P16 (Space)

Question 1

First 4 stages of the life cycle of stars

Answer 1

• nebula, cloud of dust and gas called
• protostar is when the force of gravity pull the dust and gas together. Temp rises and hydrogen nuclei undergo nuclear fusion to form helium nuclei. Energy given out
• main sequence star is where outward pressure expanding the star balances the force of gravity

Question 2

4 stages of the sequence of stars bigger than the sun

Answer 2

• red super giant
• glow brightly and they expand and contract several times eventually exploding to a supernova forming elements heavier than iron forming new planets and stars
• neutron star is left with a very dense core
• if the star is big enough a black whole is created which is super dense and light can not pass through

Question 3

3 stages of the sequence of stars smaller than the sun

Answer 3

• red giant
• white dwarf is when the red giant becomes unstable and injects outer layer of dust and gas
• black dwarf as it cools down it emits less and less energy until no more is emitted

Question 4

What makes up our solar system?

Answer 4

• 8 plantes which orbit the sun
• dwarf planets which orbit stars but do not meet all the rules for being a planet
• moons orbit planets
• artificial satellites that humans have built to orbit earth

Question 5

How do planets orbit the sun?

Answer 5

• circular motion as the force is always towards the centre of the circle (gravitational force)
• travelling at a constant acceleration and velocity but not speed

Question 6

What does the size of the orbit depend on

Answer 6

• closer you are the stronger the grav force

- this means it needs to travel quicker to feel in orbit

Question 7

Red shift

Answer 7

• when we look at light from distant galaxies the wavelength increases
• the wavelengths are longer than they should be so they shift to the red end of the spectrum
• proves that the universe is expanding as further galaxies have more red shift and are mover away faster

Question 8

How did the universe start?

Answer 8

• big bang, all matter occupied in very small space which was very dense and hot
• it ‘exploded’ and space started expanding and has been since

Question 9

Dark energy

Answer 9

• made up term for what holds galaxies together

- responsible for the accelerated expansion of the universe