Physics Kerboodle Flashcards
Ideas in ancient times of moon, sun, earth
Earth was flat
Sun eaten by monsters during solar eclipse
Earth was supported by pillars or surrounded by ocean
Earth was supported on the back of a turtle
Moon was a big rock which early earth had flung into space
When did most people in europe think earth was a sphere
300BC
For how long did china believe earth was flat
1600
Geocentric model
The earth did not move - the sun, moon, planets and stars moved around the Earth | they moved onto crystal spheres that light could travel through
Who wrote books explaining Geocentric model
When
2 greek astronomers Plato and Aristotle | over 2000 years ago
Who said there was a force between all objects when
Indian mathematician astronomer Bhaskaracharya | 1000 years ago
What force did bhaskaracharya say is between planets
Gravity
What else did bhaskaracharya work out
The Earth attracted the moon
What did astronomers use newtons predictions for
There was a planet beyond Uranus
Why was newtons idea powerful
Can be used to make predictions
Why did people believe in geocentric model
Explains observations people saw every day
Ground did not seem to move
Sun and moon appears to move
Stars appeard to move
A problem with geocentric model
Retrograde motion
Retrograde motion
Planets appear to go backwards
How did Ptolemy change geocentric model
So that the planets went in complicated orbits
When did Ptolemy publish his ideas
140AD
What did greek astronomer Aristarchus discover
Heliocentric model
Heliocentric model
Planets orbit the sun
When were Geocentric and Heliocentric models discovered
Geocentric - 2000 years ago
Heliocentric - around 200BC
When did Nicolaus Copernicus publish a book about heliocentric model
1543
Difference and similarity between geocentric and heliocentric
Geocentric says everything orbits Earth and heliocentric syas the opposite
Both models have orbiting by force gravity
Who/when invention of telescope
Italian physicist Galileo Galilei | 1609
What did Galileo see
Objects orbit Jupiter - they were moons of Jupiter and called Galilean satellites after him
Evidence Galileo found that not everything orbits earth
Moons orbiting Jupiter not Earth
Which model explains retrograde better
Heliocentric
Observations astronomer Edwin Hubble made
Galaxies move away from us - 1929 - galaxies that were further away move faster
What does the big bang explain about galaxies
Why galaxies move apart
Why galaxies that are further away are moving faster
When was the big bang
13.8 Billion years ago
When did first stars appear after big bang
150 million years after
When did galaxies form after big bang
Billions of years after
When did our solar system for after big bang and how long ago today
9 billion years after | 5 billion years ago
What did our solar system form from
A disc of dust and gas
When did life on Earth start
4 billion years ago
When did dinosaurs live
Between 200 million and 65 million years ago
How long have humans existed for
Less than half a million years
Ways to easily understand how big timescale of universe is
Make a model or analogy
Why couldn’t atoms form right after the big bang
Too hot for atoms to form
Evidence for the big bang theory
Most galaxies appear red shifted which shows they are moving away from us and the universe is expanding
What pushes a balloon forwards
Force of the air on the balloon
1st artificial satellite (not natural - moon)
Sputnik 1
When/where sputnik launched
Russians | 1957
What keeps satellites in orbit
Force of gravity
What are satellites used for
Communication, monitering weather, studying Earth and space,
Geostationary orbit
Satellites that stay over same position on the Earth all the time
How long does it take for a geostationary satellite to orbit Earth
1 day
How far from Earth is a geostationary satellite
36,000km
What do satellites need to do
Broadcast television signals
Television company transmits radio signal to satellite
Satellites broadcasts to lots of houses
Low earth orbit
Orbit below 1000km from Earth
Polar orbit
Useful for mapping | go over North and South pole
When was apollo mission from
1961 to 1975
Risks of going to space
Equipment can get damaged
People can get injured
Rocket can explode before take-off
Solar flares impacting rocket
Parachute doesn’t work well
Radiation from the sun
What does 99.9% reliable mean
1000 missions something could go wrong once
How many computers in 1963 were developed for space missions
Half
Benefits of space station
Smartphones
Computer-controlled gadgets
Shock-absorbing materials used in sports shoes
Computer programs for swiping credit cards
Water filters
Neil Armstrong saw how fragile the Earth looks from space which made people think about lookng after our planet
Ways astronomers look for habitable planets
Transit photometry
Relastivistic beaming
Pulsar timing
Ellipsoidal variations
