This is quite interesting: Two independent estimates of the evolution of Earth's gravity over the past 220 My produce very similar results. One method is based on the measured body volume and estimated weight of extinct animals (mostly dinosaurs), while the other method uses a reconstruction of Earth's past diameter from a NOAA map of oceanic lithosphere ages done by Maxlow (2012). The first method uses the circumference of femur and humerus weight-bearing bones of extinct animals to estimate their weight when they were alive. The ratio of that weight to the animals' body mass (assuming an average tissue density of 0.99 tones m-3) gives an estimate of the relative gravity in the past. The second method assumes that Earth has been expanding according to Maxlow's Expansion Tectonics. These results indicate that during the Mesozoic Era (the era of dinosaurs), from 252 My ago to 66 My ago, Earth's gravity was less than 75% of today's value. This can help explain the enormous sizes of some sauropods.