Lauren Fuge
New research throws doubt on claims that meteorite material recovered from the Pacific Ocean in 2023 is of interstellar origin.
At the time, seismic signals linked to the meteor helped Harvard scientists to locate its fragments on the sea floor. However, these new findings suggest the signals were actually just from a passing truck rumbling along the road.
The story so far
On 8 January 2014, a fiery meteor soared down through the atmosphere, put on a series of explosive displays, and broke up over the South Pacific Ocean near Papua New Guinea.
The meteor was observed by the US Department of Defense, which tracks all objects entering the Earth’s atmosphere. This one was half a metre in diameter and hit the Earth at a speedy clip of 45 km/s – faster than most meteors. It also plunged so deeply into the atmosphere that it was likely quite dense.
However, at the time researchers paid little attention to it. It was only after the discovery of the interstellar comet ‘Oumuamua (1I/2017U1) in 2017 – the first object ever confirmed to come from a solar system other than our own – that there was renewed interest in interstellar visitors.
Avi Loeb, a physicist from Harvard University in the US, searched NASA’s Centre for Near Earth Object Studies (CNEOS) database to find other objects with unusual orbital characteristics. One that jumped out was the speedy 2014 meteor, officially designated CNEOS 20140108.
Loeb’s team then modelled the path of the fireball, drawing on the seismic data from a station on Manus Island, which showed a spike in ground vibrations at the time that the meteor entered the atmosphere. This led them to zero in on a specific spot in the South Pacific: 84 km north of Manus Island in Papua New Guinea, in a narrow band 11 km long and 1 km wide.
In 2023, the team launched a controversial mission there. They spent 2 weeks dredging the sea bed with a powerful magnet in search of iron spherules: tiny spheres of material that may have condensed from the molten metal raining into the ocean after the primary meteor exploded.
As Cosmos reported at the time, Loeb’s team found 722 iron spherules of about 1 mm in size, which they believed to be from the 2014 meteor.
Analysis of 57 of these spherules showed they were extremely rich in beryllium, lanthanum and uranium, with much higher concentrations than they are naturally found on Earth.
This unusual elemental composition led Loeb to claim that the meteor had been of interstellar origin. He then further claimed that the meteor might have been an artifact of an alien civilisation.
This understandably generated controversy at the time, and since then more research has questioned the classification of the spherules.
Now, new findings may throw more doubt on the claims from a different angle.
Extraterrestrial or truck?
Searching for fragments of a meteor in the biggest ocean on Earth is no small feat. Loeb’s dredging trip relied on the seismic data from Manus Island, but new research questions the assumption that the signals were caused by the meteor.
A team of international researchers – led by Johns Hopkins University in the US – instead found that the signals could be attributed to a truck rumbling along a nearby road.
“The signal changed directions over time, exactly matching a road that runs past the seismometer,” says Benjamin Fernando, a planetary seismologist and leader of the research. “It’s really difficult to take a signal and confirm it is not from something. But what we can do is show that there are lots of signals like this, and show they have all the characteristics we’d expect from a truck and none of the characteristics we’d expect from a meteor.”
Fernando believes that Loeb’s team misinterpreted the seismic data, linking it to the meteor when in fact they may not have been related at all. Fernando’s team did not find evidence of seismic waves from the meteor, and so they argue that the meteor entered the atmosphere elsewhere.
“The fireball location was actually very far away from where the oceanographic expedition went to retrieve these meteor fragments,” he says. “Not only did they use the wrong signal, they were looking in the wrong place.”
His team then attempted to identify a more likely location for the meteor, drawing on data from underwater microphones in Australia and Palau equipped to detect sound waves from nuclear tests. They came up with a spot more than 160 km from the are Loeb’s team identified.
Fernando suggests that the spherules that Loeb’s team recovered may either be from an ordinary meteorite, or from a meteorite smashing into the planet’s surface and producing particles with a hybrid of Earthly and cosmic material.
“Whatever was found on the sea floor is totally unrelated to this [2014] meteor, regardless of whether it was a natural space rock or a piece of alien spacecraft – even though we strongly suspect that it wasn’t aliens,” Fernando concludes.
The research will be presented on March 12 at the Lunar and Planetary Science Conference in Houston, US.