Instant · Precise · Universal
32 units available
6 categories total
To convert solar radii to km: multiply by 696,340. To convert solar radii to AU: multiply by 0.00465.
1 R☉ = 6.9634 × 10⁸ m = 696,340 km ≈ 109 × Earth's radius ≈ 0.00465 AU.
For example, 1 Sun's Radius (R☉) = 1.315892e+19 Bohr Radius (a₀).
| Sun's Radius (R☉) | Bohr Radius (a₀) |
|---|---|
| 0.1 | 1.315892e+18 |
| 0.5 | 6.579459e+18 |
| 1 | 1.315892e+19 |
| 2 | 2.631784e+19 |
| 5 | 6.579459e+19 |
| 10 | 1.315892e+20 |
| 25 | 3.289730e+20 |
| 50 | 6.579459e+20 |
| 100 | 1.315892e+21 |
| 500 | 6.579459e+21 |
| 1000 | 1.315892e+22 |
The solar radius is the radius of the Sun, approximately 6.9634 × 10⁸ meters (about 696,340 km).
1 R☉ = 6.9634 × 10⁸ m = 696,340 km ≈ 109 × Earth's radius ≈ 0.00465 AU.
To convert solar radii to km: multiply by 696,340. To convert solar radii to AU: multiply by 0.00465.
Describing stellar sizes: Betelgeuse ≈ 700 R☉, Sirius ≈ 1.7 R☉, a white dwarf ≈ 0.01 R☉.
You could line up about 109 Earths across the Sun's diameter. The largest known star (UY Scuti) is about 1,700 R☉.
Confusing solar radius with solar diameter — the diameter is 2 R☉. Also, stellar catalogs list radius, not diameter.
The Sun's radius (109 × Earth) gives a sense of scale: you could fit over a million Earths inside the Sun by volume.
The Bohr radius is the most probable distance between the nucleus and the electron in a ground-state hydrogen atom, approximately 5.292 × 10⁻¹¹ meters.
a₀ = ℏ/(mec α) = 4πε₀ℏ²/(mee²) ≈ 5.29177 × 10⁻¹¹ m, where α is the fine-structure constant.
To convert Bohr radii to meters: multiply by 5.29177210903 × 10⁻¹¹.
Sets the characteristic scale for atomic sizes. Most atoms have radii of 1–3 Bohr radii.
The Bohr radius gives atoms their characteristic size of ~1 Å (10⁻¹⁰ m), explaining why matter has the volume it does.
Confusing Bohr radius with atomic radius — the Bohr radius is specific to hydrogen; other atoms have different sizes.
The Bohr radius tells you 'how big atoms are' — about 0.5 angstroms. It's the atomic analog of a ruler for atomic-scale physics.



© 2026 UntangleTools. All Rights Reserved.