It was perhaps the most spectacular collision between an asteroid and Earth ever witnessed, certainly the most spectacular ever filmed.
When a bus-sized chunk of rock weighing more than the Eiffel Tower (10,000 tonnes) entered Earth’s atmosphere February 15, it produced a shock wave that damaged 7,200 buildings and injured 1,500 in an area of southwest Russia.
It was such a significant event, it prompted the U.S. Congress to double funding for NASA’s Near Earth Object Program.
In the weeks following the explosion, hundreds of small fragments of the meteor were collected. An informal market for meteorites popped up and scientists clamoured to get their hands and scanning electron microscopes on the pieces.
Seven gold medals that will be given out on Day 8 of the Sochi Winter Olympics will feature small fragments of the meteorite.
As enticing as these rocks are as curiosities and collectibles, however, they are even valuable to science.
For six months, Russian authorities searched for the motherlode, the main fragment of the former asteroid. In September, they found what appeared to be their quarry buried deep in the sediments under 20 metres of water at the bottom of Lake Chebarkul in the Ural Mountains.
Hampered by zero visibility, weather and technical problems, several attempts to salvage the chunk of space rock failed until, on October 16, after 10 days of pumping mud away from the fragment, divers finally managed to get it corralled and it was dragged out of the lake to the delight of a large cadre of international media.
Weighing in at more than 570 kilograms, it is one of the 10 biggest meteorite fragments ever found.
The importance of meteorites lies in their age and composition. Some very old rocks have been found on Earth, the oldest confirmed sample is a from an outcrop of gneiss (a metamorphic rock) located about 300 kilometres north of Yellowknife. It is approximately four billion years old.
The thing is, the Earth is 4.5 billion years old leaving 500 million years unaccounted for in the rock record. Its crust is dynamic, in a constant state of forming and reforming, metamorphizing and eroding. In short, the oldest terrestrial rocks we’ve ever found don’t even come close to representing the stuff of the early solar system. Meteorites do.
The most exciting thing about these extraterrestrial samples is what they might tell us about how life arose on the planet. The late heavy bombardment was a period 4.1 to 3.8 billion years ago during which the planets of the inner solar system were pummelled by asteroids and gained most of their mass. It is widely theorized that carbonaceous asteroids, those that contain organic compounds including amino acids were the origin of the building blocks of life to Earth.
To be clear, these asteroids did not bring life to Earth, but they did bring the necessary materials.
Unfortunately, despite early speculation based on the explosiveness of the Russian meteor fall last winter that this was a carbonaceous asteroid—they tend to be more volatile—early analysis of smaller fragments suggest it was just an ordinary space rock. Not overly surprising considering the carbonaceous ones only make up around five per cent of the samples so-far found.
Nevertheless, a half-tonne hunk of meteorite is a very exciting find and I will be looking forward to finding out what scientists will learn from it in the coming months and years.