SEE ALSO: Life & Climate Chapter 9, What Happened to the Dinosaurs?
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.
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". http://www.youtube.com/watch?v=perqv4qByaI&feature=youtu.be
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: http://zyalt.livejournal.com/722930.html 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: http://www.nytimes.com/2012/06/26/science/natures-masons-do-double-duty-as-earths-storytellers.html?_r=1&emc=eta1
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: http://www.nasa.gov/wise
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: http://lunarscience.arc.nasa.gov
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: http://www.nasa.gov/wise [Mission website - http://wise.ssl.berkeley.edu/]
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
...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
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....
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....
Worlds, New Horizons in Astronomy and Astrophysics outlines a plan for
ground- and space- based astronomy and astrophysics for the decade of
...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,
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
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:http://www.jpl.nasa.gov/asteroidwatch
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
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
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
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
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," ...in which the bad guys use a Cern accelerator to gather
antimatter for a bomb to blow up the Vatican, and it includes scenes at
...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
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. ...it 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 http://meteoritemarket.com,
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
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
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
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: http://chandra.harvard.edu & http://chandra.nasa.gov
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
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 http://faculty.washington.edu/jcramer/BBSound.html
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.
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: http://education.gsfc.nasa.gov/video/.
2002 - present
General Astronomy Resources