P8 - space physics Flashcards
Which galaxy is our solar system part of?
The Milky Way galaxy.
How many planets make up our solar system?
Eight (plus the dwarf planets).
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 force pulled 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 star’s life cycle as dust and gas is drawn together?
Fusion reactions.
What factor determines the type of lifecycle 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
2. 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
lifecycle?
- Neutron star
2. Black hole
What two phases do stars of similar size to the sun go through between being a main sequence star and a black dwarf?
- Red giant
2. 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
2. 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 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
supernova
What allows planets and satellites to maintain
circular orbits?
● Gravity provides the gravitational force
that acts as the object’s centripetal force
● The presence of a centripetal force
allows for the object to maintain its
circular orbit
What type of satellite can a planet’s moon be
described as?
A natural satellite
Give two examples of artificial satellites.
- TV satellites
2. Satellites used for satellite imaging
Explain why for a stable orbit, the radius of orbit
must change if the speed changes.
● At higher speeds, 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 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 emitted light from a galaxy, the further away it is?
● The further away a galaxy is, the faster it is
moving
● The further away a galaxy is, the greater
the observed increase in wavelength
