The Earth as a planetary system has experienced significant change since its formation c.
4.54 Gyr ago. Some of these changes have been gradual, such as secular cooling of the …

Plate tectonics is a particular mode of tectonic activity that characterizes the present-day
Earth. It is directly linked to not only tectonic deformation but also magmatic/volcanic activity …

The conduction of heat through minerals and melts at extreme pressures and temperatures
is of central importance to the evolution and dynamics of planets. In the cooling Earth's core …

The recent determination of the gravity field of Mercury and new Earth‐based radar
observations of the planet's spin state afford the opportunity to explore Mercury's internal …

Abstract The MErcury Surface, Space ENvironment, GEochemistry, and Ranging
(MESSENGER) spacecraft, launched on August 3, 2004, is nearing the halfway point on its …

Radio tracking of the MESSENGER spacecraft has provided a model of Mercury's gravity
field. In the northern hemisphere, several large gravity anomalies, including candidate mass …

Observations of radar speckle patterns tied to the rotation of Mercury establish that the
planet occupies a Cassini state with obliquity of 2.11±0.1 arc minutes. The measurements …

The MESSENGER Gamma-Ray Spectrometer measured the average surface abundances
of the radioactive elements potassium (K, 1150±220 parts per million), thorium (Th, 220±60 …

Mercury, a planet with a lithosphere that forms a single tectonic plate, is replete with tectonic
structures interpreted to be the result of planetary cooling and contraction. However, the …

Mercury has a global magnetic field of internal origin and it is thought that a dynamo
operating in the fluid part of Mercury's large iron core is the most probable cause. However …