Astronomical Unit
An astronomical unit (AU) is the average distance between the Earth and the Sun. It is defined as exactly 149,597,871 km, and equals approximately 8.3 light-minutes. The unit is most commonly used to measure distances within our and other solar systems.[1]
Mars is about 1.5 AU from the Sun, which means it is 1.5 times the distance from the Earth to the Sun, or approximately 224 million km from the Sun (149,597,871 km • 1.5).
The distance from Earth to Mars varies from a little under 0.5 AU, to 2.5 AU, depending if the Earth is on the same side of the Sun as Mars, or we are far apart with the Sun between us.
Distances to objects in solar system
| Body | Average Distance to Sun |
|---|---|
| SUN | 0 AU |
| Mercury | 0.4 AU |
| Venus | 0.7 AU |
| Earth | 1.00 AU (by definition) |
| Mars | 1.52 AU |
| Vesta | 2.36 AU |
| Pallas | 2.77 AU |
| Ceres | 2.8 AU |
| Asteroid Belt | ~2 to ~4 AU |
| Jupiter | 5.2 AU |
| Saturn | 9.6 AU |
| Uranus | 19.2 AU |
| Neptune | 30.0 AU |
| Pluto | 39.5 AU |
| Haumea | 43.2 AU |
| Quaoar | 43.6 AU |
| Eris | 67.8 AU |
| Sedna | 489 AU |
| Kuiper belt | ~30 to ~50 AU |
| Scattered disk | ~100 to ~1,000 AU |
| Inner Oort Cloud | (~disk shaped) Inner edge ~2,000 to ~5,000 AU; outer edge ~20,000 AU. |
| Outer Oort Cloud | (spherical) ~20,000 to ~200,000 AU ? |
| Proxima Centauri | ~268,770 AU or 4.246 light years (the nearest star). |
References
- ↑ McClure, Brian. 2017. “What Is an Astronomical Unit?” EarthSky. October 23, 2017.
