What are meteorites and how did they get into Cape Cod Bay?
By Gilda Geist
June 2, 2026 at 1:43 PM EDT
Geochemist Liam Peterson with the Woods Hole Oceanographic Institution walks us through the recent fireball event over Cape Cod Bay.
Meteorites fell into Cape Cod Bay on Saturday when a meteor exploded into a fireball about 30 miles up in the atmosphere.
Liam Peterson is a geochemist and a postdoctoral researcher at the Woods Hole Oceanographic Institution. He helped clarified the differences between a meteor, a fireball and a meteorite.
An object that crosses earth’s orbit becomes a meteor when it enters the atmosphere, he said. The meteor will then start to burn up and break into pieces.
"When we say fireball, that is the burnup event that happens when the object basically heats up and starts to disaggregate. In the case of this one, it exploded and you get that big pulse of light," Peterson said. "And then when they’re going fast enough, you compress the air and then you get the sonic boom."
Whatever pieces of the object survive the fireball and make it to earth are called meteorites.
Radar information aggregated by NASA shows that the meteorites fell about 15 miles north of Sandy Neck Beach in Barnstable. In cases like this, meteorites are usually the size of a piece of gravel you might find in a driveway, Peterson said.
But according to NASA, radar data shows unusually large meteorites for this particular event—up to multiple kilograms a piece.
Peterson said the meteorites in the bay are not likely to pose any ecological risk. Even if they were made of something toxic, the bay is so big that it probably wouldn’t have an impact, Peterson said.
“Even if it was a pure contaminant—say it was like pure mercury—the mass of the body of water relative to the object that size, even if it fully dissolved, it's unlikely to constitute a significant contaminant source.”
NASA later released new information about the meteorites based on density calculations. They think these are iron meteorites, which are mostly made up of an iron-nickel alloy. The vast majority of meteorites are a type known as stony meteorites, containing mostly silicon-based minerals.
“There's actually only about two percent of meteorites that we call iron meteorites or irons," Peterson said. "Those would be the things that you could probably take a magnet to and stick it.”
Peterson encouraged people to go to the American Meteorological Society website if they think they see a fireball or hear a sonic boom and make a report.
“It really helps scientists to identify potential flight trajectories and locations of these events,” he said.
For this most recent fireball event, 86 people made eye witness reports. One of those people was R. Schott, who caught the fireball on video. It looks like a falling star appearing briefly on the right side of the frame.
Now could be a more important time than ever to make eye witness reports. The first quarter of 2026 saw a surge in large fireball events, the American Meteorological Society wrote in an article from March. Experts at the organization don’t yet know why this is happening, but they want to find out.
According to the Massachusetts Meteorological Survey, only two meteorites have been recorded in Massachusetts that we know of. The first was found in Northampton in 1963, and the second in Barnstable in 2018.
The Lunar and Planetary Institute says a fragment of the Barnstable meteorite was found on a pile of rotting leaves surrounded by wild blueberry bushes on August 18. The main meteorite was found on September 11, and more fragments turned up in the area throughout the rest of the year.
If you heard or saw the fireball, or you've tried recovering meteorites from Cape Cod Bay, CAI wants to hear from you. Call our newsroom: 508 548-9600 ext. 5.
Liam Peterson is a geochemist and a postdoctoral researcher at the Woods Hole Oceanographic Institution. He helped clarified the differences between a meteor, a fireball and a meteorite.
An object that crosses earth’s orbit becomes a meteor when it enters the atmosphere, he said. The meteor will then start to burn up and break into pieces.
"When we say fireball, that is the burnup event that happens when the object basically heats up and starts to disaggregate. In the case of this one, it exploded and you get that big pulse of light," Peterson said. "And then when they’re going fast enough, you compress the air and then you get the sonic boom."
Whatever pieces of the object survive the fireball and make it to earth are called meteorites.
Radar information aggregated by NASA shows that the meteorites fell about 15 miles north of Sandy Neck Beach in Barnstable. In cases like this, meteorites are usually the size of a piece of gravel you might find in a driveway, Peterson said.
But according to NASA, radar data shows unusually large meteorites for this particular event—up to multiple kilograms a piece.
Peterson said the meteorites in the bay are not likely to pose any ecological risk. Even if they were made of something toxic, the bay is so big that it probably wouldn’t have an impact, Peterson said.
“Even if it was a pure contaminant—say it was like pure mercury—the mass of the body of water relative to the object that size, even if it fully dissolved, it's unlikely to constitute a significant contaminant source.”
NASA later released new information about the meteorites based on density calculations. They think these are iron meteorites, which are mostly made up of an iron-nickel alloy. The vast majority of meteorites are a type known as stony meteorites, containing mostly silicon-based minerals.
“There's actually only about two percent of meteorites that we call iron meteorites or irons," Peterson said. "Those would be the things that you could probably take a magnet to and stick it.”
Peterson encouraged people to go to the American Meteorological Society website if they think they see a fireball or hear a sonic boom and make a report.
“It really helps scientists to identify potential flight trajectories and locations of these events,” he said.
For this most recent fireball event, 86 people made eye witness reports. One of those people was R. Schott, who caught the fireball on video. It looks like a falling star appearing briefly on the right side of the frame.
Now could be a more important time than ever to make eye witness reports. The first quarter of 2026 saw a surge in large fireball events, the American Meteorological Society wrote in an article from March. Experts at the organization don’t yet know why this is happening, but they want to find out.
According to the Massachusetts Meteorological Survey, only two meteorites have been recorded in Massachusetts that we know of. The first was found in Northampton in 1963, and the second in Barnstable in 2018.
The Lunar and Planetary Institute says a fragment of the Barnstable meteorite was found on a pile of rotting leaves surrounded by wild blueberry bushes on August 18. The main meteorite was found on September 11, and more fragments turned up in the area throughout the rest of the year.
If you heard or saw the fireball, or you've tried recovering meteorites from Cape Cod Bay, CAI wants to hear from you. Call our newsroom: 508 548-9600 ext. 5.