Topic 7 Flashcards
why does our weight vary across planets
- weight is dependant on weight = mass*gravity
- gravitational field strength varies as planets are different size meaning weight varies
what is gravitational field strength on earth
10N/kg
what does our solar system consist of ?
- the sun (our star)
- planets (mercury, Venus ,earth ,mars, Jupiter ,Saturn, Uranus and Neptune)
- natural statelets ; moon
- dwarf plants
- comets and asteroids
name the plantes in order closes to the sun
mercury
venus
earth
mars
jupeter
saturn
uranus
neptune
what did Ptolemy suggest abt the universe
the earth was ta the centre [geocentric]
what did Copernicus suggest abt the universe
the sun is at the centre and the plants orbit it [helocentric]
what did Galileo do to theorised abt the universe
he uses telescope to support theory and suggested that moon orbit the planets
describe the orbit of moons , planets, comets and artificial satellites
orbit in elliptical shape
explain for a stable orbit , the radius of orbit must change if speed changes
- at higher speed , the object requires greater centripetal force
- for grater centripetal force gravitational force must increase
- this is achieve by the the radius of the orbit being reduces
explain how the force of gravity acting on a satellite affects its speed and velocity
- the force can alter its velocity as direction us continuously changing
- it cant cause a change in speed since there is no force component in the diction of motion
describe the steady state theory
- the universe has always existed
- but it is expanding and creating matter to counteract the loss in density
describe the big bang theory
- universe expanded from a small dense point 14 billions ago
what is red shift
increase in the wavelength of light due to the source moving away from observer
what does the red shift provide evidence for?
- universe expanding
- big bang theory
what does the big bang theory suggest?
- the entire universe started from a small hot and dense region of space
compare the observed red shifts from two galaxies one further away from each other
- galaxy that is further away travels faster
- red shift is greater the further away it is
Explain how both the Big Bang and Steady State theories of
the origin of the Universe both account for red-shift of galaxies
- the red shift phenomenon says that galaxies are moving away from each other
- this shows expansion
what does CMB radiation stand for
cosmic microwave background radiation
how does CMB radiation provide further evidence for?
- CMB radiating produced from B.B theory
- big bang theory
how does the existence of CMBR support the expansion of universe
- gamma radiation was released in the big bang
