Space Physics

Question 1

How do stars initially form? (1)

Answer 1

From a cloud of dust and gas called a nebula.

Question 2

What is the second part of a star formation called when a protostar is formed.

Answer 2

The force of gravity pulls dust and gas together to form ma protostar.
The temperature rises as star gets denser and more particles collide with each other.
When temperature gets high enough hydrogen nuclei undergo nuclear fusion to form helium nuclei.
Gives out huge amounts of energy which keeps core of star hot.
A star is born.

Question 3

What is the third part of star fomation when it becomes a main sequence star?

Answer 3

Star enters long stable period
Outwards pressure caused by nuclear fusion that tries to expand the star balances the force of gravity pulling everything inwards.
In this stable period it is called main sequence star and typically lasts 7 billion years.
Sun is in middle of this stable period

Question 4

What is the fourth part of star formation when it becomes white dwarf?

Answer 4

A small to medium size star like sun then becomes unstable and ejects its outer layer of dust and gas.
Leaves behind hot dense solid core called a white dwarf.

Question 5

What is fifth part of star formation when it becomes a black dwarf?

Answer 5

As white dwarf cools down emits less and less energy

When it no longer emits a significant amount it is called a black dwarf

Question 6

Describe sixth part of a star when supernova is formed.

Answer 6

Big stars glow brightly as they undergo more fusion and expand and contract several times.
Form elements as heavy as iron in various nuclear reactions.
Eventually they explode into supernova forming element heavier than iron and ejecting them into universe to form new planets and stars.
Stars and all life cycle produce and distribute all naturally occuring elements

Question 7

Describe the last stage of star life cycle when it becomes a black hole.

Answer 7

Exploding supernova throws outer layers of dust and gas into space leaving a very dense core called a neutron star.
If star is big enough it becomes a black hole a super dense point in space that not even light can escape from.

Question 8

What are planets?

Answer 8

large objects that orbit a star.
8 in our solar system
have to be large enough to have ‘cleared their neighbourhoods’ this means gravity is strong enough to pulled in any near objects apart from natural satellites

Question 9

What are dwarf planets?

Answer 9

pluto
planet like objects
orbit stars
don’t meet all rules to be a planet

Question 10

What is a moon

Answer 10

orbit planets
type of natural satellite
not man made

Question 11

What are artificial satellites?

Answer 11

satellites that humans have built

Orbit the Earth

Question 12

What is milky way galaxy?

Answer 12

Collection of billions of stars that are held together by gravity.

Question 13

If an object is constantly moving in circles what is it doing?

Answer 13

Changing direction, so it is constantly accelerating.

And constantly changing direction.

Question 14

For an object to accelerate what does it need?

Answer 14

A force acting on it

Force directed towards centre of circle

Question 15

What does force do to an object?

Answer 15

Fall towards whatever it is orbiting but as object is already moving it just causes it to change direction.

Question 16

What does an object keep accelerating towards?

Answer 16

What it orbits.
But instantaneous velocity keeps it travelling in a circle
Force that makes it happen is gravitational force between planet and sun or between planet and satellite

Question 17

What happens the closer you get to a star or planet?

Answer 17

Stronger gravitational force is.

Stronger force, faster orbiting object needs to travel to remain in orbit

Question 18

For an object in a stable orbit what happens to speed of object?

Answer 18

It changes, and radius of orbit changes too.

Faster moving objects wil move in stable orbit with a smaller radius than slower moving ones.

Question 19

Evidence galaxies seem to be moving away from each other.

Answer 19

• when we look at light from most distant galaxies wavelength has increased
• wavelengths are longer than they should be so shifted towards red end of spectrum - this is red shift.

Question 20

What does red shift suggest?

Answer 20

source of light moves away from us
Measurement of red shift indicate that these distant galaxies are moving away from us quickly.
Same result whichever direction you look in.

Question 21

What has greater red shift?

Answer 21

Distant galaxies than nearer ones. So more distant galaxies are moving away faster than nearer ones.

Question 22

How do balloons relate to the expansion of the universe and how galaxies are moving further away?

Answer 22

1= balloon covered in pompoms
2= as you blow into balloon it stretches
3= Pompoms move away from each other
4= Balloon represents universe and each pompom is a galaxy 
5= as time goes on space stretches and expands, moving galaxies further from each other
6= Shows how expansion of space makes it look like galaxies move from us

Question 23

Describe big bang theory

Answer 23

All matter in universe occupied a very small space
tiny space was dense so very hot too
Then it exploded and space started to expand and expansion still goes on.

Question 24

Problem with big bang theory

Answer 24

Lots we dont know about universe

Observation of supernovae from 1998 to present day show distant galaxies move away from us faster and faster

Question 25

What do scientists curently think of the universe?

Answer 25

Made up of dark matter and dark energy

Question 26

What is dark matter?

Answer 26

unknown substance which holds galaxies together.

Doesn’t emit EM radiation

Question 27

What is dark energy?

Answer 27

Responsible for accelerated expansion of universe

Question 28

Problem with all of these theories?

Answer 28

But no one knows what these things are so lots of theories about it these theories get tested over time and either get accepted or rejected.