The Earth Story

Radiating Perseids This photograph of August’s Perseid Meteor Shower was taken on top of the Wasserkuppe Mountain in Central Germany at the peak of the meteor shower in 2015. The structure in the foreground is a Cold War vintage radio station used to watch over the border between East and West Germany.

First historic report of death by meteorite located There have been documented cases of stones falling from the sky for centuries. However, even though one stone fell through the roof and hit a sleeping woman in Alabama, and one piece of a martian meteorite is famously reported as having killed a cat, until today there were no known cases of a meteorite actually killing someone. This map, with a few details added by modern authors, shows the suspected track of a meteorite that entered the Earth’s atmosphere above what is today Iraq in 1888. The rock entered the atmosphere and as the atmosphere slowed the rock, it heated up and built so much pressure that eventually it triggered an explosion – an airburst. A just-published paper demonstrates that after this event, 3 independent documents were generated stating that fragments of this exploding rock killed one man and paralyzed another. Those documents were delivered to the Sultan of the Ottoman Empire at the time and have been stored in files in Turkey ever since, until these researchers uncovered them. The researchers suggest that there are likely other cases of people killed by rocks falling from space that have been stored in document vaults around the world, waiting to be recognized today. -JBB Image source and original paper: https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.13469

A couple of meteors from the Perseid meteor shower, fog in the valleys, and sunrise in the distance - Pisgah National Forest

Badlands Meteor

Photographer Randy Halverson was at Badlands National Park filming a time-lapse video, when he happened to catch something bright in the clouds. It was a meteor!

Meteors are what we call a “shooting star”. It refers specifically to the light we see in the sky. A meteoroid is the actual debris or dust that’s speeding through the atmosphere.

The color of the meteor is influenced by its composition. This meteoroid likely has magnesium in it because Mg appears blue-green when it collides with air molecules. The initial collisions create a vapor trail of atoms, while subsequent ones knock elections further away from the atom’s nucleus. When those electrons return to their resting state, light is emitted giving us a shooting star.

Photo Credit: Randy Halverson https://www.facebook.com/dakotalapse Photo used with permission

References: http://leonid.arc.nasa.gov/meteor.html

Previous posts on Badlands https://www.facebook.com/TheEarthStory/posts/521199994607716 https://www.facebook.com/TheEarthStory/posts/572911476103234

Meteorite skull

It’s pretty easy to recognize iron meteorites even if they’re not seen falling – a giant piece of iron sitting around does stand out. Throughout history, meteoritic iron has been recognized as a unique material useful for carvings like this ancient Buddha we discussed a while back: http://tmblr.co/Zyv2Js1IQJvcK.

The Gibeon meteorite fragments are chunks of a large iron-nickel meteorite that fell in Namibia during prehistoric times. Chunks of it have been collected over a wide area (275 kilometers long, 100 kilometers wide) and have been sold to private collectors for years.

The Gibeon meteorite fragments display san excellent Widmanstätten pattern – the pattern of interlocking crystals visible on the polished surface. These lines are created by the growth of two different types of crystals, each with a slightly different ratio of iron to nickel, while the liquid iron cooled inside of a large object early in the formation of the solar system.

This skull was carved from a chunk of that meteorite and was available at the Tucson Gem & Mineral show, the largest gem & mineral show in the world. The carvers spent over $200,000 preparing it so far, including obtaining the material, preparing, and carving it, and the list price at the show was $1,000,000.

-JBB

Image credit: John Moffitt (With permission) https://twitter.com/JohnRMoffitt

Read more: http://www.meteoritemarket.com/GNinfo.htm http://www.bernardine.com/gemstones/gibeon.htm

Original caption:

It’s rainin’ rocks

This map should make us all take a moment and go hug the atmosphere. No, you figure out how, it earned it.

When a rock enters earth’s atmosphere, it releases a lot of energy and often explodes, producing shock waves in the atmosphere that have been detected by a U.S. Government monitoring program. These events are called bolides, and this map shows the location of bolides beyond a certain size in Earth’s atmosphere over a 20-year period from 1994-2013.

This map shows a total of 556 events, basically 1 every 2 weeks, on average. The largest explosion in that time was the Chelyabinsk event in 2013, when an asteroid about 20 meters in diameter entered the atmosphere, exploded, and fragmented, damaging cities in Russia near the shock.

The smallest dots on this map are much weaker than Chelyabinsk – objects about a meter in size entering the atmosphere and vaporizing or exploding produce them. Those are pretty harmless most of the time, but they still release the same energy as 5 tons of TNT exploding. The difference between a barely-detectable blast and something that can severely damage a city, therefore, is the difference between a chunk of rock 1 meter wide versus 20 meters wide - the Chelyabinsk explosion is estimated to have released the same energy as a 500 kiloton nuclear bomb.

As Earth orbits around the sun, it is literally in a shooting gallery of debris; rocks left over from the formation of our solar system hit this planet all the time, as this map shows. The locations of these events appear random, indicating that stuff flies in from all sides with no obvious pattern. By having this data over a 20 year period, scientists will be able to use statistics to estimate how often we can expect large explosions, the scale of Chelyabinsk or larger, in the atmosphere, and use that understanding to gauge how much we need to prepare for larger impacts.

If it weren’t for our atmosphere, most of these rocks would be hitting Earth. Instead, the thin layer of air above it does a remarkable job at keeping things off our heads. We owe it some thanks for that favor.

-JBB

Image credit: NASA/JPL http://neo.jpl.nasa.gov/news/news186.html

Astronomy photo winners of the year Having shared the shortlist some time ago (seehttps://bit.ly/2PtXy6Q) we now share some of the jury’s selection, which is currently being exhibited in the National Maritime Museum in Greenwich, London. The overall winner of a photographer overlooking an eerie landscape was taken in the desert near Moab in Utah. The second image won the Skyscapes category, and was taken in the far north and depicts high altitude polar stratospheric clouds (see http://bit.ly/2EQmxNC for more on these). Our third won the young photographer category, and was taken in Autumn in the Italian Dolomites when a fortuitous meteor flashed past (see http://bit.ly/2qiURqm for more on the geology of these mountains). Our last won the Auroras category, a beautiful snap of plasma produced by atoms being excited by the solar wind. Loz Image credit: 1: Brad Goldpaint 2: Ferenc Szémár 3: Fabian Dalpiaz 4: Nicolas Lefaudeux/2018 Astronomy Photographer of the Year https://bit.ly/2yYMLau

The peak of the 2018 Perseid Meteor Shower viewed over Málaga, Spain. Watch for the ones that burn up where you can see debris!

Last week’s Perseid meteor shower over a thunderstorm. The slow spots of light that move across the sky are planes, but several meteors flash their way across also.

The couple longer light trails are planes, the brief light flashes are meteors