astrophysics Flashcards
universe
collection of billions of galaxies
galaxy
collection of stars
what is our sun
a star
what are planets
large objects that orbits a star
planets in our solar system in order
-mercury
-venus
-earth
-mars
-jupiter
-saturn
-uranus
-neptune
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comets
lumps of ice and dust that orbit the sun
-highly elliptical
shape of orbits of our sun
almost circular orbits
weight
The force acting on an object due to gravitational attraction
how does mass affect g
the greater the mass, the greater the gravitational field strength
what does a larger g mean
A higher gravitational field strength means a larger attractive force towards the centre of that planet or moon
what is the force causing orbits
centripetal force
acts towards the centre of the circle
how does distance affect g
-the closer you are to a star or planet the stronger g is
how does the strength of g of a planet affect speed needed to stay in orbit
if g is stronger, the larger the instantaneous velocity needed to balance it
-hence the faster you need to go to remain in orbit
how does the radius of orbit affect speed needed to stay in orbit
if the orbit radius is larger, speed needed to remain in orbit remains the same
orbital speed formula
orbital speed = 2 x π x orbital radius/time period
