Fire in the SkyS


Meteor

Move Over Global Warming, Let's Talk About Global Catastrophes

Susan Duclos
Digital Journal
Sun, 20 Jul 2008 05:00 UTC
Image
© Unknown
The Global Catastrophic Risks conference started yesterday morning and death by asteroids, comets and gamma ray bursts was on the agenda as experts discussed the statistical likelihood of these types of global catastrophes.

First up at the conference on Global Catastrophic Risks was the topic of asteroids, with David Morrison who is a NASA senior scientist. He spoke about the threat of a catastrophic asteroid strike and the Spaceguard Survey.

It is NASA's responsibility since 1998, to monitor the skies and detect near Earth asteroids that are larger than 1 kilometer in size, which is the size that, if it hit Earth, could end civilization.

Morrison stated that 80 percent of the near Earth asteroids that are 1 kilometer or larger have been identified and that he could assure those gathered at the conference that "We are not going the way of the dinosaurs." He also says the Spaceguard Survey has not turned up any near Earth asteroids as large as the one that is believed to have wiped out the dinosaurs.

Comment: No need to wait till the end of this century, as "one of man's important mistakes, one which must be remembered, is his illusion in regard to his I. Man such as we know him, the 'man-machine,' the man who cannot 'do,' and with whom and through whom everything 'happens,' cannot have a permanent and single I. His I changes as quickly as his thoughts, feelings and moods, and he makes a profound mistake in considering himself always one and the same person; in reality he is always a different person, not the one he was a moment ago. " ~ G I Gurdjieff

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Meteor

Best of the Web: 25 Sun-Diving Comets in 10 days?

Dr. Tony Phillips
Science@NASA
Fri, 14 Jan 2011 08:42 UTC
The sun has just experienced a storm - not of explosive flares and hot plasma, but of icy comets.

"The storm began on Dec 13th and ended on the 22nd," says Karl Battams of the Naval Research Lab in Washington, DC. "During that time, the Solar and Heliospheric Observatory (SOHO) detected 25 comets diving into the sun. It was crazy!"

Sundiving comets - a.k.a. "sungrazers" - are nothing new. SOHO typically sees one every few days, plunging inward and disintegrating as solar heat sublimes its volatile ices. "But 25 comets in just ten days, that's unprecedented," says Battams.


"The comets were 10-meter class objects, about the size of a room or a house," notes Matthew Knight of the Lowell Observatory in Flagstaff, Arizona. "As comets go, these are considered small."

SOHO excels at this kind of work. The spacecraft's coronagraph uses an opaque disk to block the glare of the sun like an artificial eclipse, revealing faint objects that no Earth-bound telescope could possibly see. Every day, amateur astronomers from around the world scrutinize the images in search of new comets. Since SOHO was launched in 1996, more than 2000 comets have been found in this way, an all-time record for any astronomer or space mission.

Battams and Knight think the comet-storm of Dec. 2010 might herald a much bigger sungrazer to come, something people could see with the naked eye, perhaps even during the day.

"It's just a matter of time," says Battams. "We know there are some big ones out there."
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Meteor

Some Comets Like it Hot - Comet Ikeya-Seki October 29, 1965

Dr. Tony Phillips
Science@NASA
Fri, 07 Jul 2000 08:51 UTC
Image
© Roger LyndsThis 4-minute exposure of comet Ikeya-Seki was captured by Roger Lynds at Kitt Peak, Arizona, on the morning of 1965 October 29.
July 7, 2000 -- In October 1965 comet Ikeya-Seki swooped past the Sun barely 450 thousand kilometers above our star's bubbling, fiery surface. Gas and dust exploded away from the comet's core as fierce solar radiation vaporized the icy nucleus. Most comets wouldn't survive passing as close to the Sun as the Moon is to the Earth, but Ikeya-Seki literally came through with flying colors. When the comet emerged from perihelion (closest approach to the Sun) it was so bright that observers on the street with very clear skies could see it during broad daylight if the Sun was hidden behind a house or even an outstretched hand.

