Live close approach data from NASA · Updated hourly
Updated 53 minutes ago
Telescopes around the world scan the night sky for moving points of light against the fixed stars. The Minor Planet Center collects those observations, NASA's Center for Near-Earth Object Studies refines each orbit, and the public NeoWs feed — the source for this page — lists every object whose path brings it close to Earth.
Newly discovered objects appear on the list regularly. Most near-Earth asteroids aren't lost; they were simply unknown until a telescope happened to catch one. The catalogue grows by roughly 3,000 objects a year and now stands at over 35,000 known near-Earth asteroids, almost all of which pose no risk to Earth.
Three survey programmes supply the bulk of new detections: Pan-STARRS in Hawaii, the Catalina Sky Survey in Arizona, and ATLAS, which uses telescopes in Hawaii, Chile, and South Africa to provide all-sky coverage. Each survey takes repeated wide-field images and software flags points of light that move between exposures.
An orbit is fully determined from as few as three observations spread over a couple of nights, but the uncertainty drops sharply with longer arcs. A first-week orbit may have positional errors of millions of kilometres years out; a multi-year arc tightens that to a few hundred. Radar follow-up from Goldstone and Arecibo (before its 2020 collapse) can pin a nearby object's range to within metres. Size estimates remain less precise — they're derived from brightness assuming an average reflectivity, and most asteroids are darker or lighter than the assumed average.
Source: NASA CNEOS — about the catalogue.
"Close" in space is not "close" the way an oncoming car is close. The Moon is about 384,400 km from Earth; many flybys on this page pass several million kilometres away — well past lunar orbit. Astronomers still call those approaches "close" because of scale: across the solar system, a million kilometres is a rounding error.
What matters for risk isn't the headline distance — it's how confidently the path is known. An object whose orbit is locked down by a decade of observations can pass much nearer than one with a wide error ellipse, and the closer pass is the lower-risk one. This page sorts by approach date, not distance, because date is exact while distance carries its own uncertainty.
Lunar distance (LD) = 384,400 km, the average Earth–Moon distance. Astronomical unit (AU) = 149.6 million km, the average Earth–Sun distance. The NASA "potentially hazardous" threshold of 0.05 AU is roughly 19.5 LD — well outside lunar orbit, but close on solar-system scales.
Every predicted approach distance is really a range, sometimes written as the closest miss inside a 3-sigma uncertainty region. For most catalogued asteroids the uncertainty is much smaller than the miss distance, so the headline figure is reliable. For freshly discovered objects with short observation arcs, the uncertainty can briefly exceed the predicted miss — which is why some asteroids appear and disappear from headline lists as more data comes in.
Yes, in principle — small ones already do, frequently. A car-sized rock burns up in the atmosphere roughly once a year, producing a fireball but almost never reaching the ground. Nothing larger has caused widespread damage in over a century. The 2013 Chelyabinsk event, caused by an object around 20 metres across, injured about 1,500 people indirectly, mostly from broken glass when the shockwave shattered windows.
The risk from any individually tracked object is reported on the Torino scale, which runs from 0 (no concern) to 10 (certain global catastrophe). Almost every object ever assessed has scored 0. The asteroid behind the dinosaur extinction event 66 million years ago is estimated to have been around 10 km across — roughly 500,000 times the mass of Chelyabinsk.
"Potentially hazardous" in NASA's terminology is a size-and-orbit definition, not an impact forecast. It applies to any asteroid larger than roughly 140 m whose orbit can bring it within 0.05 AU (7.5 million km) of Earth's orbit. Most potentially hazardous asteroids will never come anywhere near Earth in the next century — the label flags candidates worth long-term tracking, not imminent impactors.
Apophis is the textbook worked example. Discovered in 2004, it briefly held a Torino rating of 4 — the highest any object has ever reached — when early observations suggested a small chance of impact in 2029. Later observations dropped it to 0 and ruled out impact for at least the next century. It will still pass closer than geostationary satellites in 2029, around 32,000 km above the Earth's surface, visible to the naked eye over Europe and Africa.
In September 2022, NASA's DART spacecraft deliberately struck the moonlet Dimorphos and shortened its orbital period around its parent asteroid Didymos by 32 minutes. This was the first demonstration that a kinetic impactor can alter an asteroid's path at the scale needed to deflect a real impactor given enough lead time.
Every hour, a small server-side process queries NASA's NeoWs API for the catalogue of near-Earth objects making close approaches to Earth in the surrounding window. Each entry is enriched with a risk label, an estimated diameter, the closest distance, and the relative speed at the moment of closest approach.
"Close approach" is a relative term. Most listed asteroids miss Earth by millions of kilometres — many lunar distances away. The tracker exists to give that scale, not to imply imminent danger. Anything classified by NASA as potentially hazardous meets specific size and orbit-intersection criteria; that label is theirs, not ours.
Sky coordinates on the detail pages come from JPL Horizons and let you check whether an object is theoretically observable from your location at the time of closest approach — though most are far below naked-eye visibility and need a telescope.
Almost certainly not. NASA actively tracks every known near-Earth asteroid and would announce a real impact threat through the Planetary Defense Coordination Office, not through a third-party site. Anything notable enough to be a real concern would be major news.
NASA's definition: an asteroid with an absolute magnitude brighter than 22.0 (roughly larger than 140 m across) whose orbit can bring it within 7.5 million km (0.05 AU) of Earth's orbit. It's a "worth keeping an eye on" classification, not a prediction of impact.
Some "close" approaches are still farther than the Moon (about 384,400 km away), while a handful pass within geostationary satellite altitude. Use the km / lunar distance toggle to switch between absolute distance and a more intuitive scale.
Approach distances and times are generally accurate to fractions of a percent for well-tracked objects. Newly discovered asteroids can have wider uncertainty windows that shrink as more observations come in. The tracker simply reports NASA's current best estimate — it does not run its own orbital model.
Most near-Earth asteroids are small, dark, and far away — they appear as point sources even in large telescopes, except for a handful close enough for radar imaging. The page focuses on the numerical data because that is what genuinely tells you something useful.