from the impact reduced the sunlight available for photosynthesis.
But there is new evidence, reported in Science, that primary productivity in the oceans was not down for long. An analysis of sediments along a bluff in Denmark suggests that algae recovered in less than a century.
Julio Sepúlveda, a geochemist at the Massachusetts Institute of Technology and formerly at the University of Bremen in Germany, and colleagues studied a 15-inch layer of clay at Kulstirenden on the island of Zealand.
...Dr. Sepúlveda said the findings showed that “the most dramatic disruption in primary production was for a rather short period of time.” But the overall recovery of the oceans, particularly deep environments, took much longer....

2009 September 23. Space Scientists Weigh Technology, Diplomacy Challenges of Global Asteroid Threat. By Edward W. Lempinen, AAAS News. Excerpt: SAN FRANCISCO—Imagine this scenario: Astronomers discover a previously unknown asteroid. Though it is millions of miles away, initial calculations suggest that it will, in about 15 years, pass dangerously close to Earth. And though its size is modest—about 100 meters at its widest—it is more than big enough to destroy a major city.
If this were a conventional Hollywood thriller, the plot might focus on how nuclear weapons would be deployed and launched to destroy the menacing asteroid. But for former U.S. astronauts Rusty Schweickart and Edward Lu, any such mission to save the Earth would be far more complex. To create the greatest chance of success, they say, it should begin with ambitious science diplomacy and technology research and development long before the asteroid is discovered.
In a symposium at the annual meeting of the AAAS Pacific Division, Schweickart and Lu suggested that novel technology is available that would allow humans to closely track such an asteroid and to redirect its orbit. What's lacking, they said, is political recognition that asteroids will periodically threaten Earth in the future—and that the time to plan and prepare is now.
...They have proposed ambitious efforts to track and respond to threatening "Near-Earth Objects," or NEOs. The centerpiece of their strategy: A relatively simple, unmanned spacecraft that would fly to a suspect NEO and position itself close enough to exert a small pull of gravity; over a period of time, it would "tow" the object into a non-threatening orbit. NASA's Jet Propulsion Laboratory last fall concluded that the plan is viable....

2009 August 15. Report: NASA can't keep up with killer asteroids. By SETH BORENSTEIN, AP Science Writer. Excerpt: NASA is charged with spotting most of the asteroids that pose a threat to Earth but doesn't have the money to complete the job, a federal report says.
That's because even though Congress assigned the space agency that mission four years ago, it never gave NASA the money to build the necessary telescopes, according to the report released Wednesday by the National Academy of Sciences.
Specifically, the mission calls for NASA, by the year 2020, to locate 90 percent of the potentially deadly rocks hurtling through space. The agency says it's been able to complete about one-third of its assignment with the current telescope system.
NASA estimates that there are about 20,000 asteroids and comets in our solar system that are potential threats. They are larger than 460 feet in diameter — slightly smaller than the Superdome in New Orleans. So far, scientists know where about 6,000 of these objects are.
Rocks between 460 feet and 3,280 feet in diameter can devastate an entire region, said Lindley Johnson, NASA's manager of the near-Earth objects program. Objects bigger than that are even more threatening, of course.
Just last month astronomers were surprised when an object of unknown size and origin bashed into Jupiter and created an Earth-sized bruise that is still spreading. Jupiter does get slammed more often than Earth because of its immense gravity, enormous size and location.
...At the moment, NASA has identified about five near-Earth objects that pose better than a 1-in-a-million risk of hitting Earth and being big enough to cause serious damage, Johnson said....

2009 June 11. Planets will collide in 5 billion years. David Perlman, SF Chronicle Science Editor. Excerpt: From chaos we all began, and to chaos we'll all return, but not for a very, very long time - 5 billion years or so, more or less. In the journal Nature today, two French scientists, using arcane mathematical models, predict that in the distant future, the Earth and planet after planet will collide with each other as an inevitable part of the solar system's long-term evolution. For many millennia, the scientists say, the orbits of the solar system's eight planets will remain stable, just as they are today, but eventually small eccentricities in their flight paths around the sun could cause Mercury, Mars, Venus and Earth to smash into each other, either one at a time or all at once - the ultimate chaotic disaster. ... the prophets of eventual doom - astronomer Jacques Laskar and computer engineer Mickael Gastineau of France's Paris Observatory - calculate that the odds are 99-to-1 that the orbits of the four inner planets - Mercury, Venus, Earth and Mars - will remain stable for the full 5 billion years.
The time frame coincides with accepted theory that by the end of that same 5 billion years the sun will have burned up its hydrogen and in a cooler state will inflate itself into what's called a red giant star, engulfing the entire inner solar system while the planets are still colliding. So, either way, the planets of the inner solar system are safe for another 5 billion years, according to Laughlin....

