Comets


Fireball

Now they tell us...Hazardous asteroids may be colliding with the planet 10 times more often than scientists have previously believed

Joel Achenbach
PressRepublican.com
Tue, 19 Nov 2013 13:29 UTC
Image
© NASAChelyabinsk rock
There are scads of building-size, potentially hazardous asteroids lurking in Earth's immediate neighborhood, and they may be colliding with the planet 10 times more often than scientists have previously believed, according to a new study published Wednesday that examined the airburst of a 25-million-pound asteroid earlier this year near the Russian city of Chelyabinsk.

Three studies released Wednesday, two in the journal Nature and one in the journal Science, have provided the most detailed description and analysis of the dramatic event on the morning of Feb. 15. Scientists now estimate the diameter of the object at just a hair under 20 meters, or about 65 feet. Undetected by astronomers, the rock came out of the glare of the sun and hit the atmosphere at 43,000 miles per hour.

As it descended through the atmosphere, it broke into fragments, creating a series of explosions with the combined energy of about 500 kilotons of TNT, making it more than 30 times more powerful than the atom bomb that destroyed Hiroshima in 1945, although the energy in this case was spread out over a much broader area.

The shock wave blew out windows in nearly half the buildings in Chelyabinsk. It knocked people off their feet; dozens were sunburned by the blinding flash, which at its peak was 30 times brighter than the sun. About 1,200 people were hurt, most by broken and flying glass, but no one was killed.

Comment: Here's a great book that sheds even more light on this 'ongoing problem', Laura Knight-Jadczyk's latest:

Comets and the Horns of Moses

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Comet 2

Near-Earth Object 2013 US10 (Catalina) turns out to be yet another comet entering the solar system!


JPL.NASA.gov
Wed, 06 Nov 2013 13:19 UTC
While initial reports from the Minor Planet Center in Cambridge, Mass., categorized object 2013 US10 as a very large near-Earth asteroid, new observations now indicate that it is, in fact, a long-period comet, and it is now designated C/2013 US10 (Catalina). The comet was discovered by the Catalina Sky Survey near Tucson, Ariz., on Oct. 31, 2013, and linked to earlier pre-discovery Catalina observations made on Sept. 12. The initial orbit suggested this object is a large, short period, near-Earth asteroid, as reported here yesterday.

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© NASA/JPL-Caltech The orbits of 2013 UQ4, 2013 US10 and 2013 UP8 are shown as viewed from within the plane of the solar system (ecliptic plane), which makes clear their highly inclined orbits relative to Earth's orbit.
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Comet 2

Comet ISON update: Comet sprouts spectacular 8-million-mile long tail!


Spaceweather.com
Sat, 16 Nov 2013 14:17 UTC
Reports of naked-eye sightings of Comet ISON are coming in from around the world. Experienced observers put the comet's magnitude at +5.5 on Nov. 16th. This means it is now fully 10 times brighter than it was only three days ago before the outburst. To the naked eye, ISON appears as a faint smudge of pale green light low in the pre-dawn sky. The view through a telescope is more dramatic. The comet's tail has become a riotous crowd of gaseous streamers stretching more than 3.5 degrees across the sky. Amateur astronomer Waldemar Skorupa sends this picture from Kahler Asten, Germany:
Comet ISON - Nov 16 2013
© Waldemar Skorupa
The tail is so long, he couldn't fit the whole thing in the field of view. How long is it? Comet ISON's tail extends more than 8 million kilometers behind the comet's nucleus. For comparison, that's 21 times the distance between Earth and the Moon.

Comment: "Fresh veins of ice"? Where do they get such tortured explanations from?!

Oh yes, we forgot, NASA still thinks comets are giant 'dirty snowballs'!

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Comet

'Comet of the century' set to light up the night sky as it skirts just 600,000 miles from the sun - if it avoids being vapourised by 2,700-degree heat

Dan Bloom
The Daily Mail, UK
Sat, 16 Nov 2013 12:50 UTC
  • Comet ISON will skirt 150 times closer than us to the sun on November 28
  • It will either light up in magnificent spectacle... or blast to smithereens
  • Comet has already become visible without a telescope for the first time
  • Some scientists have even claimed it could shine brighter than the moon
A comet which could become the brightest for a century is racing into our solar system, to the delight of astronomers.

Comet ISON will pass exceptionally close to the sun in just under a fortnight, creating a spellbinding cosmic spectacle as ice in its body vapourises and forms a distinct bright tail.

At least, it will if the heat does not blast the comet to smithereens - which scientists warn is not out of the question.

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Cosmic show: Comet ISON, which is heading to within 600,000 miles of our sun on November 28
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Comet 2

Comets ISON and Encke fly by Mercury November 18th and 19th, 2013

Deborah Byrd
EarthSky.org
Fri, 15 Nov 2013 13:28 UTC
On November 18, 2013, Comet Encke will pass within 0.025 AU of Mercury, followed a day later by Comet ISON at 0.24 AU (1 AU is the distance between the sun and Earth, 150 million km).

