At 1:06 p.m. local time on May 30, 2026 (18:06 UTC), a fireball crossed the sky over coastal Massachusetts in broad daylight, and a sonic boom rolled across New England a short time later. Within days the rough outline was known: a large meteoroid had broken apart high over the region and dropped its fragments into Cape Cod Bay. Bright enough to see in daytime and loud enough to rattle windows, it was what astronomers call a superbolide.
A new paper posted to arXiv on October 17 now gives a much more detailed account. A team led by Juha Vierinen of UiT The Arctic University of Norway, with co-authors including Ryan Volz and Marc Fries, combined data from a VHF meteor radar network, U.S. weather radars, regional infrasound sensors and camera footage to reconstruct the object's path through the atmosphere, how it broke apart, and where it came from. The orbit reaches outward toward Jupiter, and the team could not tie it to any known meteor shower or parent body.
A radar network in the right place
This event was unusual because it happened inside the coverage of SIMONe, a meteor radar network developed by MIT, UiT and the Leibniz Institute of Atmospheric Physics. Meteor radars are built to detect meteors, not to catch rare, rock-sized objects, and catching one requires the event to happen close by.
According to Space.com's report on the study, Volz said a bolide like this would have to enter the atmosphere within about 62 miles (100 km) of a SIMONe-like meteor radar for the head echoes to be detectable, and only a handful of places in the world currently meet that criterion.
The radar recorded two kinds of signals. The first was a "head echo," the reflection from the plasma around the meteoroid itself. The network followed it from about 90 km altitude down to 71 km. The second was a set of short-lived non-specular "wake" or trail echoes left behind the object. Using interferometry to work out where these echoes came from, the team traced the wake down to about 30 km. The paper calls this the radar terminus, the altitude where breakup is expected to occur.
The combined head-echo and trail fit describes a steep descent heading southeast over coastal Massachusetts.
How big a bang?
The early numbers released just after the event, which Northeastern University reported citing NASA, described a meteoroid about 5 feet across and over 12,000 pounds, moving at roughly 42,000 mph and shattering after traveling about 26 miles through the atmosphere. Northeastern put the sonic boom's force at 230 tons of TNT.
The radar-based analysis gives a larger figure. As Space.com summarizes the study, the trail echo extends down to about 20 miles (32 km), where the rock fragmented in a release equivalent to roughly 500 tons of TNT, and the total impact energy was about 1.1 kilotons. Only three bolides recorded in 2025 were more energetic. The gap between the early and later numbers is not surprising. First estimates are usually built quickly from limited data, while the new work draws on several independent instruments.
Regional infrasound recordings, which capture very low-frequency pressure waves too deep for human ears, independently support the terminal fragmentation region. The paper's infrasound analysis yields an energy estimate of 0.5 kilotons of TNT equivalent.
Weather radar sees the rocks fall
After a meteoroid fragments and slows, surviving pieces stop glowing and fall at terminal velocity, a phase called dark flight. Cameras can't see that stage, but Doppler weather radar can sometimes pick up the falling debris, the same way it picks up rain or hail.
That is what happened here. Four NEXRAD radars recorded the debris, according to Space.com, and the paper says the weather radar returns put the likely fall region in Cape Cod Bay. That matches earlier reports that meteorites dropped into the water. It also suggests any recovered pieces would probably be on the seafloor, not on a beach or in a backyard.
The researchers also comment on the object's makeup. The paper says the radar and dark-flight evidence are consistent with a dense, mechanically strong meteoroid, possibly iron-rich, and Space.com describes it as a fairly solid body given how deep it penetrated before fragmenting.
A lone wolf with a Jupiter connection
Once the trajectory and speed were known, the team propagated the path backward to estimate the object's orbit around the Sun before it reached Earth. The orbit, Space.com reports, is comet-like, with its farthest point from the Sun (aphelion) close to Jupiter's orbit.
The paper is careful here. It says the heliocentric orbit sits near the boundaries that astronomers use to separate cometary from asteroidal orbits, and that empirical classification criteria conflict about which side it falls on. Fries told Space.com that meteoroids can be perturbed by Jupiter and that a close pass by the giant planet may have flung this one onto its Earth-crossing path.
The team found no convincing parent body. "We cannot determine its exact history, but we found no association with any known meteor shower," Vierinen told Space.com. Many large fireballs can at least be loosely linked to a stream of debris from a known comet or asteroid. This one, in the words of Space.com's headline, was a "lone wolf."
Taken together, the evidence is a little odd. The orbit looks partly cometary, but the material looks dense and possibly iron-rich. The study does not try to settle that tension. It reports where the measurements point and where they disagree.
Why It Matters
Daytime bolides are rare. Jacqueline McCleary, a physicist at Northeastern, called the Cape Cod event a rarity in early coverage. In this case, the event occurred within range of a research-grade meteor radar, several weather radars and infrasound stations at the same time. That let the team combine independent instruments to follow the object from atmospheric entry to nearly the ground, and each can be checked against the others.
This matters for several reasons. Measurements like these help constrain how much energy a fireball releases and how deep it penetrates. The work also shows that meteor radars together with the national weather radar network can contribute useful data on rare large events. Space.com notes that being able to trace meteoroids back to their orbits may in future reveal new populations of potentially hazardous impactors. And an object with no known family, arriving on an orbit shaped by Jupiter, is a reminder that some of the material reaching Earth comes from populations we have not yet cataloged.
For now, the Cape Cod superbolide stands as a very well-instrumented daytime fireball. Its fragments are probably at the bottom of the bay, and its origin is still uncertain.