2009 April 28. New Blow Against Dinosaur-killing Asteroid Theory, Geologists Find. NSF Press Release. The enduringly popular theory that the Chicxulub crater holds the clue to the demise of the dinosaurs, along with some 65 percent of all species 65 million years ago, is challenged in a paper to be published in the Journal of the Geological Society on April 27, 2009.

Neil DeGrasse Tyson: Death by Black Hole. Video of astrophysicist Neil DeGrasse Tyson discussing asteroid collision.

2009 January 1. Diamonds Linked to Quick Cooling Eons Ago. By Kenneth Chang, The New York Times. Excerpt: At least once in Earth’s history, global warming ended quickly, and scientists have long wondered why.
Now researchers are reporting that the abrupt cooling — which took place about 12,900 years ago, just as the planet was emerging from an ice age — may have been caused by one or more meteors that slammed into North America.
That could explain the extinction of mammoths, saber-tooth tigers and maybe even the first human inhabitants of the Americas, the scientists report in Friday’s issue of the journal Science.
The hypothesis has been regarded skeptically, but its advocates now report perhaps more convincing residue of impact: a thin layer of microscopic diamonds found in rocks across America and in Europe.
...At each site the scientists looked at, the diamond layer in the rocks correlates to the date of the hypothesized impact. Within the layer, the scientists report finding a multitude of diamond particles, all encased within carbon spheres. “We’ve yet to find a single diamond above it,” Dr. West said. “We’ve yet to find a single diamond below it.”
Perhaps more telling, the scientists reported last month at a meeting of the American Geophysical Union in San Francisco, the carbon atoms inside some of the diamonds are lined up in a hexagonal crystal pattern instead of the usual cubic structure. The hexagonal diamonds, formed by extraordinary heat and pressure, have been found only at impact craters and within meteorites and cannot be formed in forest fires or volcanic eruptions, Dr. West said....

2008 December. Meteorites from the Lone Rock, SK Strewn Field. Web page set up by Bruce McCurdy of the Edmonton Space & Science Foundation showing pictures of the recovery efforts of the meteor impact of 2008 November 20 at 5:26.43 MST.

2008 November 3. Astronomers hunt for Earth-bound killer rocks. By Charles Burress, San Francisco Chronicle. Excerpt: ...Giant rocks from space are hurtling toward us, on track to clobber our planet. But don't panic. Scientists say the next killer asteroid - unlike those that pummeled us in the past - can be deflected if we know about it far enough in advance.
So while many of us sleep, two Bay Area astronomers have recently begun standing sentinel against the cosmic cannonballs that could smash into Earth. Their big eye is "Nellie," the 36-inch reflecting telescope at the Chabot Space & Science Center in the Oakland hills.
"We've not discovered anything," said asteroid-tracker Gerald McKeegan, a member of the Eastbay Astronomical Society, which is affiliated with Chabot. "A lot of what we do is follow-up work."
..."You've got a rock, and now we have to figure out where that rock is going," said Chabot staff astronomer Conrad Jung. "We play a small but important role in trying to figure it out."
The Chabot center recently became the only Bay Area facility on active duty in the Earth-threatening asteroid search when it was selected to join an official worldwide network of observatories tracking potentially catastrophic "NEOs," - space talk for near Earth objects.
...Chances are small that Earth will be hit by an asteroid soon, but the consequences would be so enormous that the U.S. government and many experts around the world say we must begin to prepare. NASA's goal is to locate 90 percent of asteroids that could cause global disasters - those that come close to Earth's orbit and are larger than 1 kilometer in diameter - by the end of this year....

