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Fri, 27 Apr 2018
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Fire in the Sky


Update: Comet Lovejoy in the morning

Noted astronomer John Bortle urges observers (especially in the southern hemisphere) to "begin searching for Comet Lovejoy's bright tail projecting up out of the morning twilight beginning at dawn. The tails of some of the major sungrazing comets have been extraordinarily bright. Comet Lovejoy's apparition has been so bizarre up to this point that it is difficult to anticipate just what might happen next ... [including] the exact sort of tail it might unfurl in the morning sky."

UPDATE: This morning in New Zealand, Minoru Yoneto photographed the ghostly tail of Comet Lovejoy shining through the twilight:
© Minoru Yoneto

"I couldn't see the comet with my naked eye, but a 1.3 sec exposure with my Canon Kiss X2 digital camera revealed Lovejoy's long tail." In the clearer skies of Devonport, Tasmania, amateur astronomer Peter Sayers did see the tail with his unaided eyes--"but just barely," he says. "The tail was just naked-eye and perhaps a degree long in our Tasmanian summer early morning twilight." [image]


Russia's Failed Mars Probe Will Come Crashing Down to Earth Next Month, Space Agency Says

Russian Space Probe
© The Associated Press/The Canadian Press/Russian Roscosmos space agency/HO
In this Nov.2, 2011 file photo distributed by Russian Roscosmos space agency shows technicians working on the Phobos-Ground probe.
A Russian spacecraft bound for a moon of Mars and stuck in Earth's orbit will come crashing back next month, but its toxic fuel and radioactive material on board will pose no danger of contamination, the Russian space agency said Friday.

Between 20 and 30 fragments of the probe with a total weight of up to 200 kilograms (440 pounds) will survive the fiery plunge and shower the Earth's surface, Roscosmos warned in a statement.

The agency said the unmanned Phobos-Ground spacecraft will plummet to Earth between Jan. 6 and Jan. 19, and the rough area of where the fragments could fall could only be calculated a few days ahead of its plunge.

As of now, it said only that the probe's fragments could rain down anywhere along a broad swath between 51.4 degrees north to 51.4 degrees south, which would include most of land surface.

While the agency had lost contact with the probe following its launch on Nov. 9, this was the first time acknowledged that the $170-million craft has been lost and will come crashing down.

Since its November launch the engineers in Russia and at the European Space Agency have attempted unsuccessfully to propel it away from Earths orbit and toward its target.

Comment: SOTT wonders what is UP with all the recent alleged man-made space objects falling out of the sky? We've gone for years and years without this repeated showering of space-junk and now, all of a sudden, in just the past year, there have been at least three, and now four raining debris down on our heads? Is it possible that it is not really man-made and these explanations are being offered to cover up the fact that the planet is already being subjected to cometary fragment bombardment? Just asking.


Continued Adventures of Comet Lovejoy

The scorched core of sungrazing Comet Lovejoy is still intact as it recedes from the sun. Even the comet's flamboyant tail, temporarily lost in transit through the solar corona, has regrown. Click here to view the last 24 hours of coronagraph images from the Solar and Heliospheric Observatory (SOHO).

SOHO images show two tails: the ion tail and the dust tail. The ion tail is made of gas and is blown directly away from the sun by the solar wind. The heavier dust tail is curved and more closely traces the comet's orbit.

Now that the comet is more than five degrees from the sun, it is possible (albeit still not easy) for amateur astronomers to photograph it just before sunrise. A team led by Czech astronomer Jan Ebr captured this image at sunrise on Dec. 17th:


Comet Lovejoy Survives

Incredibly, sungrazing Comet Lovejoy appears to have survived its close encounter with the sun. Lovejoy flew only 140,000 km over the stellar surface during the early hours of Dec. 16th. Experts expected the icy sundiver to be destroyed. Instead, NASA's Solar Dynamics Observatory caught the comet emerging from perihelion (closest approach) at least partially intact:

SDO also recorded Comet Lovejoy's entry into the sun's atmosphere: movie.

Comet Lovejoy began the week as a chunk of dusty, rocky ice some 200 meters in diameter. No one can say how much of the comet's core remains intact or how long it will hang together after the searing heat of perihelion.


Comet Lovejoy Has a Friend!

Another Comet
© Sungrazer Blog
Click here to see animation.
This is too cute: Comet Lovejoy has a friend! Look in the upper-half of the animation opposite, starting at center and moving diagonally up and to the left, perfectly in step with Lovejoy... It's another Kreutz-group comet! (if you can't see it, here's a hint)

As nice as this is, I am not in the least surprised. SOHO's Kreutz-group comets are very "clumpy", for want of a better word. We frequently see them arrive in pairs or sometimes trios, and the big bright ones in particular will often have a companion comet. I suspected we would get at least one with Comet Lovejoy and indeed we do. It's much more typical of the size and brightness of Kreutz comets we see, and offers a wonderful comparison to highlight just how special Comet Lovejoy is.

