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No, a meteorite didn’t start that forest fire in the North Country

  • This photo from Tuesday night, Oct. 3, 2017, shows the fire burning on the Dilly Cliffs near Woodstock. Courtesy of the Notch Hostel

  • A fire along a ridge line in Woodstock started from an unknown cause, but experts say a meteor likely isn't to blame. Earth Trek Photography, Erin Tuveson​—

  • A fire along a ridge line in Woodstock started from an unknown cause, but experts say a meteor likely isn't to blame. Earth Trek Photography, Erin Tuveson​—

  • A fire along a ridge line in Woodstock started from an unknown cause, but experts say a meteor likely isn't to blame. Earth Trek Photography, Erin Tuveson​—

  • A fire along a ridge line in Woodstock started from an unknown cause, but experts say a meteor likely isn't to blame. Earth Trek Photography, Erin Tuveson​—

  • A fire along a ridge line in Woodstock started from an unknown cause, but experts say a meteor likely isn't to blame. Earth Trek Photography, Erin Tuveson​—

  • Earth Trek Photography, Erin Tuveson​—

  • Earth Trek Photography, Erin Tuveson​—



Monitor staff
Wednesday, October 04, 2017

Although a UNH astronomer phrases it more cautiously, it’s safe to say that a falling meteorite did not start a fire in the North Country hills Tuesday, despite some local observers’ suspicions.

Why not? Because meteorites aren’t hot.

“When a small meteor enters the atmosphere – rarely do they make it to the ground – they reach a terminal velocity and hit the ground at maybe couple hundred miles an hour. ... When they hit the ground they’re cool to the touch. You could walk over and pick one up,” said John Gianforte, an adjunct professor of physics who teaches astronomy, researches planets outside the solar system and co-founded the Astronomical Society of Northern New England.

The question came up in regard to a forest fire that erupted Tuesday evening on Dilly Cliff, opposite the Lost River Gorge near the town of Woodstock. The local fire chief told media that somebody had reported seeing something falling from the sky, leading to speculation that the rock (called a meteor when it’s in the air but a meteorite when it hits the ground) may have ignited the dry underbrush.

“It’s not impossible,” Gianforte said, “but it’s very, very unlikely and improbable.”

So unlikely that it would have taken just the right combination of bizarre events.

“I suppose if it was a metallic (meteorite) and it struck a rock when it landed, and a spark ignited a fire, that’s possible, but it seems a very unlikely series of events,” he added.

Casting more doubt on the meteorite explanation is the fact that people’s observations of events in the sky are often flawed, because it’s hard tell what is going on overhead.

“Usually, when you see a meteor flashing across the sky, it’s hundreds and hundreds of miles away and it burns up 100 miles in the sky. ... It’s very, very difficult to judge distance – impossible, really, unless you’re really trained at it,” Gianforte said.

“You really have to have two or three observers looking at the same object at the same time, and to know where they are exactly, so you can do some trigonometry and figure out where it (lands),” he added.

That doesn’t mean the report of something falling is necessarily wrong, he added. It’s possible is that the person actually saw a piece of equipment falling off an airplane that was hot enough to ignite dry underbrush. That’s not terribly likely either, however.

Meteorites can certainly create fires and cause damage if they’re big enough. The most famous case is the 1908 Tunguska event, when a meteor exploded over eastern Siberia and leveled trees for more than a hundred miles in all directions.

“When they’re really big, they take all that kinetic energy of motion and in the matter of a few seconds they transform it into thermal energy,” Gianforte said.

If that was the case on Dilly Cliffs, however, there’d be a crater big enough to be found even in the woods and steep mountainside.

“No one has found anything that has fallen from the sky. That would help the story to be more credible if someone found the smoking gun, so to speak,” he said.

There’s one more thing to know about the topic: There has never been a confirmed finding of a meteorite in New Hampshire.

This doesn’t mean they never fall on the Granite State, it just means that it’s very, very hard to find them in wooded, rocky terrain like ours. There’s a reason the vast majority of confirmed meteorites throughout history have been discovered in deserts or snow fields, where they stand out.

An estimated 1,000 tons of material falls onto the Earth from space every day. But most of it consists of micro-meteorites, barely more than dust, and most of it falls into the oceans that cover almost three-quarters of the planet’s surface.

Still, as Gianforte pointed out: “One thousand tons of material – that’s a lot of stuff.”

(David Brooks can be reached at 369-3313 or dbrooks@cmonitor.com or on Twitter @GraniteGeek.)