Mbale

In 1992 hundreds of stones rained on a town in eastern Uganda – and one small piece bounced off a banana tree onto a boy's head.

Key facts

Type

Ordinary chondrite (L5/6)

Fell or found

Fell (witnessed)

Year

1992 (14 August)

Country

Uganda

Mass

well over 100 kg, in hundreds of stones

Official name

Mbale

On the afternoon of 14 August 1992, a fireball appeared over eastern Uganda, followed by loud explosions. Moments later, stones began to fall across the town of Mbale and the surrounding countryside, near the foot of Mount Elgon. Fragments struck roofs, landed in gardens and fields, and hit the railway station. It was one of the largest meteorite showers in modern times, and it fell on a busy, populated area.

A lucky escape

One small fragment, weighing only a few grams, fell through the leaves of a banana tree and struck a boy on the head. The leaves had slowed it down, and he was unhurt. The episode is often mentioned as one of the few credible reports of a person being hit by a meteorite. It also shows that small fragments, slowed by the air to their final falling speed, are far less dangerous than many people imagine.

Gathering the stones

Ugandan authorities, local residents and visiting scientists collected many fragments over the following weeks. Hundreds of stones were found, ranging from tiny pieces to a stone of more than 25 kilograms, and the total recovered was well over 100 kilograms. A team of researchers, including scientists from the Netherlands, worked with local people to gather and record the stones and their locations. Their survey mapped the strewn field, the elongated area over which the fragments landed, and estimated the size of the original meteoroid. In a strewn field like Mbale's, the smallest fragments are slowed quickly and land first, near one end, while the heaviest carry on further along the path, a pattern that searchers use to plan where to look.

The researchers also reported that some local people crushed fragments, believing they might have healing powers. Meteorites have no medicinal properties, and they should never be crushed, tasted or eaten.

What it is

Mbale is an L5/6 ordinary chondrite. Ordinary chondrites are the most common meteorites seen to fall. They are made of silicate minerals, mainly olivine and pyroxene, together with grains of iron-nickel metal and iron sulphide. 'L' stands for low iron, one of the three main groups of ordinary chondrites. The numbers 5 and 6 mean that its parent asteroid heated it strongly, so that its chondrules, the small round grains typical of chondrites, have become blurred and recrystallised. A classification of '5/6' means that it shows features between those two types.

Fresh Mbale stones had dark fusion crusts and light grey interiors. Scientists were able to measure the effects of cosmic rays on the stones, which reveals how long they travelled in space as a small body, and to study how such a large shower breaks up in the atmosphere.

Specimens are now held in collections around the world and remain a useful reference for researchers studying L chondrites.

Why it matters

Mbale is one of the largest witnessed meteorite showers of the late 20th century, and it fell in a densely inhabited area. Its careful documentation made it a valuable case study of how meteoroids fragment and how their pieces spread across a strewn field, information that helps scientists predict where to search after future falls.

It is also a reminder that meteorite falls happen all over the world, and that local knowledge and cooperation are vital for recovering them. In many countries, meteorites belong to the state or to landowners, and laws govern how they can be collected or exported.

Above all, Mbale shows how easily a strange event in the sky can become part of a community's story. For the people who lived through it, the afternoon the stones fell is still remembered.

Did you know?

See more

Mbale in the catalogue