Chapter 3

Question 1

cosmic address

Answer 1

earth is in the solar system which is in the milky way galaxy which is in the local group which is a part of the local supercluster which is in the universe/cosmos

Question 2

dark matter

Answer 2

matter that we infer to exist due to its gravitational effects but from which we haven’t detected any light; it apparently dominates the total mass of the universe

Question 3

dark energy

Answer 3

the name sometimes given to energy that could be causing the expansion of the universe to accelerate

Question 4

the big bang

Answer 4

the scientific theory of the universe’s earliest moments, states that all the matter in our observable universe came into being at a single moment in time as an extremely hot, dense mixture of subatomic particles and radiation; prediction that universe’s chemical composition should be about 3/4 hydrogen, 1/4 helium and observations show that this is a close match to the overall chemical composition of the universe.

Question 5

nuclear fusion

Answer 5

process where two (or more) smaller nuclei slam together and make one larger nucleus; 4 hydrogen nuclei are needed to make 1 helium nucleus; stars do this a lot

Question 6

observable universe

Answer 6

the portion of the entire universe that we can potentially observe- consists only of objects that lie within 15 billion light-years of earth

Question 7

terrestrial planets

Answer 7

earthlike; made mostly of rock and metal; smaller in size and mass; higher density; solid surface; few if any moons and no rings; closer ot the sun and closer together with warmer surfaces

Question 8

jovian planets

Answer 8

larger in size and mass, lower density; made mostly of hydrogen, helium, and hydrogen compounds; no solid surface; rings and many moons; farther from the sun (and farther apart), with cool temperatures at cloud tops

Question 9

asteroid

Answer 9

made of metal and rock mostly

Question 10

comet

Answer 10

made mostly from rock and ice

Question 11

asteroid belt

Answer 11

region where most asteroids orbit; between Mars and Jupiter

Question 12

Kuiper belt

Answer 12

region beyond Neptune; where Pluto and Eris + other small objects

Question 13

Oort cloud

Answer 13

in the Kuiper belt; trillions of comets orbut the Sun with random inclinations, orbital directions, and eccentricities

Question 14

Nebular Theory

Answer 14

asteroids and comets are leftovers; solar nebula was hottest near protostar, coolest farther away; “frost line” defined as the distance from protostar at which ices could condense; asteroids and terrestrial planets formed inside frost line; comets and jovian planets formed past the frost line; after formation jovian planets can migrate (through gravitational intereractions) into the inner solar system of some stars

Question 15

charge of a proton?

Answer 15

positive

Question 16

charge of an electron

Answer 16

negative

Question 17

charge of a neutron

Answer 17

neutral

Question 18

ion

Answer 18

atoms that lose or gain electrons and then obtain a net electrical charge.

Question 19

atomic number

Answer 19

number of protons

Question 20

atomic mass

Answer 20

number of protons and neutrons

Question 21

isotope

Answer 21

version of an element with different number of neutrons

Question 22

ionization

Answer 22

stripping of electrons; changing of atoms into plasma

Question 23

allowed transitions

Answer 23

changes corresponding to a change in energy levels

Question 24

molecule

Answer 24

two or more atoms

Question 25

dissociation

Answer 25

breaking of molecules into atoms

Question 26

kinetic energy

Answer 26

energy of motion; examples: falling rocks, orbiting planets

Question 27

radiative energy

Answer 27

energy carried by light; ex: light molecules in our eyes that allow us to see. sun’s warming of the earth’s surface

Question 28

potential energy

Answer 28

stored energy; ex: rock perched on a ledge has gravitational potential energy, gasoline contains chemical potential energy that can be converted into kinetic energy of the moving car.

Question 29

wavelength

Answer 29

distance between adjacent peaks of the electric or magnetic field

Question 30

frequency

Answer 30

the rate at which the electric and magnetic fields change; unit is Hz

Question 31

energy

Answer 31

what makes matter move

Question 32

speed of light

Answer 32

300,000 km/s, 186,000 mi/s

Question 33

photon

Answer 33

“piece” of light

Question 34

accretion

Answer 34

the process by which particles stick together and grow larger

Question 35

order of electromagnetic spectrum from longest to shortest

Answer 35

radio, IR, visible, UV, x-ray, gamma

Question 36

continuous spectrum

Answer 36

a spectrum of light that spans a broad range of wavelengths without interruption by emission or absorption lines

Question 37

emission spectrum

Answer 37

a spectrum that contains emission lines

Question 38

absorption spectrum

Answer 38

a spectrum that contains absorption lines

Question 39

thermal radiation

Answer 39

the spectrum of radiation produced by an opaque object that depends only on the object’s temperature;

Question 40

polarization

Answer 40

the direction in which a light wave is vibrating; reflection can change the polarization of light