Science 8th Grade Unit 6 Vocabulary Universe

Question 1

a brightness scale used to measure how bright a star would be if it were seen from a standard distance

Answer 1

absolute magnitude

Question 2

the brightness of a star as seen from Earth

Answer 2

apparent magnitude

Question 3

a large collection of stars, dust, and gas bound together by gravity

Answer 3

galaxy

Question 4

Hertzsprung-Russell diagram, a graph that shows the relationship between a star’s surface temperature and absolute magnitude

Answer 4

H-R Diagram

Question 5

the distance that light travels in one year; about 9.46 trillion kilometers

Answer 5

light-year

Question 6

the actual brightness of an object such as a star

Answer 6

luminosity

Question 7

the region on the H-R diagram where stars spend most of their lives; it has a diagonal pattern

Answer 7

main sequence

Question 8

a large cloud of dust and gas in interstellar space; a region in space where stars are born

Answer 8

nebula

Question 9

the core of a supernova that has collapsed under gravity to the point that the electrons and protons have smashed together to form neutrons

Answer 9

neutron star

Question 10

a relatively large spherical body that orbits a star

Answer 10

planet

Question 11

a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation

Answer 11

pulsar

Question 12

the motion of a body that travels around another body in space; one trip along an orbit

Answer 12

revolution

Question 13

the spin of a body on its axis

Answer 13

rotation

Question 14

the collection of large and small bodies that orbit our central star, the sun

Answer 14

solar system

Question 15

a large celestial body that is composed of gas and that emits light; the sun is a typical star

Answer 15

star

Question 16

the distance between two adjacent troughs or crests of a wave

Answer 16

wavelength

Question 17

a gigantic explosion in which a massive star throws its outer layers into space, but its core remains

Answer 17

supernova

Question 18

space and all the matter and energy in it

Answer 18

universe

Question 19

the hot, dense, dim core of matter that remains from the collapse of a low-mass star

Answer 19

white dwarf

Question 20

a galaxy shaped like a pinwheel, with a bulge in the center and spiral arms

Answer 20

spiral galaxy

Question 21

a spherical or elongated galaxy with a bright center and very little dust and gas

Answer 21

elliptical galaxy

Question 22

a galaxy with an irregular shape that does not fit into any other category

Answer 22

irregular galaxy

Question 23

all of the different wavelengths and frequencies of electromagnetic radiation, from radio waves to gamma rays

Answer 23

electromagnetic spectrum

Question 24

the theory that all matter and energy in the universe was compressed into an extremely small volume that 13 billion to 15 billion years ago exploded and began expanding in all directions

Answer 24

big bang theory

Question 25

CMB; the electromagnetic radiation left over from the formation of the universe

Answer 25

cosmic microwave background

Question 26

a phenomenon which occurs when a star or galaxy is moving away from the earth and its point of view

Answer 26

red shift

Question 27

an observed change in frequency or wavelength when the source is moving with respect to the observer

Answer 27

Doppler effect

Question 28

a tool used to collect light from stars and separate the colors in the light

Answer 28

Spectroscope