"In Japan (where observers spied the comet 1/2 degree from the Sun) it was described as 10 times brighter than the Full Moon," recounted Brian Marsden of the Harvard Center for Astrophysics in the December 1965 issue of Sky & Telescope. "At Kitt Peak National Observatory in Arizona, Stephen Maran observed the comet with binoculars from within the shadow of a black disk erected to hide the Sun. '[It was] the most splendid thing I have ever seen,' he noted."

Ikeya-Seki, a.k.a. "The Great Comet of 1965", is a member of the family of comets called Kreutz sungrazers (after the nineteenth-century German astronomer who studied them in some detail). These ill-fated visitors to the inner solar system have been seen to pass less than 50,000 km above the Sun's photosphere. Most never make it past perihelion -- they are completely obliterated. But the few that do, like Ikeya-Seki, can be very bright.
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Meteor

Abnormal Sunbound comets may mean larger one to come


TheWeatherSpace.com
Thu, 13 Jan 2011 20:30 UTC
sun
© thewetherspace.com

In the last 10 days astronomers have counted at least 25 comets on the NASA SOHO Spacecraft, plunging into the Sun. It could mean a larger one ahead.

These comets could be part of a larger comet, according to astronomers. The comet may come without notice, much like the cosmic visitor named Comet Ikeya-Seki in 1965, which was seen in broad daylight and came without warning.

One candidate would be the newly discovered Comet 2010 X1 Elenin, which comes very close to our planet in the Fall of 2011. The comet will be so bright you can see it with the unaided eye even in a small city.
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Meteor

US: Possible Meteor Sighting in Arkansas

Robert Boyd
Los Angeles Times
Wed, 12 Jan 2011 11:15 UTC
fieball,meteor,arkansas
© theweatherspace.comLicensed to TheWeatherSpace.com, image of 1-11-11 Meteor from viewer in Little Rock, AR looking Southwest
There have been several reports, from Florida to Oklahoma, of people seeing a meteor streaking across the southern sky Tuesday night.

The sighting took place around 9 p.m. It is being described as a fireball that resulted in a bright flash. In pictures it looks like a greenish-blue streak, almost like lighting. It only lasted a second.

However, many pictures have also been identified as fakes so no one is 100 percent sure what the occurrence is.

According to astronomers, if it was a meteor it most likely contained copper which is why it gave off a greenish glow. It was also reported traveling southeast to northwest.

"Based on everyone's description instead of coming down it sounds like it came more across which gives it more time to burn up so more than likely it burned up in the atmosphere," said Stephen Meeks, amateur astronomer.

If it was a meteor it was a pretty rare sight, those types of meteors only occur five or six times a year in the United States, according to meteor expert Steve Arnold.
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Question

US: Big Boom Remains a Mystery

Chris Paschenko
The Daily News, Galveston
Thu, 13 Jan 2011 00:39 UTC
Galveston - Some island residents, firefighters, police and city hall officials heard a loud boom Wednesday, but the source of the noise remains a mystery.

Galveston Fire Chief Jeff Smith heard the explosion shortly before noon as he traveled on 12th Street.

City spokeswoman Alicia Cahill was at city hall, and police spokesman Lt. Jeff Heyse was at the police station when they heard the noise.

"We had several calls come into dispatch, and we sent an engine company out to investigate," Smith said.

One person called from 42nd Street, and the noise was heard as far west as 61st Street, Smith said.

"I was actually coming up on 12th street, and it was clearly a very loud noise," Smith said.

Firefighters found no fire and documented no sign of an explosion.
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Sun

Sundiving Comet Storm

Dr.Tony Phillips
NASA Science
Wed, 12 Jan 2011 20:28 UTC
The sun has just experienced a storm - not of explosive flares and hot plasma, but of icy comets.

