Instant · Precise · Universal
32 units available
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To convert AU to km: multiply by 149,597,870.7. To convert AU to light-years: divide by 63,241.
1 AU = 149,597,870,700 m ≈ 149.598 Gm ≈ 499 light-seconds ≈ 8.317 light-minutes.
For example, 1 Astronomical Unit (AU) = 9.255833e+45 Planck Length (ℓP).
| Astronomical Unit (AU) | Planck Length (ℓP) |
|---|---|
| 0.1 | 9.255833e+44 |
| 0.5 | 4.627917e+45 |
| 1 | 9.255833e+45 |
| 2 | 1.851167e+46 |
| 5 | 4.627917e+46 |
| 10 | 9.255833e+46 |
| 25 | 2.313958e+47 |
| 50 | 4.627917e+47 |
| 100 | 9.255833e+47 |
| 500 | 4.627917e+48 |
| 1000 | 9.255833e+48 |
The astronomical unit is a unit of length approximating the mean Earth-Sun distance, defined as exactly 149,597,870,700 meters.
1 AU = 149,597,870,700 m ≈ 149.598 Gm ≈ 499 light-seconds ≈ 8.317 light-minutes.
To convert AU to km: multiply by 149,597,870.7. To convert AU to light-years: divide by 63,241.
Spacecraft mission planning, expressing planetary orbit sizes, and solar system scale models.
Light takes about 8 minutes and 20 seconds to travel 1 AU. Mars is about 1.52 AU from the Sun, Jupiter about 5.2 AU.
Thinking the AU is the exact Earth-Sun distance — Earth's actual distance varies from ~147 to ~152 Gm over the year due to orbital eccentricity.
AU makes the solar system manageable: Mercury ≈ 0.39 AU, Venus ≈ 0.72, Earth = 1, Mars ≈ 1.52, Jupiter ≈ 5.2, Saturn ≈ 9.5.
The Planck length is the fundamental natural unit of length, approximately 1.616 × 10⁻³⁵ meters, below which the conventional concepts of space may cease to exist.
ℓP = √(ℏG/c³) ≈ 1.616255 × 10⁻³⁵ m.
To convert Planck lengths to meters: multiply by 1.616255 × 10⁻³⁵.
No practical applications — purely theoretical. It represents the scale at which quantum gravity effects become significant.
The Planck length is about 10⁻²⁰ times the diameter of a proton. It's as far below a proton as a proton is below a grain of sand.
Thinking the Planck length is the 'smallest possible length' — it's the scale where our current physics models break down, not a proven minimum.
The Planck length arises from combining the three constants that govern quantum mechanics (ℏ), gravity (G), and relativity (c).



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