And we should use larger SI prefixes for distance than just kilo (thousands). For example, the speed of light, c, is equal to about 299 megameters per secons (millions). A lightyear is equal to about 9.46 petameters (quadrillions) 1 AU (avg. distance to sun) = 149.6 gigameters (billions) Distance to moon = 385 megameters Hohmann transfer to Mars = 480 gigameters View quoted note →