Topic 8 - Space Physics

Question 1

What is the first stage if the life cycle of stars?

Answer 1

They initially form from a cloud of dust and gas called a nebula

Question 2

What is stage 2 of the life cycle of a star?

Answer 2

Gravity pulls the dust and gas together to form a protostar
The temp rises and it gets denser and more particles collide
When temp is high enough hydrogen nuclei undergo fusion to form helium nuclei
This gives out huge amounts of energy which keeps the core hot

Question 3

What is stage 3 of the life cycle of a star?

Answer 3

The star enters a long stable period where the outward pressure caused by fusion balances the gravity pulling everything inwards
Main sequence stars are typically last several billion years

Question 4

What is stage 4 of the life cycle of a star?

Answer 4

Eventually hydrogen begins to run out so the star swells into a red giant or a red super giant
It is red because the surface cools
Fusion of helium occurs
Heavier elements up to iron are created in the core

Question 5

What is stage 5 of the life cycle of a small star?

Answer 5

It then becomes unstable and ejects its outer layer of dust and gas leaving behind a hot, dense solid core - a white dwarf

Question 6

What is stage 6 of the life cycle of a small star?

Answer 6

As a white dwarf cools down it emits less energy, when it can’t emit any more it becomes a black dwarf

Question 7

What is stage 5 of the life cycle of a large star?

Answer 7

They start to glow brightly as they undergo more fusion and expand and contract servers times
Elements as heavy as iron are formed
Eventually they explode in a supernova forming elements heavier than iron and ejecting them into the universe to form new planets and stars

Question 8

What is stage 6 of the life cycle of a large star?

Answer 8

The exploding supernova throws the outer layers of dust and gas into space, leaving the dense core called a neutron star

Question 9

How does a star become a black hole?

Answer 9

If the star is large enough it will become a super dense point in space that not even light can escape from

Question 10

What is the one star in our solar system called?

Answer 10

The sun

Question 11

How many planets are there in our solar system?

Answer 11

8 and one dwarf planet

Question 12

What galaxy is our solar system a part of?

Answer 12

The Milky Way

Question 13

What creates orbits?

Answer 13

Gravity

Question 14

What does the size of a planets orbit depend on?

Answer 14

The planets speed

Question 15

Where is a planets gravitational forces strongest?

Answer 15

Closest to it

Question 16

What does a strong force mean for the speed of the orbit?

Answer 16

The stronger the force, the faster the planet needs to travel to remain in orbit

Question 17

What happens when we look at light from distance galaxies?

Answer 17

We observe an increase in wave length

Question 18

What is redshift?

Answer 18

The further away the galaxies, the faster they are moving and the bigger the observed increase in wavelength so it’s shifted towards the red end of the spectrum.

Question 19

What does redshift provide evidence for?

Answer 19

That space is expanding and was caused by the Big Bang theory

Question 20

What is the Big Bang theory?

Answer 20

The universe began from a very small region that was extremely hot and dense

Question 21

What have observations of supernova led scientists to believe?

Answer 21

Since 1988 onwards evidence suggest that distant galaxies are receding ever faster