2008 Apr 15. Gauging a Collider's Odds of Creating a Black Hole. By DENNIS OVERBYE, NY Times. Excerpt: ... the Large Hadron Collider... starts smashing protons together this summer at the European Center for Nuclear Research, or Cern, outside Geneva, in hopes of grabbing a piece of the primordial fire, forces and particles that may have existed a trillionth of a second after the Big Bang.
Critics have contended that the machine could produce a black hole that could eat the Earth or something equally catastrophic.
To most physicists, this fear is more science fiction than science fact. ...In a paper published in 2000 with the title "Might a Laboratory Experiment Destroy Planet Earth?" Francesco Calogero, a nuclear physicist at the University of Rome and co-winner of the 1995 Nobel Peace Prize for his work with the Pugwash conferences on arms control, deplored a tendency among his colleagues to promulgate a "leave it to the experts" attitude. ...society has never agreed on a standard of what is safe in these surreal realms when the odds of disaster might be tiny but the stakes are cosmically high. In such situations, probability estimates are often no more than "informed betting odds," said Martin Rees, a Cambridge University cosmologist, the astronomer royal and the author of "Our Final Hour." ...the random nature of quantum physics means that there is always a minuscule, but nonzero, chance of anything occurring, including that the new collider could spit out man-eating dragons.
...Next year will see the release of the film version of "Angels and Demons," which the bad guys use a Cern accelerator to gather antimatter for a bomb to blow up the Vatican, and it includes scenes at Cern.
...Neither Dr. Calogero nor Dr. Rees say they are losing sleep over the collider. Some risk is acceptable, even inevitable, in the pursuit of knowledge, they say, and they trust the physicists who have built it....

2007 September 20. Meteorite likely caused crater in Peru. By MONTE HAYES Associated Press Writer. The Associated PressExcerpt: Peruvian astronomers said Thursday that evidence shows a meteorite crashed near Lake Titicaca over the weekend, leaving an elliptical crater and magnetic rock fragments in an impact powerful enough to register on seismic charts….
The Earth is constantly bombarded with objects from outer space, but most burn up in the atmosphere and never reach the planet's surface. Only one in a thousand rocks that that people claim are meteorites turn out to be real, according to Jay Melosh, an expert on impact craters and professor of planetary science at the University of Arizona….
Such impacts are rare, and astronomists still want to do other tests to confirm the strike…. Meteorites are actually cold when they hit Earth, astronomists say, since their outer layers burn up and fall away before impact…..
More details emerged when astrophysicist Jose Ishitsuka of Peru's Geophysics Institute reached the site about 6 miles from Lake Titicaca. He confirmed that a meteorite caused a crater 42 feet wide and 15 feet deep, the institute's president, Ronald Woodman, told The Associated Press on Thursday.
Ishitsuka recovered a 3-inch magnetic fragment and said it contained iron, a mineral found in all rocks from space. The impact also registered a magnitude-1.5 tremor on the institute's seismic equipment - that's as much as an explosion of 4.9 tons of dynamite, Woodman said….
Peasants living near the crater said they had smelled a sulfurous odor for at least an hour after the meteorite struck and that it had provoked upset stomachs and headaches….
Meteor expert Ursula Marvin said that if people were sickened, "it wouldn't be the meteorite itself, but the dust it raises...."

2007 March 16. The Sky Is Falling. Really. By RUSSELL L. SCHWEICKART (a former Apollo astronaut, is the chairman of the B612 Foundation, which promotes efforts to alter the orbits of asteroids). Tiburon, Calif. Americans who read the papers or watch Jay Leno have been aware for some time now that there is a slim but real possibility - about 1 in 45,000 - that an 850-foot-long asteroid called Apophis could strike Earth with catastrophic consequences on April 13, 2036. What few probably realize is that there are thousands of other space objects that could hit us in the next century that could cause severe damage, if not total destruction.

2007 January 6. What Landed in New Jersey? It Came From Outer Space. By KAREEM FAHIM. Excerpt: The object that tore through the roof of a house in the New Jersey suburbs this week was an iron meteorite, perhaps billions of years old and maybe ripped from the belly of an asteroid, experts who examined it said yesterday. landed - and ruined a second-floor bathroom - the meteorite is only the second found in New Jersey, said Jeremy S. Delaney, a Rutgers University expert who examined it. ...from looking at it, Dr. Delaney and other experts were able to tell that the object it had been part of - perhaps an asteroid - cooled relatively fast. It is magnetic, and reasonably dense, they determined. The leading edge - the one that faced forward as it traveled through the earth's atmosphere - was much smoother, while the so-called trailing edge seemed to have caught pieces of molten metal. ..."The worth of a meteorite like this is almost completely determined by where it fell," said Eric Twelker, a geologist and a dealer in meteorites, who buys and sells perhaps a hundred of them a month on, his Web site. He was speaking of the premium placed on meteorites with a compelling back story, like the football-size rock that crashed into a parked Chevrolet in Peekskill, N.Y., in 1992.

