astrophysics

Question 1

order of size space

Answer 1

moon/satellite- planet - star - solar system - galaxy - universe

Question 2

satellites

Answer 2

orbit planets
natural - moon
artificial - International Space Station

Question 3

planets

Answer 3

orbit stars

Mercury- Venus - Earth - Mars - Jupiter - Saturn - Uranus - Neptune

Question 4

comets

Answer 4

orbit star in an elliptical orbit
consists of ice rock and dust
fastest when closest to star
when close to star has trail (ice melts)

Question 5

what keep in orbit

Answer 5

gravuty

Question 6

orbital velocity

Answer 6

v = 2 pi r/T

convert time and radius into units to match velocity or use own

Question 7

life cycle of a low mass star

Answer 7

nebula > protostar > main sequence star > red giant > white dwarf

Question 8

life cycle of a high mass star

Answer 8

nebula > protostar > main sequence star > red super giant > supernova > neutron star/black hole

Question 9

nebula

Answer 9

cloud of dust and gas (H)

Question 10

protostar

Answer 10

GPE > KE + heat

dust and gas forced together by gravity

Question 11

main sequence

Answer 11

nuclear fusion of H > He when temp is high enough

stable - gravitational force balanced by radiation pressure due to heat

Question 12

red giant / super giant

Answer 12

H starts to run out (no nuclear fusion)
core collapses
fusion of He > heavier elements

Question 13

white dwarf

Answer 13

outer layers float away leaving small core (no nuclear fusion)

Question 14

supernova explosion

Answer 14

heat from explosion fuses Fe > even heavier elements

Question 15

neutron star

Answer 15

the very dense core left after a supernova

Question 16

black hole

Answer 16

an object whose gravity is so strong that nothing not even light can escape

Question 17

gravitational field strength

Answer 17

g measured in N/kg

Question 18

hertz spring russel diagram

Answer 18

absolute magnitude of luminosity against temp.

Question 19

hertz spring russel diagram temp.

Answer 19

colour determines surface temp.
blue - hot
red - cooler

Question 20

hertz spring russel diagram absolute magnitude

Answer 20

how bright they appear to be if all at same distance away
affected by temp + size
bigger + hotter = brighter
- red giants are cool but big so bright
- white dwarfs are hot but small so not that bright

Question 21

spectra

Answer 21

when we look at white light that has past through the prism it splits into colours (continuous spectrum)

Question 22

absorption spectrum

Answer 22

when we look at light from stars and galaxies we see this

• brightest wavelength determines temp
• absorption lines - gas surrounding star absorbed diff wavelengths or colours and appear as dark lines

Question 23

absorption spectra use

Answer 23

we can identify what elements exist in star

each element absorbs its own unique set of wavelengths

Question 24

doppler effect

Answer 24

change in wavelength (or frequency) due to relative motion between the source of waves and observer

Question 25

red shift

Answer 25

same pattern of lines moved towards red end of the spectrum | wavelength increased moving away

Question 26

cause of redshift

Answer 26

the doppler effect - can happen to any wave (sound or light) - change in wavelength (or freq. ) due to relative motion between the source of waves and observer

Question 27

blue shift

Answer 27

wavelength decreased - moving towards

Question 28

velocity of moving source

Answer 28

change in wavelength/ wavelength = velocity / speed of light

Question 29

speed of light

Answer 29

3 x 10^8 m/s

Question 30

big bang theory

Answer 30

creation of the universe (space and time) universe began at a single hot dense point > expanded since big bang > cooled since big bang

Question 31

evolution of universe

Answer 31

big bang > protons / electrons > atoms > stars > galaxies > life in earth

Question 32

evidence of big bang theory

Answer 32

- red shift of light from distant galaxies - CMBR galaxies are moving away at speed - big explosion started this at some point CMBR is left over energy from big explosion

Question 33

red shift as evidence for big bang

Answer 33

hubble used redshift to calculate speed moving further away galaxy = moving faster therefore universe is expanding and at some point must’ve started at one point

Question 34

CMBR as evidence for big bang

Answer 34

light released when atoms first formed should still exist all around universe has been expanding so wavelength of light should redshift (to microwave) CMBR was discovered to exist in every direction