Astronomy Flashcards
(21 cards)
What is in the solar system?
Planets, moons, artificial satellites, asteroids, comets
What are asteroids
Rock/metal that orbit the sun. Found in asteroid belt
What are comets
Ice/dust. Orbit sun. Elliptical orbits. TRAVELS FROM NEAR THE SUN TO OUTSKIRTS OF SOLAR SYSTEM.
What are satellites
Natural satellites - moons, orbit planets
Artificial satellites - orbit earth. Ones we have built. Circular orbits.
What does centripetal force cause
Objects that move in a circular orbit at a constant speed is accelerating.
What does instantaneous velocity do
Keeps the object accelerating towards what its orbiting, travelling in a circle.
What does gravitational force provide
The force attracts any 2 objects with mass, tries to pull masses together.
What effects gravitational field strength
Mass - larger the mass the stronger the force
Distance - closer you get, the stronger the force
As the gravitational force increases so does the… why?
Instantaneous velocity because the closer you get the faster you need to go to remain in orbit
What is needed for an object to stay in orbit if the speed changes
The size of its orbit must change to. Fast objects move in a stable orbit with a smaller radius.
What’s the geocentric model
Everything orbit earth in perfect circles
What’s the heliocentric model
All planets orbited the earth in perfect circles
What did Galileo notice
The moon around Jupiter followed Jupiter. Showed not everything was in orbit.
What does the current model state
Planets in our solar system orbit the sun i elliptical orbits. Sun isn’t really in the centre if the universe.
What does the steady state theory state
The universe has always existed and it always will. As the universe expands, new matter is constantly being created meaning the density of the universe is always roughly the sae. No beginning or end to the universe.
What does the Big Bang theory state
Initially, all the matter in the universe occupied a very small space which was very dense/ hot. Then it exploded, space started expanding and the expansion is still going on. Theory gives a finite age of the universe. Red shift proves this theory
What does red shift suggest
That the universe is expanding.. Most galaxies need to be moving away from each other
What evidence is there for red - shift
Different elements: absorbs different frequencies of light, produces a specific part of a dark lines at the frequencies it absorbs.
When we look at light fro distance galaxies we see them the same but at different frequencies
What is red - shift
When there’s an observed increase in the wavelength of light coming from the galaxies and the patterns have been shifted towards the red end of the spectrum
What does red shift suggest about distant galaxies
Distant galaxies ar moving away faster than nearer ones. Shows that the universe is expanding.
What is microwave radiation
Low frequency radiation that comes from all parts of the universe that have been detected, this radiation is mainly in the microwave part of the EM spectrum. Also known as the cosmic microwave background radiation (CMB radiation)
