topic 8:space physics Flashcards
Which galaxy is our solar system part of?
The Milky Way galaxy
How many planets make up our solar system?
Eight
What do the planets in our solar system orbit around and what type of body is it?
The planets orbit around the Sun
The Sun is a star
what type of fast pull together the cloud of dust and gas to form the Sun?
Gravitational force of attraction
What word is used to describe a cloud of dust and gas?
A nebula
what type of reactions take place at the start of a stars life cycle as dust and gas is drawn together
Fusion reactions
what factor determines the type of life-cycle a star undergoes?
The size of the star
which two phases do all stars of the same or greater size than the Sun undergo?
Protostar phase
Main sequence phase
what do stars of a similar magnitude to the Sun become at the end of their life cycle
A black dwarf
what two things can stars much bigger than the Sun become at the end of their life cycle?
Neutron star
Black hole
what two phases do stars of similar size to the song go through between being a main sequence star and a black dwarf?
Red giant
White dwarf
what two phases do stars of greater size than the Sun go through between being a main sequence star and a neutron star/black hole?
Red super giant
Supernova
what are produced during the fusion processes in a star?
All of the naturally occurring elements
What condition is required for fusion reactions to occur in a star?
Very high temperatures
how are elements heavier than iron produced?
In a supernova
What type of nuclei fuse is together to form heavier elements in a star?
Hydrogen nuclei fuse to form heavier elements
How are elements distributed throughout the universe?
Through the explosion of a massive star
what allows planets and satellites to maintain circular orbits?
Gravity provides the gravitational force the acts as the object centripetal force
The presence of a centripetal force allows for the object to maintain its circular orbit
What type of satellite can a planet moon be described as?
A natural satellite
give two examples of artificial satellites
TV satellite
Satellite to use for satellite imaging
explain why for a stable orbit, the radius of orbit must change if the speed changes
At higher speed, the object requires a greater centripetal force
For a greater centripetal force, the gravitational force must increase
This is achieved by the radius of the orbit being reduced
explain how the force of gravity acting on a satellite affects its speed and velocity
The force can alter its velocity since the direction is continually changing
It can’t cause a change of speed since there is no force component in the direction of motion
what is a red shift?
An observed increase in the wavelength of light from distant galaxies
What two things can be said about the motion and wavelength of emmited light from a galaxy, the further away it is
The further away a galaxy is the faster it is moving
The further weight a galaxy is the greater the observed increase in wavelength 
What does red shift provide evidence for?
provides evidence that the universe is expanding
Supports the Big Bang theory
What does the Big Bang theory suggest?
The entire universe started from a very small, hot and dense region in space
compare the observed red shift of two galaxies, one further away than the other
The galaxy that is further away is travelling fast faster
The observed red shift is greater the further way it is
what did scientists observe to provide evidence that the universe is expanding at an ever faster rate?
they observed supernovae which suggested that galaxies are moving away at an ever faster rate
prior to observations of supernovae, what was believed about the rate of expansion of the universe and why?
The rate of expansion was expected to occur at an ever slower rate
It was thought that the gravitational force would cause this slowing down
What two ideas could explain the universe ever increasing rate of expansion?
The existence of energy and mass that we can’t detect, known as dark matter and dark energy
These ideas are still being developed by scientist and are not yet fully understood
