An Earth mass (denoted as M🜨, M♁ or ME, where 🜨 and ♁ are the astronomical symbols for Earth), is a unit of mass equal to the mass of the planet Earth. The current best estimate for the mass of Earth is M🜨 = 5.9722×1024 kg, with a relative uncertainty of 10−4. It is equivalent to an average density of 5515 kg/m3. Using the nearest metric prefix, the Earth mass is approximately six ronnagrams, or 6.0 Rg.