Near-Earth Object
2021 HC3
NASA ID: 54142826
2021 HC3 will pass Earth on 21 April 2027 at a distance of 132.62 lunar distances (LD) - about 50,979,190 km - travelling at 126,630 km/h. Its estimated diameter is between 129 and 288 metres, roughly the size of The Shard in London (310 m tall). NASA classifies it as a potentially hazardous asteroid (PHA) - a designation based on size and orbital proximity, not on any predicted impact.
Close Approach Date
21 April 2027
In 301 days
Miss Distance
132.62 LD
50,979,190 km
133 times the Moon's distance from Earth
Velocity
126,630 km/h
4.6 times the orbital speed of the International Space Station
Est. Diameter
129–288 m
Absolute Magnitude
H = 21.57
The brightness measure astronomers use to estimate size
Hazard Classification
Potentially Hazardous
A watch-list label based on size and orbit, not a predicted impact
The real orbit in 3D
The actual path of 2021 HC3 around the Sun, computed from JPL orbital elements. Drag to rotate, scroll to zoom, and use the time controls to run the orbit forwards or back.
Every recorded pass
Each dot is one close approach of 2021 HC3 to Earth between 1901 and 2059, from JPL's records. Lower means closer: a dot under the dashed line passed nearer than the Moon. The orange dot is the approach on this page.
Size Comparison
Reading the Numbers
- A lunar distance (LD) is the average gap between Earth and the Moon, about 384,400 km. It is the standard yardstick for close approaches. Read more →
- Diameter estimates come from brightness. A dark surface reflects less light than a bright one, so the true size can sit anywhere in the quoted range. Read more →
- Potentially hazardous is a watch-list label based on size and orbital proximity. It does not mean an impact is expected. Read more →
