Scientists have discovered a crater beneath Greenland's Hiawatha Glacier that they say could be one of the 25 largest impact structures on Earth.
It's a 31-kilometre-wide circular bedrock depression up to a kilometre below the ice and was likely caused by a fractionated iron asteroid about a kilometre wide.
Its impact would have had substantial environmental consequences in the Northern Hemisphere and perhaps even more widely, say the researchers, led by led by Kurt Kjær from the University of Copenhagen, Denmark.
The crater is the only one of its size that retains a significant portion of its original surface topography.
Comment: The Guardianreports a few more intriguing details:
Crater appears to be result of mile-wide iron meteorite just 12,000 years ago
An illustration of the ice-filled crater discovered in Greenland.
A huge impact crater has been discovered under a half-mile-thick Greenland ice sheet.
The enormous bowl-shaped dent appears to be the result of a mile-wide iron meteorite slamming into the island at a speed of 12 miles per second as recently as 12,000 years ago.
The impact of the 10bn-tonne space rock would have unleashed 47m times the energy of the Little Boy nuclear bomb dropped on Hiroshima in 1945. It would have melted vast amounts of ice, sending freshwater rushing into the oceans, and blasted rocky debris high into the atmosphere.
At 19.3 miles wide, the crater ranks among the 25 largest known on Earth and is the first to be found beneath an ice sheet.
"You have to go back 40 million years to find a crater of the same size, so this is a rare, rare occurrence in Earth's history," said Kurt Kjær, of the Natural History Museum of Denmark in Copenhagen.
Scientists first suspected a crater in 2015 when they spotted a huge depression in Nasa radar images of the bedrock beneath the Hiawatha glacier in north-west Greenland. Kjær, who passes a 20-tonne meteorite to reach his office every day, wondered if such a space rock might be the culprit. "It all snowballed from there," said Joseph MacGregor, a senior scientist on the team at Nasa's Goddard Space Flight Center in Maryland.
It so happened that researchers at the Alfred Wegener Institute in Germany were about to test a powerful new ice-penetrating radar system that was operated from the air. In May 2016 the scientists flew over the Hiawatha glacier and used the radar to map the underlying rock in unparalleled detail.
The images revealed all the hallmarks of an impact crater. "It became very clear that this was a circular feature with a rim around it and an elevated central region," said Kjær. The basin itself was more than 300 metres deep, according to a report in the journal Science Advances.
To search for solid proof of an impact, the researchers flew out to the glacier and collected sediments that had washed from the crater on to a nearby floodplain. Among the gathered grains, the scientists found particles of shocked quartz and other materials that are typically produced by the violence of a extraterrestrial impact. Geochemical tests of the grains suggest the meteorite was made of iron.
So far it has been impossible to put a firm age on the crater, but its condition suggests it formed after ice began to cover Greenland about 3 million years ago. But the crater may have formed much more recently. The radar images show that while the surface layers of the glacier immediately above the crater look normal,deeper layers that are older than 12,000 years are badly deformed and strewn with rocks, with some lumps as big as trucks.
"When it happened is the $64,000 question," said MacGregor. For a final answer, the researchers will need to drill through half a mile of ice and collect crater material for dating, or wait for rocks from the impact basin to be brought to the surface as the glacier flows to the sea. Either way, the scientists have a wait on their hands.
"We live on a planet where you can survey anything and you think you know everything," said Kjær. "But when you see such a big thing as this hiding in plain sight, you realise that the age of discovery is not over yet."
Two mystery 'explosions' were heard across large parts of Doncaster early this morning.
People across town reported hearing two loud bangs with residents in Edenthorpe, Kirk Sandall and Barnby Dun among those hearing the noise between 5.30am and 6am.
On Facebook, Fiona Stocks wrote: "what the hell were those two explosion sounds just now? They were too loud for a firework surely."
Nicola Bloore said: "I heard them as well," and Hilary Clayton said: "We heard them as well couldn't make out what they were."
Sharon Williamson posted: "Same sounds I heard last week too at about 4.50."
Astronomers at an observatory in Central Spain said they spotted two pieces of debris from space falling over the skies of southern Spain yesterday (Sunday).
Scientists at the La Hita observatory in Toledo said the fireballs, one a comet and the other an asteroid, fell within around two hours of each other.
They were also sighted by observers in the Calar Alto observatory in Almeria Province and those at the Granada Province-based La Sagra.
The first debris fell over Spain at around 2.08am yesterday morning. A University of Huelva team who analysed footage of it said it travelled over Andalucia at around 72,000 kilometres per hour before breaking up about 42 kilometres above Jaen Province.
A fireball - thought to be an exploding meteor - has been spotted in the sky over Leicestershire.
Amateur astronomer Derek Robson captured the spectacle from his back garden in Loughborough.
Dr Robert Massey, deputy executive director of the Royal Astronomical Society, confirmed the footage appeared to show a genuine fireball.
He said they occur in the UK a number of times each year but they were difficult to predict, so witnessing one or capturing it on camera came down to being in the right place at the right time.
