SP7 Flashcards
(33 cards)
What is a geocentric model
Model that Ptolemy made that states that the other planets and the sun orbited the Earth
What is a heliocentric model
Model suggested by Copernicus that stated the sun was in the centre and we all orbited it
What’s a difference between Ptolemy and Copernicus’ models
In Ptolemy’s models, the planets orbited the Earth. In Copernicus’, they orbited the sun. Ptolemy’s model had planets that moved in small circles while orbiting the Earth
What’s a moon
A natural satellite made of rock that orbits planets
What’s an asteroid
Remnants of bodies that never grew to become planets
What’s a comet
Small bodies made of frozen gases, rock and dust
Why do we use telescopes in orbit
They’re clearer than those on Earth since gas and dust don’t interfere with the images
What is the gravitational field strength on Earth
9.8N/kg
How is the current version of the solar system different to Copernicus
Copernicus’ model doesn’t include Neptune and Uranus
How did Galelio’s discovery support Copernicus’ theory
He used a telescope to view Jupiter’s moons, he then plotted their movements, showing not everything orbited the Earth
What is gravitational field strength determined by
The body’s mass and the radius (bigger mass smaller radius=larger gravitational field strength)
What is meant by elliptical orbits
Oval shaped orbits
What are highly elliptical orbit satellites used for
Communications in parts of Earth near the poles
How does a satellite always stay in orbit
The gravitational force between the Earth and the satellite is always at a 90 degree angle to its movement of direction. It also moves at a constant speed
What happens if a satellite slows down
It will crash into the planet it is orbiting
What happens if a satellite speeds up
The gravitational attraction between the satellite and Earth will be too weak and it will spin out of orbit
Name the sequences a red supergiant goes through
Nebula, Protostar, massive main sequence, supernova, black hole
Name the sequences a red giant goes through
Nebula, protostar, main sequence star, red giant, white dwarf, black dwarf
What is a Nebula
A cloud of dust and gas
How is a protostar made and what is it
when a nebula is pulled together by gravity it creates a protostar, gas and dust gets absorbed and the gravity gets stronger. Particles start to collide more often and the kinetic energy of the particles raises the temperature
What is a main sequence star
When the temperature of a protostar is high enough, hydrogen nuclei fuse to create helium. The outward pressure caused by nuclear fusion and inward pressure
How does a red giant turn into a white dwarf
When all reactions have taken place the stars gravity pulls in all of its mass, condensing it. It gives off lots of light
What does red shift tell us
That galaxies are moving away from each other
What happens if you move at the same velocity as a source or if you and the source are stationary
The frequency will be constant
