Instant · Precise · Universal
32 units available
6 categories total
To convert Bohr radii to meters: multiply by 5.29177210903 × 10⁻¹¹.
a₀ = ℏ/(mec α) = 4πε₀ℏ²/(mee²) ≈ 5.29177 × 10⁻¹¹ m, where α is the fine-structure constant.
For example, 1 Bohr Radius (a₀) = 8.324647e-18 Earth's Polar Radius (R⊕ (polar)).
| Bohr Radius (a₀) | Earth's Polar Radius (R⊕ (polar)) |
|---|---|
| 0.1 | 8.324647e-19 |
| 0.5 | 4.162324e-18 |
| 1 | 8.324647e-18 |
| 2 | 1.664929e-17 |
| 5 | 4.162324e-17 |
| 10 | 8.324647e-17 |
| 25 | 2.081162e-16 |
| 50 | 4.162324e-16 |
| 100 | 8.324647e-16 |
| 500 | 4.162324e-15 |
| 1000 | 8.324647e-15 |
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.
The Earth's polar radius is the distance from Earth's center to either pole, approximately 6,356.752 km.
R⊕(polar) = 6,356,752.3 m. It is about 21.385 km shorter than the equatorial radius.
To convert Earth polar radii to meters: multiply by 6,356,752.3.
Geodetic calculations, gravity modeling, and precise cartography near the poles.
At the poles, you are about 21 km closer to Earth's center than at the equator — you weigh very slightly more!
Approximating Earth as a perfect sphere — the difference between equatorial and polar radii matters for precision applications.
Earth's shape (oblate spheroid) is like a slightly squished ball — wider at the equator, flatter at the poles.



© 2026 UntangleTools. All Rights Reserved.