Imagine a news alert: a peanut-shaped asteroid the size of the Eiffel Tower is heading toward Earth. Sensational headlines make it sound like doomsday, but in most cases the reality is far less alarming.
Asteroid 2026 JH2 was first spotted on May 10, 2026 and was predicted to pass by Earth eight days later at a distance under a quarter of the space between Earth and the Moon. That sounds close, but current observations show it is very unlikely to strike our planet. Still, the approach generated broad media coverage — a familiar pattern when any near-Earth object (NEO) shows up on radar.
Those scare stories are routine. A similar wave of alarm accompanied Asteroid 2024 ON in 2024, even though it was never actually on a collision course. As Juan Luis Cano from the European Space Agency’s Planetary Defense Office puts it, dramatic headlines draw attention, but astronomers track many such visitors every day.
Every day about 100 tons of space material reach Earth, mostly as tiny dust and pebbles that burn up in the atmosphere. Large, dangerous impacts are far rarer.
What are near-Earth objects?
The United Nations Office for Outer Space Affairs defines NEOs as asteroids or comets that come close to Earth’s orbit. More technically, NEOs have a perihelion (their closest orbital distance to the Sun) of less than about 195 million kilometers. Since Earth orbits the Sun at roughly 150 million kilometers, NEOs occupy our solar neighborhood.
Astronomers currently know of about 34,000 NEOs. Most of the larger bodies are well tracked and not on a collision course with Earth at present.
How likely is a damaging impact?
Small NEOs hit Earth frequently but cause little harm. Objects the size of 2024 ON are extremely unlikely to do damage; impacts from that size class are expected only once every 10,000 years or so. The truly catastrophic strikes — objects larger than a kilometer that could trigger global devastation, like the asteroid linked to the dinosaur extinction 66 million years ago — are far rarer, on the order of once every hundreds of millions of years. Scientists estimate roughly 1,000 objects larger than a kilometer exist and about 95% of them have been discovered.
Smaller asteroids, however, can still be dangerous locally. A roughly 40-meter-wide rock, depending on its speed and angle of entry, could destroy a city. Many hundreds of thousands of these smaller objects remain to be catalogued. Astronomers are discovering around 3,000 new near-Earth asteroids each year, but they emphasize the need to accelerate detection.
Finding and tracking NEOs is hard work
Several space-based and ground observatories search for NEOs. NEOWISE, launched in 2009, catalogued more than 158,000 objects before it was retired in 2024. Canada’s NEOSSat also monitors asteroids, comets and space debris. The next major mission, the Near-Earth Object Surveyor (NEO Surveyor), is planned to start operations in 2027 and aims to find the potentially hazardous asteroids within about 50 million kilometers of Earth’s orbit.
Even with powerful telescopes, measuring how far away an object is can be surprisingly difficult. As planetary scientist Amy Mainzer has explained, seeing an object in the sky doesn’t automatically tell you its distance or precise trajectory; repeated observations are needed to pin down its orbit.
New facilities will boost discovery rates. The Vera Rubin Observatory in Chile will produce a decade-long time-lapse map of the sky and is expected to dramatically increase the number of asteroids found. The European Space Agency is also building several small, wide-field “Flyeye” telescopes to scan large areas of sky quickly.
Why tracking matters for planetary defense
Thanks to sustained tracking and orbit calculations, no known asteroid poses a threat to Earth for at least the next century. That confidence comes from repeatedly observing objects and refining their trajectories, which often removes initial uncertainty and calms alarm.
Apophis provides a good example. Discovered in 2004, the 340-meter-wide asteroid was once considered a significant risk with potential impact windows in 2029, 2036 or 2068. Further observations and improved orbit models ruled out those impact scenarios. Apophis will come relatively close — within about 30,000 kilometers, inside the distance of some geostationary satellites — but current projections show it will not strike Earth.
If a hazardous object were discovered on a collision path with enough warning time, engineers could try to alter its course. NASA’s Double Asteroid Redirection Test (DART) mission in 2022 successfully impacted the small moonlet Dimorphos and measurably changed its orbit, demonstrating that a kinetic impactor can be used to nudge an asteroid and providing a practical tool for planetary defense.
Bottom line
Close flybys like that of 2026 JH2 can generate alarming headlines, but careful detection, repeated observation, and orbit calculation are the tools that tell the true story. Ongoing and upcoming surveys, combined with proven deflection techniques, make it unlikely that known objects will surprise Earth in the near future.
This article was originally published on October 4, 2024, around the time of Asteroid 2024 ON’s flyby, and was updated on May 15, 2026 before the expected flyby of Asteroid 2026 JH2.