The Planets and Space Exploration
The four planets
at the center of the solar system are solid, rocky bodies like the
Earth. They include Mercury, Venus, and Mars.
Neptune are all made mostly of
gas and are
called giant planets because they are so large compared to Earth.
Their are several dwarf planets that are much smaller than Earth. Pluto, Haumea, Eris, Makemake, and the asteroid Ceres are all dwarf planets.
Unmanned spacecraft have traveled to all the planets in the solar system and
taken pictures of the planets and many of their moons. They have also
taken measurements that tell us what the planets are like inside.
Big, Bigger, Biggest
A Solar System Model Builders Guide
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