Author Topic: Russian meteorite  (Read 1631 times)

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Offline toonfandangl

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Russian meteorite
« on: October 18, 2013, 04:06:22 AM »


The object plunged into Lake Chebarkul in central Russia on 15 February, leaving a 6m-wide hole in the ice.

Scientists say that it is the largest fragment of the meteorite yet found.

More than 1,000 people were injured when a 17m, 10,000-tonne space rock burned up over Central Russia, breaking windows and rocking buildings.



Meteorite
During the fiery plunge through the atmosphere, a thin layer of rock on the surface melts. This black layer is known as the "fusion crust"
The surface of a meteorite is generally smooth and featureless, but will often have shallow depressions called regmaglypts that resemble thumb-prints
Dr Caroline Smith says these form during the fireball stage, "as vortices of hot gases scour away (ablate is the correct term) the surface of the meteoroid".
They generally have a high density compared with Earth rocks and often contain some iron-nickel metal, which may make them magnetic
Meteorites are almost never round - they are irregular in shape and come in a variety of sizes
Live footage showed a team pull out a 1.5-metre-long (five-foot-long) rock from the lake after first wrapping it in a special covering and placing it on a metal sheet while it was still underwater.

The rock broke into three parts as it was pulled from the depths.

Once ashore, it was placed on top of a scale for weighing.

However, the scale broke as it hit the 570kg (1,255lb) mark.

Dr Caroline Smith, curator of meteorites at London's Natural History Museum, confirmed that the object was a meteorite from characteristic features known as fusion crust and regmaglypts, which are obvious in images.

She told BBC News: "Fusion crust forms as the meteoroid is travelling through the atmosphere as a fireball.

"The outer surface gets so hot it melts the rock to form a dark, glassy surface crust which we term a fusion crust. Regmaglypts are the indentations, that look a bit like thumbprints, also seen on the surface of the meteorite."

Lake Chebarkul
The fragment left a 6m-wide hole in the frozen lake back in February
Sergey Zamozdra, an associate professor at Chelyabinsk State University, told the Interfax news agency: "The preliminary examination... shows that this is really a fraction of the Chelyabinsk meteorite.

"This chunk is most probably one of the top 10 biggest meteorite fragments ever found."

The divers' mission had been hampered by a number of factors. The rock fragment lay at 13m depth, not 6m or 8m as was originally thought.

The Vesti 24 rolling news channel reported that divers had already recovered more than 12 pieces from Lake Chebarkul since the incident on 15 February.

The station said that only four or five of them had turned out to be real meteorites................




Freedom is the freedom to say two plus two makes four. If this is granted then all else follows".......George Orwell 1984........UTRINQUE PARATUS.

Offline Michael Alexander

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Re: Russian meteorite
« Reply #1 on: October 18, 2013, 08:54:00 AM »
Meanwhile back here in good ol' Namibia....



"The runaway winner at approaching twice the weight of its nearest rival, Namibia’s Hoba must have taken some stopping. Measuring over 6.5 metres sq, this 60-tonne slab of metal is believed to have been slowed by the Earth's atmosphere to the point where it fell to the surface at a speed that left it intact and barely buried. It’s even been suggested that the meteorite’s unusually flat shape caused it to skip along much as a skipping stone bounces across water. "
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Offline Michael Alexander

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Re: Russian meteorite
« Reply #2 on: October 18, 2013, 08:56:58 AM »
We saw what the Russian meteorite looked like as it blazed away through the Russian atmosphere, can you only imagine the fireball caused by the Hoba Meteorite when it came down?

What scares me, is the fact that nobody saw the Russian Meteorite coming..... when is the next one we cannot see due to strike....?

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Offline toonfandangl

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Re: Russian meteorite
« Reply #3 on: October 19, 2013, 05:00:37 AM »
You have to wonder!....... this one that hit Arizona and left its crater The Barringer Meteor Crater was also known as the Canyon Diablo Crater around hit 50,000 years would have been spectacular sight but there again you would not have been around much longer to tell your mates.






                                                                                                                   
           





Freedom is the freedom to say two plus two makes four. If this is granted then all else follows".......George Orwell 1984........UTRINQUE PARATUS.

