The Space Book
Activities for Experiencing the Universe and the Night Sky
Chapter One
The Sun
Traveling at the speed of light, our spaceship arrives at a roiling
globe of gas-the Sun-8.3 minutes after we leave the Moon.
A sunbeam must travel 93 million miles (150 million km) at
light speed to reach Earth. Luckily, that distance allows the Sun's
heat to cool just enough to make life possible. Can you imagine
the heat if Earth were located any closer to the Sun than it is? Or
the cold if it were farther away?
The Sun is composed largely of hydrogen, with a smaller
amount of helium and other elements. Hydrogen is the lightest
and most abundant element in the universe. On Earth, hydrogen
is found in water. It's also used to make rocket fuels and ammonia.
In the past, people used hydrogen to fill dirigibles (blimps)
because it is so light. But because it is also very explosive, it was
replaced by helium.
In reality, we could not get very close to the Sun and expect to
survive. The Su ... read full excerpt from The Space Book: Activities for Experiencing the Universe and the Night Sky ebook
