Earth: 15 Million Years Ago
  In Einstein's general relativity theory the metric component gxx in the direction of motion (x-direction) of the sun deviates from unity due to a tensor potential caused by the black hole existing around the center of the galaxy. Because the solar system is orbiting around the galactic center at 200 km/s, the theory shows that the Newtonian gravitational potential due to the sun is not quite radial. At the present time, the ecliptic plane is almost perpendicular to the galactic plane, consistent with this modification of the Newtonian gravitational force. The ecliptic plane is assumed to maintain this orientation in the galactic space as it orbits around the galactic center, but the rotational angular momentum of the earth around its own axis can be assumed to be conserved. The earth is between the sun and the galactic center at the summer solstice all the time. As a consequence, the rotational axis of the earth would be parallel to the axis of the orbital rotation of the earth 15 million years ago, if the solar system has been orbiting around the galactic center at 200 km/s. The present theory concludes that the earth did not have seasons 15 million years ago. Therefore, the water on the earth was accumulated near the poles as ice and the sea level was very low. Geological evidence exists that confirms this effect. The resulting global ice-melting started 15 million years ago and is ending now. 
Masataka Mizushima