8 - space physics

Question 1

1st life cycle of a star (like out sun)

Answer 1

1. cloud of dust and gas/ nebula
2. protostar
3. main sequence star
4. red giant
5. white dwarf
6. black dwarf

Question 2

2nd life cycle of a star (much bugger than our sun)

Answer 2

1. cloud of dust and gas/ nebula
2. protostar
3. main sequence star
4. super red giant
5. supernova
6. neutron star // black hole

Question 3

2. hows a protostar formed

Answer 3

• gravity pulls the dust and gas together
• temp rises and gets dense as particles collide
• v high temp hydrogen nuclei undergo nuclear fusion
• this gives out loads of energy keeping it v hot

Question 4

3. hows a main sequence star formed

Answer 4

• outward pressure from nuclear fusion tries to expand the star but the inward pressure of gravity keeps it balanced
• this lasts several billions of years

Question 5

4. hows a red giant or red super giant formed

Answer 5

• hydrogen runs out
• the star swells into red giant (if its small) or a red super giant (if its larger)
• red bc the surface cools
• fusion of helium occurs
• heavier elements up to iron are created in its core

Question 6

5a. hows a white dwarf formed

Answer 6

• red gaint becomes unstable and ejects outter layer of fust and gas
• leaves a hot dense soli core - white dwarf

Question 7

6a. hows a black dwarf formed

Answer 7

• as white dwarf cools it emits less and less energy
• when it no longer can emit a significant amount its called a black dwarf

Question 8

5b. hows a supernova formed

Answer 8

• sig stars undergo more fusion and expand and contract lots forming elements as heavy as iron in nuclear reactions
• eventually they explode forming elements heavier than iron and ejecting them into the universe forming new planets and stars

Question 9

6b. how is a neutrons star and black hole formed

Answer 9

• exploding supernova throws out layers of dust and gas
• this leaves very dense core - neutron star
• if star is big enough it will become black hole - a super dense point in space no light can escape from

Question 10

4 things that orbit the sun

Answer 10

• planets
• dwarf planets
• moons
• natural and artificial satellites

Question 11

explain how planets orbit the sun

Answer 11

• planets travel in a circle shape around the sun
• this means that they are constantly changing direction
• and therefore constantly accelerating and changing velocity (not changing speed)
• for something to keep accelerating it needs a force and this force is gravity between the sun and the planet

Question 12

what keeps our planets orbiting the sun in a circle shape

Answer 12

instantaneous velocity

Question 13

the theory of the red shift

Answer 13

• the wavelengths of the light from distant galaxies has increased
• they are longer than they should be and have shifted to the red end of the spectrum
• this shows that the source of light is moving away from us and we get the same result which ever direction you look in
• more distant galaxies have greater red shifts than closer ones which shows they are moving away at a faster rate
• overall this shows that the universe is expanding

Question 14

red shift balloon concept

Answer 14

• balloon covered in pompoms
• each pompom represents a glaxaxy and as the balllon (universe) expands, the galaxys appear further away

Question 15

the big band theory

Answer 15

• all matter in the universe took up a very small space which was v dense and v hot
• ## it then exploded - space started expanding and now this is still going on