Astrophysics
● the universe is a large collection of billions of galaxies
● a galaxy is a large collection of billions of stars
● our solar system is in the Milky Way galaxy
Object that orbits a planet is called a satellite
- Natural → moon (aren't man made)
- Artificial → telescopes (are man made)
My very educated mother just served us noodles
Mercury venus earth mars jupiter saturn uranus neptune
- Planets orbit the sun in a slightly elliptical orbit
Strength of gravity affects objects weight
Nearby masses are attracted by strong gravitational field
● Asteroids (made of rock and metal)
● Comets (made of ice and dust) → much elliptical orbit around the sun
Because of weight → objects stay on the ground → objects will always fall to the ground → satellite are kept in orbit
The greater the mass of the planet then the greater its gravitational field strength
larger attractive force towards the centre of that planet or moon
G varies with distance and mass
gravitational force always acts towards the centre of the larger body
Similarities Differences
Orbits are all slightly elliptical They orbit at different distances from the Sun (different
orbital radius)
They all travel the same direction around the Sun They orbit at different speeds
They all take different amounts of time to orbit the Sun
Further → slower it travels → longer it takes
Closer → shorter time → greater speed
Moon has a circular path
Comets have a highly elliptical orbit
comet approaches the sun, its speed increases
As it moves further away from the sun, its speed decreases
● the universe is a large collection of billions of galaxies
● a galaxy is a large collection of billions of stars
● our solar system is in the Milky Way galaxy
Object that orbits a planet is called a satellite
- Natural → moon (aren't man made)
- Artificial → telescopes (are man made)
My very educated mother just served us noodles
Mercury venus earth mars jupiter saturn uranus neptune
- Planets orbit the sun in a slightly elliptical orbit
Strength of gravity affects objects weight
Nearby masses are attracted by strong gravitational field
● Asteroids (made of rock and metal)
● Comets (made of ice and dust) → much elliptical orbit around the sun
Because of weight → objects stay on the ground → objects will always fall to the ground → satellite are kept in orbit
The greater the mass of the planet then the greater its gravitational field strength
larger attractive force towards the centre of that planet or moon
G varies with distance and mass
gravitational force always acts towards the centre of the larger body
Similarities Differences
Orbits are all slightly elliptical They orbit at different distances from the Sun (different
orbital radius)
They all travel the same direction around the Sun They orbit at different speeds
They all take different amounts of time to orbit the Sun
Further → slower it travels → longer it takes
Closer → shorter time → greater speed
Moon has a circular path
Comets have a highly elliptical orbit
comet approaches the sun, its speed increases
As it moves further away from the sun, its speed decreases
