History of the Chelyabinsk meteor

Remember that big space rock/asteroid that exploded over the Russian city of Chelyabinsk Feb. 15, 2013, injuring 1,200 people and blowing out windows throughout the area? Here’s a photo to jog your memory:

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Well, scientists have released findings that tell us exactly where it came from. Not just that, but a detailed history that resembles a family tree. It is actually almost unbelievable (almost). The Chelyabinsk meteor/asteroid/meteorite was 20 meters wide (65 feet) when it entered our atmosphere, thankfully, at an angle. This angle gave the asteroid extra time to cook in the extreme temperatures needed to unleash it’s nuclear-bomb power at a safer distance than, say, ground level. This can sometimes be the WORST place to unleash an umpteen-megaton bomb, but in this case, it was their saving grace. By the time it reached the ground in fragments, the largest piece was just a couple feet wide and (mostly) crashed into a frozen lake. Below is the photo of the impact site.

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This is just the end of the story though. Technically, one of the endings. Where did this chain of events begin? Well, 4.56 billion years ago. This is where it gets amazing – a detailed look into the birth and evolution of what began as (at least) a 60 mile wide steroid before Earth was barely an itch in the Sun’s pants.

David Kring of the Lunar and Planetary Institute in Houston says that molten droplets that found their way into the Chelyabinsk object formed within the first four million years of solar system’s history. That is obnoxiously specific. That puts it among the first objects manufactured here.

Over the next 10 million years, these tiny pieces, along with generous helpings of dust, coalesced into an asteroid on the order of 60 miles (100 kilometers) wide. Textures spotted within pieces of the Chelyabinsk asteroid recovered here on Earth reveal that the rock was likely once buried several kilometers beneath the surface of this larger object, which scientists call the LL chondrite parent body, Kring added.

So, not only were they able to pinpoint it’s birthday, but also that the Chelyabinsk asteroid was buried a few miles within a MUCH larger asteroid. It doesn’t end there.

Shock veins within meteorite particles indicate this parent body withstood a violent collision 125 million years after forming.. and then again between 4.3 and 3.8 billion years ago. This is not unheard of, as the whole solar system endured what is known as the late-heavy bombardment, a period of extremely violent collisions.

Then the  LL chondrite parent body apparently then got a break for a few billion years until two collision events happened within the last 500 million years, with one happening within the last 25 million years.

Previous work states that the Chelyabinsk asteroid was only recently taken from the depths of it’s parent body and has only been exposed to open space 1.2 million years ago. This is possibly when a final collision struck and made this Russian asteroid what it was until the recent impact.

A final interesting point: The Japanese sent a probe to the Itokawa asteroid in 2005 and, surprise, it is also a chunk of same LL chondrite parent body that the Chelyabinsk object once resided within. Pictured below are photos taken by the Japanese probe before it captured sampled which it returned to Earth 5 years later in 2010.

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