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Sat, 27 Aug 2016
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Fire in the Sky


One Hundred Years Ago Today, A Mars Meteorite Fell in a Blaze

One of the two original pieces of Nakhla sent to the Smithsonian, virtually untouched since 1911. Photo courtesy of the Natural History Museum.

On the morning of June 28, 1911, somewhere between 8:30 and 9:00 in the morning, a fireball was observed northwest of Alexandria, Egypt. Few would realize what it was. But soon after, W.F. Hume, minister of the Geological Survey of Egypt, began taking eyewitness statements, and two months later published his report, "The First Meteorite Record in Egypt."

One of those statements, from a farmer who claimed to have seen a fragment fall on a dog, gave rise to the popular myth that Nakhla, as the meteorite would be named, was "the dog killing meteorite," an unsubstantiated claim, but the dramatic account is irresistible: "The fearful column which appeared in the sky at Denshal was substantial. The terrific noise it emitted was an explosion which made it erupt several fragments of volcanic materials. These curious fragments, falling to earth, buried themselves into the sand to the depth of about one metre. One of them fell on a dog. . .leaving it like ashes in a moment."

Approximately 40 stones were recovered southeast of Alexandria, near the town of Abu Hummus. Of the stones recovered, Hume immediately sent two of them to the Smithsonian Institution, weighing 117g and 52g (or 4.3 4.13 ounces and .117 1.83 ounces). They arrived in August of 1911 and have been a part of the Natural History Museum's collections ever since. Today, we celebrate the 100th anniversary of Nakhla's landing.

Bizarro Earth

Peekskill Meteorite

You may not have known it, but yesterday (Monday, June 27, 17:00 UTC) a 10 meter diameter asteroid called 2011 MD passed within 12,400 km (7430 miles) of the Earth's surface. For reference, that's about one Earth diameter away from us and about 31 times closer than the Moon. There was no danger of it hitting but sometimes the Earth's gravitational field happens to catch one of these space rocks. Here's the story of a much smaller meteorite which came crashing into the Hudson Valley 20 years ago.

On October 9, 1992, a meteorite entered Earth's atmosphere somewhere over Kentucky, exploded into fragments, which continued over West Virginia, where it was first filmed at 11:48 pm. The trajectory was toward the northeast, moving as a fireball through the skies over Maryland, eastern Pennsylvania, and finally crashing down to Earth striking a 1989 Chevy Malibu belonging to a Michelle Knapp at 207 Wells Street in Peekskill - a town in the in the lower Hudson Valley of New York (across the river from Bear Mountain).

At least 16 people in several states were able to film the meteorite fragments flying through the sky that evening. The Peekskill fragment was the only one found, but there were others that didn't make such a conspicuous touchdown.


What's Going On With the Sun?

A solar flare crackles from the site of a sunspot on the solar surface.
Earlier this month a lot of column inches were devoted to the news that the Sun continues to behave in a peculiar manner - and that solar activity could be about to enter a period of extended calm. The story emerged after three groups of researchers presented independent studies at the annual meeting of the Solar Physics Division of the American Astronomical Society, which appear to support this theory. But are the new findings really that clear-cut and what implications do they have for the climate here on Earth? Physicsworld.com addresses some of the issues.

Why the recent interest in the Sun's activities?

Solar physicists agree that the Sun has been acting strangely of late. It relates to apparent abnormalities in the solar cycle, an approximately 11-year period during which the Sun's magnetic activity oscillates from low strength to high strength, then back again. When the Sun's magnetic activity is low, during a solar minimum, its surface remains relatively quiet, which leads to fewer sunspots. Then, as magnetic activity begins to increase, the surface becomes more dynamic and the sunspot numbers begin to increase in the lead up to a solar maximum.


Britain in list of countries 'most at risk' if an asteroid strikes

© Associated Press/NASA
Britain has been identified among a host of countries scientists believe would be worst affected in the event of an asteroid strike.

Experts at Southampton University have drawn up a league table of countries most likely to suffer severe loss of life or catastrophic damage should a large asteroid hit Earth.

The list is largely made up of developed nations including China, Japan, the United States and Italy, on the basis that the size of their populations would mean millions of deaths.

The US, China, Indonesia, India and Japan are most in danger on this basis. Canada, the US, China, Japan and Sweden are rated most at risk in terms of potential damage to their infrastructure.


Looking for threats from outer space

© Leonid Kulik Expedition, Wikipedia
Tunguska: The Largest Recent Impact Event
If you think that the worst that could happen to us is a run on the banks and economic meltdown then think again.

This Monday 27th June 2011 a small asteroid will pass within 8,000 miles of the Earth, a mere hair's breadth by astronomical standards.

NASA's Near Earth Object Observation Programme though is on the watch for those objects that threaten to actually collide with our planet. Their aim is to detect these threats as far ahead as possible, leaving us many years, if not decades or more, to work out how to prevent any collision.

This month 103 years ago a large comet entered the atmosphere and caused an air burst over Podkamennaya Tunguska River, Siberia. As a result some 80 million trees were flattened. The trees nearest the epicentre were still standing but stripped as bare as telephone poles. Although no-one was reported to have died in this event in such a remote area, hundreds of the reindeer the locals relied on for their livelihood were killed.


South Carolina, US: Charleston's about to party for the 103rd anniversary of The Tunguska Event

© Soviet Academy of Science
Trees knocked over by the Tunguska blast.
Charleston's about to party for the 103rd anniversary of The Tunguska Event

On June 30th, 1908, the largest explosion in Earth's recent history occurred near the Tunguska River in remote Siberia.

