Key Facts
- Categorized as a Apollo-class Asteroid
- Comparable in size to a football field
- Will pass within 5,349,096 km of Earth in 2023
- Classified as a Near Earth Asteroid (NEA)
- Classified as a Potentially Hazardous Asteroid (PHA)
- See orbit simulation
Overview
2021 SZ4 is a very small asteroid whose orbit crosses the orbit of Earth. NASA JPL has classified 2021 SZ4 as a "Potentially Hazardous Asteroid" due to its predicted close pass(es) with Earth.
2021 SZ4 orbits the sun every 700 days (1.92 years), coming as close as 0.30 AU and reaching as far as 2.79 AU from the sun. Its orbit is highly elliptical. Based on its brightness and the way it reflects light, 2021 SZ4 is probably between 0.215 to 0.481 kilometers in diameter, making it a small to average asteroid, very roughly comparable in size to a football field.
Close Approaches
2021 SZ4's orbit is 0.04 AU from Earth's orbit at its closest point. This means that there is a wide berth between this asteroid and Earth at all times.
2021 SZ4 has 7 close approaches predicted in the coming decades:
| Date | Distance from Earth (km) | Velocity (km/s) |
|---|---|---|
| Oct. 26, 2023 | 5,349,096 | 29.956 |
| Oct. 25, 2046 | 6,404,912 | 30.355 |
| Oct. 23, 2069 | 11,413,538 | 31.687 |
| Oct. 18, 2092 | 25,913,555 | 34.722 |
| Nov. 1, 2136 | 25,692,470 | 25.504 |
| Oct. 30, 2159 | 12,086,187 | 28.270 |
| Oct. 28, 2182 | 9,342,388 | 29.431 |
Images and Observations
2021 SZ4's orbit is determined by observations dating back to Sept. 4, 2021. It was last officially observed on Dec. 1, 2021. The IAU Minor Planet Center records 48 observations used to determine its orbit.
Accessibility and Exploration
This asteroid is not considered a viable target for human exploration by the NHATS study.Similar Objects
These objects have orbits that share similar characteristics to the orbit of 2021 SZ4:References
Search
or view a random objectOrbital Elements
- Epoch: 2460200.5 JD
- Semi-major axis: 1.543 AU
- Eccentricity: 0.8072
- Inclination: 26.41°
- Longitude of Ascending Node: 28.39°
- Argument of Periapsis: 129.57°
- Mean Anomaly: 315.05°
Physical Characteristics
- Diameter: ~0.278 km
- Magnitude: 20.46
Derived Characteristics
- Orbit Period: 700 days (1.92 years)
- Avg. Orbit Speed: 23.98 km/s
- Aphelion Distance: 2.79 AU
- Perihelion Distance: 0.30 AU
Map Comparison
Orbit Simulation
Sky Map
The position of 2021 SZ4 is indicated by a ◯ pink circle. Note that the object may not be in your current field of view. Use the controls below to adjust position, location, and time.
Size Rendering
The below comparison is an artistic rendering that uses available data on the diameter of 2021 SZ4 to create an approximate landscape rendering with New York City in the background. This approximation is built for full-resolution desktop browsers. Shape, color, and texture of asteroid are imagined.
