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Cuts cast doubt on asteroid plan

Plans to more precisely plot the orbit of an asteroid with a small chance of hitting Earth in 2036 may be badly hit by funding cuts to a US radar facility. Radar measurements set to be made in January 2013 by the Arecibo Observatory in Puerto Rico, US, could help rule out an impact by asteroid Apophis.

But the cuts mean Arecibo needs an extra $2m-$3m a year to continue.

If not, the observations planned for 2011-2013 will have to be abandoned, the facility's director told BBC News.

Dr Michael Nolan said he was "moderately optimistic" that the money could be found.

http://news.bbc.co.u...ech/8579319.stm

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It has been called the Big Freeze, the Last Blast of the Ice Age or -- to use the scientific name -- the Younger Dryas, and for climate experts it is one of the big mysteries of their field.

Around 12,900 years ago, Earth was on a steadily warming trend.

For nearly 100,000 years, the planet had been gripped in glaciation. Ice sheets placed a swathe of the northern hemisphere under a dead hand, extending their thrall as far as south as New England and Wales.

But just as the glaciers were beginning to retreat, and an easier life at last beckoned for Earth's small population of humans, everything went into reverse.

Temperatures fell dramatically by up to eight degrees Celsius (14.4 degrees Fahrenheit), heralding a cruel winter that would last 1,300 years.

But what caused it?

Crunching powerful equations and weighing fresh evidence, an astrobiologist in Britain is pointing the finger at an unusual culprit.

Earth collided with debris from a vast comet, measuring 50-100 kilometres (31-62 miles) across, that had wandered into the inner Solar System some 30,000 years ago before breaking up, says Bill Napier, a professor at Cardiff University's Astrobiology Centre.

http://news.yahoo.co..._20100402113312

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Comet "Shower" Killed Ice Age Mammals? Ancient extinction could be linked to annual Taurid meteors, study says

The comet that created the annual Taurid meteor shower was also responsible for snuffing out large mammals in North America 13,000 years ago, a controversial new study says.

The geologic record shows that global temperatures plummeted by as much as 14 degrees Fahrenheit (8 degrees Celsius) just as Earth was thawing out from the last ice age.

This cold snap probably led to the extinction in North America of large animals such as saber-toothed cats and wooly mammoths. But scientists have been unsure what triggered the abrupt change.

For more than 15 years, astrobiologists Bill Napier and Victor Clube have argued that the culprit was a 30- to 60-mile-wide (50- to 100-kilometer-wide) comet that entered the inner solar system—the region between the sun and the asteroid belt, just past Mars's orbit—20,000 to 30,000 years ago.

In the new study, Napier, of Cardiff University in the U.K., suggests that the huge comet settled into a new, faster orbit around the sun and began to break apart, creating fragments that pummeled Earth about 13,000 years ago.

http://news.national...-meteor-shower/

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WISE finding more asteroids

Most of the asteroids WISE is finding are in the main asteroid belt between Mars and Jupiter, but a fraction of them are different—they're the kind of Earth-approaching asteroids that send shivers all the way down a Brontosaurus' spine.

"WISE has only been in orbit for about three months, but we've already found a handful of asteroids classified as 'potentially hazardous,' including one seen in 1996 but lost until re-observed by WISE. To be named 'potentially hazardous,' an asteroid's orbit has to pass within about 5 million miles of Earth's orbit. One of our discoveries' orbit will cross Earth's orbit less than 700,000 miles away."

WISE tracks each potentially hazardous near-Earth object (NEO) it finds every three hours for up to 30 hours and then produces a "short track" predicting where it will be for the next few weeks. The WISE team sends all of this information to the NASA-funded Minor Planet Center in Boston. They post it on a publicly available NEO confirmation page, where scientists and amateur astronomers alike can continue to track the asteroid.

http://www.physorg.c...s189107151.html

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Asteroid to Fly by Within Moon's Orbit Thursday 15 April 2010

A newly discovered asteroid, 2010 GA6, will safely fly by Earth this Thursday at 4:06 p.m. Pacific (23:06 U.T.C.).

At time of closest approach 2010 GA6 will be about 359,000 kilometers (223,000 miles) away from Earth - about 9/10ths the distance to the moon. The asteroid, approximately 22 meters (71 feet) wide, was discovered by the Catalina Sky Survey, Tucson, Az.

"Fly bys of near-Earth objects within the moon's orbit occur every few weeks," said Don Yeomans of NASA's Near-Earth Object Office at the Jet Propulsion Laboratory in Pasadena, Calif.

