1. Lesson 1 Observing the Universe
Chapter Introduction
Lesson 1 Observing the Universe
NASA/Ames Wendy Stenzel
Chapter Menu

2. How do humans observe and explore space?
Chapter Introduction

3. Lesson 1 Reading Guide - KC
Observing the Universe
How do scientists use the electromagnetic spectrum to study the universe?
What types of telescopes and technology are used to explore space?
Lesson 1 Reading Guide - KC

4. Lesson 1 Reading Guide - Vocab
Observing the Universe
light year
electromagnetic spectrum
wave length
wave frequency
radio telescope
Lesson 1 Reading Guide - Vocab

5. Lesson 1 Reading Guide - Vocab
Observing the Universe
optical telescope
refracting telescope
reflecting telescope
concave lens
convex lens
Lesson 1 Reading Guide - Vocab

6. Observing the Sky
Telescopes enable astronomers to observe many more stars than they could with their eyes alone.
telescope
from Greek tele, means “far”; and Greek skopos, means “seeing”
Lesson 1-1

7. Observing the Sky (cont.)
Astronomers use many kinds of telescopes to study the light energy emitted by stars and other objects in space.
Michael Matisse/Getty Images
Lesson 1-1

8. Electromagnetic Waves
Stars radiate energy into space. This energy travels as electromagnetic waves.
The entire range of radiant energy carried by electromagnetic waves is the electromagnetic spectrum.
Lesson 1-2

9. Most wavelengths of the electromagnetic spectrum are not visible to the human eye.
Lesson 1-2

10. Electromagnetic Waves (cont.)
The type of radiant energy a star emits depends on the star’s temperature.
Some stars are so far away that it takes billions of years for their radiant energy to reach Earth.
Lesson 1-2

11. Measuring Distances
Light Year – All electromagnetic waves travel at a constant speed of 300,000 km/s
Light from the Moon reaches Earth in 1 second
Light from the Sun takes 8 minutes to reach Earth
It can take billions of years for the light from distant stars to reach Earth

12. Earth-Based Telescopes
Optical telescopes gather visible light.
Refracting telescopes and reflecting telescopes are the two types of optical telescopes.
Lesson 1-3

13. A telescope that uses a convex lens to concentrate light from a distant object is a refracting telescope.
Lesson 1-3

14. A telescope that uses a concave mirror to concentrate light from a distant object is a reflecting telescope.
Lesson 1-3

15. Earth-Based Telescopes (cont.)
Radio telescopes collect invisible radio waves and some microwaves. They look like TV satellite dishes.
Steve Allen/Brand X Pictures
Lesson 1-3

16. Telescopes in space collect energy of all wavelengths, including those absorbed by Earth’s atmosphere.
Lesson 1-4

17. Space Telescopes Why do astronomers put some telescopes in space?
Lesson 1-4

18. Space Telescopes (cont.)
The first optical space telescope, the Hubble Space Telescope, is a reflecting telescope that orbits Earth.
CORBIS
Lesson 1-4

19. Scheduled for launch in 2014, the Webb telescope will help astronomers study the origin of the universe.
Lesson 1-4

20. Reflecting telescopes use mirrors to concentrate light.
Lesson 1 - VS

21. Earth-based telescopes can collect energy in the visible, radio, and microwave parts of the electromagnetic spectrum.
Space-based telescopes can collect wavelengths of energy that cannot penetrate Earth’s atmosphere.
Lesson 1 - VS

22. What determines the types of electromagnetic waves that a star emits?
A. age of the star
B. distance of the star from Earth
C. size of the star
D. temperature of the star
Lesson 1 – LR1

23. Which of these is NOT an optical telescope?
A. radio telescope
B. reflecting telescope
C. refracting telescope
D. the Hubble Space Telescope
Lesson 1 – LR2

24. B. reflecting telescope C. refracting telescope D. space telescope
Which phrase refers to any telescope that uses a concave mirror to concentrate light from a distant object?
A. radio telescope
B. reflecting telescope
C. refracting telescope
D. space telescope
Lesson 1 – LR3

25. 1. Astronomers put telescopes in space to be closer to the stars.
Do you agree or disagree?
1. Astronomers put telescopes in space to be closer to the stars.
2. Telescopes can work only using visible light.
Lesson 1 - Now