  It can be demonstrated that no motion of masses can generate gravitational
waves. Accordingly: i) the time decrease of the orbital period of the famous
binary PSR1913+16 cannot yield an experimental proof of the emission of
gravitational waves; ii) measurements of the propagation of the quasar
J0842+1835 radio-signals past Jupiter cannot reveal the propagation of
gravitational waves sent forth by the planet in its motion around the Sun:
indeed, this motion does not generate any gravitational radiation; iii) the
binary RX J0806.3+1527 has the shortest known revolution period (only 321 s):
however, it cannot be a candidate for the detection of gravitational waves
because no kind of motion of a mass can give origin to a gravitational wave.
