Name: 3. Astronomers have observed that Mercury's orbit precesses by 0.159 per Earth-century. The table below shows how each planet contributes to the precession of Mercury's orbit, based on detailed calculations using Newton's law of universal gravitation. How well does Newton's law of universal gravitation predict the precession of Mercury's orbit? Explain. Predicted Precession of Mercury Planet Responsible Predicted Amount of Precession (degrees per century) Venus 0.074 7 Earth 0.025 6 Mars 0.000 667 Jupiter 0.044 4 Saturn 0.002 11 Uranus Approx. 0 Neptune Approx. 0 Total Precession Source: American Journal of Physics, vol. 81, 2013, pp. 695-701, Table II. 4. What are some possible explanations for the discrepancy between the observed precession and the predicted precession? Discuss with your classmates, and make a list of possibilities