Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PHYSICS > Chapter 20 - Cosmology > Flashcards

Chapter 20 - Cosmology Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

define planets

A

objects with mass sufficient enough for their own gravity, forcing them to take a spherical shape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

define dwarf planets

A

planets where the object has not been cleared by other objects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

define planetary satellites

A

man-made objects which orbit a planet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

define asteroids

A

objects which are too small and spherically uneven to be planets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

define comets

A

small irregularly sized balls of rock, dust and ice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

define solar system

A

a system containing stars and orbiting objects like planets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

define galaxies

A

a collection of stars, dust and gas. has a supermassive black hole at its centre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

define nebulae

A

gigantic clouds of dust and gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what does a Hertzsprung russel diagram show

A

the relationship between a stars temperature and its luminosity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is continuous line spectra

A

where all visible wavelengths of light are present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is Stefan’s law

A

power output is directly proportional to its surface area and temperature ^4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

define light year

A

distance travelled by light in a vacuum in one year. 9.5x10^15m

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

doppler effect

A

the change in wavelength and frequency observed as an object moves towards or away from the observer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

define parsec

A

distance from which 1 Astronomical Unit subtends to an angle of one arc second

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Hubbles law

A

velocity of receding objects is directly proportional to their distance from earth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

big bang theory

A

the universe exploded from an extremely hot and dense point, and is still expanding to this day

17
Q

what is an astronomical unit

A

the average distance from earth to sun

18
Q

what can stellar parallax be used to measure

A

distance between nearby stars

19
Q

cosmological principle

A

the universe is isotropic and homogenous, and the laws of physics are universal.

20
Q

isotropic

A

universe looks the same from all directions to the observer

21
Q

homogenous

A

matter is uniformly distributed across the universe

22
Q

what is happening if the recessional velocity is negative

A

the object is moving towards us

23
Q

how is the temperature of microwave background radiation evidence for the Big Bang

A

shows universe has cooled over time, whilst still expanding - proving that the universe has expanded from a singular point and is continuing to expand

24
Q

two characteristics of black holes

A

infinite density
escape velocity is greater than the speed of light

25
Q

define luminosity

A

total radiant power of a star

26
Q

chandrasekhars limit

A

maximum mass a white dwarf can have whilst remaining stable. (x1.4 solar masses)

27
Q

weins law

A

peak wavelength of emitted radiation is inversely proportional to its absolute temperature

28
Q

describe the formation of a star

A

-gravitational attraction pulls together dust and gas to form clouds
-gravitational collapse accelerates as dust and gas gets closer together
-some regions become denser and pull in more gas and dust
- GPE transferred into thermal energy
-result is a hot dense sphere = a protostar
-temperature and pressure must be high enough so that the hydrogen gas nuclei in protostar overcomes the electrostatic repulsion and undergo fusion
- fusion produces helium nuclei - producing a star

29
Q

Hertzsprung-Russell diagram composition

A

super giants at top
giants second
dwarfs bottom
main sequence diagonally across (uL - bR)

30
Q

what is meant by a white dwarf when describing the evolution of a star

A

core left behind after a red giant has shed its layers

31
Q

why is our understanding of the very earliest moments of the universe unreliable

A

state of matter unknown

32
Q

what is Olber’s paradox

A

infinite universe
all lines of sight end on stars
night sky should be bright

33
Q

what does a shorter wavelength mean

A

a hotter star

34
Q

what does a greater red shift mean

A

that galaxies are receding at a greater rate

PHYSICS (24 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions