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Tue, 24 Jan 2017
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Comets


Fireball 4

Brilliant green meteor fireball photographed over Southern India

© Prasenjeet Yadav
While exploring the sky islands of the Western Ghats in 2015, molecular ecologist turned photographer Prasenjeet Yadav shot a rather rare photograph with a green meteor up in the sky and the twinkling lights of the town below. It earned him a plethora of awards, including National Geographic Nature Photographer of the year, 2016, and also an Honourable Mention in the Landscape Category by National Geographic. The photograph was shot on October 9, 2015, and Yadav was at the Nilgiri's near Ooty when he shot the green meteor. The town he is overlooking is Mettupalayam.

"This is probably the only composed photo of a green meteor. No photographer can plan this shot. This can happen for a fraction of second anywhere in the universe, and the fun part is, I was sleeping when my camera captured it. Everything else was hard work but for those 15 seconds, I was the luckiest photographer on the planet," says Yadav, who was working on a story on sky islands of Western Ghats when he shot this. Along with bird ecologist Dr Robin Vijayan, Yadav was working on a project to understand the role these mountains play in the formation of new species.

Born in Nagpur, Yadav went to Bangalore to pursue research at the National Center for Biological Science. In 2013, he moved to photography and began concentrating on environment and conservation stories. He is reportedly the only Indian to be represented by the National Geographic Creative. Although he has stepped away from the academic realm, Yadav considers himself a non-traditional scientist and often collaborates with researchers, policy makers and conservationists for his projects in the world of nature photography. Currently, he is working on a story on the sky islands of southern India for National Geographic and is documenting the unseen species of amphibians, reptiles, birds and mammals found only in the south Western Ghats.

Fireball 2

Meteor fireball blazes across Siberian city of Omsk

© CEN
Motorists were given an extraordinary experience as the meteor blazed across the sky.
Motorists in the city of Omsk in Siberia were treated to the rare phenomenon as the falling space rock crashed to earth. The meteor, which appeared in the Omsk Oblast, appeared to be a massive fireball and was visible for miles. However experts say the flaring object was actually probably small enough to fit in your pocket.

Vladimir Krupko, head of the local planetarium, said: "Most likely it was a small meteorite, the size of a walnut.

"Since it was flying up high in the air, it was visible from other cities as well.

"When it entered the atmosphere it caught fire at about 120 kilometres (74.5 miles) above the ground, and by the time it was 40-60 kilometres (25-37 miles) above the ground the fire had gone out."

Despite there being plenty of larger objects whizzing around our solar system, no large meteorites, which are debris from a comet, asteroid, or meteoroid, are expected for at least 100 years, Mr Krupko said.

Comment: A few weeks ago two large meteor fireballs were caught on camera in northwestern Russia.


Sherlock

Lost 'Dark Age' Kingdom of Rheged uncovered in Scotland

A "lost" dark age kingdom has been discovered in Dumfries and Galloway after archaeologists finally solved the mystery surrounding the location of the elusive stronghold. The kingdom of Rheged has been found following excavation work by Gatehouse of Fleet in Dumfries and Galloway.

© GUARD Archaeology
A recreation of the royal stronghold of Rheged which has been discovered in Dumfries and Galloway.
Previously, it was thought the kingdom was headquartered in Cumbria although no evidence of it was ever found. Archaeologists were first drawn to the site by Pictish carvings in stones at Trusty's Hill given the unusual southerly location of the markings. But the team from GUARD Archaeology now believe the carvings belong to the stronghold of King Urien's where inauguration ceremonies for the Britons of Galloway were held around 600AD.

Ronan Toolis, who led the excavation, said: "The new archaeological evidence suggests that Galloway may have been the heart of the lost Dark Age kingdom of Rheged, a kingdom that was in the late sixth century pre-eminent amongst the kingdoms of the north." Excavations have revealed the summit of the hill was fortified with a timber-laced stone rampart.

Fireball 2

Are we next? Researchers reconstruct the dark and frozen conditions on Earth after asteroid megastrike

The apocalyptic time that many believe wiped out the dinosaurs has been reconstructed by scientists in unprecedented detail. They found tiny droplets of sulfuric acid formed high up in the air after the well-known impact of a large asteroid 66 million years ago, blocking the sunlight for several years.

They say this 'big chill' had far more catastrophic effects that first thought, causing global temperatures to plummet for three years, even mixing oceans and killing off sea life.
'The big chill following the impact of the asteroid that formed the Chicxulub crater in Mexico is a turning point in Earth history,' says Julia Brugger from the Potsdam Institute for Climate Impact Research (PIK), lead author of the study to be published today in the Geophysical Research Letters.

'We can now contribute new insights for understanding the much debated ultimate cause for the demise of the dinosaurs at the end of the Cretaceous era.'

Comet 2

New Comet: C/2017 A3 (Elenin)

MPEC nr. 2017-A75, issued on 2017, January 11, announces the discovery of a comet (magnitude ~18.2) by L. Elenin on CCD images obtained with 0.4-m f/2.4 reflector + CCD at the ISON-SSO Observatory, Siding Spring on Jan. 5.4 UT. The new comet has been designated C/2017 A3 (Elenin).

I performed follow-up measurements of this object, while it was still on the neocp. Stacking of 20 unfiltered exposures, 120 seconds each, obtained remotely on 2017, Jan 06.5 from Q62 (iTelescope network) through a 0.50-m f/6.8 astrograph + CCD + f/4.5 focal reducer, shows that this object is a comet with a compact coma nearly 10 arcsec in diameter elongated toward PA 40.

