Astronomers can now track small impactors before they hit Earth

Civilization-ending earth percussionists continually capture our imaginations. But even a small asteroid that explodes low enough in the earth’s atmosphere causes serious damage locally.

Until recently, astronomers have been helpless to get any sort of warning about these smaller meteors traversing Earth’s atmosphere. But a team at Hungary’s Konkoly Observatory in the hills above Budapest has been conducting an ongoing search for such near-Earth objects for several years.

Using a modest 60cm telescope in Hungary’s Matra Mountains combined with a pair of well-preserved human eyes, Konkoly Observatory astronomer Krisztián Sárneczky spotted three of the nine known objects identified as such before they hit Earth.

However, the observatory also owes its success in part to a state-of-the-art camera and software that filters out background noise to focus on prospective impactors.

This means that astronomers do not need to clean any given entire image, but only the potential impactors that the software has selected.

Warning times typically range from two to 12 hours. And even a few hours’ warning would be enough to alert residents of an impending impact. This could, in theory, give people time to seek shelter in a basement or on the ground floor of a safe building in the same way that residents in areas prone to hurricanes and tornadoes seek shelter when threatened by weather storms.

Any object over one to two meters can be observed.

But anything over 50 meters in diameter could do a lot of damage, while at the upper end, a 250-meter object could destroy a large city, Robert Szabo, an astronomer and director of Hungary’s Konkoly Observatory in Budapest, told me in his office. . . However, we would like to see a 50m to 100m object as soon as possible, he says.

As for locating the items beforehand?

There are two factors: size and brightness (or albedo, the fraction of light reflected off the surface), Szabo says. All possible combinations occur — big and dark, big and bright, small and bright, small and dark, he says.

New Moon

The night during the new moon is ideal. But these objects are very faint, moving at thousands of kilometers per second, so the team usually points out anything they find in their images that creates a streak.

Apparent brightness depends on these two factors (visible area times unit area brightness) – and on their distance, Szabo says. But both small and large objects create streaks on the CCD (charged pair detector). Even so, bright stars, artificial satellites, defects in the camera’s CCD can all cause false alarms (or obscure candidates), he says.

Going through the pictures

The eye and the human brain are still very good at spotting these potential shockers in the data, Szabo says. But we’re getting to the point where it’s no longer feasible to do that in real time, he says.

Given the fact that 70 percent of the earth’s surface is covered by water, most of the time, impactors that hit land are minimal.

We mainly look for near-Earth objects (NEOs) that come close to Earth, and some of them turn out to be on an imminent collision course, Szabo says. That’s when we can issue a warning, he says.

The software improves the signal-to-noise ratio so that fainter potential impactors can be found long before they hit Earth, Szabo says. But the damage they cause depends on, among other things, their density, composition, porosity and velocity in the object, he says.

Even so, these are early days for finding such shock substances.

We have a very special location here, so we are ahead of America and we are after night in Asia, says Szabo. So if it’s nighttime in Europe, then we’re in the right place and have a chance to see them first, he says.

One of the most recent was found on January 20, 2024. Sárneczky discovered a new asteroid using the 60 cm Schmidt telescope at the Piszkéstető mountain station, part of the Konkoly Observatory in Hungary, the European Space Agency says.

It hit our planet’s atmosphere 50 km west of Berlin, producing a spectacular fireball. Dubbed ‘2024 BX1’, this is just the eighth asteroid that humanity has spotted before the impact – and the third discovered by Sárneczky, ESA says.

The goal for the Konkoly Observatory is to expand the number of 60 cm telescopes on Mount Matra up to four. This would not only help protect Hungary from possible impacts but also Europe as a whole.

Szabo and his colleagues are in negotiations to become part of ESA’s planetary defense network.

The bottom line?

Szabo says that finding one of these potential impactors is like finding a needle in a haystack. But he says this new technology has allowed the observatory to track these small objects to a degree not previously possible.