Offline Michael Alexander

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Re: Russian meteorite
« Reply #4 on: October 19, 2013, 08:01:26 AM »
Then again looking how many of these craters are surrounded by desert or bush, you have to wonder if the land was originally green and was transformed into desolation after impact....

Here is a snap of Oranjemund's crater, The Roterkamm, about 90 km north east of us...



Looks quite similar to your snap there Frank, ours is in the Sperrgebiedt and therefore has been well protected....

Also , do a google for the Veredfort Dome in Sa......

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Offline toonfandangl

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Re: Russian meteorite
« Reply #5 on: October 31, 2013, 02:11:47 AM »

A cross-section of rock at the Vredefort Dome shows the dark grey granite that was melted by the impact and flowed, carrying chunks of unmelted granite within it. The vertical face seen here is two to three metres high

Read more: http://www.southafrica.info/travel/cultural/vredefort-080605.htm#.UnGczvlmA6o#ixzz2jFkyfdqp

The meteorite impact that happened in the Free State made a crater that was about 300 km wide (from Johannesburg to Welkom!). This is the biggest meteorite impact that geologists have yet found on Earth and it is nearly twice as big as the impact that killed the dinosaurs 65 million years ago. This makes it a site of great importance for scientists. It is also the oldest impact crater that has been found on Earth. It is mainly for these reasons that it has been made a World Heritage Site.
 
Over many decades, geologists from South Africa and other parts of the world have been studying the broken and melted rocks around Parys and Vredefort to understand this Vredefort Impact Even. This is what they have found:
 
1. The meteorite impact happened about 2023 million years ago, at a time when there were no people or even animals of plants like we see today. The only living thing was a type of algae, like the green slime seen in dams today.
 
2. To make a crater 300 km wide, the meteorite must have been about 10 km across (as big as a mountain) and travelling at more than 10 km per second (36 000 km/h!).
 
3. The Vredefort Dome is only the central part of the impact crater. It is called a dome because the rock layers were bent into the shape of an upside-down bowl 90km across by the impact.
 
Shooting stars and meteorite impacts
 
If we look up into the sky on a dark night we often see "shooting stars". These are bright streaks of light that move very fast across the sky for only a few seconds before they disappear. They are not real stars - the streaks of light are caused by tine pieces of burning rock, flying faster than bullets that enter Earth's atmosphere from Outer Space. Because they are moving so fast (more than 10 km per second, which means they would take 30 seconds to fly from Parys to Bloemfontein!), when they enter the atmosphere they start to burn. (This burning is caused by friction with the air. When you rub your hands together very fast, they also get hot. To melt rock, though, the temperature must reach more than 1000 °C!)
 
There are many, many millions of such small pieces of rock in Outer Space, left over from when our Sun and the planets were formed. Thousands of them become shooting stars every day. But among them are also larger pieces of rock, ranging from football size to some up to many kilometers across. These asteroids also sometimes fall into the Earth's atmosphere, but not as often as the smaller pieces. When they do, they are too big to burn up or slow down and so they hit the ground at very high speed. An asteroid that hits the Earth is called a meteorite. Thousands of small meteorites have already been found around the world.)
 
The damage caused when a meteorite collides with the Earth is massive. The speed of a meteorite is so high that is explodes when intense heat of many thousands of degrees Celsius that can even melt rock. In this way, the meteorite itself is completely destroyed. This is what happened in the Free State near Parys and Vredefort millions of years ago. The explosion was so great that it was many millions of times more powerful than the biggest atomic bomb ever built on Earth. If it happened today it would kill almost all living things on Earth, including most people
Michael I think if you had spent a great deal of money building a bomb shelter in the days of the cold war looks like a waste of it.

 
Freedom is the freedom to say two plus two makes four. If this is granted then all else follows".......George Orwell 1984........UTRINQUE PARATUS.

Offline Michael Alexander

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Re: Russian meteorite
« Reply #6 on: November 01, 2013, 11:49:36 AM »
I was talking to a mate of mine who is a Warden for the Sperrgebiedt National Park. He was saying that he recently took a group of scientist types from Europe in the Roterkamm . They had a mini drone for aerial surveying. Reckon the meteorite came in from the east. Vaporised everything around it and even caused those mountains to "shape" in that specific direction. There is not a single part of the meteorite left as the entire object vaporised on impact....

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