Pultusk

In 1868 a fireball over Poland released one of the largest showers of stones ever recorded – tens of thousands of them.

Key facts

Type

Ordinary chondrite (H5)

Fell or found

Fell (witnessed)

Year

1868 (30 January)

Country

Poland

Mass

tens of thousands of stones, most of them small

Official name

Pultusk

On the evening of 30 January 1868, a brilliant fireball lit up the winter sky over central Poland, then part of the Russian Empire. It exploded near the town of Pułtusk, north of Warsaw, with a roar that witnesses compared to cannon fire. Moments later, a hail of stones fell across the snowy countryside, over villages and fields and onto the frozen surface of the River Narew. It was one of the most abundant meteorite showers ever recorded.

A rain of stones

The number of stones that fell is not known exactly, but estimates run into the tens of thousands, making Pułtusk one of the largest meteorite showers in history by number of pieces. Most were very small. Many weighed only a few grams and were about the size of peas or hazelnuts, and collectors still call these tiny specimens 'Pultusk peas'. Larger stones, weighing several kilograms, were also found.

Some stones fell on the frozen river and broke through the ice, while others landed on the snow, where their black crusts made them easier to see. Local people collected many of them, and specimens were sold or given to scientists and museums across Europe. As a result, Pułtusk is represented in a very large number of collections around the world, and for many collectors a small Pultusk pea has been their very first meteorite.

Why so many stones?

When a meteoroid enters the atmosphere, it is compressed by the air in front of it. If the pressure becomes greater than the strength of the rock, it breaks apart. A weak meteoroid can fragment repeatedly as it descends, scattering a shower of small stones. Each fragment then slows down and falls more gently; by the time small stones reach the ground they are travelling at no more than a few hundred kilometres per hour. Pułtusk appears to have broken up in this way into an enormous number of pieces.

The stones were scattered over an elongated area called a strewn field, with smaller pieces at one end and larger pieces travelling further. This typical pattern helps scientists reconstruct the path and break-up of the meteoroid.

What it is

Pułtusk is an H5 ordinary chondrite. Ordinary chondrites are the most common meteorites seen to fall. 'H' means high iron: H chondrites contain abundant grains of iron-nickel metal, so they are heavy for their size and attract a magnet. The number 5 means the rock was strongly heated inside its parent asteroid, making its chondrules, the small rounded grains typical of chondrites, less distinct. Some Pułtusk stones are breccias, made of broken fragments cemented together, a sign of collisions on the parent asteroid.

Fresh specimens show a black fusion crust, the thin glassy coating formed as the surface melted during the fall. Small whole stones often have smooth, rounded shapes, and some show flow lines in the crust where molten rock streamed backwards.

Why it matters

Pułtusk was one of the great meteorite showers of the 19th century to be studied systematically, and it became an important reference collection for 19th-century scientists who were still learning what meteorites were and how they fall. Because so many pieces were distributed to museums, Pułtusk stones have been used for countless studies of ordinary chondrites, their minerals, and the effects of cosmic rays during their journey through space.

It also inspires today's meteorite hunters. Even more than 150 years after the fall, occasional stones are still reported from the area, often found by farmers or by careful searchers with permission from landowners.

If you ever see a Pultusk pea in a museum, remember that it was one of a vast swarm of stones that rattled down over a frozen Polish landscape on a single winter's evening.

Did you know?

See more

Pultusk in the catalogue