Asteroids that didn’t hit Earth

Hi, Pascal here, part of the Datawrapper app team. This week, we're staying in outer space and taking a look at asteroids that have come close to Earth, and at how early we can detect them and their potential impacts.

In this Weekly Chart, my colleague David mapped out every meteorite we saw falling down to Earth. That raised some questions for me: What about the ones that did not hit the Earth? How close did the asteroids fly by, and could we have seen them coming?

One of the closest recorded asteroid flybys happened last year. The asteroid 2025 TF flew over Antarctica at just 428 kilometers, roughly the same altitude as the International Space Station (ISS), and was detected a few hours later by the Catalina Sky Survey. It was the second closest asteroid flyby at the time, which might seem scary, but the asteroid was only 2 meters wide, and would have burned up in Earth’s atmosphere before hitting ground.

The last asteroid that came close and could have caused real damage if it hit Earth was asteroid 2025 FA22. With a size of around 200 meters, its impact could release energy equivalent to 150 megatons of TNT explosives, enough to wipe out a major metropolitan area with damage extending hundreds of kilometers outwards. It was discovered about half a year before its flyby in September 2025, which, if it were on a collision course, would still be far too late for a DART-style mission to deflect the asteroid. However, we need to put the word “close” into perspective here. At its closest point, the asteroid was over 800,000 kilometers away, or about twice the distance of the moon from the Earth. (That is why it didn't make it onto the chart above.)

All in all, the closest-flying asteroids were small and practically harmless, and the potentially more dangerous ones passed the Earth at a large enough distance.

Did we see them coming?

So, let’s take a look at how our ability to detect these asteroids coming close to Earth has changed over the years and how their size plays into it.

Looking at the data, we see a reassuring picture: we’ve gotten much better at detecting asteroids and discovering the bigger ones early. But how, and what changed over the years?

Mandates and technological advances

In the late 1990s, NASA received a mandate from the U.S. Congress to find 90% of the extinction-level asteroids (size of over 1 kilometer), and the LINEAR project and later the Catalina Sky Survey carried out a deep scan of the sky using ground telescopes. 2008 TC3 was the first asteroid that was discovered and its impact predicted before it entered the atmosphere.

Around 2005, another mandate was issued to also include asteroids larger than 140 meters. To accomplish higher resolution, new ground telescopes were built (e.g., Pan-STARRS in Hawaii), and NASA launched the NEOWISE space telescope to scan the sky in the infrared spectrum.

Over time, the existing hardware was upgraded, and new software rapidly improved data processing capabilities. In 2022, the global telescope network ATLAS (Asteroid Terrestrial-impact Last Alert System) became fully operational, scanning the entire sky every night, improving both detection rates and times for all sizes of asteroids.

Challenges and solutions for future detection

Still, despite these improvements, a significant number of asteroids still fly by undetected. How come, and what is being done to improve our chances? Major hurdles to further improving our abilities to discover asteroids (at all, or early enough) are budgetary limits, the Sun, which essentially blinds optical ground-based instruments, and the fact that many asteroids reflect very little light due to their material composition, or they only become visible for a brief period.

Two projects aim to help us in this fight — the world’s largest digital camera in the Vera C. Rubin Observatory in Chile, able to capture less reflective asteroids, which started taking first pictures in June last year, and the NEO Surveyor space telescope, set up to monitor Earth's blind spots, planned to launch in 2027.

Thanks for reading, I hope you enjoyed this peek into our planetary defense and maybe learned something new. Come back next week for a Weekly chart from Michi!

Curious to go and explore yourself?

• Explore asteroids around the Earth and in the solar system: Eyes on Asteroids

• Monthly planetary defense update by NASA: December 2025

• Databases for close approaches of near-Earth objects: CNEOS, ESA

• Detailed information on asteroids, e.g., 2025 FA22