P16 Space Physics Flashcards
What are properites of our Sun?
- Main sequence star
- The only luminous object in out solar system; all other objects are non-lumious and they relfect light from the sun
What are the eight planets of the Solar System?
- Mercury
- Venus
- Earth
- Mars
- Jupiter
- Saturn
- Uranus
- Neptune
What are considered small planets?
- Mercury
- Venus
- Earth
- Mars
What is a theory?
An explanation based on observable evidence and data
Which planets are considered gas giants?
Jupiter,Saturn, Uranus and Neptune
What are two criteria to classify an object as a planet?
- The object must orbit the sun
- It’s mass must be large enough to extract enough gravitational force to pull smaller objects
Give two key features of a planet.
- They orbit in an elliptical path
- They have a cetripetal force acting on them
How do you calculate the speed of planet?
2π x orbital radius / Time
Why do planets around the sun have a circular motion?
Gravitational force between the Sun and plantes acts as the centripedal force to keep the planets in a circular motion
What two factors can affect the Graviational force between the sun and the planets?
- mass of objects
- distance between two objects
What is a satellite?
Something that orbits a planet
What are the two types of satellites?
- Natual - Moon
- Manmade - Communication
Which planets have moons?
- Small planets have none or very few moons
- Large gaseous planets have many moons due to their high mass resulting in a high graviational pull
What are asteroids?
Large pieces of rock that orbit the sun
Where is the asteroid belt?
Inbetween Mars and Jupiter
What are comets?
Objects made of dust and ice
- they have in more elliptical paths then planets
What is the Big Bang theory?
All matter and energy was concentrated at a single dense point which exploded sending matter and energy outwards thus creating the universe. The universe has been expanding ever since.
What is the steady state theory?
There is no origin to the universe and it was already existing. The universe is expanding as galaxies moves away from each other
What is evidence for the Big Bang theory?
- Red Shift
- Cosmic Microwave Background Radiation (CMBR)
What is red-shift?
This is when an object producing visible light is moving away from the observer, it’s wavelength increases and the frequency decreases so that it is shifted towards the red end of the spectrum.
What is Cosmic Microwave Background Radiation (CMBR)?
The Big Bang released a large amount of energy as waves with high energy, As the universe is expanding wave lentth of these energy waves increased and the frequency decreases. These waves currently exist as low energy microwaves in the background
How does CMBR provide evidence for the Big Bang theory?
As the origin of CMBR can only be explained by the Big Bang
What happens at the birth of a protostar?
- Particles in nebula are attracted by gravitational force and they start to collide with each other
- This releases a large amount of thermal energy
- When the amount of energy is high enough it can start nuclear fusion reactions in a protostar
What is nebula?
Large clouds of gases and dust
What is the Life-Cycle of a a sun-sized star?
Nebula - Protostar - Main sequence star - Red giant - White dwarf - Black dwarf
What is the life-cycle of a massive star?
Nebula - Protostar - Main sequence star - Red Super giant - Supernova - (Either a neutron star if small or Black hole if big)
Why is the main sequence star stage the most stable stage of any star?
Because the outwards force created by nuclear fusion is balanced by inverse gravitational force
What happens at red giant stage?
1.Rate of nuclear fusion slows down as the hydrogen fuel runs out meaning the inward gravitational force becomes stronger that outwards nuclear force.
2. The inner core of the star shrinks whereas the outer layer expands.
3. The star looks bigger and it’s temperature decreases.
What happens at white dwarf stage?
1) The outer layer of red giant is ejected into space so that the star becomes smaller when it turns into a white dwarf.
2) Another set of nuclear fusion reactions starts to release more energy so that the star is hotter.
What happens during then black dwarf stage of a star?
Nuclear fusion reactions stop and there is no emmission of any radiation
What happens during the supernova stage of a star?
1) The outer layer of a red super giant is ejectd outwards and the inner layer condenses to form a supernova.
2)More nuclear fussion takes place to form elements heavier than iron.
3) When the amount of energy in a supernova is really high it undergoes through supernova explosion to form a neutron star (if the reminant is small) or black hole (if the reminant is large).
