Name______Date ______Hour______
A. Observing the Sky
1. In times past, people used to observe the sky and use the ______to help them tell time.
2. People today use to help them see many stars and other objects in the night sky that people in the past were unable to see with their eyes alone.
B. Electromagnetic Waves
3. Stars send energy called waves into space.
a. Unlike other types of waves, electromagnetic waves travel through ______.
b. The kind of energy that electromagnetic waves carry is called ______energy.
4. The is the entire range of energy carried by electromagnetic waves.
.
5. The amounts of different types of radiant energy stars emit vary from star to star, depending on the ______of the star.
a. Hot stars emit most of their radiant energy as electromagnetic waves, such as gamma rays and X-rays. These waves have energy.
b. Cool stars emit most of their radiant energy as electromagnetic waves with energy, such as radio waves and infrared waves.
6. Planets and moons do not emit their own light. Instead, they ______light from the Sun. That is the reason we can see these objects in the sky.
7. All light waves travel at km/s, which is called the speed of light.
C. Earth-Based Telescopes
8. Telescopes that are based on Earth gather three different kinds of electromagnetic waves:______, ______, and some microwaves.
9. telescopes gather and focus visible light.
a. A(n) telescope uses a convex lens to concentrate light from distant objects.
b. A(n) telescope uses a curved mirror to concentrate light from distant objects.
10. A telescope that uses an antenna that looks like a satellite dish to gather and concentrate radio waves and some microwaves from distant objects is called a(n) ______telescope.
11. The ______of a telescope affects the clarity of the images Earth-based telescopes can produce.
D. Space Telescopes
12. Some types of electromagnetic waves are completely blocked by Earth’s ______. However, telescopes in space can collect radiation from all wavelengths, including those that do not penetrate this layer.
13. telescopes work on Earth, but they work better in space because there are no atmospheric gases, the sky is darker, and there is no ______.
14. The Hubble Space Telescope is the only space telescope that collects ______; more than a dozen space-based telescopes gather other forms of electromagnetic radiation.
Directions: In each blank, write the letter of the phrase that correctly completes the sentence.
a. eliminate the distortion caused by Earth’s atmosphere
b. look for galaxies formed long ago
c. reflect light from a primary mirror to a secondary mirror
d. observe many more stars than with eyes alone
e. observe objects too old and too cold to emit visible light
f. bend light rays to form a small, bright image
g. send to Earth spectacular images of objects in space
h. collect radio waves and some microwaves
i. visible light, radio waves, and some microwaves
1. Radio telescopes use an antenna that looks like a TV satellite dish to .
2. Telescopes on Earth gather the electromagnetic energy in .
3. Telescopes in space can collect energy at all wavelengths so they .
4. All kinds of telescopes gather and focus light emitted by objects in space to .
5. Refracting telescopes use convex lenses to .
6. Reflecting telescopes use curved mirrors to .
7. The Hubble Space Telescope is the only telescope that collects visible light to .
8. The Spitzer Space Telescope orbits the Sun to collect infrared waves and .
9. The James Webb Space Telescope will have a larger mirror than the Spitzer and will ______.
Name Date Class
LESSON 1
Observing the Universe
Key Concept How do scientists use the electromagnetic spectrum to study the universe?
Directions: Use the underlined terms in the sentences to label the diagram on the lines provided.
• A TV remote uses infrared waves.
• X-rays help doctors diagnose
disease.
• Radio waves have the longest
wavelengths, and gamma rays
have the shortest.
• When you talk on a cellular phone,
you use microwaves.
• Visible light includes all the colors
you see.
• Some sunglasses block ultraviolet
waves.
Relative
size Wavelength Uses Name
1.
2.
3.
4.
5.
6.
7.
Name Date Class
LESSON 1
Observing the Universe
Key Concept How do scientists use the electromagnetic spectrum to study the universe?
Directions: On each line, write the term from the word bank that correctly completes each sentence. Some terms
may be used more than once or not at all.
electromagnetic waves galaxies gamma rays
Milky Way Moon planets
radio waves solar system stars
visible light
1. The , planets, and stars can be seen at night with an
unaided eye.
2. The galaxy contains our Sun and billions of other stars.
3. There are eight planets in our .
4. Earthlike planets in faraway might support life.
5. Galaxies and emit electromagnetic waves.
6. The hottest stars emit X-rays and .
7. Cooler stars emit infrared waves and .
8. Our Sun emits much of its energy as .
9. and moons reflect light from the Sun.
10. produce their own energy and existed many millions
of years ago.
11. Young stars and planets hidden by dust and gas cannot be viewed
by .
12. formed early in the history of the universe.
13. carry radiant energy.
18 Exploring Space