🌌 Astrophysics & Deep Space Scales
Astronomical Distance ($\text{AU} \leftrightarrow \text{ly} \leftrightarrow \text{pc}$) Converter
Convert cosmic distances across Astronomical Units ($\text{AU}$), Light-Years ($\text{ly}$), Parsecs ($\text{pc}$), Kiloparsecs ($\text{kpc}$), Megaparsecs ($\text{Mpc}$), and Light-Travel Times.
☀️ Sun to Earth (1.0 AU = 8.32 light-min)
🪐 Neptune Orbit (30.0 AU = 4.16 light-hours)
✨ Proxima Centauri (4.25 ly = 1.30 pc)
🌀 Milky Way Center Sgr A* (8.2 kpc = 26,700 ly)
🌌 Andromeda Galaxy M31 (2.54 Mly = 778 kpc)
Input Cosmic Distance
Light-Travel Time
8.317 Light-Minutes
Light-Years (ly)
1.581e-5 ly
Parsecs (pc)
4.848e-6 pc
AU
1.000 AU
💡 Cosmic Scale Equivalences:
$$1\text{ Parsec (pc)} = 3.26156\text{ ly} = 206,264.8\text{ AU} \approx 3.0857 \times 10^{13}\text{ km}$$
Understanding Astronomical Distance Units
Distances in the universe span dozens of orders of magnitude, requiring specialized units:
- Astronomical Unit (AU): Standardized by the IAU as exactly $149,597,870,700\text{ meters}$ ($\approx 92.96\text{ million miles}$), representing the mean distance from Earth to the Sun.
- Light-Year (ly): The distance that a photon in vacuum travels in one Julian year ($365.25\text{ days}$): $$1\text{ ly} = c \times 1\text{ yr} \approx 9.46073 \times 10^{12}\text{ km} = 63,241.1\text{ AU}$$
- Parsec (pc): Parallax of one arcsecond. The distance at which $1\text{ AU}$ subtends an angle of $1\text{ arcsecond}$ ($1/3600^\circ$): $$1\text{ pc} = \frac{1\text{ AU}}{\tan(1'')} \approx 3.26156\text{ ly} = 206,265\text{ AU}$$