Sikhote-Alin
Key facts
- Country
- Russia
- Diameter
- 27 m
- Age
- formed on 12 February 1947
- Location
- 46.16° N, 134.65° E
Dozens of small craters and pits scattered through the forest of the Sikhote-Alin mountains, the largest about 26 m across, now overgrown with trees.
On the morning of 12 February 1947 one of the largest meteorite falls in recorded history struck the Sikhote-Alin mountains in the far east of the Soviet Union, north-east of Vladivostok. A brilliant fireball, as bright as the Sun, crossed the sky in daylight, leaving a trail of smoke that lingered for hours. Moments later a shower of iron fragments rained down on the snowy forest.
The fall. Eyewitnesses saw the fireball over a wide area and heard booms like thunder. As the meteorite plunged through the atmosphere it broke apart, and the fragments spread over an area of more than a square kilometre. The largest pieces dug craters in the frozen ground, while smaller ones snapped branches and buried themselves in the soil. The total mass of the meteorite before entry has been estimated at about 70 to 100 tonnes.
The craters. Scientific expeditions, led by the Committee on Meteorites of the Soviet Academy of Sciences, reached the site within weeks. They found more than 100 craters and pits. The largest was about 26 m across and about 6 m deep. Some fragments were found at the bottom of the craters, while many others were scattered around them.
The meteorite. About 23 tonnes of meteorite fragments have been recovered, and many more are probably still in the ground. The largest single piece weighs about 1.7 tonnes and is displayed in Moscow. The Sikhote-Alin meteorite is an iron of group IIAB, made almost entirely of iron with a little nickel. It has a very coarse crystal structure. Its fragments come in two forms: individuals, which separated high in the atmosphere and have smooth, sculpted surfaces with thumbprint-like hollows called regmaglypts, and shrapnel, jagged, torn pieces created when fragments shattered on impact.
A famous fall. The fall was so important that in 1957, ten years later, the Soviet Union issued a postage stamp showing the fireball, based on a painting by an artist who saw it. Sikhote-Alin specimens are among the most familiar iron meteorites in museums and private collections worldwide.
Why it matters. Sikhote-Alin is the best-documented large iron meteorite fall. It was studied soon after it happened, so scientists could record exactly how the fragments were spread and how the craters formed. It shows what happens when a large iron meteorite breaks up in the atmosphere and creates a crater field, the same process that formed older sites such as Henbury and Kaali.
The site today. The craters lie in the forests of Primorsky Krai and are now overgrown with trees. Anyone thinking of visiting or collecting should check current Russian rules first.
Did you know?
A fireball as bright as the Sun lit up the sky over the Sikhote-Alin mountains in 1947.
About 23 tonnes of iron fragments have been recovered.
The Soviet Union issued a stamp in 1957 showing a painting of the fireball.