Attention, space geeks and celestial prospectors. NASA has some sad news about the meteor that fell to Earth above western Maine early Tuesday.

Despite a $20,000 reward offered by a Bethel mineral museum for anyone who can turn up a 1-kilogram chunk of the cosmic debris – which lit up the night sky from Pennsylvania to Quebec with the brightness of several full moons – a NASA scientist said Wednesday that the likelihood of finding a piece that large is astronomically small.

The American Meteor Society determined that the meteoroid seen over the northeastern part of the United States on Tuesday morning broke into two pieces. This is from the Burlington, Vt., airport video that shows the two objects. The inset enlarges the image and the circles indicate the two pieces.

FIVE NOTABLE METEORITES

The Willamette Meteorite is shown in 2000 at the American Museum of Natural History. Associated Press file photo

• The 32,000-pound Willamette meteorite discovered in Oregon in 1902 is the largest found in the United States. There was no impact crater, and some scientists believe it is a glacial erratic transported to the Willamette Valley at the end of the last ice age. Long held sacred by the Clacakamas Indians, it is now in the American Museum of Natural History in New York City.

• The Hoba meteorite found at Hoba Farm, near Grootfontein in Namibia in 1920, is the largest meteorite ever discovered, weighing about 132,000 pounds and measuring roughly 9 feet wide, 9 feet long and 3 feet thick. It left no crater, which scientists speculate could have happened if it entered Earth’s atmosphere at a low speed and shallow angle.

• The Anighito meteorite is the world’s second-largest, weighing roughly 75,000 pounds. It was discovered by Lt. Robert Peary at Cape York in Greenland in 1892.

• The Chassigny meteorite fell in Chassigny, Haute-Marne, France, on Oct. 3, 1815. The small meteorite weighed only about 9 pounds and is notable for its origin: It came from Mars.

• The Tunguska meteorite is believed to have been a 100-foot-wide asteroid that exploded 5 miles above an uninhabited area of Siberia near the Tunguska River on June 30, 1908. The shock wave from the explosion leveled millions of trees, covering an estimated 800 square miles. No meteorite definitively associated with Tunguska has ever been found.

Sources: sciencechannel.com, rockcollector.co.uk, geology.com, fallofathousandsuns.com

LARGEST IMPACT CRATERS

1. Vredefort Crater

Estimated impact date: 2 billion years ago

Location: Free State, South Africa

Diameter: 236 miles

2. Sudbury Basin

Estimated impact date: 1.8 billion years ago

Location: Ontario, Canada

Diameter: 81 miles

3. Acraman Crater

Estimated impact date: 580 million years ago

Location: Lake Acraman, South Australia, Australia

Diameter: 56 miles

4. Woodleigh Crater

Estimated impact date: 364 million years ago

Location: Western Australia, Australia

Diameter: 25 to 75 miles. This crater is not exposed at the surface and there are discrepancies about its size.

5. Manicouagan Crater

Estimated impact date: 215 million years ago

Location: Lake Manicouagan, Quebec, Canada

Diameter: 62 miles

Source: NationalGeograhic.com

Bill Cooke, lead for NASA’s Meteoroid Environment Office, which tracks and forecasts meteors, said preliminary data indicates Tuesday’s meteoroid was large, roughly 5 feet across with a mass of about 13,000 pounds. But it appears to have fractured into two pieces rapidly, indicating the interplanetary debris was likely made of a fragile, pumice-like material that is not well-suited to surviving the hot, violent trip to Earth’s surface, Cooke said.

“This thing broke apart almost as soon as it hit the atmosphere,” he said. “That usually indicates the object is very fragile at best. Stuff like that, it’s hard for it to make it all the way down to the ground. It could come down in a cloud of dust.”

Still, Cooke, a 22-year NASA veteran based in Alabama, said it’s fair to hold out hope, especially considering the sum of money on the line.

“I don’t think this thing produced meteorites on the ground, but for $20,000 I’d be out up there looking, too,” he said. “What do you got to lose?”

