Page 40 - Ultimate Visual Dictionary (DK)

THE UNIVERSE

The Earth TILT AND ROTATION OF THE EARTH
Axis of Axial tilt
rotation of 23.4°
THE EARTH IS THE THIRD of the eight planets that orbit
the Sun. It is the largest and densest rocky planet, and the
only one known to support life. About 70 percent of the North Orbital
Pole plane
Earth’s surface is covered by water, which is not found in
liquid form on the surface of any other planet. There are
four main layers: the inner core, the outer core, the mantle,
and the crust. At the heart of the planet the solid inner core
THE EARTH
has a temperature of about 11,900°F (6,600°C). The heat
from this inner core causes material in the molten outer core and mantle to South Pole
circulate in convection currents. It is thought that these convection currents
generate the Earth’s magnetic field, which extends into space as the
One rotation takes
magnetosphere. The Earth’s atmosphere helps screen out some of the Perpendicular to
23 hours and
orbital plane
harmful radiation from the Sun, stops most meteoroids from reaching the planet’s 56 minutes
surface, and traps enough heat to prevent extremes of cold. The Earth has one
natural satellite, the Moon, which is thought to have formed when a huge asteroid
impacted Earth in the distant past.
Microorganisms began
THE FORMATION OF THE EARTH to photosynthesize,
creating a build
up of oxygen
The heat of the collisions
caused the planet to
glow red

The cloud formed
a disk of material
around the young
Sun’s equator.
The disk material
stuck together to
form planets
4.6 BILLION YEARS THE EARTH WAS 4.5 BILLION YEARS THE CONTINENTS BROKE
AGO, THE SOLAR FORMED FROM AGO THE SURFACE UP AND REFORMED,
SYSTEM FORMED COLLIDING COOLED TO FORM GRADUALLY MOVING
FROM A CLOUD OF ROCKS THE CRUST TO THEIR PRESENT
ROCK, ICE, AND GAS POSITIONS
Solar wind enters atmosphere and produces aurora Magnetosphere (region affected
by magnetic field)

Solar wind (stream of
electrically charged
particles)

THE EARTH’S
MAGNETOSPHERE
Axis of geographic poles
Van Allen radiation belt Earth Axis of magnetic poles

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