space physics (topic 8)

Question 1

describe what a nebula is (1)

Answer 1

a cloud of dust and gas

Question 2

state the name of the stage of stellar evolution that our Sun is in

Answer 2

main sequence

Question 3

describe what will happen to our Sun between main sequence and the end of its stellar life cycle (3)

Answer 3

• the Sun will expand to become a red giant
• then the star will collapse to become a white dwarf
• the star will cool to become a black dwarf

Question 4

describe the evolution of star through its stellar life cycle (6)

Answer 4

• starts as a nebula
• gravity brings the gas together to form a protostar
• main sequence
• star cools and expands to become a red supergiant
• red supergiant collapses and explodes in a supernova
• leaving behind a very dense neutron star or black hole

Question 5

state the name of the gas fused during the early stages of the stellar life cycle

Answer 5

hydrogen

Question 6

Answer 6

Question 7

explain why the Sun is described as stable during the main sequence phase (3)

Answer 7

• inward pull of gravity
• is in equilibrium
• with the outward force due to fusion

Question 8

describe the process of nuclear fusion in stars (3)

Answer 8

• two small nuclei
• join together (to produce a larger nucleus)
• releasing energy

Question 9

what will this star become after it leaves the main sequence

Answer 9

red supergiant

Question 10

what is the name of the fuel in stars that undergoes nucleus fusion to release huge amounts of energy

Answer 10

hydrogen

Question 11

describe the evolution of a star with a mass similar to our Sun (6)

Answer 11

• nebula
• pulled together due to the force of gravity to form a protostar
• hydrogen nuclei fuse to form helium
• and the star becomes a main sequence star
• when hydrogen begins to run out, star cools and expands to become a red giant
• outer layers of red giant are dissipated to leave a hot dense core known as a white dwarf

Question 12

when the star runs out of hydrogen, it will expand and cool, the star is now known as a

Answer 12

red giant

Question 13

the outer layers will then dissipate, leaving a hot dense core known as a

Answer 13

white dwarf

Question 14

Answer 14

Question 15

the observed wavelength of light coming from a distant galaxy is higher than when that light was emitted, state the name of this phenomenon

Answer 15

red shift

Question 16

explain how the red shift of galaxies provides evidence in support of the big bang theory (2)

Answer 16

• if galaxies are now moving apart from one another, they must have previously been closer together
• tracing this pattern back, they originated from a very dense region in space where the big bang occurred

Question 17

explain how the image above provides evidence for the expansion of the universe (2)

Answer 17

• light from all 4 galaxies has increased in wavelength
• light has red shifted

Question 18

which galaxy is the furthest away from Earth (2)

Answer 18

• galaxy C
• as it has been red shifted by the greatest amount

Question 19

describe how light from distant galaxies provides evidence of the universe expanding (2)

Answer 19

• light from distant galaxies has a longer wavelength or light is red shifted
• the further a galaxy is from Earth, the more red shifted it is

Question 20

andromeda is a galaxy which is moving towards Earth, explain how the light from Andromeda appears to astronomers on Earth (2)

Answer 20

• wavelength of light decreases
• light is shifted towards the blue end of the spectrum or blue shift