2006 November 14 Ancient Crash, Epic Wave. By SANDRA BLAKESLEE, NY Times. Excerpt: Did catastrophe fall from above in 2807 B.C.? Mega-tsunamis following meteor impacts left their mark, researchers say. At the southern end of Madagascar lie four enormous wedge-shaped sediment deposits, called chevrons, that are composed of material from the ocean floor. Each covers twice the area of Manhattan with sediment as deep as the Chrysler Building is high. On close inspection, the chevron deposits contain deep ocean microfossils that are fused with a medley of metals typically formed by cosmic impacts. And all of them point in the same direction - toward the middle of the Indian Ocean where a newly discovered crater, 18 miles in diameter, lies 12,500 feet below the surface. The explanation is obvious to some scientists. A large asteroid or comet, the kind that could kill a quarter of the world's population, smashed into the Indian Ocean 4,800 years ago, producing a tsunami at least 600 feet high, about 13 times as big as the one that inundated Indonesia nearly two years ago. The wave carried the huge deposits of sediment to land. Most astronomers doubt that any large comets or asteroids have crashed into the Earth in the last 10,000 years. But the self-described "band of misfits" that make up the two-year-old Holocene Impact Working Group say that astronomers simply have not known how or where to look for evidence of such impacts along the world's shorelines and in the deep ocean. ...Peter Bobrowski, a senior research scientist in natural hazards at the Geological Survey of Canada, said "chevrons are fantastic features" but do not prove that megatsunamis are real. There are other interpretations for how chevrons are formed, including erosion and glaciation... It is up to the working group to prove its claims, he said. ...Bruce Masse, an environmental archaeologist at the Los Alamos National Laboratory in New Mexico ...thinks he can say precisely when the comet fell: on the morning of May 10, 2807 B.C. Dr. Masse analyzed 175 flood myths from around the world, and tried to relate them to known and accurately dated natural events like solar eclipses and volcanic eruptions. ...14 flood myths specifically mention a full solar eclipse, which could have been the one that occurred in May 2807 B.C. Half the myths talk of a torrential downpour, Dr. Masse said. A third talk of a tsunami. Worldwide they describe hurricane force winds and darkness during the storm. All of these could come from a mega-tsunami. Of course, extraordinary claims require extraordinary proof, Dr. Masse said, "and we're not there yet."

Weather Photography has images of many types of weather/atmospheric phenomena.


22 November 2005. Asteroid Poses Tiny Danger, but It May Be Lured Away. By HENRY FOUNTAIN, NY Times. Excerpt: From a human perspective, Earth-crossing asteroids can have good timing or bad timing. Good timing is when the asteroid and the Earth don't meet. Bad timing is when they do. Astronomers say that a 1,000-foot diameter asteroid discovered last year may have bad timing. There is a slight possibility that the rock, 99942 Apophis, will hit Earth in 2036 after coming within about 20,000 miles in 2029. A collision could cause regional devastation on a scale far worse than last year's tsunami. "The most likely thing is that it is not going to be a threat," said Rusty Schweikart, the former Apollo astronaut and chairman of the B612 Foundation, which is concerned about protecting Earth from asteroids. "There's 5,499 chances out of 5,500 that it's going to miss us." The trouble with Apophis, Mr. Schweikart said, is that that one chance cannot yet be ruled out. Better optical and radar observations are needed to determine the asteroid's orbit, but the best measurements cannot be made until 2013.
That creates a different timing problem. If the threat from Apophis cannot be ruled out by then, will there be time to deflect it? Mr. Schweikart's group is not sure and has urged NASA to plan a robotic mission to put a radio transponder on the asteroid so that its orbit can be precisely determined. If such a mission takes 10 years to design and execute, it will still give plenty of time to plan and carry out a deflection mission. NASA has said that planning for a transponder mission can wait till after the more precise measurements are made in 2013. "I have a very high confidence that we can pinpoint exactly the track it's going to follow," said Andy Dantzler, director of NASA's solar system division. In the unlikely event that in 2013 a transponder mission would still be necessary, there would be enough time for that and a deflection mission, if needed, as well, he added. Mr. Schweikart said that NASA's response was "probably fine." But he added that it made "aggressive assumptions about how good things are going to be, and how much we're going to know." Edward T. Lu, a current astronaut and a board member of B612, ... and another astronaut, Stanley G. Love, have a proposal for how to go about deflecting the asteroid: by using a spacecraft to tow it, but without a tow line. In a brief paper in Nature, the two describe how such a gravitational tractor, hovering near an asteroid with its engines canted to avoid the exhaust's hitting the surface, can slowly pull it into a different orbit. The pulling force would only be about one newton, or roughly the amount of force used to hold a full cup of coffee. "But the point is, if you hang out long enough, it can add up to a substantial oomph," Mr. Lu said.

