In January of 2014, a meteor fell from space off the coast of Papua New Guinea. That might have been the end of it, but several years later Avi Loeb, a theoretical astrophysicist at Harvard, drew on seismic data from near the site, looked for crash remains on the ocean floor and proposed that the remains “may reflect an extraterrestrial technological origin.”

Dr. Loeb has previously been accused by his peers of wild speculation and sensationalism. Last fall, Benjamin Fernando, a planetary seismologist at Johns Hopkins University, led a team that re-examined the nearby seismic signals and concluded that they were not evidence of the extraterrestrial, or anything close to it.

On Tuesday, Dr. Fernando will present the data in detail at scientific conference. Recently, he sat down with The New York Times to preview what his team had found. This interview has been edited and condensed for clarity.

How did this all start?

In 2014, a meteor entered the atmosphere and went “bang.” Sometimes, you hear these meteors on seismometers. Avi Loeb wrote a paper to say that he’d found the seismic signal from this meteor and that he’d used it to locate exactly where the meteor debris fell. And from that, they mounted an expedition and picked stuff up off the sea floor.

In one paper, Dr. Loeb and a co-author wrote that they “confirmed the fireball location” in the ocean from “the timing of the strong seismic signal.” But you’ve determined that the seismic information wasn’t coming from a meteor. What do you think it was coming from?

A truck.

As in, a hyperspeed alien truck?

No, it was an ordinary truck, like a normal truck driving past a seismometer. Not being seismologists, the Loeb team may have misunderstood the data. In reality, all they did was find a truck.

And that truck was traveling where? In the Milky Way?

No, no, no. The truck was traveling on the same island in Papua New Guinea. It’s an ordinary Earth truck. I guess technically that’s in the Milky Way!

How did you conclude that we’re not being invaded by aliens?

We looked at two weeks of data around the time of this event. We saw hundreds of similar signals like the one Loeb studied. If there are hundreds, they can’t all be meteors. Of those hundreds of signals, most occur during daylight hours. The one Loeb saw, the ones we saw, all happen much more during the day. That’s an indication of anthropogenic noise.

Human-created noise?

Yes.

Then we looked at the exact signal he was looking at, and it was coming from a main road. Over time, it moved from a main road in the direction of a hospital, and then back to the main road. So, from analyzing the data, it looks to us like the signal is much more likely to have come from a truck turning off the main road, driving past the seismometer near the hospital and then driving the other way.

There was no meteor involved whatsoever.

In the conclusion of your paper, you write that you have “a very high degree of confidence that the purported fragments of the meteor recovered from the seafloor have nothing to do with the fireball” — and therefore, that the stuff plucked from the ocean floor was probably just stuff from Earth, or maybe a bit of the thousands of tons of meteorites that reach Earth every year. So we shouldn’t worry that aliens are invading our hospitals?

You’d be quite reasonably justified in not worrying about aliens invading hospitals.

What’s the bigger lesson from all this?

There are two: One, if you want to do seismic analysis, it’s ideal if you check with a seismologist first. The other is, it’s not aliens.