the earth in the universe

Question 1

what are asteroids?

Answer 1

irregular lumps of rock

Question 2

what are comets?

Answer 2

small objects made of rock and ice

Question 3

what is the order of the planets from the heaviest?

Answer 3

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

Question 4

what are dwarf planets?

Answer 4

small spherical lumps of rock

Question 5

what is the milky way?

Answer 5

one of thousands of millions of galaxies which make up the universe

Question 6

what are light years?

Answer 6

distance that light travels in a year

Question 7

what speed does light travel in?

Answer 7

through a vacuum at speed of 300 000 km/s

Question 8

where does the evidence from distant stars and galaxies come from?

Answer 8

radiation

Question 9

whats the relationship between the distance of the star and its’ relative brightness?

Answer 9

the further away a star, the smaller the relative brightness

if know distance to 1 star, diff in relative brightness can be used to calculate the other

Question 10

what are the uncertainties of measuring the distance to stars in this way?

Answer 10

estimating distance to 1 star

difficult to make precise observations e.g dust, rain, light pollution

Question 11

what is parallax?

Answer 11

as earth orbits sun, nearby stars move against fixed background of distant stars

Question 12

what is nuclear fusion?

Answer 12

hydrogen nuclei jammed so they combine in pairs to form helium, releasing energy

Question 13

how do galaxies appear to us?

Answer 13

to be moving away, increasing wavelength of light we receive from them

Question 14

what is redshift?

Answer 14

increase of wavelength from a galaxy moving away

Question 15

what is the relationship between redshift and distant galaxies?

Answer 15

amount of redshift increases with distance from earth

further away from earth a galaxy is, faster its moving away

Question 16

when was the universe created?

Answer 16

14 000 million years ago from a single point

Question 17

when was the sun created?

Answer 17

5000 million years ago

Question 18

when was earth created?

Answer 18

4500 million years ago

Question 19

what evidence supports the big bang theory?

Answer 19

detection of cosmic background radiation

Question 20

what does the fate of the universe depend on?

Answer 20

how it continues to expand

if enough mass in universe, gravity will slow down expansion and make it collapse again

Question 21

why is the fate of the universe hard to predict?

Answer 21

can only measure mass of parts of universe which emits radiation

speed and distance of galaxies = diff to measure bc radiation travels a long way to get to us

Question 22

what was wegeners theory?

Answer 22

single land mass split into several continents which drifted

Question 23

what evidence did wegener base his theory on?

Answer 23

continents fit together so well

Question 24

why didnt geologists accept wegeners theory?

Answer 24

had simpler theories

not a trained geologist

no one could measure the movement of continents

Question 25

what is the structure of the earth?

Answer 25

core = liquid iron

semi liquid rock in mantle floats on core

outer core = layer of liquid nickel and iron, 1250 km thick

thin layer of solid rock in crust floats on mantle

Question 26

what are the two types of seismic waves that are generated when tectonic plates move?

Answer 26

p waves

s waves

Question 27

what are p waves?

Answer 27

move through liquid core and solid crust

longitudinal

Question 28

what are s waves?

Answer 28

move through only slowly through solid crust

transverse

Question 29

what is a wave?

Answer 29

transfers energy from a vibrating source

Question 30

what is an amplitude?

Answer 30

maximum height of the disturbance

Question 31

what is the wavelength?

Answer 31

distance from one maximum disturbance to the other

Question 32

what is an oscilloscope?

Answer 32

machine that displays waves on the screen

grid on screen lets you compare wavelength and amplitude of waves:

• sound is louder if larger amplitude
• sound is higher pitched if shorter wavelength

Question 33

what is the wave equation?

Answer 33

wave speed (m/s) = frequency (Hz) x wavelength (m)

Question 34

what are geohazards?

Answer 34

natural hazards

precautionary measures:

• buildings withstand tremors
• refuse planning permission in areas prone to flooding

Question 35

what is a supernova?

Answer 35

heavy stars in this way

massive explosion where diff elements are made (heavier than iron)

Question 36

what are tectonic plates?

Answer 36

meet at plate boundary forming mountains, earthquakes and volcanoes

Question 37

how are volcanoes formed?

Answer 37

liquid magma forces through cracks where tectonic plates are moving apart

Question 38

how are fold mountains formed?

Answer 38

2 tectonic plates meet head on

Question 39

explain sea floor spreading?

Answer 39

convection currents cause magma to rise , currents move solid part of mantle and tectonic plates

when plates moving apart, magma reaches surface and hardens forming oceanic crust and pushing floor out

new crust forming at the crest of an oceanic ridge and old rock pushed out

Question 40

explain the magnetic field?

Answer 40

magnetic field changes polarity producing rock stripes of alternating polarity occurring at constructive plate boundaries

Question 41

whats subduction?

Answer 41

when oceanic and continental plates collide, the denser oceanic plate is forced under the continental plate

occurs at destructive plate boundaries

Question 42

how do earthquakes occur?

Answer 42

plates slide past each other or collide

pressure builds up

stored energy is released and waves of energy spread from the epicentre

Question 43

why are plate movements crucial in the rock cycle?

Answer 43

old rock destroyed by subduction

igneous rock is formed when magma reaches surface

plate collisions produce high temp and pressure causing rock to fold

sedimentary rock becomes metamorphic rock