My confirmation image (click on it for a bigger version)
© Remanzacco Blogspot
M.P.E.C. 2017-A75 assigns the following preliminary parabolic orbital elements to comet C/2017 A3: T 2017 Jan. 20.6; e= 1.0; Peri. = 301.87; q = 3.91; Incl.= 99.12

Comet 2

Another close shave: Asteroid discovered 4 days ago whizzes past Earth

© Erik Simonsen / Getty Images
An asteroid between 11 to 34 meters across (36 to 111ft), roughly the size of 10 jumbo African elephants, made a remarkably close approach to Earth on Monday morning, passing by at a distance only half that of the Moon.

According to the Slooh Observatory, the space rock, dubbed 2017 AG13, was moving at about 10 miles per second, making it hard to spot with a telescope.

"This is moving very quickly, very nearby to us," Eric Edelman, an astronomer with Slooh, said during a live broadcast of the surprise flyby at 7:47am ET on January 9.

Fireball

NASA's Near-Earth Object hunting mission spots a Comet and a body that's 'either a Comet or an asteroid'

On Thursday, NASA's Near-Earth Object Wide-field Survey Explorer (Neowise) mission announced the discovery of two objects — one of which is a comet while the other is a mysterious object that seems to straddle the line between a comet and an asteroid.

The comet, C/2016 U1 NEOWISE, made its closest approach to Earth on Dec. 12, when it flew by at a distance of 0.71 AUs (1 AU, or the mean distance between Earth and the Sun, is roughly 93 million miles). As it nears the sun, there is "a good chance" that it might be seen with a pair of binoculars next week, although it's hard to be certain, given the unpredictable nature of a comet's brightness.

"As seen from the northern hemisphere during the first week of 2017, comet C/2016 U1 NEOWISE will be in the southeastern sky shortly before dawn," NASA said in a statement. "It is moving farther south each day and it will reach its closest point to the sun, inside the orbit of Mercury, on Jan. 14, before heading back out to the outer reaches of the solar system for an orbit lasting thousands of years. While it will be visible to skywatchers at Earth, it is not considered a threat to our planet."

The nature of the other object, named 2016 WF9, is less clear. Scientists at NASA believe that given its 4.9-year-orbit — which, at its closest approach on Feb. 25, will bring it to a distance of roughly 32 million miles from Earth — it can have multiple possible origins. It may once have been a comet, or it may be a dark asteroid that has strayed from the asteroid belt.


Fireball 2

Comet 45P to make New Year's Eve Northern Hemisphere appearance

Even if you're not a fan of New Year's Eve fireworks, you'll have another reason to look to the skies Saturday. NASA says that as we ring in the new year, a comet will near the moon and be visible to those looking west.

But here's the catch — you'll need a pair of binoculars to see it. NASA says comet 45P/Honda-Mrkos-Pajdušáková, named for the astronomers who discovered it in 1948, takes 5.25 years to complete its orbit.This year, it was first visible on the low western horizon on Dec. 15. On New Year's Eve, it will appear in the sky right near the moon.
© NASA
The comet will be observable from the Northern Hemisphere of the planet, and here's an easy way to check if it will be visible in your location on New Year's — go to TheSkyLive.com. It will reach its perihelion — the point of orbit when an object is closest to the sun — on New Year's Day, making its orbit around the sun and disappearing from visibility from Earth. It will be viewable, and reach its maximum brightness, once it swings back around the sun in 2017.

Comet

Comets & Asteroids - Summary for November 2016

During the months of November 2016, 1 new comet has been discovered. "Current comet magnitudes" & "Daily updated asteroid flybys" pages are available at the top of this blog (or just click on the underline text here).

The dates below refer to the date of issuance of CBET (Central Bureau Electronic Telegram) which reported the official news & designations.

© K. Battams & M. Knight
Comet Discoveries

Nov 03 Discovery of C/2016 U1 (NEOWISE)

Other news

Nov 02 Newly discovered asteroid 2016 VA came to about 90.000 km from the Earth's surface on the second day of November, reaching magnitude 12. It crossed the Earth shadow for a few minutes (between 23:24-23:35 UT on Nov 01, just 0.3 LD from Earth), challenging astronomers to observe a peculiar "asteroidal eclipse".

Below you can see an animation showing this spectacular event as observed by G. Masi (Virtual Telescope Project). According to Masi: "Each frame comes from a 5-seconds integration. At the eclipse time, the asteroid was moving with an apparent motion of 1500"/minutes".

Comet 2

Incoming star Gliese 710 could spawn swarms of comets when it passes our Sun

© ESO
Artist’s impression of Gliese 710, a sun-like star that will travel through our Solar System’s Oort Cloud in about 1.3 million years.
For years, scientists have known that Gliese 710 will come excruciatingly close to our Solar System in about a million years. An updated analysis suggests this star will come considerably closer than we thought, during which time it's expected to spawn dangerous cometary swarms.

Gliese 710 is currently 64 light-years from Earth, but for all intents and purposes, it's heading straight for us. A new study published in the journal Astronomy and Physics projects the close encounter will happen about 1.35 million years from now, and that the star will come within 13,365 AU of our sun (where 1 AU is equal to the average distance of the Earth to the sun), or 1.2 trillion miles. At that distance, it would take light 77 days to reach the Earth.

That's obviously far, but not in cosmological terms. That distance is well within the Solar System's Oort Cloud—a large bubble of ice and rock that surrounds the sun to a distance as far as 50,000 to 200,000 AU. So while Gliese 710 is sure to avoid a direct hit with any object in the inner Solar System, it'll likely travel through the Oort Cloud. And with its tremendous gravitational influence (it's about 60 percent the size of our sun), it'll perturb the many large rocks currently sitting idle way out there in the outer reaches. This star is poised to send a shower of comets into the inner Solar System, possibly causing a serious impact event with Earth.