Physics Topic 8 - Space Flashcards
Which galaxy is our solar system part of?
The Milky Way
How many planets make up our solar system?
8
What do the planets in our solar system orbit around and what kind of body is this?
-orbit around the sun
-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 lifestyle a star undergoes?
The size of the star
Which two phases do all stars of the same or greater size than the sun undergo?
1-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?
1-neutron star
2-black hole
What two phases do stars of similar size to the sun go through between a main sequence star and a black dwarf?
1-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?
1-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
Explain why for a stable orbit, the radius of orbit must change if the speed changes
-at higher speeds, the object requires a grater centripetal force
-for a greater centripetal force, the gravitational force must increase
-this is achieved by the radius of the orbit being reduced
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, the faster it is moving
-the further away 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 form a very small, hot and dense region in space
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 than
What two ideas could explain the universe’s 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 scientists and are not yet fully understood