So what is this new comet called? Is it another "Comet Lovejoy"? Sadly not. It looks to me like it was actually spotted in the LASCO C3 images by seasoned comet hunter Zhijian Xu at Dec 14 2011 11:48:48. So will it be Comet Xu?? No again. It will be Comet SOHO, number 2190-something, I think. Oh, and notice how it's orbit is obviously slightly different from Lovejoy's? That's also something we see all the time; the companion comets are frequently in slightly different orbits. They are obviously closely related though and the smaller one must have fragmented from Lovejoy some significant time ago, and with some slight (non-gravitational) force between them to "push" them apart like this. These kinds of break-ups are theorized to happen decades before they reach the Sun in order for them to have this kind of separation in space, though this process is not well-known or well-understood at all. It one reason that studying these Kreutz comets is so important, as this knowledge can be applied to all comets and solar system bodies, and give a broader understanding of their orbital and physical evolution.


Geminid Fireballs

On the night of Dec. 13/14, NASA's All-Sky Meteor Network recorded 35 fireballs streaking over the southern USA. Twenty-two of them had remarkably similar orbits:

Fireball Orbits
The clustered green orbits match the trajectory of near-Earth asteroid 3200 Phaethon, source of the annual Geminid meteor shower. The Geminids have been active this week as Earth passes through the asteroid's mysterious debris stream. The other, non-Geminid orbits correspond to random meteoroids. Not belonging to any organized debris stream, random meteoroids litter the inner solar system and produce a daily drizzle of "sporadic" fireballs.

NASA's fireball network, which connects multiple cameras in New Mexico, Alabama, Georgia and Tennessee, is a "smart" system. It rapidly and autonomously calculates meteoroid orbits from the fireballs it records. Another orbit diagram is just hours away; stay tuned.


Comet Lovejoy update - will it miss the sun?


Canada: Meteorite Alert! Remote Cameras Capture Slow-Moving Fireball near Toronto

Canadian Fireball
© University of Western Ontario
The huge fireball event as seen from a remote camera in Orangeville, Ontario.
In newly released footage from the University of Western Ontario, a bright, slow-moving fireball was captured in the skies near Toronto, Canada on December 12, 2011 by remote cameras watching for meteors. Although this meteor looks huge as it burns up in Earth's atmosphere, astronomers estimate the rock to have been no bigger than a basketball. Footage reveals it entered the atmosphere at a shallow angle of 25 degrees, moving about 14 km per second. It first became visible over Lake Erie then moved toward the north-northeast.

See below for the video.

But in a meteorite-hunter alert, Peter Brown, the Director of Western's Centre for Planetary & Space Exploration said that data garnered from the remote cameras suggest that surviving fragments of the rock are likely, with a mass that may total as much as a few kilograms, likely in the form of many fragments in one gram to hundreds of a gram size range.


Significant Comet Plunges in the Sun

A comet nearly as wide as two football fields (200m) is plunging toward the sun where it will most likely be destroyed in a spectacular light show on Dec. 15/16. Although Comet Lovejoy (C/2011 W3) could become as bright as Jupiter or Venus when it "flames out," the glare of the sun will hide the event from human eyes. Solar observatories in space, however, will have a grand view. Yesterday the brightening comet entered the field of view of NASA's STEREO-B spacecraft.

"You can clearly see the comet heading diagonally through the images," says Karl Battams of the Naval Research Lab who prepared the animation. "During the 16-hour sequence, the comet brightens from magnitude +8 to +6.5, approximately."

It will soon grow much brighter. "This comet is a true sungrazer, and will skim approximately 140,000 km (1.2 solar radii) above the solar surface on Dec. 15/16," notes Battams. At such close range, solar heating will almost certainly destroy the icy interloper,creating a cloud of vapor and comet dust that will reflect lots of sunlight. The Solar and Heliospheric Observatory (SOHO) will have a particularly good view.


US: Mysterious Explosion and Fireballs Seen as Homes Shaken in Rural Kentucky

There are still no answers as to what caused an apparent explosion in Perry County Sunday night.

Crews spent hours searching Sunday night after initial reports of a possible plane crash, but they gave up the search around 1:00 a.m. and said it was probably an explosion at an abandoned mine.

Now officials with the Division of Abandoned Mine Lands are saying there is no evidence at the mine that would support an explosion.

Some say they felt their homes shaking, others say they saw a fireball, but as of now no one can say for sure what happened in Perry County Sunday night.

Preliminary reports of possible plane crash were ruled out after searching for hours and finding no crash scene, that led officials to this explanation.