10 May 2005. NASA RELEASE: 05-120. NASA'S Chandra Observatory Catches X-ray Super-flares. New results from NASA's Chandra X-ray Observatory about the Orion Nebula imply super-flares torched our young solar system. Such X-ray flares likely affected the planet-forming disk around the early sun, and may have enhanced the survival chances of Earth. ..."We don't have a time machine to see how the young sun behaved, but the next best thing is to observe sun-like stars in Orion," said Scott Wolk of Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "We are getting a unique look at stars between one and 10 million years old - a time when planets form." A key finding is the more violent stars produce flares one hundred times as energetic as the more docile ones. This difference may specifically affect the fate of planets that are relatively small and rocky, like the Earth. "Big X-ray flares could lead to planetary systems like ours, where Earth is a safe distance from the sun," said Eric Feigelson of Penn State University in University Park. He is the principal investigator for the international Chandra Orion Ultradeep Project. "Stars with smaller flares, on the other hand, might end up with Earth-like planets plummeting into the star." According to recent theoretical work, X-ray flares can create turbulence when they strike planet-forming disks, and this affects the position of rocky planets as they form. Specifically, this turbulence can help prevent planets from rapidly migrating towards the young star. "Although these flares may be creating havoc in the disks, they ultimately could do more good than harm," said Feigelson. "These flares may be acting like a planetary protection program." Additional info at: &

6 April 2005. NASA Release 05-094. Explosions in Space May Have Initiated Ancient Extinction on Earth. Scientists at NASA and the University of Kansas say that a mass extinction on Earth hundreds of millions of years ago could have been triggered by a star explosion called a gamma-ray burst. The scientists do not have direct evidence that such a burst activated the ancient extinction. The strength of their work is their atmospheric modeling -- essentially a "what if" scenario. The scientists calculated that gamma-ray radiation from a relatively nearby star explosion, hitting the Earth for only ten seconds, could deplete up to half of the atmosphere's protective ozone layer. Recovery could take at least five years. With the ozone layer damaged, ultraviolet radiation from the Sun could kill much of the life on land and near the surface of oceans and lakes, and disrupt the food chain. Gamma-ray bursts in our Milky Way galaxy are indeed rare, but the scientists estimate that at least one nearby likely hit the Earth in the past billion years. Life on Earth is thought to have appeared at least 3.5 billion years ago.

18 February 2005. Cosmic Explosion Among the Brightest in Recorded History. NASA Feature. Scientists have detected a flash of light from across the Galaxy so powerful that it bounced off the Moon and lit up the Earth's upper atmosphere. The flash was brighter than anything ever detected from beyond our Solar System and lasted over a tenth of a second.... The scientists said the light came from a "giant flare" on the surface of an exotic neutron star, called a magnetar. .... The light was brightest in the gamma-ray energy range, far more energetic than visible light or X-rays and invisible to our eyes. Such a close and powerful eruption raises the question of whether an even larger influx of gamma rays, disturbing the atmosphere, was responsible for one of the mass extinctions known to have occurred on Earth hundreds of millions of years ago. Also, if giant flares can be this powerful, then some gamma-ray bursts (thought to be very distant black-hole-forming star explosions) could actually be from neutron star eruptions in nearby galaxies.


26 December 2004. About tsunami from asteroidal impacts: Deep-sea waves generated at contact by asteroids varying in diameter from 1-100km (unaffected by interaction with sea floor) could reach heights of about 1 km, according asteroidal impact modeling studies (e.g. Gisler, Weaver, et al. 2002). This would translate into multi-km wave heights upon arrival in shallow/shore waters. Thankfully, these are rather rare events, even by geological standards.

2004 Sound of the Big Bang


4 September 2002. NASA SCIENTISTS DETERMINED TO UNEARTH ORIGIN OF THE ITURRALDE CRATER. Excerpt: NASA scientists will venture into an isolated part of the Bolivian Amazon to try and uncover the origin of a 5 mile (8 kilometer) diameter crater there known as the Iturralde Crater. Traveling to this inhospitable forest setting, the Iturralde Crater Expedition 2002 will seek to determine if the unusual circular crater was created by a meteor or comet.

Our Home: Earth from Space --video -- (available fall 2002) Two student moderators engage the audience with satellite imagery, computer graphics, and historical footage to make the point that the Earth is an interconnected system of air, land, water, and life. The video includes segments on: An introduction to Earth system science; Using satellites to look at Earth from space; El Niño; Global Warming; Drought; Hurricanes (2:03), and An epilogue. Length: 22:00. The video can also be downloaded as QuickTime movies from: