Convert Ergs to Millijoules

Convert Ergs (erg) to Millijoules (mJ) instantly and accurately.

Conversion Formula

mJ = erg × 1.000000000e-4

About Ergs

An erg is the CGS unit of energy - the work done by one dyne through one centimetre - exactly 10⁻⁷ J. Despite SI adoption, the erg persists in astrophysics: the Sun's luminosity is 3.828 × 10³³ erg/s; gamma-ray burst isotropic energies are quoted in units of 10⁵¹ erg ('one foe'). Surface tension of water is 72.8 dyn/cm; the work to create 1 cm² of new water-air interface is 72.8 erg. Earthquake seismic moment M₀ is in dyn·cm = erg; the 2004 Boxing Day earthquake had M₀ ≈ 10²³ J = 10³⁰ erg. 1 erg = 10⁻⁷ J = 624.15 eV.

About Millijoules

A millijoule (mJ) is 10⁻³ J - the scale of surgical lasers, spark ignition, and the kinetic energy of small everyday objects. Nd:YAG lasers for ophthalmology and tattoo removal deliver 10-200 mJ per pulse. The minimum spark energy to ignite methane-air is ~0.29 mJ; an automotive spark plug discharges 30-60 mJ per cycle. A 2 g mosquito flying at 1 m/s has kinetic energy ½ × 0.002 × 1² = 1 mJ. Electrocautery monopolar pulses deliver 50-500 mJ to coagulate blood vessels. 1 mJ = 10⁻³ J = 0.2390 cal.

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