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

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Does the Sun have a companion star - Nemesis - that could be responsible for periodic extinction events ?

http://www.lbl.gov/S...ns-nemesis.html

Note the article ends with

Quote

Humanity has never had to face the megablast of even one major comet impact. Perhaps the most important aspect of the Nemesis theory, and the one for which we as a species can be most grateful, is that the deadly little companion star is not due to return until the year 15 million A.D.

I beg to disagree and i you have been following this thread you will see my arguments for the occurrence of multiple large scale impacts during human history, and in the first post i put forward an alternative explanation for the cyclical nature of large scale impact events, namely the sun's transition through giant molecular clouds

From my first post -

Quote

Where do these comets come from ? It has been argued that they are made from matter that never made it into the main planets, others argue that the comets are the remamnets of an exploded planet or planets that collided.

A more interesting origin involves understanding how dynamic our solar system actual is. You see the sun orbits our galactic center ( and the galaxy orbits around within a cluster of galaxies)

Now differnet stars move at different speeds around the center of the galaxy, and stars pass through the spiral arms as they rotate ( the spiral arms are themselves dynamic) It takes about 250 million years for the sun to complete one orbit of the galactic center

At the same time the sun moves up and below the galactic plane in a cyclical fashion taking 120 million years to comple a single cycle

No one really knows what spiral arms are made of, it is thought that they are very dynamic and that the galactic core is constantly generating new ones and it is now thought that comets coalesce in the spiral arms, it takes about 50-100 million years for the sun to pass through a spiral arm and cou[led with the "up and down" cycles we think that the sun enters spiral arms every 30 milliom years or so

The sun also encounters Giant molecular clouds which can be inside spiral arms or outside them. these are star nurseries and also may contain many newly formed comets. In the suns lifetime it may have come close to a GMC on 50 occasions and possibly emtered some on 12 occasions

Whem the sun enters any of these comet rich areas it "grabs hold" of some comets which enter the oort cloud, others are knocked out of their orbits and spiral into the kuiper belt and there is a knock on effect which sends others into the inner solar system

This is a regular cycle of events with a 30 million year cycle modulated by another 250 million year cycle which can be directly linked to extinction events occuring on earth 94.5 million years ago, 65 million years ago and 36.9 million years ago. These can all be linked to massive earth impacts. We are due another extinction level event..now ..Unless of course it has occured..on mars

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Meteorite Wisconsin April 2010

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Peekside Meterorite 1992

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Meteor Edmonton Canada November 2008

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Bishop Gregory of Tours:

"580 AD in Louraine, one morning before the dawning of the day, a great light was seen crossing the heavens, falling toward the east. A sound like that of a tree crashing down was heard over all the countryside, but it could surely not have been any tree, since it was heard more than fifty miles away... the city of Bordeaux was badly shaken by an earthquake ... a supernatural fire burned down villages about Bordeaux. It took hold so rapidly that houses and even threshing-floors with all their grain were burned to ashes. Since there was absolutely no other visible cause of the fire, it must have happened by divine will. The city of Orleans also burned with so great a fire that even the rich lost almost everything."

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The Chinese records of lethal impact events include the death of 10 victims from a meteorite fall in 616 AD, an "iron rain" in the O-chia district in the 14th century that killed people and animals, several soldiers injured by the fall of a "large star" in Ho-t'ao in 1369, and many others. The most startling is a report of an event in early 1490 in Ch'ing-yang, Shansi, in which many people were killed when stones "fell like rain." Of the three known surviving reports of this event, one says that "over 10,000 people" were killed, and one says that "several tens of thousands" were killed.

On 14 September 1511, a meteorite fall in Cremona, Lombardy, Italy, reportedly killed a monk, several birds, and a sheep. In the 17th century we find reports of a monk in Milano, Italy, who was struck by a meteorite that severed his femoral artery, causing him to bleed to death, and of two sailors killed on shipboard by a meteorite fall in the Indian Ocean.

In addition to these shipboard fatalities, there have been several striking accounts of near disasters involving impacts very close to ships. Near midnight of 24 February 1885, at a latitude of 37 degrees N and a longitude of 170 degrees 15 minutes E in the North Pacific, the crew of the barque Innerwich, en route from Japan to Vancouver, saw the sky turn fiery red: "A large mass of fire appeared over the vessel, completely blinding the spectators; and, as it fell into the sea some 50 yards to leeward, it caused a hissing sound, which was heard above the blast, and made the vessel quiver from stem to stem. Hardly had this disappeared, when a lowering mass of white foam was seen rapidly approaching the vessel. The noise from the advancing volume of water is described as deafening. The barque was struck flat aback; but, before there was time to touch a brace, the sails had filled again, and the roaring white sea had passed ahead."

