This past spring, a meteor exploded into a fireball about 30 miles above Cape Cod Bay.
Scientists have been using data from that event to better understand our atmosphere and how to predict when asteroids could pose a risk to humans.
Phil Erickson is the director of Massachusetts Institute of Technology's Haystack Observatory in Westford. He and his colleagues have been working with scientists in New Hampshire, New Mexico, Germany, and Norway to research the May fireball event.
CAI's Gilda Geist spoke with Erickson to learn more about what they've found so far.
Gilda Geist Can you just tell me a little bit about how you all kind of came together and started working on this and what the goal of this research was?
Phil Erickson Here at Haystack Observatory, we run a number of instruments for measuring the atmosphere and its properties, space weather, and then out into the solar system. We happen to be running something called a meteor radar with our collaborators. We were doing that for measuring what the atmosphere was doing. They're on all the time. And it so happened that this very large thing called a bolide, in fact called a superbolide, which was a particularly large meteor, happened to appear in our field of view as this thing was entering and eventually splashing down in pieces over Cape Cod Bay. It was not only a large and unusual event, but it happened to be pretty well instrumented. So that's where the collaboration started. You have this, in this case, large rock, a few meters in size. It's very cold, it's at space temperatures. As it comes into the atmosphere, it begins to heat up because the atmosphere is basically colliding with it, and it's getting really, really hot on the outside, but the core is still very, very cold. At some point, the difference between the outside and the inside becomes so strong that the meteor explodes. It literally tears itself apart. It can't deal with that much of a temperature gradient. When that happens, you get an explosion, and then you get fragments that come down. It is not that usual to have this kind of an event happen where you have a good number of diagnostics. So that's why we went and did the study.
GG What are the societal implications of the kind of stuff that you guys are looking for here?
PE So, there's a basic science aspect to it, but there is an applied science aspect to it. When a meteor gets really, really large, of course, it can pose a threat to society. Every day the Earth has tiny little microgram particles that it's scooping up in its orbit. Happens every day. Then you go to bigger things and yet bigger things and yet bigger things. And this starts to inform, for example, what we understand about asteroids. And you may have heard that there are certain asteroids that if they happen to hit, we get another real problem. And so understanding how this size distribution happens can also help us predict what's happening for the really big ones that have very destructive consequences that we might want to be able to prepare for. To give you an idea, there were three of these bolides in the year 2025, so we're not talking about that many. All of them were greater than to exploding a kiloton of TNT. So these are very, very large amounts of energy released. [In our case], the fragments fell into Cape Cod Bay where they may be accessible. My colleagues at Woods Hole Oceanographic Institution may try to go out and find some of them so that we could conclusively trace back what we think the composition of that is.
GG When the event actually happened, people were saying that in theory you could go to the bottom of Cape Cod Bay and get these pieces. I talked to a scientist at the time, and they were like, well, it might not be worth the resources that would be required for that. So, what I'm hearing is now it's maybe going to happen. Does that have to do with your guys' research?
PE We hope that the study that we have will sort of add to the motivation to do that. That would then nail down some things that we had to sort of infer about what came down based on what we were able to measure, because then you could do a chemical analysis of what you have, and be more precise. Being able to close the loop on that is, I think, even more unusual given the amount of rich data we had compared to other events. That will also help us in the future do a better job when we maybe cannot recover the fragment. So, I am hopeful that someone at Woods Hole can make that happen.
GG What are your most important or most surprising findings?
PE These studies, when you can make a more precise measurement, almost invariably lead to your better understanding of the fundamentals of the atmosphere. And as humans become a spacefaring society and people like SpaceX launch a whole bunch of satellites into low Earth orbit, the ability to understand our atmosphere is actually becoming a much more urgent need than it was even a decade ago. People are trying to go to the moon. There are people who would like to go to Mars. But to get there and to have something there that's stable, you really need to understand the thing you're going through. So, in some sense, we are still sort of data-starved for trying to understand the basic physics and chemistry of what's going on above our heads.
