Near-Earth Asteroid Tracker

NASA and the Minor Planet Center call an asteroid "potentially hazardous" when two things are both true: its orbit comes within 0.05 astronomical units of Earth's orbit (about 7.5 million km, or roughly 19.5 lunar distances), and it is bright enough (absolute magnitude 22.0 or brighter) to be roughly 140 meters across or larger. The label describes orbital geometry and size, not a predicted impact. Most potentially hazardous asteroids pass at safe distances for decades.

A close approach is the moment an asteroid passes nearest to Earth on a given orbit, and the miss distance is how far away it is at that point. Distances are often given in lunar distances (LD): 1 LD is the average distance from Earth to the Moon, about 384,400 km. An asteroid passing at 10 LD comes no closer than ten times the Moon's distance. In astronomy a "close" approach can still be millions of kilometers away.

The feed uses NASA's NeoWs (Near Earth Object Web Service) API, which publishes close-approach data from NASA's Center for Near-Earth Object Studies (CNEOS) at JPL. Each entry includes the object's estimated size range, approach date, relative velocity, miss distance and whether it is classified as potentially hazardous. Sizes are estimates based on brightness, so they are given as a minimum to maximum diameter.

The list always covers today or the next seven days, depending on the tab you pick, so it moves forward each day. Responses from NASA are cached for up to 15 minutes to stay within API rate limits. NASA itself refines the underlying orbits continuously as new telescope observations come in, so predicted miss distances can shift slightly over time.

No known asteroid is on course to hit Earth in the foreseeable future. CNEOS keeps a public Sentry risk table listing every object with any nonzero calculated impact chance, and nearly all of them drop off once more observations pin down their orbits. Apophis, which once caused concern for 2029, has been ruled out as an impact risk for at least the next century; it will pass about 32,000 km from Earth on April 13, 2029. Small objects a few meters across do still enter the atmosphere regularly, and most burn up harmlessly.

Yes, but most look like faint star-like points, and you can only tell them apart from stars by their slow movement over minutes or hours. Most near-Earth asteroids are too small and dim for backyard telescopes except during unusually close passes by larger objects. To find one, look up its predicted position for your date and location (for example with JPL Horizons or the Minor Planet Center), then compare views or photos taken some time apart to spot the moving dot. Apophis is expected to be visible to the naked eye from dark sites during its 2029 flyby.