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Sun, 19 Aug 2018
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Comets

Fireball

'Oumuamua' - Definitely not your average asteroid or comet

Oumuamua
© SpaceRef
Oumuamua.
In October astronomers were surprised by a visitor that came racing into our Solar System from interstellar space. Now, researchers using the Gemini Observatory have determined that the first known object to graze our Solar System from beyond is similar to, but definitely not, your average asteroid or comet. "This thing is an oddball," said Karen Meech of the University of Hawaii's Institute for Astronomy who leads an international team studying this interstellar interloper.

Originally denoted A2017 U1, the body now goes by the Hawaiian name 'Oumuamua, in part because of its discovery by Meech's team using the Pan-STARRS1 survey telescope on Haleakala in Hawai'i. When discovered in mid-October 'Oumuamua was only about 85 times the Earth-Moon distance away and its discovery was announced in early November.

Since its discovery 'Oumuamua has faded from view. The object's rapidly increasing distance from the Earth and Sun now makes it too faint to be studied by even the largest telescopes.

"Needless to say, we dropped everything so we could quickly point the Gemini telescopes at this object immediately after its discovery," said Gemini Director Laura Ferrarese who coordinated the Gemini South observations for Meech's group.

Fireball

Crater in Rajasthan proven to be caused by a meteorite

Ramgarh Crater
© Hindustan Times
The Ramgarh Crater in Rajasthan’s Baran district.
For long the origin of the Ramgarh crater has been a subject of debate among researchers. While some believe that it was caused by 'meteorite impact', others are of the view that it evolved from 'tectonic' or 'structural' activity or 'magmatism'.

For years the crater - located near Ramgarh village, about 12 km east of Mangrol - has been considered as a 'meteorite impact' site, but the theory lacked unambiguous evidence. However, a study by geologist Satyanarayan Rana has found diagnostic evidence of 'meteorite impact' at the crater.

Rana, a research scholar at the department of geology, Mohanlal Sukhadia University (MSU), Udaipur, has found evidence in the form of shatter cones in sandstones, planar deformation features (PDFs) and planar fractures (parallel sets of multiple planar cracks) in quartz grains.

Shatter cones are rare geological features and are only known to form in the bedrock beneath meteorite impact craters or underground nuclear explosions. PDFs are also formed by extreme shock compressions on the scale of meteor impacts.

"This regional geological structure has invited the interest of various geologists throughout the world since its discovery and the past five decades have witnessed a number of theories on the origin of this structure, but the issue of origin remained debatable," the 33-year-old PhD researcher, who started his research in 2013 and he completed it in April this year.

Comet

Astronomers discover comet shaped like a giant pink fire-extinguisher

comet path
© NASA/JPL-Caltech/IAU
Previously known as C/2017 U1 (PANSTARRS) and A/2017 U1, approaching from above, it was closest to the Sun on 9 September. Traveling at 44 kilometres per second, the comet is headed away from the Earth and Sun on its way out of the solar system.
A newly discovered object from another star system that's passing through ours is shaped like a giant pink fire extinguisher, astronomers have revealed.

Astronomers who have been observing this first-ever confirmed interstellar visitor have named it Oumuamua, which in Hawaiian means a messenger from afar arriving first.

Scientists are certain this 600-foot-long, pale pink asteroid or comet originated outside our solar system.

'I'm surprised by the elongated shape - nobody expected that,' said astronomer David Jewitt of the University of California, Los Angeles, who led the observation team that reported on the characteristics.

Fireball

Meteor fireball caught on CCTV footage over South African city

Meteor over SA
© YouTube/Roodepoort Record
A meteor in full flight is a spectacular sight that most of us don't get to see in person up close. Where real life fails, technology and social media have stepped in to make sure we don't miss a thing.

The Roodepoort Record reports that a local resident and his wife made an interesting discovery while reviewing their CCTV footage. The man wanted to assist his neighbour in Vuurlelie Street after their dog was poisoned, so he thought he would take a look at the footage.

While they might not have found information about the dog, they did discover a meteor shooting through the sky around 9PM on Sunday.

While it only lasted a few seconds, the sheer brightness and apparent proximity of the object should be enough to satisfy your curiosity.

You can see the video of the event below.

Fireball

4 ways NASA plans to save us from Earth-bound asteroids

Divert, intercept, destroy: 4 ways NASA plans to save us from Earth-bound asteroids
© NASA
An Earth-bound asteroid would need to be spotted decades in advance if scientists are to have a chance of stopping a disaster.
Hollywood movies have long dramatised the threat of Earth being wiped out in by an asteroid discovered at the 11th hour, only for disaster to be averted by all-American heroes such as Bruce Willis, Ben Affleck or a gristly Robert Duvall.

