The Inner Solar System: The Sun, Mercury, Venus, Earth, and Mars

Ancient people around the globe once believed the Moon, Sun, planets, and stars were gods and goddesses, demons and angels revolving around Earth, the centre of their universe. Little did they know that Earth is a mere speck in a vast universe. It took many centuries for people to realize that Earth isn’t even the centre of our solar system. It is, however, one of the components of what’s known as the inner solar system— comprised of the Sun, four terrestrial planets, and the moons that orbit them—which is examined thoroughly in this book.
With the development of modern astronomy and the advent of scientifi c tools, particularly the telescope, scientists began examining the solar system and theorizing about our place in it. The solar system and the space just beyond it form the extent of our physical reach in the universe.
Even with manned and unmanned spacecraft, we may never explore farther than the outer boundary of the solar system. So scientists observe and study our solar system in order to learn more about the universe itself. Much of our knowledge comes from the celestial bodies within the inner solar system, but there is still much to learn. Our solar system includes the Sun, eight planets (formerly nine), many moons....