There are currently 3 astronomical definitions for the tag 'earth'.
Earth
earthsciences, solarsystem, continent, core, crater, crust, earthquake, geocorona, geodesy, geoid, geomagnetism, geophysics, glaciology, mantle, perigee, polarcap, radiationbelt, scintillation, seismology, siderealtime, solarterrestrialrelation, spacegeodesy, topography, troposphere
Earth