From Cavendish to PLANCK: Constraining Newton’s gravitational constant with CMB temperature and polarization anisotropy

We present new constraints on cosmic variations of Newton's gravitational constant by making use of the latest CMB data from WMAP, BOOMERANG, CBI and ACBAR experiments and independent constraints coming from big bang nucleosynthesis. We found that current CMB data provide constraints at the 10% level, that can be improved to 3% by including big bang nucleosynthesis data. We show that future data expected from the Planck satellite could constrain G at the 1. 5% level while an ultimate, cosmic variance limited, CMB experiment could reach a precision of about 0. 4%, competitive with current laboratory measurements.