P16 - Space✔️

Question 1

Describe what is in our solar system?

Answer 1

One star, eight planets and the dwarf planets that orbit the sun - natural satellites, the moon that orbits planets

Question 2

Explain how the sun was formed?

Answer 2

Formed from a cloud of dust and gas (nebula) pulled together by gravitational attraction

Question 3

Explain how a prostar is formed?

Answer 3

Dust and gas pulled together - as the temperature rises the star gets denser and more particles collide with ecah other - hydrogen nuclei undergo nuclear fusion for form helium nuclei - which gives out lots of energy and keeps the stars core hot

Question 4

Describe the conditions when a star is in its main sequence?

Answer 4

Star enters a long stable period where the outward pressure caused by nuclear fusion (that tries to expand the star) balances the force of gravity pulling everything inwards - lasts several billion years

Question 5

Explain what happens when the stars hydrogen begins to run out?

Answer 5

The star then swells into a red giant (if its a small star) or a red super giant (if its a larger star) - becomes red as the surface cools - fusion of helium and other elements occurs and heavier elements (up to iron) are created in the core

Question 6

What happens after a red giant becomes unstable?

Answer 6

Will leave behind a white dwarf which will then cool down and become a black dwarf

Question 7

Explain how a small/medium star becomes a white dwarf?

Answer 7

Red giant becomes unstable and ejects its outer layer of dust and gas - leaving behind a hot dense solid core

Question 8

Explain how a white dwarf becomes a black dwarf?

Answer 8

As white dwarf cools down it emits less and less energy - when it no longer emits a significant amount, it is called a black dwarf

Question 9

Give the order of a small/medium stars life?

Answer 9

nebula → prostar → main sequence star → red giant → white dwarf → black dwarf

Question 10

Explain how a red super giant explodes in a supernova?

Answer 10

Starts to glow brighter as they undergos more fusion and expands and contracts several times, forming elements as heavy as iron in various nuclear rections - eventually they explode, forming elements heavier then iron and ejecting them into the universe

Question 11

Explain how all naturally occuring elements are distributed in the universe?

Answer 11

Through the explosion of a supernova - which ejects elements heavier than iron into the universe to form new planets and stars

Question 12

Explain how a neutron star is formed from a supernova?

Answer 12

Supernova throws the outer layer of dust and gas into space - leaves behind a very dense core (neutron star)

Question 13

Explain how a black hole can form?

Answer 13

After a supernova and if the star is larger enough enough a black hole can form - a super dense point where not even light can escape

Question 14

Give the life cycle of a large star?

Answer 14

main sequence star → red super giant → supernova → neutron star / black hole (if star is big enough)

Question 15

Define a planet?

Answer 15

Large objects which orbit a star

Question 16

Define dwarf planet?

Answer 16

Planet-like objects that orbit stars - don’ meet all requirments to be a star

Question 17

Define moon?

Answer 17

Natural satelite - orbit planets

Question 18

Define artificial satelite?

Answer 18

Are satellites that humans have built

Question 19

Effect of a stronger gravitational force on an orbitting object?effects of changes in speed?

Answer 19

Will need to travel faster to remain in orbit - if the speed changes, the radius of its orbit must do so too - faster moving objects will have a stable orbit with a smaller radius

Question 20

Evidence that the universe is expanding?

Answer 20

wavelength from light traveling from different galaxies has increased more towards the red end of the spectrum (red-shift) suggest light is moving away from us - further away galaxies have greater red-shifts indicating they are moving futher then closer galaxies

Question 21

Explain the theory of the big bang?

Answer 21

Initially all the matter in the universe occupied a very small space which was very dense and very hot - then it exploded and space started expanding and is still expanding now

Question 22

Define dark matter?

Answer 22

Name given to an unknown substance which holds galaxies together - but does not emit any electromagnetic radiation

Question 23

Define dark energy?

Answer 23

Thought to be responsible for the accelerated expansion of the universe