SPACE PHYSICS Flashcards
What is the basic life cycle of a neutron star/black hole?
Cloud of dust and gas
Protostar
Main sequence star
Red SUPER giant
Super nova
Neutron star/black hole
What is the basic life cycle of a black dwarf?
Cloud of dust and gas
Protostar
Main sequence star
Red giant
White dwarf
Black dwarf
What is a cloud of dust and gas that stars originate from called?
A nebula
How does a cloud of dust and gas form a protostar?
Force of gravity pulls the dust and gas together
Temp rises as the star gets denser and more particles collide
Nuclear fusion occurs which uses large amounts of energy to keep the star core hot
How does a protostar form a main sequence star?
Long stable period where the outward pressure (caused by nuclear fusion) that tries to expand the star balances the fore of gravity pulling everything inwards
How does a main sequence star form a super/red giant?
Hydrogen begins to run out
Star swells into super/red giant
Becomes red because surface cools
Fusion of helium occurs
How does a super red giant form a supernova?
Undergo more fusion and expand/contract several times
Explode into supernova
How does a supernova form a neutron star?
Exploding supernova throws the outer layers of dust and gas leave a very dense core called a neutron star
How does a supernova form a black hole?
If the supernova star is massive enough a black hole will be formed
How does a red giant form a white dwarf?
Red giant becomes unstable and ejects its outer later of dust and gas which leaves behind a hot dense solid core (white dwarf)
How does a white dwarf form a black dwarf?
White dwarf cools down and emits less and less energy
When it no longer emits a significant amount of energy it becomes a black dwarf
What is our solar system?
All the stuff that orbits our sun
What are planets?
Large objects that orbit a sun
Have to be large enough to have ‘cleared their neighbourhoods’
What are dwarf planets?
Planet-like objects but don’t meet all of the rules for being a planet
What does it mean when planets have ‘cleared their neighbourhoods’?
Their gravity is strong enough to have pulled in any nearby objects apart from their natural satellites
What are moons?
Orbit planets
Type of natural satellite
What are artificial satellites?
Satellites that humans have built
What is the milky way galaxy?
Massive collection of billions of stars that are all held together by gravity
What happened during the Big Bang?
All matter in the universe was very dense and hot in a small space
Then it ‘exploded’ and space started expanding
What is dark matter?
An unknown substance which holds galaxies together but does not emit any electromagnetic radiation
What is dark energy?
Thought to be responsible for the accelerated expansion of the universe
What is the evidence for the universe expanding?
Light from distant galaxies show wavelength has increased
They have shifted to red end of the spectrum (red-shift)
This suggests source of light is moving away from us
How do planets move around the sun?
Orbit in a circle
Same speed but changing velocity due to always changing direction so constantly accelerating
Force must be acting on planet to accelerate (gravitational force)
Why do planets not fall into what they are orbitting?
Object is moving so force causes it to change direction
It keeps accelerating towards object it is orbiting however instantaneous velocity keeps it travelling in a circle
What happens the close an object gets towards a star it is orbiting?
The stronger the gravitational force
What happens to the speed of an object orbiting a star if it is closer and has a strong gravitational force?
The faster it has to travel to not crash into the object it is orbiting
What happens to an object in a stable orbit if the speed of the object changes?
The size of its orbit must change
