Asteroids: AI algorithm discovers previously unseen 'potentially hazardous asteroid' - how safe is Earth?

A new AI algorithm created to identify huge asteroids from small data fragments has discovered a 600-foot asteroid that had previously gone unidentified, close enough to Earth to qualify as a PHA - a potentially hazardous asteroid.

But the danger to life is minimal, since asteroid 2022 GN1 - which is about the size of a skyscraper - flew past the Earth at a distance of 4.5 million miles (7.2 million kilometres) in September 2022.

The worry is not the rock itself, but the fact that it is another asteroid that was not seen by astronomers on Earth before, during or after the approach, as it was obscured by starlight from the Milky Way. How many more PHAs could be out there that human eyes have so far missed?

PHAs are typically larger asteroids with a diameter of at least 460 feet (140 meters), and must have an orbit that brings it within less than 0.05 astronomical units (AU) from the Earth, which is approximately 4.6 million miles (7.4 million kilometers).

The new algorithm, called HelioLinc3D was able to locate 2022 GN1 by examining data from the Zwicky Transient Facility (ZTF), a telescope built to look for quickly moving objects in the night sky, and was able to detect it even though the asteroid was only visible for a short while.

What does it mean?

With 2022 GN1 being found hidden in year-old telescope data, its discovery could alter how near-Earth objects are tracked, and serves as a reminder that astronomers have yet to find many potentially hazardous asteroids.

There are 2,350 PHAs that are currently known to scientists, but more than 3,000 are likely still out there waiting to be discovered.

The HelioLinc3D algorithm will be officially put to work sifting through data collected by the Vera C. Rubin Observatory, a cutting-edge telescope in the Chilean mountains that is slated to start its asteroid-hunting operations in early 2025.

"This is just a small taste of what to expect with the Rubin Observatory in less than two years, when [the algorithm] HelioLinc3D will be discovering an object like this every night," said Mario Jurić, the team leader behind the new algorithm, said in a statement.

"By demonstrating the real-world effectiveness of the software that Rubin will use to look for thousands of yet-unknown potentially hazardous asteroids, the discovery makes us all safer," said Rubin scientist Ari Heinze, the principal developer of the algorithm.

How safe is the Earth?

It is expected that many more PHAs will be detected and monitored as a result of the partnership between the Vera C. Rubin Observatory and the HelioLinc3D algorithm, leading to a better understanding of the potential risks.

By monitoring these objects, scientists can calculate their orbits accurately and predict their future paths, allowing for timely responses and potential mitigation efforts if any hazardous asteroids are found to be on a collision course with our planet.

The size of an asteroid required to cause mass destruction on Earth depends on several factors, including its composition, speed and angle of impact, but generally, a PHA with a diameter of about 0.6 miles (1 km) or larger could cause global devastation if it were to collide with Earth.

Such an impact could lead to widespread destruction, trigger tsunamis, cause severe climate change, and even threaten the survival of various species, including humanity. But according to current data, the probability of an impact from such a large asteroid within the next 100 years is relatively low, likely less than 1%.