NASA's MESSENGER spacecraft, now orbiting Mercury, will turn away from the sun's innermost planet for a time and toward the passing comets. Astronomer Ron Vervack at the Johns Hopkins University Applied Physics Lab and a member of the science team for MESSENGER, called it:
... a unique coincidence and a golden opportunity to study two comets passing close to the sun.
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Comet 2

New Comet: C/2013 V5 (OUKAIMEDEN)

Ernesto Guido, Nick Howes & Martino Nicolini
Remanzacco Observatory
Fri, 15 Nov 2013 12:17 UTC
Cbet nr. 3713, issued on 2013, November 15, announces the discovery of an apparently asteroidal object (discovery magnitude ~19.4) by Michel Ory on CCD images obtained with a 0.5-m f/3 reflector at the Oukaimeden Observatory, Marrakech. The object has been found to show cometary appearance by CCD astrometrists elsewhere. The new comet has been designated C/2013 V5 (OUKAIMEDEN).

We performed follow-up measurements of this object, while it was still on the neocp. Stacking of 58 unfiltered exposures, 30-sec each, obtained remotely from MPC code Q62 (iTelescope, Siding Spring) on 2013, November 12.6 through a 0.43-m f/6.8 astrograph + CCD, shows that this object is a comet: diffuse coma about 10" in diameter elongated toward PA 300.

Below our confirmation image. Click here for a bigger version.

C/2013 V5
© Remanzacco Observatory
M.P.E.C. 2013-V95 assigns the following parabolic orbital elements to comet C/2013 V5: T 2014 Sept. 27.93; e= 1.0; Peri. = 314.39; q = 0.62; Incl.= 154.92
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Fireball 4

Ancient seawater entombed in ancient impact crater yields secrets


United Press International
Thu, 14 Nov 2013 15:35 UTC
The world's oceans 100 million to 145 million years ago were more than twice as salty as they are today, U.S. scientists studying ancient sediments say. Sediments retrieved from a crater formed when a 2-mile-wide asteroid or comet struck off the Atlantic coast of North America 35 million years ago containing remnants of Early Cretaceous North Atlantic seawater allowed them to make a direct estimate of the water's age and salinity, the researchers reported in the journal Nature.

"Previous evidence for temperature and salinity levels of geologic-era oceans around the globe have been estimated indirectly from various types of evidence in deep sediment cores," said Ward Sanford, a U.S. Geological Survey hydrologist and lead author of the study. "In contrast, our study identifies ancient seawater that remains in place in its geologic setting, enabling us to provide a direct estimate of its age and salinity."
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Comet

Comet ISON Breaking News: Huge outburst in pre-perihelion - Now visible to the naked eye


Astronomia.udea.edu
Thu, 14 Nov 2013 11:46 UTC
On November 13th 06:35 UT, Emmanuel Jehin from the Trappist telescope in Chile reported that the water production rate had increased by a factor of x2 in 24 hours. The value they were measuring was 2.0x10^28 molecules/s at 10.000 km. They suspected that an outburst was going on.

On November 13th, 06:51 UT Francois Kugel of the French group of observers, reported that they were seeing a magnitude increase of 1 magnitude in 24 hours.

(3) On November 14th, 01:42 UT, Nicolas Biver reports that comet ISON was visible to the naked eye. He measured magnitudes 8.1 on Nov. 12.2, 7.4 on Nov. 13.22, and 6.4 on Nov. 14.2.

Additional datasets are being reduced and we will show the results soon. A possible interpretation of these plots is that fragmentation has begun, and the larger exposed area is producing the outburst. We still lack visual evidence to confirm if the nucleus is intact or has begun its fragmentation. The outburst began at -0.66 AU from the Sun pre-perihelion, practically identically to the disintegration distance of comet Bressi.

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Comet 2

Comet ISON surged in brightness by approximately 2 magnitudes in little more than 24 hours


SpaceWeather
Thu, 14 Nov 2013 11:00 UTC
Multiple observers are reporting that Comet ISON brightened sharply last night. It started the week as an 8th magnitude object invisible to the human eye, but now it has surged to the threshold of naked-eye visibility. "The comet is definitely much brighter than before," says Brad Timerson of Newark, NY. "This morning it was an easy find in binoculars." Jim Saueressig II of Burlington, Kansas, adds that "under dark skies you may now possibly see it with adverted vision." In this picture taken just hours ago by Brian Emfinger of Ozark, Arkansas, the comet is passing by a comparison star of magnitude +6.25:
Comet ISON
© Brian Emfinger
Apparently, Comet ISON has surged in brightness by approximately 2 magnitudes in little more than 24 hours. If the trend continues, it could be a faint but easy naked-eye object by the end of the week.
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Fireball 3

New security cam video of meteor explosions over Slab City, California

Robi Hutton
Slab-City Official Website
Sat, 09 Nov 2013 00:00 UTC
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A Slab City Resident caught the 2013 Southern California Meteor Fireball Explosion on his security camera in the desert. This video shows that there were two explosions. The interesting part of this film is that it shows how bright the two flashes were. They lit up the whole desert like it was daytime.

This is from a camera filming the Security Cam TV as the owner did not know how to save and convert the file. It was filmed as the owner clicked frame by frame the action.
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