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Mon, 30 Nov 2020
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Fireball 5

Tunguska explosion in 1908 caused by asteroid grazing Earth says new theory

A new theory explains the mysterious explosion in Siberia, scientists say, suggesting Earth barely escaped a far greater catastrophe.
Asteroid
© Dotted Yeti/Shutterstock
In the early morning of June 30, 1908, a massive explosion flattened entire forests in a remote region of Eastern Siberia along the Tunguska River. Curiously, the explosion left no crater, creating a mystery that has puzzled scientists ever since — what could have caused such a huge blast without leaving any remnants of itself?

Now Daniil Khrennikov at the Siberian Federal University in Russia and colleagues have published a new model of the incident that may finally resolve the mystery. Khrennikov and co say the explosion was caused by an asteroid that grazed the Earth, entering the atmosphere at a shallow angle and then passing out again into space.

"We argue that the Tunguska event was caused by an iron asteroid body, which passed through the Earth's atmosphere and continued to the near-solar orbit," they say. If they are correct, the theory suggests Earth escaped an even larger disaster by a hair's breadth.

First some background. Scientists have long speculated on the cause of the Tunguska impact. Perhaps the most widely discussed idea is that the explosion was the result of an icy body, such as a comet, entering the atmosphere. The ice then rapidly heated up and evaporated explosively in mid-air but without ever hitting the ground.

Fireball 4

Meteor fireball lights up Mexican skies and rains fire on northern states

Meteor Fireball
© AMS Meteors Org
Residents across northeastern Mexico were stunned when a green-hued fireball lit up the night sky on Tuesday. Authorities reported that the fiery debris caused localised bushfires in the vicinity.

Reports came flooding in from across the northern state of Nuevo Leon after the suspected meteorite streaked across the sky at approximately 22:14 local time on Tuesday night.

Eyewitness and doorbell cam videos captured the intensity of the fiery phenomenon as it burned bright through the darkness.


Fireball 2

Meteor fireball recorded over Pittsburgh, Pennsylvania

Pittsburgh meteor fireball
© YouTube/AMS (screen capture)
The American Meteor Society (AMS) received 24 reports (event 5549-2020) about a meteor fireball seen over DE, IN, KY, MD, NJ, NY, OH, PA, VA and WV on Tuesday, October 6th 2020 around 06:11 UT.

A video from a Pittsburgh resident was uploaded to their website.


Question

Residents report hearing 'loud explosion' across Nottingham, UK

Carrington
© Joseph Raynor/Nottingham Post
Residents right across Nottingham have reported hearing a "loud explosion" and a "sonic boom" on Sunday evening.

Numerous reports have been made across social media and messaged into Nottinghamshire Live, with people reportedly hearing the 'loud bang' at around 10pm.

One reader messaged through to Nottinghamshire Live and said he heard it in Mapperley Park and that it made his flat feel like it was "shaking".

Fernando Martins, who described it as a "big and very quick explosion", said: "[It was] just as simple as a very loud muffled bang. "I cannot really make much sense of it, but at the same time it felt like a big and very quick explosion.

Meteor

Ground shaking, loud boom reported across Escambia County, Florida

Mystery boom (stock)
© myjournalcourier.com
The sounds of an explosion or rattling and shaking were heard or felt across part of Escambia County Saturday afternoon, and so far no one seems to know why.

Beginning about 2 p.m., NorthEscambia.com was flooded with over 600 messages and comments from people reporting the incident, and Escambia County 911 also received numerous calls.

A majority of the comments were concentrated from Molino to the north to Beulah in the south, but other reports were received from across Escambia, Santa Rosa and Baldwin counties.

Escambia Fire Rescue checked the area out and found nothing. And the U.S. Geological Survey did not report a earthquake.

Click here to see a Facebook post with hundreds of reader reports.

Fireball 5

Superbolide turns night into day over Rio Grande do Sul, Brazil

Superbolide over Brazil
© BRAMON
A superbolide was recorded in Rio Grande do Sul and Santa Catarina states by the cameras of BRAMON, Clima ao Vivo and Heller & Jung Observatory in the early morning hours of October 1st, 2020. Check out the video:


Fireball 5

Bright meteor fireball blazes over central Spain

Central Spain meteor
© YouTube/Meteors (screen capture)
This fireball was almost as bright as the Full Moon and overflew Spain on 2020 September 30 at about 1:23 local time (equivalent to 23:23 universal time on September 29). It was generated by a rock (a meteoroid) from an asteroid that hit the atmosphere at around 95,000 km/h. It began at an altitude of about 95 km over the province of Ciudad Real, and ended at a height of around 40 km.

