Stars and Planets

Question 1

Order of planets

Answer 1

Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune

Question 2

Where is the asteroid belt?

Answer 2

Between mars and jupiter

Question 3

How was our sun and solar system formed?

Answer 3

Formed out of the nebula that came from the supernova death of a huge star.
Nebula collapsed in on itself due to gravity causing gas to be compressed making it hotter
Protostars formed and as it collapsed due to gravity gas and dust were drawn into it from the surrounding nebula
Pressure inside its core rose and temp exceeded 15 million °C and nuclear fission reactions happened and a star was born.

Question 4

What is a protostar?

Answer 4

Part of a nebula collapsing due to gravity.

Question 5

What are the rocky planets?

Answer 5

Mercury
Venus
Earth
Mars

Question 6

What are the gas giants?

Answer 6

Jupiter
Saturn
Uranus
Neptune

Question 7

Why are the gas giants, gas giants?

Answer 7

They have atmospheres and are mostly composed of hydrogen, helium and some methane.

Question 8

Why is pluto now a dwarf planet?

Answer 8

Because of its small mass and very irregular, elliptical orbit.

Question 9

The orbit of a planet …

Answer 9

The orbit of a planet becomes longer as distance from the sun increases

Question 10

What is astronomical unit?

Answer 10

The average distance of the Earth from the sun

Question 11

How long is 1 AU

Answer 11

150 000 000 km = 1.5x10¹¹m

Question 12

What is a light year?

Answer 12

The distance that light travels in one year

Question 13

How long is a light year?

Answer 13

9.46x10¹⁵

Question 14

How are stars formed?

Answer 14

Stars are born from a cloud of dust and gas in a galaxy.
Gravitational attraction between the particles draws them together so the cloud becomes denser.
Temp and pressure increases as particles move together
Nuclear fission occurs which releases lots of energy
Heat energy causes gaseous expansion (outwars force) and gravity is the inwards force
Eventually and equilibrium is established where the 2 forces balance.

Question 15

How does a star die?

Answer 15

Eventually the star runs out of the gas nuclei that can undergo fusion.
The outwards gas pressure decreases so the system is no longer in equilibrium.
Gravitational collapse occurs and the star nears the end of its life
Star gets bigger, surface area increases, surface temp decreases becoming a red giant and star collapses
Once the star collapses a white dwarf is formed and once cooled a black dwarf

Question 16

HR diagram from left to right

Answer 16

Blue giants
Red supergiants
Main sequence
Red giants
White dwarfs

Question 17

What colour is coolest in HR diagram?

Answer 17

Red

Question 18

What colour is hottest in HR diagram?

Answer 18

Blue

Question 19

Where does the sun lie in the HR diagram?

Answer 19

1 luminosity
6000K

Question 20

What happens to a nebula if its a small nebula?

Answer 20

Nebula
Average star
Red giant
Planetary nebula
White dwarf
Black dwarf

Question 21

What happens to a nebula if its a large nebula?

Answer 21

Nebula
Massive star
Red supergiant
Supernova
Neutron star OR black hole (depends on how big)

Question 22

What happens to massive main sequence stars?

Answer 22

They form a red supergiant star when fusion stops the supergiant undergoes rapid collapse and results in a supernova.
During the collapse the energy released is so great that elements heavier than iron are formed.
Very massive stars form a black hole.