"The storm began on Dec 13th and ended on the 22nd," says Karl Battams of the Naval Research Lab in Washington, DC. "During that time, the Solar and Heliospheric Observatory (SOHO) detected 25 comets diving into the sun. It was crazy!"

Sundiving comets - a.k.a. "sungrazers" - are nothing new. SOHO typically sees one every few days, plunging inward and disintegrating as solar heat sublimes its volatile ices. "But 25 comets in just ten days, that's unprecedented," says Battams.

"The comets were 10-meter class objects, about the size of a room or a house," notes Matthew Knight of the Lowell Observatory in Flagstaff, Arizona. "As comets go, these are considered small."

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Meteor

US: Meteor Over the Southern States


CNN
Wed, 12 Jan 2011 14:55 UTC
CNN takes a look at images of what could have been a meteor over the Southern states.

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Meteor

About four seconds warning: When heaven and earth collide


Herald Scotland
Sat, 08 Nov 2008 14:02 UTC
Image
© Unknown
Scientists have discovered evidence of a catastrophic meteorite strike in Scotland's distant past. Stephen Phelan visited the scene of our armageddon to find out how likely it is to recur - and how little warning we would have.

Long before Scotland was Scotland, when the population consisted only of green algae and the Highlands were as dry as Death Valley, a large natural object fell out of space and struck the Earth near where the village of Stoer now stands, in Sutherland. This incident occurred 1.2 billion years ago, but it has only been confirmed in the last few months. "If the same thing happened today," says planetary geologist Scott Thackrey, "all the trees in Aberdeen would be felled. The trees in Inverness would actually ignite. Most man-made structures would collapse. Everything made of paper would burn. You wouldn't be safe in Glasgow. But sitting here, we would be vapourised."

As it happens, we are sitting out a rainstorm in a rented car beside the Stoer church graveyard. And if tombstones are monuments to life's impermanence, then geologists serve to remind us that even the mountains and seas are not nearly as eternal as we tell ourselves.
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Meteor

Apocalypse then: How a comet ended the Roman Empire

Steve Connor
The Independent
Sat, 09 Sep 2000 13:51 UTC
Image
© Unknown
A close shave with a comet nearly 1,500 years ago caused a catastrophic change in the global climate, leading to famine, plague, the end of the Roman Empire, the birth of the Dark Ages and even the legend of King Arthur, a leading British scientist said at the British Association meeting in London yesterday.

Debris from the near miss bombarded the Earth with meteors, which threw enough dust and water vapour into the atmosphere to cut out sunlight and cool the planet to cause crop failure across the northern hemisphere. The cataclysmic famines weakened people's resistance to disease and led to the great plague of the emperor Justinian. It could also be responsible for the Arthurian stories about gods appearing in the sky followed by a fertile kingdom becoming a wasteland.

Mike Baillie, professor of palaeoecology at Queen's University in Belfast, said the central piece of evidence for a sudden global climate change about AD540 comes from the study of tree rings, which highlight the years when plant growth was poor or non-existent. "Oaks live for a long period and in order for a lot of them to show narrow rings at the same time it must have been a profoundly unpleasant event as far as the tree is concerned," Professor Baillie said.

"The event of AD540 is in or at the start of the Dark Ages and in my view probably caused the Dark Ages. It was a catastrophic environmental downturn which shows up in trees from Siberia, Scandinavia, northern Europe, north America and South America," he said. "The idea is that the Earth was hit by a 'cosmic swarm', a whole stack of cometary debris in a short period of time and that loaded the atmosphere with dust and debris and caused some sort of environmental downturn," Professor Baillie explained.

Tree rings round the world clearly indicate a major climate change unprecedented in the past two millenniums. This could have cooled the Earth by a few degrees, enough to cause crops to fail for several years in succession.

"It only requires a few degrees cooler conditions across the year for a few years, wiping out several consecutive harvests, and you've got a serious problem for any agricultural society," Professor Baillie said.
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