That is exactly right. The uncertainty in the Earth's mass is for, all practical purposes, entirely due to the uncertainty in G.rbj said:i think what this also means (and i don't know which is cause and effect) is that we don't know the mass of the Earth precisely.
Vanadium 50 already asked the key question here. Piling on, one of the key sources of insight into the dimensions and composition of the Earth comes from remote sensing projects such as http://grace.jpl.nasa.gov/" . The problem here is that these remote sensing experiments are sensitive only to the product G*Me.but i find it unexpected that knowing the dimensions and composition of the Earth well
What these observations give us insight into is the Earth's standard gravitational parameter, the Earth/Moon mass ratio, and the Sun/(Earth+Moon) mass ratio. They do not give direct insight to the Earth's mass unencumbered with G.... of the mutual orbit of these (unequal) twin planets around their common center of gravity, that with years of astronomical observation of the Moon, that we wouldn't have gotten that more precisely.
The standard gravitational parameter, denoted as μ, is a constant that describes the gravitational field of a celestial body. It is the product of the gravitational constant, G, and the mass of the celestial body, M.
The standard gravitational parameter is important because it allows scientists to calculate the trajectories of objects in orbit around a celestial body, such as planets, moons, or artificial satellites. It is also used in the field of astrodynamics to calculate the energy required for a spacecraft to enter or exit orbit.
The standard gravitational parameter is calculated by multiplying the gravitational constant, G, by the mass of the celestial body, M. The value of G is a fundamental constant of nature and is known to a high degree of precision. The mass of the celestial body can be determined through various measurements or calculations.
The standard gravitational parameter can be expressed in various units, depending on the system of measurement used. Some common units include meters cubed per second squared (m^3/s^2), kilometers cubed per second squared (km^3/s^2), and astronomical units cubed per day squared (au^3/d^2). These units can be converted to each other using appropriate conversion factors.
No, the standard gravitational parameter varies depending on the mass of the celestial body. For example, the standard gravitational parameter for Earth is different from that of the Moon or Mars. It also varies for different points on the same celestial body, such as the equator or the poles.