Sometimes I think my job title should be Wet Blanket Reporter – the man who throws cold water on fun but unlikely tales. A case in point:
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 County 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 Gianforre, an adjunct professor physics who teaches astronomy, does research on planets outside the solar system, and co-founded the Astronomical Society of Northern New England.
The question came up in regards 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,” said Gianforte, “but it’s very, very unlikely and improbable.
“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.
Among the factors that raise suspicion 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,” said Gianforte.
“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 worng , he added. It’s possible is that the peron actually saw a piece of equipment falling off an airplane that was hot enough to ignite dry underbrush. Not terribly likely, 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,” said Gianforte.
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 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 that 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, Gianforte noted, “1,000 tons of material – that’s a lot of stuff.”
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