Convert Attojoules to Joules
Convert Attojoules (aJ) to Joules (J) instantly and accurately.
Conversion Formula
J = aJ × 1.000000000e-18
About Attojoules
An attojoule (aJ) is 10⁻¹⁸ J - the scale of individual X-ray photons and superconducting qubit circuits. A 1 keV X-ray photon carries 160 aJ; a visible green photon (~550 nm) carries ~0.36 aJ. Josephson junction energies in superconducting qubits are set in tens to hundreds of aJ to achieve quantum coherence at millikelvin temperatures. XRISM's cryogenic TES X-ray spectrometer resolves individual photon energies at the hundreds-of-aJ level with ~7 eV FWHM resolution. 1 aJ = 10⁻¹⁸ J = 6.242 eV.
About Joules
The joule (J) is the SI unit of energy, defined as one newton acting through one metre (1 J = 1 N·m = 1 kg·m²/s²). Named after James Prescott Joule, whose 1840s paddle-wheel experiments established the mechanical equivalent of heat (~4.15 J = 1 calorie). One joule is modest: it lifts a 100 g apple by 1 m, heats 0.239 mL of water by 1°C, or powers a 1 W LED for 1 second. Daily adult resting metabolism is ~6-9 MJ. 1 J = 1 W·s = 0.23901 cal = 9.4782 × 10⁻⁴ BTU = 2.7778 × 10⁻⁷ kWh.
Quick Reference Table
| Attojoules (aJ) | Joules (J) |
|---|---|
| 1 aJ | 1 × 10-18 J |
| 2 aJ | 2 × 10-18 J |
| 5 aJ | 5 × 10-18 J |
| 10 aJ | 1 × 10-17 J |
| 25 aJ | 2.5 × 10-17 J |
| 50 aJ | 5 × 10-17 J |
| 100 aJ | 1 × 10-16 J |