The gravitational field strength of the Earth at a distance equal to the orbital radius of the Moon is very nearly the same value as the orbital centripetal acceleration of the Moon. Which of the following is not a part of the explanation for this?
(1) The Moon's orbit is not circular.
(2) The centre of rotation of the Moon's orbit is not at the centre of the Earth.
(3) The Moon's mass is significantly smaller than the mass of the Earth.
(4) The Earth does not remain motionless during an orbit of the Moon.