A massive space rock traveling at a speed of 33,500 miles per hour plunged into the atmosphere before detonating in the sky, releasing energy equivalent to that of 185 Hiroshima bombs. Seismic shockwaves were registered as far away as England. There is no direct evidence that any humans perished. There are many theories abound as to what exactly happened, but we may never know the entire truth.

To celebrate the 103rd anniversary of this cataclysmic anomaly, Tivoli Studios & Garden will be hosting The Tunguska Event, a celebration of art, music, and mobile cuisine in an explosive setting on Thursday, June 30th, from 6 to 10 p.m. The South Carolina Broadcasters will play several sets throughout the evening, as live art demonstrations take place around the warehouse. Roti Rolls, Diggity Donuts, and Taco Boy will be on hand to feed you from their trucks. All of the artist studios at Tivoli will be open to the public.


Astronomers: Incoming Near-Miss Asteroid Calculations Wrong

© Unknown
First Photos of Incoming Asteroid 2011 MD
Astronomers observing inbound asteroid 2011 MD found that their calculations were a little off. The asteroid, which measures 15 feet by 60 feet wide, is what is known as a PHA (Potentially Hazardous Asteroid), and was headed toward Earth. It is just one of many that NASA's Near Earth Objects Observation Program regularly tracks. But this particular massive space rock was scheduled to arrive Monday morning and pass about 7,500 miles above the Earth's surface. It did neither.

Getting calculations wrong by a degree or two could mean the difference between a fly-by and a devastating impact. This time, the calculations erred in the Earth's favor...

2011 MD arrived as planned, but not where or when astronomers first suspected, according to the Associated Press. Updated information put the asteroid passing by the Earth at just after noon (1:00 p.m. EDT). It did not come as close as they thought it would, either. Calculations also found the asteroid passing by the Earth at a distance of 7,600 miles away.

Although science fiction movies and television shows thrill us with the horrors of an impending asteroid-based cosmic hit job (think: Armageddon and Deep Impact), shelving the thought of an apocalyptic run-in with a gigantic space rock is a distinct possibility. It is theorized -- and subsequent data and studies have reinforced the theory -- that just such a collision occurred 65 million years ago, slamming into the Gulf of Mexico region and forming the Chixulub Crater. It is believed to be the major cause of the extinction of the dinosaurs and the mass die-off at the end of the Cretaceous Period, forming what scientists call the K-T boundary, the geologic boundary that exists between the Cretaceous and Tertiary Periods of geologic time.

Comment: There now, don't you feel better? Asteroids are itty-bitty and they only come now and again. No big rocks for a couple million years or so. Back to sleep. But if you are one who prefers to know what's really going on you can start here:

Meteorites, Asteroids, and Comets: Damages, Disasters, Injuries, Deaths, and Very Close Calls


International Space Station Evacuated After Debris Threatens Craft

The ISS, the largest space station ever built, is used for scientific experiments and is in low earth orbit, an altitude cluttered with space junk
Fragments of space debris came perilously close to colliding with the International Space Station on Tuesday, prompting its crew to seek temporary refuge in two Russian-built escape craft.

The worrying incident, thought to be only the third of its kind since the international project began in 1998, saw space debris pass within just 820 feet of the space station at high speed and at late notice.

Comment: Considering the attention given by NASA to cataloging and tracking 'space junk', we wonder what this unexpected 'debris' actually was?


Yet another asteroid skims past Earth today!

© Denis Scott/Corbis
If the asteroid enters the Earth's atmosphere on a future pass it will burn up harmlessly.
Asteroid 2011 MD will make its closest approach to Earth at 6.14pm BST on Monday but is highly unlikely to hit anything

A lump of space rock the size of a small house will hurtle past Earth on Monday evening in a close encounter that poses no threat to the planet, astronomers said today.

The asteroid, which is 8 metres across and called 2011 MD, is due to pass within 12,000km of Earth, making its closest approach over the southern Atlantic Ocean at around 6.14pm BST on Monday evening.

With clear skies, the asteroid may reflect enough of the sun's light as it shoots past to be visible to amateur astronomers with sizeable telescopes.

The rock - a fragment smashed off a much larger asteroid - was spotted by astronomers last week using a pair of robotic telescopes in Socorro, New Mexico.

Comment: Other recent near misses, nearly all of which were spotted as they flew past!

An Asteroid Missed Earth this Week -What are the Odds that We'll Always be Lucky?

Scientists find asteroid with potential power of 15 atomic bombs. Heading this way. Tonight.

House-Size Asteroid Zooms Close by Earth

February 11, 2011: 2011 CA7 flew within 64,300 miles from Earth.

October 12, 2010: Asteroid 2010 RD54 came within 28,000 miles (45,000 km) of Earth


Getting Closer: Images, Video of Asteroid 2011 MD

© Peter Lake
Asteroid 2011 MD
Accomplished amateur astronomer and blogger Peter Lake, a.k.a "AstroSwanny" from Australia captured some of the first images of what will be a very close pass of Earth by asteroid 2011 MD. He actually took the image at 07:00 UTC on June 26th with a 20 inch telescope in New Mexico controlled via his iPhone, through the Global Rent-A-Scope program. Ahh, the wonders of technology! As Peter says, "Its not every day, that an asteroid misses by less than 3-5 earth Radii."