Asteroid Watch
Real-time tracking of near-Earth asteroids from NASA's Center for Near
Earth Object Studies.
Updated daily with the latest close
approach data.
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Asteroids Today
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Potentially Hazardous Today
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Closest Approach Today
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Largest Today
Miss Distance Overview — Lunar Distances from Earth
What makes an asteroid potentially hazardous?
NASA classifies an asteroid as "Potentially Hazardous" based on two
things: size and orbit.
It must be larger than about 140 meters AND its orbit must bring it
within about 7.5 million kilometers of Earth. That's roughly 20
times the distance to the Moon.
So, an asteroid can pass closer to Earth but still be "safe" if it's
small, while a larger asteroid further away might be flagged as
hazardous because of how its orbit is shaped. It doesn't mean it
will hit Earth, just that it's worth watching closely!