Structure of the Earth

The interior structure of the Earth is layered in spherical shells, like an onion. These layers can be defined by either their chemical or their rheological properties. Earth has an outer silicate solid crust, a highly viscous mantle, a liquid outer core that is much less viscous than the mantle, and a solid inner core. Scientific understanding of the internal structure of the Earth is based on observations of topography and bathymetry, observations of rock in outcrop, samples brought to the surface from greater depths by volcanoes or volcanic activity, analysis of the seismic waves that pass through the Earth, measurements of the gravitational and magnetic fields of the Earth, and experiments with crystalline solids at pressures and temperatures characteristic of the Earth's deep interior.

Mass

The force exerted by Earth's gravity can be used to calculate its mass, and by estimating the volume of the Earth, its average density can be calculated. Astronomers can also calculate Earth's mass from its orbit and effects on nearby planetary bodies.

Earth

Earth /ˈɜːrθ/ (also the world, in Greek: Γαῖα Gaia, or in Latin: Terra) is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrestrial planets, and the only astronomical object known to harbor life.

According to evidence from radiometric dating and other sources, Earth was formed about 4.54 billion years ago. Earth gravitationally interacts with other objects in space, especially the Sun and the Moon. During one orbit around the Sun, Earth rotates about its own axis 366.26 times, creating 365.26 solar days or one sidereal year. Earth's axis of rotation is tilted 23.4° away from the perpendicular of its orbital plane, producing seasonal variations on the planet's surface with a period of one tropical year (365.24 solar days). The Moon is Earth's only permanent natural satellite. Its gravitational interaction with Earth causes ocean tides, stabilizes the orientation of Earth's rotational axis, and gradually slows Earth's rotational rate.

Core

Core may refer to:

Computers and technology

The Core

The Core is a 2003 American science fiction disaster film. It concerns a team that has to drill to the center of the Earth and set off a series of nuclear explosions in order to restart the rotation of the Earth's core. The film was directed by Jon Amiel, and starred Aaron Eckhart, Hilary Swank, Delroy Lindo, Stanley Tucci, Tchéky Karyo, DJ Qualls, Bruce Greenwood and Alfre Woodard.

The film earned mixed reviews from critics and was a box office flop.

Plot

Geophysicist Dr. Josh Keyes (Aaron Eckhart) and scientists Serge Leveque (Tchéky Karyo) and Conrad Zimsky (Stanley Tucci) become aware of an instability of Earth's magnetic field after a series of incidents across the globe. They determine that the Earth's molten core, which generates this field, has stopped rotating, and within a year the field will collapse exposing the planet's surface directly to devastating solar radiation. Backed by the U.S. Government, Keyes, Leveque, and Zimsky create a plan to bore down to the core and set off several nuclear explosions to restart the rotation. They gain help of rogue scientist Ed "Braz" Brazzelton (Delroy Lindo) who has devised a vessel made of "Unobtainium" that can withstand the heat and pressure within the Earth's crust and convert it to energy, as well as a laser-driven boring system that will allow them to quickly pass through the crust. Construction starts immediately on the Virgil, a multi-compartment vessel to be helmed by Space Shuttle pilots Commander Robert Iverson (Bruce Greenwood) and Major Rebecca "Beck" Childs (Hilary Swank) who will join Keyes and the others. To prevent a worldwide panic, Keyes enlists computer hacker Theodore Donald "Rat" Finch (DJ Qualls) to scour the Internet and eliminate all traces of the pending disaster or their plan.

Mantle (geology)

The mantle is a layer inside a terrestrial planet and some other rocky planetary bodies. For a mantle to form, the planetary body must be large enough to have undergone the process of planetary differentiation by density. The mantle lies between the core below and the crust above. The terrestrial planets (Earth, Venus, Mars and Mercury), the Moon, two of Jupiter's moons (Io and Europa) and the asteroid Vesta each have a mantle made of silicate rock. Interpretation of spacecraft data suggests that at least two other moons of Jupiter (Ganymede and Callisto), as well as Titan and Triton each have a mantle made of ice or other solid volatile substances.

Earth's mantle

The interior of Earth, similar to the other terrestrial planets, is chemically divided into layers. The mantle is a layer between the crust and the outer core. Earth's mantle is a silicate rocky shell with an average thickness of 2,886 kilometres (1,793 mi). The mantle makes up about 84% of Earth's volume. It is predominantly solid but in geological time it behaves as a very viscous fluid. The mantle encloses the hot core rich in iron and nickel, which makes up about 15% of Earth's volume. Past episodes of melting and volcanism at the shallower levels of the mantle have produced a thin crust of crystallized melt products near the surface, upon which we live. Information about structure and composition of the mantle either result from geophysical investigation or from direct geoscientific analyses on Earth mantle derived xenoliths and on mantle exposed by mid-oceanic ridge spreading.