PSR Discoveries

Lesson 1 from the Moon: Formation by Impact

Planet's birth by Impact This frame from a computer simulation captures a moment in time when a wandering planetesimal the size of Mars struck the young Earth (shown as the large circle of colorful dots) to form the Moon. In this hypothesis, both the planetesimal and Earth already had formed cores (shown in blue-green). Computer simulations of such an impact indicate that the core of the planetesimal is added to Earth's iron core and much of the rocky mantles (orange and gold) of the two bodies melts or vaporizes, and some ends up in orbit around the Earth. This debris then accreted to form the Moon. The formation of Mercury may also have involved a giant impact.

RETURN


PSR Discoveries

Lesson 2 from the Moon: Initial Melting of the Planets

Lunar Magma Ocean When the Moon formed it was enveloped by a layer of molten rock (magma) hundreds of kilometers thick (shown on the left of the blue arrow). As that magma crystallized, the minerals more dense than the magma sank while those less dense (such as feldspar) floated, forming the anorthosite crust. The dense minerals (olivine and pyroxene) sank and later remelted to produce the basalts that compose the maria on the Moon. We do not know if Mercury had a magma ocean.

RETURN


PSR Discoveries

Lesson 3 from the Moon: Volcanism

Moon Iron Map This image shows the FeO concentration of the earth-facing hemisphere of the Moon. Red and white are highest FeO, blue lowest. FeO was measured by a technique developed by Paul Lucey of the University of Hawai'i; it uses the relative intensity of two wavelengths of light reflected off the Moon. The maria (white, red, and orange areas) contain much more FeO than do the surrounding highlands (blue areas).

RETURN


home [ About PSRD | Archive | Search | Subscribe ]

[ Glossary | General Resources | Comments | Top of page ]

1997
psrd@higp.hawaii.edu
main URL is http://www.psrd.hawaii.edu/