A strikingly similar event occurred only 2 years later on the opposite side of the world. Captain C.D. Swart of the Dutch barque J.P.A. reported in the American Journal of Meteorology 4 (1887) that, when sailing at 37 degrees 39 minutes N and 57degrees W, at about 5 pm on 19 March 1887, during a severe storm in which it was "as dark as night above," two brilliant fireballs appeared as in a sea of fire. One bolide "fell into the water very close alongside the vessel with a roar, and caused the sea to make tremendous breakers which swept over the vessel. A suffocating atmosphere and perspiration ran down every person's face on board and caused everyone to gasp for fresh air. Immediately after this, solid lumps of ice fell on deck, and everything on deck and in the rigging became iced, notwithstanding that the thermometer registered 19 degrees C."

On 20 August 1907, the steamship Cambrian arrived in Boston from England with an equally extraordinary tale to tell. When the ship was several hundred miles south of Cape Race, Newfoundland, steaming along under a clear sky, a brilliant fireball appeared near the northeastern horizon and "rushed across the sky like a rocket. The next moment it passed over the topmast of the liner with a tremendous roar and plowed up the sea about fifty yards from the boat. The upheaval of the water was terrific, but the ship was not damaged." The report of this event was carried in the New York Times.

Next, according to the Times, on 13 September 1930, a fireball plunged into the sea near Eureka, California, barely missing the tug Humboldt, which was towing the Norwegian motorship Childar out to sea. It requires little imagination to appreciate that such an event, if it were to strike a ship, should easily cause fatalities, or even the loss of the vessel with all hands. [Lewis, 1999]

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University of Alaska Fairbanks scientist Michael Whalen is part of a team of distinguished scientists who recently compiled a wide swath of evidence striking a definitive blow in the ongoing battle over what killed the dinosaurs.

In a review published in the March 5 issue of the journal Science, the research group reaffirmed the recently challenged theory that an asteroid ended the age of the dinosaurs.

Scientists first proposed the asteroid impact theory of dinosaur mass extinction 30 years ago. The discovery of a massive crater at Chicxulub [CHICK-shuh-loob], in Mexico’s Yucatán Peninsula in 1991, strengthened that hypothesis. The Chicxulub crater is more than 120 miles wide--about the distance from Fairbanks to the Arctic Circle--and scientists believe it was created when an asteroid more than six miles wide crashed into Earth 65 million years ago. The cataclysmic impact--a million times more powerful than the largest nuclear bomb ever tested--triggered massive earthquakes, atmospheric discharge and oceanic upheaval. The ensuing mass extinction ended both the reign of the dinosaurs and the Cretaceous period, which gave way to the Paleogene period. This theory, having steadily accumulated evidence, was thought to be a near-consensus view.

Recently, however, in a series of articles, researchers posed an alternate hypothesis for the mass extinction. Some scientists claim that long-term volcanic activity at the Deccan Traps, in what is now India, caused acid rain and global cooling, gradually making life untenable for the dinosaurs and other large animals. They also suggest that the Chicxulub impact occurred some 300,000 years before the mass extinctions.

The alternate hypothesis spurred Whalen and other Chicxulub impact proponents to respond. The current Science article dispels the Deccan Traps hypothesis, arguing that the geological record favors the Chicxulub impact event theory.

“It’s as tight a case for a synchronous chain of events as we can find in the fossil record,” Whalen said. Whalen is an associate professor at the UAF geology and geophysics department and the Geophysical Institute. He first began studying the Chicxulub site in 2002. His expertise is in carbonate rock, or limestone--a handy specialty, as limestone forms the layers above the Cretaceous-Paleogene geological boundary in the Chicxulub crater. He studied a 2001 core from the crater and compared it to seismic data gathered in 2006. His analysis offered insight on the geography of the area prior to impact, how it changed during the impact and the eventual infill of the crater by limestones deposited after the impact event.

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Pan-Starrs telescope begins operations to hunt asteroids

A new telescope facility in Hawaii designed to search for asteroids and comets which could threaten Earth has been made operational.

The Pan-STARRS 1 telescope will map large portions of the sky each night to track not only close space objects, but also exploding stars (supernovae).

The telescope has been taking science data for six months but is now operating from dusk-dawn each night.

Pan-STARRS 1 (PS1) is expected to map one-sixth of the sky every month.

http://news.bbc.co.u...nt/10340488.stm

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LOS ANGELES – Worried about Earth-threatening asteroids? One of NASA's newest space telescopes has spotted 25,000 never-before-seen asteroids in just six months.


http://news.yahoo.co...pping_telescope