The event was recorded in the framework of the SMART project, which is being conducted by the Southwestern Europe Meteor Network (SWEMN). The event was spotted from the meteor-observing stations located at Sevilla, La Sagra (Granada), La Hita (Toledo), and Sierra Nevada (Granada).


Fireball 3

Hundreds report meteor fireball blazing over Eastern US - UPDATE

AMS event 5441-2020 - Observers map
© AMS (screen capture)
AMS event 5441-2020 - Observers map
A streak of bright light, described as a meteor, was sighted in parts of the United States Wednesday morning, according to Twitter users.

The astronomical event was sighted in Cincinnati and in Kentucky. Twitter users reported the sighting before 6:30 a.m.

Many users said it appeared blue or green, then turned orange before it burned out.

"Just happened to look southeast this morning before 6:30 and caught a meteor in the sky. Lit up all red, looked like a contrail fizzling out. Can't remember ever seeing one before - very cool," twitter user Ryan Wichman said.

According to NASA, meteoroids are objects in space that range in size from dust grains to small asteroids. When they enter Earth's atmosphere at high speed and burn up they become meteors. They can become visible fireballs or "shooting stars."


Comment: The American Meteor Society (AMS) has received 264 reports about a meteor fireball seen over DC, IL, IN, KY, MD, MI, NC, NJ, NY, OH, Ohio, Ontario, PA, SC, TN, VA, WI and WV on Wednesday, September 30th 2020 around 10:24 UT.

Update: 1st Oct. 2020

This meteor fireball event has now had 567 reports posted to the AMS website, making it the most widely reported meteor fireball in the US since July 2019.

More videos have been uploaded to the AMS website:






Info

The Younger Dryas impact research debate update

Ice Age Skeletons
© Jonathan Chen / CC BY-SA 4.0
Ice Age Diorama. From left to right: Equus hemionus, Mammuthus primigenius, Coelodonta antiquitatis, Bison exiguous skeletal mounts at the Tianjin Natural History Museum.
The Younger Dryas impact hypothesis has received considerable attention since its publication in 2007 in the prestigious peer-reviewed journal PNAS (Proceedings of the National Academy of Sciences). It suggests the Younger Dryas geological period and mini Ice-Age, from around 10,850 to 9600 BC, along with associated megafaunal extinctions and human societal changes, was triggered by a catastrophic cosmic impact, probably with a fragmented comet from the Taurid meteor stream.

As of now, this paper by Richard Firestone, Allen West and Simon Warwick-Smith and colleagues has amassed over 550 citations in Google Scholar - which is a lot! It is on its way to becoming a classic. But it has also received more than its fair share of criticism, mostly sustained from just a handful of vehement opponents. But has any of their criticism stuck? And what is the status of Firestone et al.'s paper today? Has the dust settled on an outcome? Are we there yet?
Evolution of Temperatures
© Evolution of temperature in the Post-Glacial period according to Greenland ice cores/CC BY-SA 4.0
Evolution of temperatures in the post glacial period, after the Last Glacial Maximum (LGM), showing very low temperatures for the most part of the Younger Dryas, rapidly rising afterwards to reach the level of the warm Holocene, based on Greenland ice cores.

Fireball 2

Meteor fireball over Spain on Sep. 25

FIREBALL
This bright meteor overflew the south of Spain on 2020 September 25 at about 23:52 local time (equivalent to 21:52 universal time). It was generated by a rock (a meteoroid) from an asteroid that hit the atmosphere at around 39,000 km/h. It began at an altitude of about 80 km over Seville, and ended at a height of around 26 km over Córdoba.

The event was recorded in the framework of the SMART project, which is being conducted by the Southwestern Europe Meteor Network (SWEMN). The event was spotted from the meteor-observing stations located at Sevilla, La Sagra (Granada), La Hita (Toledo), Sierra Nevada (Granada), and Calar Alto.