Separate Physics - 6.8 Flashcards
Separate Q. Describe our solar system
One star (the Sun), eight planets and dwarf planets which orbit it (there are also natural satellites (moons) orbiting the planets)
Separate Q. Where is our solar system located?
Within the Milky Way galaxy
Separate Q. How did our Sun form?
From a cloud of dust (nebula) pulled together by gravitational attraction
Separate Q. How does fusion keep a star’s form?
Fusion leads to an equilibrium between the gravitational collapse of the star and the expansion (due to fusion energy)
Separate Q. What do stars go through and what are these determined by?
Life cycles – determined by the size of the star
Separate Q. Draw the life cycle of a star for sizes similar to our Sun and for stars much more massive than our Sun
Separate Q. What produces all of the naturally occurring elements?
Fusion processes
Separate Q. What produces elements heavier than iron?
Supernova
Separate Q. What is a supernova and what does it cause?
The explosion of a massive star, distributing elements throughout the universe
Separate Q. What maintains circular orbits of planets and satellites (both natural and artificial)?
Gravity
Separate Higher Q. For a circular orbit, what does the force of gravity cause?
Changing velocity (but unchanged speed)
Separate Higher Q. For a stable orbit, what happens if the speed changes
The radius must change if the speed changes
Separate Q. What is red-shift?
The observed increase in the wavelength of light from most distance galaxies
Separate Q. What does red-shift show?
The further away the galaxies, the faster they are moving and the bigger the observed increase in wavelength
Separate Q. What does red-shift provide evidence for?
Space itself is expanding, supporting the Big Bang theory
Separate Q. What does the Big Bang theory suggest?
The universe began from a very small region that was extremely hot and dense
Separate Q. Since 1998, observations of supernova have suggested what?
Distant galaxies are receding ever faster
Separate Q. Is the theory of how the universe formed complete?
No – there is still much that is not understood (e.g. dark mass and dark energy)
