How can we learn about objects in the sky?

Targets

At the end of this Unit you should be able to answer the following questions 

1. What does studying the sky teach us about the Sun, Moon, planets, and stars?<

1.1 How can we learn about objects in the sky?

1.2 What patterns can be seen in the stars (constellations)?

1.3 What can we learn about the movement of objects in the sky by observing them?

targets

asteroid: a small rocky body that orbits the Sun

comet: a body made up of ice and dust that orbits the Sun


solar system: the Sun, planets, stars, and other orbiting bodies

telescope: an optical device that makes distant objects look closer

How can we observe objects in the sky?

Astronomers usually work at night since that is when the stars come out.  But, one star is visible during the day.  That is our Sun. 

If you use a small telescope or a pair of high-power binoculars, sometimes you can see the planet Venus (the brightest star-like object in the night sky) as a large crescent, which proves that it shines by reflected light.

The objects that we see can be placed into one of two categories:

Luminous objects produce their own light. All stars, such as our own Sun, are luminous objects.

Illuminated objects such as the Moon, asteroids, comets, the planets, and their moons are visible to us by reflecting light. 

Try This!

Drag and drop each of the following objects from our sky into the correct category.
Images from left to right are Saturn, comet, Moon, stars, satellite, Sun.