Sun Feb 17, 2013, 09:17 PM
Posteritatis (18,807 posts)
Meteorite fragments found in Russia's Urals region
Source: BBC News
Fragments from a meteorite have been found in Russia's Urals region where it struck on Friday, injuring some 1,200 people, Russian scientists say.
The fragments were detected around a frozen lake near Chebarkul, a town in the Chelyabinsk region, where the meteorite is believed to have landed.
Viktor Grohovsky, of the Urals Federal University, told Russian media that the material contained about 10% iron.
Read more: http://www.bbc.co.uk/news/world-europe-21494963
Looks like a stony meteorite instead of a nickel-iron one, and NASA's thinking it was quite a lot bigger than the initial reports suggested going by the energy from the blast.
16 replies, 4160 views
Meteorite fragments found in Russia's Urals region (Original post)
|Tom Rinaldo||Feb 2013||#11|
Response to 1620rock (Reply #1)
Sun Feb 17, 2013, 10:49 PM
dipsydoodle (42,239 posts)
2. Bounty sets off hunt for meteorite pieces
THE Russian city where the biggest meteorite to hit earth in more than 100 years crashed last week is facing a gold rush, with collectors offering more than $15,000 for a fragment of the rock.
A day after the fireball streaked across the sky and exploded with the force of an atomic bomb, residents in Chelyabinsk were out in force searching for pieces to sell. Potential buyers posted messages on the Russian internet calling on finders to come forward. One Russian buyer offered 500,000 roubles ($16,000) for a single fragment.
At a frozen reservoir outside the nearby town of Chebarkul, where the largest meteorite pieces are thought to have crashed, authorities stopped "meteorite hunters" searching around a 8m-wide crater punched in the ice by the impact.
"Off to look for pieces of meteorite! Who knows, maybe I'll strike gold!" a local resident called Sergei wrote online.
Response to dipsydoodle (Reply #2)
Mon Feb 18, 2013, 01:44 AM
DallasNE (4,369 posts)
5. I Always Thought These Things
Would both break up and burn up from the friction as they fell to earth. Now I learn that they explode powerfully. So, what provides the fuel as the explosive force was greater than one would expect from 10 tons of, say, dynamite. With volcanoes I always presumed the explosions came from the sudden release of high pressure like a balloon breaking rather than a true blast. Time to change my thinking.
Response to DallasNE (Reply #5)
Mon Feb 18, 2013, 02:45 AM
kiri (190 posts)
6. energy is a human mental construct, not in the Bible, but explains much
The "explosion" comes from the huge kinetic energy the meteor has, 1/2 mass times velocity squared. v-squared is a big number; mass is relatively unimportant. At the end of its trajectory, all this energy has to go somewhere. Some goes into making the rock hot--but in the short time, thermal conduction cannot dissipate all the heat from the surface to the inner mass. Much of the energy then goes into heating the nearby air. But air molecules cannot get out of the way fast enough--so they bunch up. That creates a pressure wave--a sonic boom. Atoms in the outer layer glow to incandescence; huge thermal stresses appear. Something has to give.
So the combination of very hot atoms, internal stresses, air molecules, makes for an explosion as the kinetic energy is released and dissipated. A small fraction of the energy goes into the kinetic energy of the fragments, but most goes into heat. Light (electromagnetic) and sound (acoustic pressures) arise.
Response to kiri (Reply #6)
Mon Feb 18, 2013, 11:48 AM
lunatica (31,520 posts)
13. Cool. That's what I thought but without all the scientific words
Welcome to DU. We like knowledgeable people like you. In my mind I saw it like a tomato being thrown at a wall with the tomato being the meteor and the wall representing the air resistance at that point where it creates that sonic boom. Am I even close?
Response to lunatica (Reply #13)
Tue Feb 19, 2013, 05:18 PM
kiri (190 posts)
It's not bad. But the splat of the tomato takes place over a second or so (and it does actually warm up--very slightly--as its kinetic energy has to go somewhere; energy always has to go somewhere, usually into heat).
Here we have an object growing hotter and hotter--on its surface--over maybe 20 seconds. But heat conduction does not happen that fast, so the interior is still cold. Hence, stresses--exactly the same happens when you pour hot water into a glass and it cracks. But stresses release energy as molecule separates from molecule. Electrons are promoted to higher energy orbits, and then return releasing light and X-rays. And hot atoms have chemical reactions with air molecules--this takes place in milliseconds. Atoms/molecules reacting with oxygen atoms is what we call fire. (Or very accelerated rusting!)
When you get to temperatures of 1000-3000 C, the world is very different. Kitchen experiences with heat are not an adequate guide.
The situation in the meteor and its nearby air gets ever more unhappy and complicated. So much energy, so little space and time. Something has to give, as the energy can no longer be contained by the pre-existing forces. Out comes light and sound.
I am curious as to whether there was any fogging on photographic materials, from X-rays. The energy might not have been quite great enough, but I suspect there were some.
Heat is a form of energy; not the same as temperature. There are only 4 fundamental forces in our Universe. That is profound.
Response to NBachers (Reply #3)
Mon Feb 18, 2013, 01:01 AM
Baclava (5,804 posts)
4. I'll take one full of gemstones
When a 925-pound meteorite crash landed in Fukang, China, in 2000, there were few signs of the beauty that lay within. But when a thin slice was removed from the rock creating a window to the inside, a breathtaking site was revealed. This was no ordinary meteorite. It was an extremely rare pallasite – a type of stony-iron meteorite – that contained large, translucent, gem-quality olivine (or peridot) in a silvery honeycomb of nickel-iron.
Response to NBachers (Reply #3)
Mon Feb 18, 2013, 10:13 AM
Tom Rinaldo (16,595 posts)
11. They are available - I used to sell some for awhile
I was never a real "player" in that market but I had a friend who was - so I handled some from time to time. The most common iron-nickle meteorites came from a massive fall that happened over two thousand years ago in South America. I dunno current pricing - but I was buying quais wholesale at $60 a pound. The more exotic meteorites (with internal "space gems" etc) are also very available. You really should buy one. A seven pounder is quite impressive - they feel much much heavier because they trick your mind - they are so dense that you expect a piece to be much lighter than it really is when you go to pick one up.
Response to Posteritatis (Original post)
Mon Feb 18, 2013, 04:17 AM
AnotherDreamWeaver (2,180 posts)
8. 20 ft hole was made by something
And if that something is 20 feet in diamater and 10% iron, what will be needed to lift it from the lake bottom?
Response to AnotherDreamWeaver (Reply #8)
Mon Feb 18, 2013, 07:18 AM
Posteritatis (18,807 posts)
10. Impactors are usually *much* larger than their craters
If it was twenty feet across when it hit the ground, you'd be able to build a small apartment building in the crater.
Most meteorites tend to be either "alter the real estate for a significant distance" scale or surprisingly small when they're recovered.