Astronomy Unit 2

Question 1

an area on the Sun where magnetic fields are concentrated; sunspots, prominences, flares, and
CMEs all tend to occur in active regions

Answer 1

active region

Question 2

light radiated by atoms and ions in the ionosphere excited by charged particles from the Sun, mostly
seen in the magnetic polar regions

Answer 2

aurora

Question 3

the part of the solar atmosphere that lies immediately above the photospheric layers

Answer 3

chromosphere

Question 4

of the Sun) the outer (hot) atmosphere of the Sun

Answer 4

corona

Question 5

a region in the Sun’s outer atmosphere that appears darker because there is less hot gas there

Answer 5

coronal hole

Question 6

a solar flare in which immense quantities of coronal material—mainly protonsand electrons—is ejected at high speeds (500–1000 kilometers per second) into interplanetary space

Answer 6

coronal mass injection

Question 7

the phenomenon that occurs when different parts of a rotating object rotate at different
rates at different latitudes

Answer 7

differential rotation

Question 8

the rice-grain-like structure of the solar photosphere; granulation is produced by upwelling
currents of gas that are slightly hotter, and therefore brighter, than the surrounding regions, which are flowing downward into the Sun

Answer 8

granulation

Question 9

a period during the eighteenth century when the number of sunspots seen throughout
the solar cycle was unusually low

Answer 9

Maunder minimum

Question 10

the region of the solar (or stellar) atmosphere from which continuous radiation escapes into
space

Answer 10

photosphere

Question 11

a bright region of the solar surface observed in the light of some spectral line

Answer 11

plage

Question 12

a hot ionized gas

Answer 12

plasma

Question 13

a large, bright, gaseous feature that appears above the surface of the Sun and extends into the
corona

Answer 13

prominence

Question 14

a sudden and temporary outburst of electromagnetic radiation from an extended region of the
Sun’s surface

Answer 14

solar flare

Question 15

a flow of hot, charged particles leaving the Sun

Answer 15

solar wind

Question 16

large, dark features seen on the surface of the Sun caused by increased magnetic activity

Answer 16

sunspot

Question 17

he semiregular 11-year period with which the frequency of sunspots fluctuates

Answer 17

sunspot cycle

Question 18

the region in the Sun’s atmosphere where the temperature rises very rapidly from the relatively low temperatures that characterize the chromosphere to the high temperatures of the corona

Answer 18

transition region

Question 19

process by which heat is directly transmitted through a substance when there is a difference of
temperature between adjoining regions caused by atomic or molecular collisions

Answer 19

conduction

Question 20

movement caused within a gas or liquid by the tendency of hotter, and therefore less dense material, to rise and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.

Answer 20

convection

Question 21

breaking up of heavier atomic nuclei into lighter ones

Answer 21

fission

Question 22

building up of heavier atomic nuclei from lighter ones

Answer 22

fusion

Question 23

study of pulsations or oscillations of the Sun in order to determine the characteristics of the solar interior

Answer 23

helioseismology

Question 24

balance between the weights of various layers, as in a star or Earth’s atmosphere, and the pressures that support them

Answer 24

hydrostatic equilibrium

Question 25

fundamental particle that has no charge and a mass that is tiny relative to an electron; it rarely
interacts with ordinary matter and comes in three different types

Answer 25

neutrino

Question 26

particle with the same mass as an electron, but positively charged

Answer 26

positron

Question 27

series of thermonuclear reactions by which nuclei of hydrogen are built up into nuclei of
helium

Answer 27

proton-proton chain

Question 28

emission of energy as electromagnetic waves or photons also the transmitted energy itself

Answer 28

radiation