space (paper 2)

Question 1

what is the name of our galaxy?

Answer 1

Milky Way

Question 2

how is a nebula formed

Answer 2

cloud of dust and gas

Question 3

how is a protostar formed

Answer 3

gravity pulls dust and gas together and it heats up

Question 4

how is a white dwarf formed

Answer 4

red giant collapses under gravity leaving a small hot star

Question 5

how is a black dwarf formed

Answer 5

white dwarf cools down

Question 6

describe the life cycle our sun is going through

Answer 6

dust and gas - nebula - protostar - main sequence star - red supergiant - supernova - black hole

Question 7

describe the life cycle of a star

Answer 7

dust and gas - nebula - protostar - main sequence star - red giant - white dwarf - black dwarf

Question 8

which nuclear reaction happens in stars?

Answer 8

nuclear fusion

Question 9

what forces make a star stable?

Answer 9

• gravity tries pulls it inwards,
• radiation pressure from the nuclear reactions expands it outwards

Question 10

how do the planets orbit around the sun?

Answer 10

gravity

Question 11

how do satellites orbit around the earth

Answer 11

gravity

Question 12

what type of velocity will an object moving in a circle have?

Answer 12

perpendicular (90 degrees) to the direction of the force of gravity on it.

Question 13

what is the doppler effect?

Answer 13

the change in frequency of a wave due to the source moving relative to the observer

Question 14

red-shift definition

Answer 14

when light changes frequency due to the doppler effect.

Question 15

why do almost all galaxies exhibit red-shift

Answer 15

the universe is expanding

Question 16

what does the big bang theory state (3)

Answer 16

• the universe is expanding from a small point
• this point was an extremely hot and dense region of energy
• in the big bang space and matter was created

Question 17

what is cosmic background radiation (CMBR)?

Answer 17

electromagnetic radiation created shortly after the big bang as gamma

Question 18

state the effect fusion has on the main sequence star’s size, and the temperature of its core

Answer 18

• keeps star steady size
• keeps core hot

Question 19

planets are another type of object in our solar system. State one similarity + one difference between the orbits of a planet and a moon in our solar system

Answer 19

• both have circular orbits
• moons orbit planets, planets orbit sun

Question 20

how does a star stay stable?

Answer 20

• balanced forces
• gravity + radiation pressure are required

Question 21

what do scientists believe is the origin of CMBR?

Answer 21

Big Bang

Question 22

how is the wavelength of CMBR likely to change, if at all, over the next billion years? Give a reason for your answer.

Answer 22

increasing wavelength because the universe is still expanding