A potential windfall is rarely the motivation for hunting for a hunk of rock that’s rarer than gold.

Meteorites, the term for meteoroids that reach the ground, often are made of rare combinations of elements or metals such as iron and nickel that help researchers gather new information about the Earth, the solar system and sometimes other planets.

For amateur hunters, the attraction is something else, often the simple, mind-bending awe of holding a rock formed billions of years ago that traveled from outer space, surviving a brutal trip through the atmosphere, only to be plucked from some ordinary hillside by human hands.

It’s the thought that, of all the planets in all the solar systems, it fell onto this one.

“They’re the rarest material on Earth,” said Mike Hankey, operations manager for the American Meteor Society and a devoted meteorite fanatic. “They’re not made here.”

RENEGADE FROM ASTEROID BELT

The meteor – technically, a meteor is the light emitted by a meteoroid – that streaked through the sky over western Maine specifically came from far outside the neighborhood.

Cooke said Tuesday’s meteoroid originated in the main asteroid belt between Mars and Jupiter at least 200 million miles from the sun, and was first tracked traveling about 38,900 mph about 52 miles above the Earth’s surface over the White Mountain National Forest. The meteoroid broke up about 28 miles above the surface of Upper Richardson Lake. Pieces could be spread farther north, in the area west of Kennebago Lake in Franklin County, although more precise estimates could be released by the U.S. Department of Defense in the coming days or weeks.

Even if chunks of the meteoroid made it all the way to the ground, finding them would be difficult, Hankey said.

First, there is the size of the meteorites themselves. Most fragments that make it to the ground range from the size of a grape to the size of a golf ball, he said.

The charcoal-black hunks of rock and metal can blend easily into the forest floor or lie hidden under leaves and sticks. If the area has tall grass cover, finding anything is nearly impossible, he said.

“You might be able to get lucky if a thousand people go out, but it’s a very wide area that you have to hunt right now,” Hankey said.

Typically the strewn field, the term for the elliptical-shaped area of debris where meteorites land, stretches roughly 10 miles long and 2 miles wide, but those dimensions can change based on the wind conditions and the material that fell from the sky, Hankey said.

And there are other difficulties.

Often accessing the area where a meteoroid fell is difficult, and there are legal considerations before making that trip, he said.

“You’ve got to be a wheeler and a dealer when talking to landowners, saying to some guy, ‘Hey, do you mind if I walk all over your farm looking for rocks?’ People look at you like you’re frickin’ crazy.”

Things can get even more complicated when a landowner knows that meteorites can be worth money, he said. Avoiding potential litigation over ownership means striking a deal before setting out onto private property.

METEORITE HUNTERS HOLDING OFF

U.S. law is generally settled on the ownership of a meteorite. Barring any previous agreements, meteorites that land on private property belong to the landowner. The principle applies to government-owned land, too.

Right now the small, tight-knit community of meteorite hunters is waiting for more data to develop on the location and likely composition of the Maine meteor, Hankey said.

Currently, the amount of information gathered on the meteor is simply not yet developed enough to justify the expense of trekking through the western Maine woods.

While the Maine Mineral and Gem Museum in Bethel is offering $20,000 for a 1-kilogram chunk, or roughly 2.2 pounds, a piece that large could actually fetch double that, Hankey said.

“It’s a tall order, for one, to even get a 1,000-gram stone,” he said. “We’d be lucky to even get a 10-gram stone.”

Museum director Barbra Barrett did not comment on the estimate that the museum’s reward offer was low, but said she hopes it will drum up public interest in meteorite study – and bring more people to the museum.

So far her prediction has held.

Since Tuesday, she has been showered with calls and inquiries, not only from media outlets, but prospective meteorite hunters, people who believe they found a meteorite (no, she said, most were “meteor-wrongs”) and even from a Massachusetts-based manufacturer of metal detectors, who said he’s seen a spike in business in the past two days.

“It’s from our own state, we want to celebrate that,” Barrett said.

But then she caught herself.

“I mean, it’s not really from our state,” she said. “It’s from the solar system.”