Solar System Flashcards
What is in our solar system
Planets
Dwarf planets
Moons
Artificial satellites
What do planets have to be large enough to have done
To have cleared their neighbourhoods
Which means that their gravity is strong enough to have pulled in any nearby objects apart from their satellites
What is a moon a type of
Natural satellite
How do the planets be around the sun
In circular orbits
What does it mean if it’s constantly changing direction
It’s constantly accelerating
And is constantly changing velocity but not changing speed
What force is acted on the orbiting object for it to accelerate
Gravitational force from the centre planet
Why does the object just orbit the thing it’s orbiting and not fall straight into it
The object keeps accelerating towards what it’s orbiting but the instantaneous velocity keeps it travelling in a circle so the forces kind of act against each other
What does the size of the orbit depend on
The orbits speed
What does a stronger gravitational force mean on the object
The faster the orbiting object needs to travel to remain orbit
What must happen if the speed of an orbit changes
The size of the orbit must do to
What is the red shift
The lights wavelengths from the most distant galaxies are all longer than they should be and they’re shuffled towards the red end of the spectrum
What does the red shift suggest
The source of light is moving away from us and the distant galaxies are
More distant galaxies have greater red shift than nearer ones so more distant galaxies are moving away faster than nearer ones
What conclusion is Made from the red shift
What model can show this
That the whole universe is expanding
Balloon can show this
What does the Big Bang state
Initially all matter in the universe occupied a very small space which was very dense and hot
It then exploded and started expanding
What is dark matter
An unknown substance which holds galaxies together but didn’t emit any electromagnetic radiation
