Thursday, November 28, 2013

As earthquakes keep rocking North Texas, residents are rattled -- by The Extinction


Sent: Wed, Nov 27, 2013 11:35 pm
Subject: !!!!! [New post]
 As earthquakes keep rocking North Texas,
residents are rattled
-- by The Extinction Protocol

As earthquakes keep rocking North Texas, residents are rattled

November 27, 2013TEXAS -
On Tuesday morning, yet another earthquake rocked the small Tarrant County town of Azle. It was the sixth within a week in Tarrant and Parker counties. More than a dozen quakes have rattled North Texas in November.
Azle residents are getting nervous and seismologists are trying to get to the bottom of what’s going on.
Some point to natural gas drilling that’s happening in the Barnett Shale, a massive geological formation that covers about 20 North Texas counties.  But a geophysicist with the National Earthquake Information Center says more testing is needed to make such a connection.
Donna Luce is worried. “I was sitting there watching TV, and my house just shook, and I've never felt that before, ever,” she said. “Now, actually, I'm afraid of sinkholes.”
Debbie Raub and her husband, Fred, described the big quake with a 3.6 magnitude as “real spooky. Real loud boom, and then it just started shaking the ground under our mobile home,” she said. “Just rocking it. And our dogs, they go totally insane. They know it before it happens.” Each time there's a quake, their two-bedroom trailer has to be re-leveled. “You just have to get under there, and jack it up in spots, put a level on underneath the trailer, and level it,” Debbie Raub said. “It's just pulling the ground out beneath our stands.”
Fred Raub, who was born in Azle, says he doesn't think the quakes are natural. He blames local natural gas drilling. “They say it ain't what happens, but till then, we didn't have it,” he said. “You gotta drill about every mile. You just start looking around at all the drills they're putting down.”
Don Blakeman, a geophysicist with the National Earthquake Information Center, says the quakes could be the result of oil and gas production. But he says more testing is needed to know that for sure. ”Obviously, if it is oil and gas production related, they might continue until that activity stops,” he said. “The other possibility is that it's just a natural swarm, because we do see that sort of thing occurring sometimes in areas where we haven't had quakes before.”
A natural swarm is a series of small quakes. And Blakeman says they aren't as dangerous as quakes with bigger magnitudes – quakes at 5.0 magnitudes can produce structural damage.
 In the meantime, in case the ground starts to shake again, Blakeman advises individuals and families to be prepared if a bigger quake strikes North Texas.  Scientists and other experts are reportedly teaming up with the U.S. Geological Survey to collect more data to learn more about why these quakes keep occurring in North Texas. –KERA
The Extinction Protocol | November 27, 2013 at 6:17 pm | URL:

Sent: Wed, Nov 27, 2013 11:29 pm
  COMETS REALLY ARE ROCKY ASTEROIDS NOT PHONEY "DIRTY SNOWBALLS" >>> Rock Comet Sprouts a Tail -- NASA Science News for Nov. 27, 2013

NASA Science News for Nov. 27, 2013
"Rock comet" 3200 Phaethon has sprouted a tail, confirming that the mysterious object  is the source of the annual Geminid meteor shower.