This bright meteor event was spotted over southern Spain on 11 Nov. 2018 at 2:08 local time (1:08 universal time). It was generated by a rock from an asteroid that hit the atmosphere at about 72,000 km/h. The meteor overflew the province of Jaén.
It began at an altitude of about 90 km and ended at a height of around 42 km.
The event was recorded in the framework of the SMART project (University of Huelva) from the meteor-observing stations located at La Hita (Toledo), Calar Alto (Almeria), La Sagra (Granada) and Sevilla.
Dust associated with Comet Encke hits the Earth's atmosphere at 65,000 mph creating the Taurid meteor shower. Video of fireball near Lexington, KY taken Thursday, November 8th.
The Taurids are actually two separate showers, with a Southern and a Northern component. The Southern Taurids originated from Comet Encke and are active from September 10th to November 20th. They are known for being rich with fireballs. By the way, a fireball is just another word for a meteor brighter than the planet Venus. Despite the fact that we are past peak, Ron Malinowski saw this a couple hours ago looking north from Lexington, KY...
Saw part of the Turid Meteor Shower here looking north from Northern Lexington, KY on the drive home tonight looking North Time is ET (local time) #kywxpic.twitter.com/7pxHCiUkAD
See another blockbuster confirmation of the Younger Dryas cosmic impact below. I keep a pretty close eye on our subject but had no idea such intricate, original and thorough work was underway in the Czech Republic. Gunther Kleteschka has appeared on several YDB papers, but has clearly been busy in his own laboratory collecting entirely new, informative and well dated expressions of the YDB boundary in lake sediments. His work and that of his local colleagues is clearly exciting and in keeping with the predictions made by the Younger Dryas Impact Hypothesis.
Cosmic-Impact Event in Lake Sediments from Central Europe Postdates the Laacher See Eruption and Marks Onset of the Younger Dryas
Gunther Kletetschka,1,2,3,* Daniel Vondrák,4 Jolana Hruba,2 Vaclav Prochazka,2 Ladislav Nabelek,1,2 Helena Svitavská-Svobodová,5 Premysl Bobek,5 Zuzana Horicka,6,7 Jaroslav Kadlec,8 Marian Takac,2 and Evzen Stuchlik7
Institute of Geology, Czech Academy of Sciences, CZ-252 43 Průhonice 770, Czech Republic; 2. Institute of Hydrogeology, Engineering Geology and Applied Geophysics, Charles University, Albertov 6, CZ-128 43 Prague 2, Czech Republic; 3. Geophysical Institute, University of Alaska Fairbanks, 903 North Koyukuk Drive, Fairbanks, Alaska 99775-7320, USA; 4. Institute for Environmental Studies, Charles University, Benátská 2, CZ-128 01 Prague 2, Czech Republic; 5. Institute of Botany, Czech Academy of Sciences, Zámek 1, CZ-252 43 Průhonice, Czech Republic; 6. Branch of Applied Ecology, T. G. Masaryk Water Research Institute, Podbabská 30, CZ-160 00 Prague 6, Czech Republic; 7. Institute of Hydrobiology, Biology Centre, Czech Academy of Sciences, Na Sádkách 7, CZ-370 05 České Budějovice, Czech Republic; 8. Institute of Geophysics, Czech Academy of Sciences, Boční II 1401, CZ-141 31 Prague 4, Czech Republic
This stunning North Taurid meteor event was spotted over the south of Spain on 3 Nov. 2017 at 0:46 local time (23:46 universal time on 2 Nov.). It was brighter than the full Moon.
It was produced by a fragment from Comet Encke that hit the atmosphere at about 110,000 km/h.
The event overflew the Mediterranean Sea and the province of Almeria. It began at an altitude of about 122 km and ended at a height of around 63 km.
The meteor was recorded in the framework of the SMART project (University of Huelva) from the meteor-observing stations located at La Hita (Toledo), Sierra Nevada (Granada), La Sagra (Granada) and Sevilla.
With Halloween festivities been and gone, Mother Nature had a spooky and jaw-dropping show up her sleeve in the form of a fiery meteor blazing a trail across the sky near a US airport.
The fiery space rock, part of the annual Taurid meteor shower, was spotted in several locations above Alabama and Arkansas on Friday night. One video shows the speeding meteor falling from the sky near a US National Weather Service station at Shelby County Airport.
"We have about 50% of the world's wealth but only 6.3% of its population. This disparity is particularly great as between ourselves and the peoples of Asia. In this situation, we cannot fail to be the object of envy and resentment. Our real task in the coming period is to devise a pattern of relationships which will permit us to maintain this position of disparity without positive detriment to our national security. To do so, we will have to dispense with all sentimentality and day-dreaming; and our attention will have to be concentrated everywhere on our immediate national objectives. We need not deceive ourselves that we can afford today the luxury of altruism and world-benefaction."
~ US State Department, 1948
- George Kennan
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With no evidence of net, or even any, benefit, and clear evidence of a devastating death toll, this study's important findings show that even for...
Comment: The Guardian reports a few more intriguing details: And for more on the evidence of what was happening back then, check out: Of Flash Frozen Mammoths and Cosmic Catastrophes