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Mon, 19 Oct 2020
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Comets

Telescope

More on Holmes: Comet phenomenon is spotted in UK

A Devon astronomer was able to track the unexpected brightness of a comet with a telescope in the Canary Islands.

©n/a
The earth in relation to the comet is 244 million km (151 614 570 miles) away

Star

Planets, meteors and comets mean plenty to see in November's sky

Though the nights are definitely chillier now, there's much to see in the night sky worth getting out for, especially this month.

Dress warmly and head for a dark site away from city lights and enjoy the special treats on display for those with the fortitude to venture forth.

The show starts just after sunset, with Jupiter shining brightly low in the southwest sky. You'll have to be quick to spot Jupiter's four largest moons - Io, Europa, Callisto and Ganymede - as Jupiter will follow the sun below the horizon soon after darkness falls. On Nov. 12, look for the slender, three-day old crescent moon just to the lower left of Jupiter.

Telescope

Comet Holmes explodes in evening sky, now rivals Sun in size

The first literate humans, living in Mesopotamian cities like Ur and Erech more than 5,000 years ago, seemed to believe that comets caused bad things to happen or, at the very least, they foretold that bad things would happen. Either way, they regarded a new comet in the evening sky as a portent of some future disaster.

Telescope

Extinction by comet?

Overhunting. Abrupt climate change. Disease.

Scientists have cited those and other theories in their decades-old debate about why mammoths, mastodons, sloths, saber-toothed cats, camels, horses and other large creatures disappeared from North America at the end of the last ice age.

Comment: The fact that large scale cometary impacts have happened so relatively recently, and seem to happen in cycles, and are getting so much attention lately, makes one wonder if Something Wicked This Way Comes.
Right now, NASA is tracking 127 asteroids that have a very small chance of striking the planet. That number is about to get a lot higher. Stronger telescopes, and a new mandate from Congress, will allow scientists to detect thousands of smaller asteroids more likely to hit Earth. And scientists are plotting ways to stop them, from "gravity tractors" to solar ray guns. "There is no question that these will hit the Earth," says Russell Schweickart, a former Apollo astronaut who is involved in a group studying asteroids. "The question is how often we will have to do something about it." In fact, Schweickart thinks world leaders might have to do something about it very soon, within the next 15 years.
Stronger telescopes or more asteroids and comets?

And what would cause these cycles?
Cometary evidence of a massive body in the outer Oort cloud

Approximately 25% of the 82 new class I Oort cloud comets have an anomalous distribution of orbital elements that can best be understood if there exists a bound perturber in the outer Oort cloud. Statistically significant correlated anomalies include aphelia directions, energies, perihelion distances and signatures of the angular momentum change due to the Galaxy. The perturber, acting in concert with the galactic tide, causes these comets to enter the loss cylinder - an interval of Oort cloud comet perihelion distances in the planetary region which is emptied by interactions with Saturn and Jupiter. More concisely, the impulse serves to smear the loss cylinder boundary inward along the track of the perturber. Thus it is easier for the galactic tide to make these comets observable. A smaller number of comets are directly injected by the impulsive mechanism. We estimate that the perturber-comet interactions take place at a mean istance of  25000 AU. The putative brown dwarf would have a mass of 3 +/- 2M Jupiter and an orbit whose normal direction is within 5 degrees of the galactic midplane. This object would not have been detected in the IRAS database, but will be detectable in the next generation of planet/brown dwarf searches, including SIRTF. It is also possible that its radio emissions would make it distinguishable in sensitive radio telescopes such as the VLA.
The paper can be read here. Figures and tables are here.


Star

EXPLODING COMET: 17P-Holmes is now larger than Jupiter.

Astronomer Eric Allen of Quebec's Observatoire du Cégep de Trois-Rivières combined images he captured on three consecutive nights (Oct. 25, 26 and 27) and placed them beside a picture of Jupiter scaled to the same distance as the comet:

Click on above photo for animation.

Meteor

Something Wicked This Way Comes

War, rumors of war, corrupt governments run by psychopaths, phony terrorism, burgeoning police states...but is that all we have to worry about? What if there was something to put it all in context? Or rather, what if there is something else we are missing, something that is beyond the control of even the political and corporate elite; something that is driving them to attempt to herd the global population to an ever finer order of control...

A new sott.net video production:



SOTT's blog on Fireballs and Meteorites.

Better Earth

Sudden Naked-Eye Comet Shocks the Astronomy World

A distant comet that was as faint as magnitude 18 on October 20th has suddenly brightened by a millionfold, altering the naked-eye appearance of the constellation Perseus.

This startling outburst of Comet Holmes (17P) may be even stronger than the one that occurred 115 years ago, in November 1892, when the comet was first spotted by English amateur Edwin Holmes.

Telescope

Obscure Comet Brightens Suddenly

A small and very faint comet has surprised observers around the world by overnight becoming bright enough to see with the unaided eye.

Comet Holmes, which was discovered in November 1892 by Edwin Holmes, in London England, was no brighter than magnitude 17 in mid-October - that's about 25,000 times fainter than the faintest star that can normally be seen without any optical aid. In order to view an object this faint, one would need a moderately large telescope.

©Space.com
Comet Holmes' location as of Oct. 24th at 8 p.m. local time from midnorthern latitudes.

Bizarro Earth

Did a comet destroy civilization 12,900 years ago?

Did a comet kill the mammoths and destroy a civilization 12,900 years ago? S.C. site could provide evidence

Info

ESA's SOHO sights a periodic comet

The European Space Agency said its Solar and Heliospheric Observatory has sighted -- for the first time -- the third passage of a specific comet.

The space observatory, called SOHO -- a joint ESA project with the National Aeronautics and Space Administration -- has found more than 1,350 comets. But this is the first time it's found a rare type of comet called a periodic comet -- meaning it flies by the sun at regular intervals. While many SOHO-discovered comets are believed to be periodic, this is the first that's been officially declared as such, the ESA said.