Refining the Earth's Pear Shape

  title={Refining the Earth's Pear Shape},
  author={D. G. King-hele and G. E. Cook},
QUITE soon after the launching of the first artificial satellites, analysis of their orbits led to the reshaping of the world. The orbital plane of Sputnik 2 rotated less rapidly than expected, indicating1 that the polar flattening was about 0.35% less (the polar diameter about 150 m greater) than had been thought. The variations in the perigee height of Vanguard 1, as perigee moved successfully north and south of the equator, showed2 that the polar section of the geoid—the profile of the… 
The pear-shaped section of the Earth
The Earth's gravitational field, and hence the shape of the Earth's sea-level surface, the geoid, can be determined from analysis of the motion of artificial satellites in orbit about the Earth. The
Satellite Orbital Precessions Caused by the Octupolar Mass Moment of a Non-Spherical Body Arbitrarily Oriented in Space
I consider a satellite moving around a non-spherical body of mass M and equatorial radius R, and calculate its orbital precessions caused by the body’s octupolar mass moment J4. I consider only the
Satellite orbital precessions caused by the first odd zonal J3 multipole of a non-spherical body arbitrarily oriented in space
An astronomical body of mass M and radius R which is non-spherically symmetric generates a free space potential U which can be expanded in multipoles. As such, the trajectory of a test particle
The Earth's gravity field
The Earth's gravity field can be determined from gravity measurements made on the surface of the Earth, and through the analysis of the motion of Earth satellites. Gravity data can be used to solve
Growth, shrinking, and long‐term evolution of plates and their implications for the flow pattern in the mantle
Surficial manifestations of the long-term evolution of plates are examined and used to derive constraints on the pattern of flow in the mantle. Generation and consumption of plates are not balanced
The Gravitational Potential
The gravitational attraction force is a conservative force, i.e. it can be represented by a potential. A potential surrounds the source mass of the gravitational attraction force. We shall refer to
Satellite Cluster Tracking via Extent Estimation
This dissertation proposes a new paradigm for initial tracking of clusters of objects: instead of tracking the objects independently, the cluster is tracked as a single entity, parameterized by its centroid and extent, or shape, which could improve spaceflight safety by providing quantitative tracking information for the entire cluster much earlier than would otherwise be available through typical means.
Lateral diffusion in plasma membrane of mouse egg is restricted after fertilisation
The results indicate that diffusion of the lipid probe and of proteins in the membrane of unfertilised eggs occurs at about the maximum rate expected for these molecules, while in fertilised eggs, both markers seem to diffuse at greatly reduced rates.
The Spherical Harmonic Analysis of Free Wave Fields in Practice
As we saw in Chapter Two, a free wave field used to model a spatially complex, random wave field may be completely described by its plane wave weighting function. Associated with the weighting
The Origin of Trophoblast and Its Role in Implantation
What tissues arise from the trophectoderm cell lineage, how and when the lineage is established in development, and what its role is in implantation are discussed.


Use of Artificial Satellites to Explore the Earth's Gravitational Field: Results from Sputnik 2 (1957β)
Use of Artificial Satellites to Explore the Earth's Gravitational Field: Results from Sputnik 2 (1957β)
Vanguard Measurements Give Pear-Shaped Component of Earth's Figure.
Vanguard satellite orbit variations indicate third zonal harmonic in earth gravitational field