Astronomy

Question 1

Solar System definition

Answer 1

Everything that orbits the Sun

Question 2

Planet definition

Answer 2

Large objects that orbit a star

Question 3

Solar system planets in order

Answer 3

Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune

Question 4

Dwarf planet definition

Answer 4

Objects that orbit the Sun but not big enough to be a planet

Question 5

Moon definition

Answer 5

Objects that orbit a planet in almost-circular orbits

Type of natural satellite

Question 6

Artificial satellite definition

Answer 6

Man-made objects that orbit planets in fairly circular orbits

Question 7

Asteroid definition

Answer 7

Lumps of rock and metal that orbit the Sun

Usually found in asteroid belt

Question 8

Comet definition

Answer 8

Lumps of ice and dust that orbit the Sun in highly-elliptical orbits

Question 9

Centripetal force definition

Answer 9

Force needed to keep something moving in a circle

Question 10

How something keeps its orbit

Answer 10

Object moves in one direction
Centripetal force attempts to drag objects towards centre of planet
Object instead changes direction as it is already moving in one direction (instantaneous velocity)
This keeps it moving in its orbit

Question 11

Factors of gravitational field strength

Answer 11

Mass of object creating field

Distance from centre of object creating field

Question 12

What orbit’s distance from centre of planet means

Answer 12

Closer to planet, stronger the gravity so stronger centripetal force
Faster the object has to move to keep moving in stable orbit

Question 13

Geocentric model

Answer 13

Earth is centre of Solar System
Everything orbited the Earth in perfect circles
There were no telescopes and saw just the Sun and Moon moving across the sky in same way
Accepted model since Ancient Greeks to 1500s

Question 14

Heliocentric model

Answer 14

Earth and other planets orbited the Sun in perfect circles

Galileo saw “stars” (moons) following Jupiter instead of orbiting the Earth through his telescope

Question 15

Current model of Solar System

Answer 15

Similar to heliocentric model (planets orbited Sun)
Planets orbited Sun elliptically
Sun isn’t centre of the universe

Question 16

Steady State theory

Answer 16

Universe has no beginning or end
As Universe expands, new matter is created
Density of the Universe stays the same

Question 17

Big Bang theory

Answer 17

All matter initially occupied a very small space 
Tiny space was very hot and dense
It “exploded” and rapidly expanded
No new matter is being created
Universe has a finite age

Question 18

How red-shift proved Universe’s expansion

Answer 18

Different elements absorb different wavelengths of light
Elements produce specific patterns of dark lines of frequencies it absorbs in visible light spectrum
Light at other galaxies produces same patterns but shifted towards lower frequencies (red side)
Further the galaxy = greater the red-shift

Question 19

CMB radiation definition

Answer 19

Low frequency electromagnetic radiation coming from all parts of the Universe

Question 20

How CMB radiation proved Big Bang theory

Answer 20

CMB radiation shows there is a beginning of the Universe

Supports Big Bang theory

Question 21

How stars are born

Answer 21

Clouds of dust and gas (nebula) come together due to gravity to form protostar
Temperature rises as star gets denser and more particles collide with each other
When hot enough, hydrogen nuclei undergo nuclear fusion to form helium nuclei
Huge amounts of energy are given out, keeping core hot
Star is born

Question 22

Main sequence star

Answer 22

Long stable period (several billion years)
Outward pressure from thermal expansion balances force of gravity
Heavier the star, shorter its time on main sequence

Question 23

Red (super)giant

Answer 23

Hydrogen in core runs out
Force of gravity becomes greater than outward force from expansion
Star is compressed so it is dense and hot enough so energy creates makes outer layers of star expand
Becomes red because the surface cools
Small star = red giant
Big star = red supergiant

Question 24

White dwarf

Answer 24

Small/medium size stars (from red giant phase) become unstable and eject outer layers of dust and gas
Hot, dense solid core is left behind

Question 25

Supernova

Answer 25

Big stars (from red giant phase) flow brightly again as fusion of heavier elements takes place They expand and contract multiple times as balance between gravity and thermal expansion shifts Eventually explode in a supernova

Question 26

After a supernova

Answer 26

Supernova throws outer layers of dust and gas into space Leaves very dense core (neutron star) If star was massive enough, it will collapse and become a black hole

Question 27

How optical telescopes work

Answer 27

Uses reflection and refraction to help see distant objects clearly

Question 28

How to improve image quality of optical telescopes

Answer 28

``` Increase aperture (diameter) of objective lens Use a higher quality objective lens ```

Question 29

Best conditions for telescopes

Answer 29

Light pollution makes it difficult to see dim objects Earth’s atmosphere and air pollution reflect and absorb light from space Best view from earth is on top of a mountain in dark place Best view is in space above Earth’s atmosphere

Question 30

What X-ray telescopes see

Answer 30

Violent, high-temperature events in space e.g. supernovas

Question 31

What radio telescopes see

Answer 31

CMB radiation

Question 32

Improvements of telescopes

Answer 32

Computers help create clearer and sharper images and make it easy to capture images Computers can collect huge amounts of data without human work and analyse them quicker Bigger telescopes give better resolution and gather more light, so fainter objects can be detected Also improved magnification so can see deeper into space