Rock Comet Sprouts a Tail

Nov. 27, 2013: Astronomers have long been puzzled by a certain meteor shower.
Every year in mid-December the sky fills with flashes of light shooting out of the constellation Gemini.  The Geminids are fast, bright, and reliable.  They never fail to show up and many observers count them as the finest meteors of the year.
But where do they come from?  That is the puzzle.
A new ScienceCast video explores the mysteries of "rock comet" 3200 Phaethon.  Play it
Meteor showers are supposed to come from comets, yet there is no comet that matches the orbit of the Geminid debris stream. Instead, the orbit of the Geminids is occupied by a thing called "3200 Phaethon."  Discovered in 1983 by NASA's IRAS satellite, Phaethon looks remarkably like a rocky asteroid.  It swoops by the sun every 1.4 years, much like a comet would, but it never sprouts a dusty tail to replenish the Geminids.
That is, until now.
A group of astronomers led by Dave Jewitt of UCLA have been using NASA’s STEREO probes to take a closer look at 3200 Phaethon when it passes by the sun.  The twin spacecraft were designed to monitor solar activity, so they get a good view of sungrazing comets and asteroids.  In 2010 one of the STEREO probes recorded a doubling of Phaethon's brightness as it approached the sun, as if sunlight were shining through a cloud of dust around the asteroid. The observers began to suspect 3200 Phaethon was something new:
"A rock comet", says Jewitt. A rock comet is, essentially, an asteroid that comes very close to the sun--so close that solar heating scorches dusty debris right off its rocky surface. This could form a sort of gravelly tail.
Indeed, in further STEREO observations from 2009 and 2012, Jewitt along with colleagues Jing Li of UCLA and Jessica Agarwal of the Max Planck Institute have spotted a small tail sticking out behind the "rock."
This STEREO image of 3200 Phaethon reveals a stubby but distinct tail.  More
"The tail gives incontrovertible evidence that Phaethon ejects dust," says Jewitt. 
Jewitt's team believes that the dust is launched by thermal fracturing of the asteroid’s crust.  A related process called “desiccation fracturing”--like mud cracks in a dry lake bed--may play a role too.
Seeing 3200 Phaethon sprout a tail, even a small one, gives researchers confidence that Phaethon is indeed the source of the Geminids--but a mystery remains: How can such a stubby protuberance produce such a grand meteor shower?
Adding up all of the light STEREO saw in Phaethon’s tail, Jewitt and colleagues estimate a combined mass of some 30 thousand kilograms. That might sound like a lot of meteoroids but, in fact, it is orders of magnitude too small to sustain the massive Geminid debris stream. 
Perhaps Phaethon experienced a "big event" in the recent past. “The analogy I think of is a log in a campfire,” says Jewitt. “The log burns, makes a few embers, but occasionally will spit out a shower of sparks.”
Continued monitoring by NASA's STEREO probes might one day catch the rock comet spitting out a shower of dust and debris, solving the mystery once and for all.
Until then, it's a puzzle to savor under the stars.  This year's Geminid meteor shower peaks on the nights of Dec. 13-14 with dozens of “rock comet meteors” every hour. Bundle up and enjoy the show.
Author: Dr. Tony Phillips | Production editor: Dr. Tony Phillips | Credit: Science@NASA
More information:

EPSC 2013: Phaethon Confirmed as Rock Comet by STEREO Vision

The Sun-grazing asteroid, Phaethon, has betrayed its true nature by showing a comet-like tail of dust particles blown backwards by radiation pressure from the Sun. Unlike a comet, however, Phaethon’s tail doesn’t arise through the vaporization of an icy nucleus. During its closest approach to the Sun, researchers believe that Phaethon becomes so hot that rocks on the surface crack and crumble to dust under the extreme heat. The findings will be presented by David Jewitt on Tuesday 10 September at the European Planetary Science Congress (EPSC) 2013 in London.
Most meteor showers arise when the Earth ploughs through streams of debris released from comets in the inner solar system. The Geminids, which grace the night sky annually in December, are one of the best known and most spectacular of the dozens of meteor showers. However, astronomers have known for 30 years that the Geminids are not caused by a comet but by a 5 km diameter asteroid called (3200) Phaethon.
Until recently, though, and much to their puzzlement, astronomer’s attempts to catch Phaethon in the act of throwing out particles all ended in failure. The tide began to turn in 2010 when Jewitt and colleague, Jing Li, found Phaethon to be anomalously bright when closest to the Sun. The key to success was their use of NASA’s STEREO Sun-observing spacecraft. Phaethon at perihelion appears only 8 degrees (16 solar diameters) from the sun, making observations with normal telescopes impossible. Now, in further STEREO observations from 2009 and 2012, Jewitt, Li and Jessica Agarwal have spotted a comet-like tail extending from Phaethon.
“The tail gives incontrovertible evidence that Phaethon ejects dust,” said Jewitt. ‘That still leaves the question: why? Comets do it because they contain ice that vaporizes in the heat of the Sun, creating a wind that blows embedded dust particles from the nucleus. Phaethon’s closest approach to the Sun is just 14 per cent of the average Earth-Sun distance (1AU). That means that Phaethon will reach temperatures over 700 degrees Celsius – far too hot for ice to survive.”
The team believes that thermal fracture and desiccation fracture (formed like mud cracks in a dry lake bed) may be launching small dust particles that are then picked up by sunlight and pushed into the tail. While this is the first time that thermal disintegration has been found to play an important role in the Solar System, astronomers have already detected unexpected amounts of hot dust around some nearby stars that might have been similarly-produced.
So, is Phaethon an asteroid or a comet? Asteroids and comets derive from entirely different regions of the solar system; asteroids from between Mars and Jupiter (roughly 2 to 3.5 AU) and comets from the frigid trans-Neptunian realms (30 AU and beyond).
“By the shape of its orbit, Phaethon is definitely an asteroid. But by ejecting dust it behaves like a ‘rock comet’,” said Jewitt.
Zoomed, contoured STEREO image showing the south-eastward extension of the image of (3200) Phaethon. Credit: Jewitt, Li, Agarwal /NASA/STEREO
Movie showing Phaethon moving across the sky. Credit: Li/Jewitt/Agarwal /NASA/STEREO

No comments:

Post a Comment