Meteorites

A swift streak of light across the night sky is a meteor, commonly called a falling or shooting star. Most incoming material vaporizes as it passes through the atmosphere. When a larger fragment survives the descent and reaches the ground, it is called a meteorite—and becomes part of Maine’s geological record.

What is a meteorite?

A meteorite is a piece of metallic or stony material from space that reaches Earth’s surface. Such rocks may originate in the asteroid belt, on the Moon, or on other planetary bodies. Material dislodged by an impact or collision can orbit the Sun, and a small fraction eventually crosses Earth’s orbit.

Meteoroids enter the atmosphere at very high speeds. Air resistance heats their outer surfaces, producing the visible streak associated with a meteor. Only material that remains after this fiery passage becomes a meteorite.

Meteorites vary greatly in size. Most recovered specimens are small, while the largest known examples weigh many tons. Size and composition help determine whether an object disintegrates, explodes, or survives its journey through the atmosphere.

Maine meteorites

Many meteorites may have landed in Maine, but five have been found and scientifically confirmed. Portions of each are preserved in museum collections. Four were observed falling and collected soon afterward. Meteorites are generally named for a geographic feature or community near the recovery site.

Nobleboro meteorite

Maine’s first recorded meteorite—and the second recorded in the United States—arrived between 4 and 5 p.m. on August 7, 1823, at Nobleboro. A witness heard sounds resembling musket fire, saw a small whitish cloud spiraling toward the ground, and described a noise like a whirlwind stirring leaves. The impact startled nearby sheep. Digging about half a foot into the ground revealed five or six pounds of sulfurous-smelling material.

Nearly 100 grams of the original mass are preserved in museum collections worldwide. Nobleboro is an achondrite, a comparatively uncommon class of stony meteorite, making it especially significant for scientific study.

Castine meteorite

The second recorded Maine meteorite fell near Castine at about 4:15 a.m. on May 20, 1848. The single stone was described as no larger than a hen’s egg and weighed 42 grams. It was identified as a chondrite, and fragments were later distributed among museum collections. An account appeared in the American Journal of Science that year.

Searsmont meteorite

At about 8:15 a.m. on May 21, 1871, another meteorite fell at Searsmont. A contemporary account described the event:

“There was first heard an explosion, like the report of a heavy gun, followed by a rushing sound resembling the escape of steam from a boiler. The stone fell in a field … The hole that it made was soon found and the stone dug out. It was quite hot and so much broken as to be removed only in pieces.”

The known specimens of the Searsmont meteorite have a combined weight of about two pounds. Reports noted that the stone penetrated hard soil to a depth of approximately two feet.

Andover meteorite

The fourth confirmed Maine meteorite landed at Andover on August 5, 1898. A witness reported that it came from the northwest, accompanied by a loud buzz-saw-like noise and a trail of smoke. Digging at the impact site produced one fragment weighing more than seven pounds and several smaller pieces that had broken when the meteorite struck a stone fence.

The main mass, later recorded at 2,791 grams, entered the Smithsonian Institution’s collection.

Walnut Hill meteorite

Maine’s only confirmed twentieth-century recovery was reported in 1978 in North Yarmouth. During repairs to a poultry shed roof, a small black stone was found below a hole near the eaves. It was taken to the University of Southern Maine and identified as a meteorite.

The 218-gram Walnut Hill specimen is an ordinary chondrite. A thin black fusion crust covers it, formed when the outer surface melted during its descent through the atmosphere.