True polar wander as a mechanism for second-order sea-level variations     

JE Mound  JX Mitrovica 《Science (New York, N.Y.)》1998,279(5350):534-537

Long-term wander of the rotation pole can be a significant contributor to second-order (time scales of approximately 100 million years) sea-level variations. Numerical predictions based on realistic viscoelastic Earth models and paleomagnetically constrained polar motion yield global-scale, differential sea-level trends that can be as large as approximately 200 meters. From the results presented here, it is argued that the well-documented, second-order, Cretaceous-Tertiary sea-level cycle should be reinterpreted as some combination of a eustatic and a regionally varying rotational signal.  相似文献   

A free-fall determination of the newtonian constant of gravity     

JP Schwarz  DS Robertson  TM Niebauer  JE Faller 《Science (New York, N.Y.)》1998,282(5397):2230-2234

Recent determinations of the Newtonian constant of gravity have produced values that differ by nearly 40 times their individual error estimates (more than 0.5%). In an attempt to help resolve this situation, an experiment that uses the gravity field of a one-half metric ton source mass to perturb the trajectory of a free-falling mass and laser interferometry to track the falling object was performed. This experiment does not suspend the test mass from a support system. It is therefore free of many systematic errors associated with supports. The measured value was G = (6.6873 +/- 0. 0094) x 10(-11) m3 kg-1 sec-2.  相似文献