Page 32 - Ultimate Visual Dictionary (DK)

THE UNIVERSE
The solar system PLANETARY ORBIT

(EXAGGERATED)
Perihelion (orbital
THE SOLAR SYSTEM consists of a central star (the
point closest to Sun)
Sun) and the bodies that orbit it. These bodies
include eight planets and their more than 160
Sun
known moons; dwarf planets; Kuiper Belt objects;
asteroids; comets; and meteoroids. The solar
Elliptical
system also contains interplanetary gas and dust. orbit
The planets fall into two groups: four small rocky Planet
orbiting Sun Direction of
planets near the Sun (Mercury, Venus, Earth, and
planetary
Mars); and four planets farther out, the giants (Jupiter, Saturn, rotation
Uranus, and Neptune). Between the rocky planets and giants is the
asteroid belt, which contains thousands of chunks of rock orbiting the
Aphelion (orbital
Sun. Beyond Neptune is the Kuiper Belt and, more distant, the Oort Cloud.
point farthest
Most of the bodies in the planetary part of the solar system move around the Sun from Sun)
in elliptical orbits located in a thin disk around the Sun’s equator. All the planets
orbit the Sun in the same direction (counterclockwise when viewed from above)
and all but Venus and Uranus also spin about their axes in this direction. Moons Aphelion of Neptune:
2.8 billion miles
also spin as they, in turn, orbit their planets. The entire solar system orbits the
center of our galaxy, the Milky Way (see pp. 14-15).
Perihelion of
Perihelion of Venus: 66.7 million miles
ORBITS OF INNER PLANETS Mercury
Perihelion of Earth: 91.4 million miles
Average orbital speed of Venus: 21.8 miles/sec
Average orbital speed of Mercury: 29.8 million miles/sec
Average orbital speed of Earth: 18.5 miles/sec
Average orbital speed of Mars: 15 miles/sec

Mars Perihelion of Mars:
128.4 million miles
Earth
Venus
Sun
Aphelion of Mercury: 43.3 million miles
Aphelion of Venus: 67.7 million miles
Asteroid Aphelion of Pluto:
belt Aphelion of Earth: 94.5 million miles 4,583 million miles
MERCURY
Year: 87.97 Earth days Aphelion of Mars: 154.8 million miles
Mass: 0.06 Earth masses
Diameter: 3.051 miles

VENUS EARTH MARS JUPITER
Year: 224.7 Earth days Year: 365.26 days Year: 1.88 Earth years Year: 11.87 Earth years
Mass: 0.81 Earth masses Mass: 1 Earth mass Mass: 0.11 Earth masses Mass: 317.83 Earth masses
Diameter: 7,521 miles Diameter: 7,926 miles Diameter: 4,217 miles Diameter: 88,850 miles

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