Potentially Hazardous Asteroids
What makes an asteroid “potentially hazardous”, and a live list of notable PHAs with their orbits, sizes and next close approaches to Earth.
| Object | Diameter | Next approach | Miss distance | Class |
|---|---|---|---|---|
Apophis 99942 |
375 m | 2029-Apr-13 | 0.1 LD | Aten |
Bennu 101955 |
490 m | 2054-Sep-30 | 15.3 LD | Apollo |
Didymos 65803 |
780 m | 2062-Oct-20 | 19.3 LD | Apollo |
Ryugu 162173 |
900 m | 2033-Dec-21 | 18.5 LD | Apollo |
Phaethon 3200 |
5.1 km | — | — | Apollo |
2024 YR4 2024 YR4 |
55 m | 2032-Dec-22 | 0.72 LD | Apollo |
Toutatis 4179 |
2.8 km | 2069-Nov-05 | 7.7 LD | Apollo |
Apollo 1862 |
1.5 km | 2046-Nov-13 | 13.7 LD | Apollo |
Nereus 4660 |
330 m | 2060-Feb-14 | 3.1 LD | Apollo |
Florence 3122 |
4.9 km | 2057-Sep-02 | 19.4 LD | Amor |
A potentially hazardous asteroid (PHA) is one whose orbit comes within 0.05 AU (about 7.5 million km, or roughly 19.5 lunar distances) of Earth’s orbit and that is large enough — brighter than absolute magnitude 22, very roughly 140 m across — to cause regional damage if it ever struck. The label is about proximity and size, not an impending collision: most PHAs will never come anywhere near Earth, and none of the objects below are on a predicted impact course. Their orbits are refined continuously and close approaches are projected decades ahead.
Browse the live close-approach calendar for objects passing soon, or the full near-Earth object database.
Frequently asked questions
What makes an asteroid potentially hazardous?
Two things together: its orbit passes within 0.05 AU of Earth’s orbit, and it is large enough (about 140 m or more across) to do regional damage on impact. Meeting the distance test alone is not enough — small nearby asteroids are not classed as PHAs.
Are any potentially hazardous asteroids going to hit Earth?
No PHA is currently on a predicted impact trajectory. Classification reflects how close an orbit can bring an object to Earth, not a forecast of collision. Trajectories are continuously refined as new observations come in.
How many potentially hazardous asteroids are there?
Around 2,400 are catalogued, and the number grows as surveys discover more. The objects listed here are among the most studied and most frequently searched.