Visual wavelength image

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These clouds of gas are

so far away that their

light takes 7200 years to

reach Earth. They are a

small part of a larger

cloud that has formed a

cluster of stars. More

stars are probably forming

in the darkest, densest

parts of the cloud. (NASA,

ESA, and The Hubble Heritage

Team, STScI/AURA)

Guidepost
As you study astronomy, you will learn about yourself. You are a planet walker, and this
chapter will give you a preview of what that means. The planet you live on whirls around
a star that drifts through a universe fi lled with other stars and galaxies. You owe it to
yourself to know where you are in the universe because that is the fi rst step to knowing
what you are.
In this chapter, you will meet three essential questions about astronomy:

Where are you in the universe?

How does human history fi t into the time scale of the universe?

Why should you study astronomy?

AS you study astronomy, you will see how science gives you a way to know how
nature works. In this chapter, you can begin thinking about science in a general way.
Later chapters will give you more specifi c insights into how scientists work and think
and know about nature.
This chapter is a jumping-off place for your exploration of deep space and deep time.
The next chapter continues your journey by looking at the night sky as seen from Earth.

Here and Now

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