Study Notes for Chapter 30:

Study Notes forChapter 30:

Stars, Galaxies, and the Universe

1 A galaxy is made of stars, dust, and

gas bound together by ______. gravity

2 A large, bright star whose hot core

has used most of its hydrogen is a _____.

giant

3 A light-year is the distance ____

travels in a year. light

4 A small, hot, extremely dense core

left after a star collapses is a _____ dwarf.

white

5 A star moving away from the Earth

has a spectrum that is shifted toward ______.

red

6 A star with the sun’s mass would

stay on the _____ sequence of the H-R diagram for about 10 billion years.

main

7 A white ______ is a hot, extremely

dense core of matter left after a star _______.

dwarf collapses

8 About ______ stars are visible from

Earth without a telescope. 6,000

9 ______ magnitude is the true

brightness of a star. Absolute

10 After its temperature rises to

10,000,000°C, a _____ becomes a star when nuclear fusion begins.

protostar

11 _______ magnitude is the brightness

of a star as it appears from Earth. Apparent

12 Astronomers believe that cosmic

background _______ formed shortly after the big bang.

radiation

13 By analyzing the light that a star

emits, astronomers can determine the ______ and ________ of a star.

composition temperature

14 During the main sequence stage,

______ fuses into ______ to generate energy in a star’s core.

hydrogen helium

15 Hubble’s discovery that there was

____ shift in the spectra of galaxies lead to an understanding that the universe is ____.

red expanding

16 Many astronomers believe that

black _____ do not exist. dwarfs

17 Most of the universe is made of

_____ energy and dark _______. dark matter

18 Red shift in the spectra of galaxies

told ______ that the universe is expanding.

Hubble

19 Scientists determine the

composition and temperature of stars by analyzing the ________ of the light that stars emit.

spectra

20 Stars _____ to move in the sky

because ______ is moving. appear Earth

21 The ____ bang occurred about __

billion years ago. big 14

22 The ____ stars are ____ in color, the

hottest stars are _____. coolest red blue

THE END