As NASA's Planetary Defense Coordination Office uses the asteroid "2012 TC4" to test its ability to respond to the existential threat posed by Near Earth Objects (NEOs), we look at four methods the international community hopes could one day help us avoid going the way of the dinosaurs.

Comet 2

Newly discovered Comet Heinze (C/2017 T1) to zip past Earth in January

Just discovered, Comet Heinze (C/2017 T) will zoom by Earth in January and may just show up in your binoculars.

Comet Heinze (C/2017 T1)
© Mike Olason
Comet Heinze (C/2017 T1) was only a tiny, 17th-magnitude patch of fuzz with a short, fan-shaped tail on October 22nd.
Ah, 2017. A year busy with binocular-bright comets has been on the quiet side lately. But the recent discovery of Comet Heinze (C/2017 T1) by the University of Hawaiʻi's Ari Heinze gives comet watchers hope for a bright and fuzzy start to the new year.

Heinze searches for near-Earth asteroids with the Asteroid Terrestrial-impact Last Alert System (ATLAS) project, and came across the comet in images taken on October 2nd. The survey uses two telescopes, one at Mauna Loa Observatory on Hawaiʻi Island, and a second on the summit of Haleakala on Maui, about 100 miles to the northwest. Among other benefits, two widely-spaced "eyes" allow for distance determination using parallax, which also helps in calculating a new object's orbit.

Crusader

Witches, Comets and Planetary Cataclysms

witch1
© Dot Connector Magazine
When you think of Halloween, what is the first image that comes to mind? I took a little informal poll among my friends, family and associates. Guess what image came in first? Jack-o-lanterns! Bet you thought I was going to say "witches". Well, I sure thought it would be witches, but they only came in a close second!..

When I think of Halloween, I think of grade-school art projects where we cut out silhouettes of witches to paste onto large yellow moons made of construction paper. The witch was always on a broom with her black dress flying in the wind, accompanied by a black cat sitting on the back of the broom. I wondered even then how the cat managed to stay on and why anybody would think that straddling a broomstick as a seat would be even remotely comfortable.

Comet 2

First-known interstellar comet spotted by astronomers

Telescopes only picked it up a week ago, but it's likely been traveling through interstellar space for millions of years.
Comet PanSTARRS (C/2017 U1)
© NASA/JPL/Horizons
Comet PanSTARRS (C/2017 U1) raced within about 0.25 astronomical unit of the Sun in early September and is now relatively close to Earth. Based on its extreme orbit, astronomers believe it arrived here from interstellar space.
For centuries, skywatchers have chronicled the comings and goings of thousands of comets. Every one of them has come from someplace in our own solar system, either the Kuiper Belt beyond Neptune or the much more distant Oort Cloud at the fringes of the Sun's realm.

But an object swept up just a week ago by observers using the PanSTARRS 1 telescope atop Haleakala on Maui has an extreme orbit - it's on a hyperbolic trajectory that doesn't appear to be bound to the Sun. Preliminary findings, published earlier today by the International Astronomical Union's Minor Planet Center (MPC), suggest that we are witnessing a comet that escaped from another star.

"If further observations confirm the unusual nature of this orbit," notes Gareth Williams, the MPC's associate director, "this object may be the first clear case of an interstellar comet."

Fireball 4

Unidentified object, possibly a meteorite, crashes down near St. John's, Canada

Meteorite
© CBC News Canada
A security camera on the waterfront in St. John's captured this shot of a light falling from the sky near the South Side Hills, across the harbour.
Andrew Wilkins was eating dinner at a downtown St. John's pub, looking out over the city's iconic harbour, when a flash of green light caught his attention.

"The whole sky just lit up," he said. "It was coming in on a 45 degree angle, coming down to the right."

Wilkins stopped eating and stared as the moving ball of light crashed down on the opposite side of the harbour, towards the largely uninhabited Southside Hills area.

He paused to determine if he could hear a crash, but the noisy chatter of the busy pub prevented him from hearing any sound the flash of light may have made.

"It was like a big green ball of fire, is what it looked like. At first I thought, 'Wow, geez, that's a really bright firework,' but fireworks don't shoot downwards."

Fireball

Meteor explosion brightens southern Sri Lanka's skies

Meteor
© Daily Mirror, Sri Lanka
Colombo University Physical Science Department Prof. Chandana Jayaratne confirmed that the bright light and sound which was heard from the Southern Province (SP) this evening was because of an explosion caused by a meteor.

Speaking to the Daily Mirror he said the explosion was known as a 'fireball explosion' and occurs after an asteroid enters the earth's atmosphere.

"The asteroid could be a size of 50 centimetres. Every asteroid enters the earth's photosphere at a speed of 65 kilometers per second. With that speed one side of the asteroid gets heated up due to friction and the other side does not, therefore causing an explosion," Prof Jayaratne said.