SOLAR SYSTEM; STABILITY OF ORBITAL MOTIONS; SATELLITES

Question 1

After the big bang the universe was filled with what type of gas?

Answer 1

Hydrogen gas, the lightest of the elements.

Question 2

What is a moon?

Answer 2

A natural satellite that orbits a planet.

Question 3

What is a galaxy?

Answer 3

A massive group of stars (hundreds of billions in milky way)

Question 4

What do stars for from?

Answer 4

Clouds of gas and dust ( a nebula)

Question 5

What is the main gas in a nebula?

Answer 5

Hydrogen

Question 6

What is the first stage of a star forming?

Answer 6

Gravity causes the cloud of dust and gas to collapse, as the dust particles move faster the temp rises to millions of degrees Celsius

Question 7

What is a protostar?

Answer 7

A collapsing cloud of hot gas and dust (due to gravity)

Question 8

What happens to a protostar if the temperate gets high enough?

Answer 8

Nuclear Fusion-Hydrogen nuclei join together to form helium

Question 9

After which stage has the protostar become a star?

Answer 9

After nuclear fusion.

Question 10

Nuclear fusion releases…….

Answer 10

Nuclear fusion releases a huge amount of energy

Question 11

What are the two opposing forces acting within the star?

Answer 11

Gravity is acting inwards and tends to make the star collapse. The energy from nuclear fusion creates a force acting outwards.

Question 12

How do stars expand?

Answer 12

If the force of nuclear fusion pushing outwards is greater than the inward force of gravity.

Question 13

When is a star at equilibrium?

Answer 13

When the force due to gravity is equal to the force due to nuclear fusion.

Question 14

What happens when the amount of hydrogen in a star runs out?

Answer 14

The outward force due to fusion energy is less than the inward force due to gravity. Causing a star to collapse inwards

Question 15

What happens to a star when it collapses inwards?

Answer 15

The temperature increases, so helium nuclei fuse together to form heavier elements

Question 16

How are heavier elements formed in a star and what does this form?
(Main- sequence star)

Answer 16

In a main sequence star, after the hydrogen runs out helium nuclei fuse together to create heavier elements making the star expand to form a Red- Giant

Question 17

How is a red-giant formed?

Answer 17

By helium nuclei fusing together to form heavier elements, making the star expand.

Question 18

What happens to form a White Dwarf?

Answer 18

At some stage a red giant stops fusing helium so the star shrinks and forms a white dwarf.

Question 19

Why do White Dwarfs gradually cool down?

Answer 19

Because the white dwarf is no longer carrying out fusion.

Question 20

What happens when a white dwarf stops releasing any energy?

Answer 20

It becomes a black dwarf.

Question 21

What is a main sequence star?

Answer 21

A star about the same size of our sun

Question 22

What happens to a star much larger than the sun after running out of hydrogen?

Answer 22

The star expands and leaves the main sequence stage to form a Red Super Giant.

Question 23

What happens in Red Super Giants

Answer 23

Helium nuclei fuse together to produce much heavier elements

Question 24

Nuclear fusion cannot make elements heavier than….

Answer 24

Iron

Question 25

Where do elements heavier than iron come from?

Answer 25

At some point red super giant stops carrying out nuclear fusion. Then the star explodes (FORMS SUPERNOVA) and the temperature in a supernova produces elements heavier than iron.

Question 26

What happens when a supernova explodes?

Answer 26

The elements get distributed throughout the universe.

Question 27

What can the remains of the supernova form?

Answer 27

Either a neutron star (neutrons densely packed together)

Or a black hole

Question 28

Why can’t light escape a black hole?

Answer 28

A black hole has such a large gravity that not even light can escape.