Convert Light Days to Astronomical Units
Convert Light Days (ld) to Astronomical Units (AU) instantly and accurately.
Conversion Formula
AU = ld × 173.1446327
About Light Days
A light day (ld) is the distance light travels in one day through a vacuum, equal to approximately 25.9 billion kilometers. This unit bridges the gap between planetary distances and interstellar space. The Voyager 1 spacecraft, humanity's most distant object, is currently over 0.9 light days from Earth. The outer edge of our solar system (heliopause) is roughly 0.6-0.7 light days away. The Oort Cloud, a theoretical sphere of icy objects surrounding our solar system, extends from about 0.16 light days to possibly 1.6 light years.
About Astronomical Units
An astronomical unit (AU) is the average distance between Earth and the Sun, precisely defined as 149,597,870.7 kilometers. This unit provides a convenient scale for measuring distances within our solar system. Mars orbits at 1.5 AU, Jupiter at 5.2 AU, and Neptune at about 30 AU from the Sun. The dwarf planet Pluto reaches up to 49 AU away. Light takes about 8.3 minutes to travel 1 AU, explaining why we see the Sun as it was 8 minutes ago. The AU is fundamental in astronomy and space exploration.
Quick Reference Table
| Light Days (ld) | Astronomical Units (AU) |
|---|---|
| 1 ld | 173.145 AU |
| 2 ld | 346.289 AU |
| 5 ld | 865.723 AU |
| 10 ld | 1731.45 AU |
| 25 ld | 4328.62 AU |
| 50 ld | 8657.23 AU |
| 100 ld | 17314.5 AU |