Topic 7 - Astronomy

Question 1

Weight of any object depends on

Answer 1

Gravitational field strength(g)

Question 2

Gravitational field strength depends on

Answer 2

The mass of the body creating the field
The distance from the body

Question 3

The stronger the gravitational field strength

Answer 3

the larger the velocity needed to balance it and stay in orbit

Question 4

Our solar system consists of

Answer 4

The sun
8 planets and their satellites
Dwarf planets
Asteroids and comets

Question 5

The names of the 8 planets in order from least distance to the sun

Answer 5

Mercury, venus, earth, mars, jupiter, saturn, uranus, neptune

Question 6

The geocentric model stated

Answer 6

The earth was the centre of the solar system. The sun, moon and planets orbited earth in perfect circles.

Question 7

The heliocentric model

Answer 7

The sun is the centre. The planets orbited the sun in perfect circles. Moons orbited planets.

Question 8

The current soalr system model

Answer 8

The sun is the centre. Planets orbit in elliptical orbits ratehr than circles.

Question 9

Moon orbits

Answer 9

Almost circular orbits

Question 10

Planet orbits

Answer 10

Orbit a star in an elliptical shape

Question 11

Comet orbits

Answer 11

Highly elliptical orbits

Question 12

Artificial satellites are

Answer 12

Human built objects that orbit the earth

Question 13

Artificial satellite orbits

Answer 13

Fairly circular orbits

Question 14

For planet and moon orbits, they move at

Answer 14

A constant speed but a changing velocity, so they are constantly accelerating

Question 15

The force that makes the planet or moon change direction is called

Answer 15

The centripetal force

Question 16

How does centripetal force work

Answer 16

The planet is constantly trying to move straight rather than in an orbit. The centripetal force is always towards the centre of the orbit, so it causes the planet to keep moving but change direction.

Question 17

If orbital speed changes then

Answer 17

The radius of the orbit must also change

Question 18

orbital speed increases or decreases effect

Answer 18

Increases - Orbital radius decreases
Decreases - Orbital radius increases

Question 19

The two theories for the creation of the universe

Answer 19

The steady state theory
The big bang

Question 20

Steady stae theory states that

Answer 20

The universe has always been how it is now, and always will.
As the universe expands, new matter is constantly created
The density of the universe stays the same
No beginning or end to the unvierse

Question 21

The big bang theory

Answer 21

All the matter in the universe was in a very small space
Ver ydense and very hot
It exploded, and the expansion started
A finite age for the universe(13.8bn yrs)

Question 22

Evidence of the big bang theory

Answer 22

Red-shift
Cosmic microwave background radiation

Question 23

Why is the big bang the accepted theory

Answer 23

It has more evidence than the steady state theory

Question 24

Red shift full process

Answer 24

Different elements absorb different frequencies and wavelengths of light
When we look at light from distant galaxies compared to erath, it is lower frequency
Theis means it is shifted to the red side of the spectrum

Question 25

Red shift proves

Answer 25

That all distant galaxies are moving away from us fast More distant galaxies have greater red-shifts, so the further away, the faster ther moving

Question 26

CMB radiation is

Answer 26

Cosmic microwave background radiation. Low frequency EM raqdiation(moslty microwaves) detected form all parts of the Universe.

Question 27

CMB proves big bang because

Answer 27

There has to have been an original source of the radiation, which is the explosion

Question 28

Red shift can prove both

Answer 28

Big bang and steady state because they both state the universe is expanding

Question 29

The stages of a star life-cycle

Answer 29

Nebula Protostar main sequence star Red giant/supergiant Supernova/white dwarf Neutron star/black hole

Question 30

Nebula is

Answer 30

A cloud of dust and gas

Question 31

Protostar process

Answer 31

The force of gravity pulls nebula together. The temperature rises with density. Nuclear fusion starts to occur, which makes the core hot

Question 32

Main sequence star process

Answer 32

A long stable period The gravity and nuclear fusion trying to expand the star balance out The heavier the shorter it spends as this

Question 33

Red supergiant process

Answer 33

Stars much bigger than the sun become this. Hydrogen in core runs out, so the nuclear fusion stops and it gets compressed by gravity The hydrogen and helium outside go through nuclear fusion, so it get even bigger It turns red because the surface cools

Question 34

Red giant process

Answer 34

Stars the size of the sun Hydrogen in core runs out, so the nuclear fusion stops and it gets compressed by gravity The hydrogen and helium outside go through nuclear fusion, so it get even bigger It turns red because the surface cools

Question 35

White dwarf process

Answer 35

A red giant becomes unstable and ejects its outer layers. Only a hot, dense solid core is left

Question 36

Supernova process

Answer 36

Red supergiants undergo mroe fusion and get brighter again Heavier elements are made The balance constantly shifts betwenn graivty and thermal expansion Eventually it explodes into a supernova

Question 37

Neutron star/balck hole process

Answer 37

Supernova throws outer layers of dust and gas into space Leaves a very dense core called a neutron star. If the star is massive enough, it will collapse and become a black hole Balck holes are very dense points in space that absorbs everything around it, including light

Question 38

Telescopes are used to

Answer 38

Observe the universe

Question 39

Telescopes use

Answer 39

Refraction and reflection to see distant objects

Question 40

Optical telescopes

Answer 40

Detect visible light

Question 41

Ways to increase resolution of optical telescopes

Answer 41

Increase aperture of the objective lens Higher quality objective lens

Question 42

Aperture is

Answer 42

The diameter of the objective lens(big lens at end of telescope)

Question 43

Space telescopes

Answer 43

Telescopes located outside the atmosphere

Question 44

Space telescopes are in space to

Answer 44

Capture light absorbed by the atmosphere Avoid light pollution and air pollution

Question 45

Different telescoeps can see

Answer 45

Different types of EM radiation

Question 46

Different types of telescopes eg

Answer 46

X-ray telescopes Radio telescopes