CLEVELAND – The Antarctic equivalent of a hurricane had been blowing for nearly a week, and geologist Ralph Harvey was beginning to wonder if his team would ever get out of their rattling tents and onto the ice.

It was early December 2005. Members of the Antarctic Search for Meteorites program, based at Cleveland’s Case Western Reserve University, were on their annual trek to the planet’s best hunting grounds – vast ice fields, where rocks that scorch down from the heavens stand out against the featureless white plain.

Finally, the winds calmed and on Dec. 11 the searchers eagerly headed out on the Miller Range. Within a half-mile of camp, they spotted a golf ball-sized lump half-buried in the snow. The sun glinted off its shiny black surface – a sure sign the rock had been exposed to intense heat, enough to partially melt it.

The shiny coating is called fusion crust, and Harvey jokes that it’s a meteorite’s party clothes, “because it hides as much as it reveals.”

When scientists back in the United States chipped away the crust and examined the rock’s interior, they got a big surprise.

This wasn’t just space rubble. It was a piece of the moon, and an old one too, possibly blasted off the lunar surface by an asteroid impact soon after the moon’s formation 4½ billion years ago.

The rock is volcanic, a product of the moon’s once-molten interior. Rather than being belched to the surface as lava, however, MIL 05035’s big crystals suggest that it cooled slowly, smothered deep in the moon’s crust.

Then, something smashed it from the moon’s grip. Scientists surmise this because a component called plagioclase feldspar has been transformed to glassy maskelynite.

“The conversion of feldspar to glass only happens when you impact the heck out of it – really shock it,” said Harvey.

Only one other lunar meteorite has that shocked feldspar glass. Analysis has shown that the meteorite, Asuka 881757, is one of the moon’s most ancient volcanic rocks. Its age, at least 3.7 billion years, is close to the time called the late heavy bombardment.

, when the inner solar system was relentlessly pelted by asteroids and comets.

Such impacts could have shattered pieces of the moon’s crust, which Earth’s gravity could eventually capture and pull down to the Antarctic ice.

“Asuka looks like part of this heavy bombardment,” Harvey said. Considering its similarity to MIL 05035, “it’s our hope this rock is another representative of that time period.”

“It’s not the most photogenic meteorite we’ve ever seen, but it’s maybe one of the most interesting,” said Tim McCoy, curator of the Smithsonian Institution’s National Meteorite Collection, who has examined the sample.

Only further analysis will tell. Like their counterparts scooped from the lunar dust by the Apollo astronauts more than a generation ago, MIL 05035 and the other meteorites shed by the moon hold tantalizing secrets about their home world.

Until America’s planned resumption of lunar landings in 2020, the meteorites “are really the best source of new information about what the moon’s surface is like,” McCoy said. “They’re asking all sorts of questions that our return will help us answer.”