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A solar system refers to a star and all the objects that
travel in orbit around it. Our solar system consists of the
sun - our star - eight planets and their natural satellites
(such as our moon); dwarf planets; asteroids and comets.
Our solar system is located in an outward spiral of the
Milky Way galaxy.
The Sun is the star at the center of the Solar System. It has a diameter of
about 109 times that of Earth, and its mass accounts for about 99.86%
Solar System. Chemically, about three quarters of the Sun's mass
consists of hydrogen, while the rest is mostly helium. The Sun formed
about 4.567 billion and it will live up to about 10 billion years old.
An interesting Video made by NOVA in PBS will teach more facts:
Secrets of the Sun
The four inner or terrestrial planets have dense, rocky compositions,
few or no moons, and no ring systems. They are composed largely of
refractory minerals, such as the silicates, which form their crusts and
mantles, and metals, such as iron and nickel, which form their cores.
Three of the four inner planets (Venus, Earth and Mars) have
atmospheres substantial enough to generate weather; all have
impact craters and tectonic surface features, such as rift valleys and
volcanoes.
The four outer planets, or gas consist overwhelmingly of hydrogen
and helium. All four gas giants have rings, although only Saturn's ring
system is easily observed from Earth.
Interactive Universe
Dwarf planets are not able to clear their orbital
path so there are no similar objects at roughly the
same distance from the Sun. A dwarf planet is
much smaller than a planet (smaller even than
Earth's moon), but it is not a moon. Pluto is the best
known of the dwarf planets.
NASA List of Dwarf Planets
Comets are cosmic snowballs of frozen gases, rock and dust roughly the size of a
small town. When a comet's orbit brings it close to the sun, it heats up and spews dust
and gases into a giant glowing head larger than most planets. The dust and gases
form a tail that stretches away from the sun for millions of kilometers.
Explore the Solar system