Space Flashcards
What is our solar system made up of?
Eight planets
Dwarf planets
Moons
Asteroids
Comets
All objects that orbit the sun
Located in the Milky Way Galaxy which contains billions of stars
How do stars form?
The sun was formed from a huge cloud of dust and gas ( a nebula ) pulled together by gravitational attraction
Gravitational attraction between particles of the dust and gas causes them to merge together to form a protostar
The protostar becomes more dense as gravitational forces continue to pull it together so the particles collide more often
More energy from the Gp energy store of the particles is transferred to the thermal energy store so the temperature increases
Hydrogen nuclei fuse when the temperature is high enough to form helium nuclei
These nuclear fusions release huge amounts of energy and the protostar becomes a main sequence star
The star is stable because the fusion reactions produce outwards forces which are in equilibrium with the gravitational forces pulling inwards
What is the lifecycle of a star?
Protostar
Main sequence
Red supergiant/ red giant
Supernova/ white dwarf
Black hole/ black dwarf
How are elements formed?
Nuclei for all naturally occurring elements are produced by nuclear fusion in stars
Hydrogen fused to form helium
Other small nuclei formed in stars with large masses
When a star becomes a red (super)giant, helium, lithium and other small nuclei are fused to form larger nuclei
Heavier elements than iron require more energy and are only produced from a supernova ( the explosion of a large star)
What is orbital motion?
The Earth and other planets orbit the Sun
The moon is a natural satellite of Earth
When one object orbits another, the smaller object orbits the bigger one
What are circular objects?
Orbits of the planets around the Sun are almost circular
An object in orbit is constantly changing direction, velocity
The object is constantly accelerating
Resultant force is the centripetal force and is always directed to the centre of the circular orbit
Acceleration is always directed towards the centre
Right angle between resultant force and velocity
For planets and satellites gravity provides the resultant force
How does a stable orbit happen?
Orbit occurs at a fixed distance and at a particular speed
If the speed changes, radius must also change
Slower speed is a larger orbit
What is a red shift?
Wavelengths of light longer if the light source is moving away from the observer
Wavelengths from most distant galaxies are longer than expected
This suggest the galaxies are moving further away
The further away the galaxies are, the more their light is red shifted, suggesting distant galaxies are moving away faster than close galaxies
Suggest universe is expanding
What is the Big Bang Theory?
Start of universe from extremely small hot and dense object that exploded
Existence of electromagnetic radiation produced from Big Bang
Red shift
Dark energy could be responsible for acceleration of the expansion of the universe and dark matter may provide the gravitational force holding galaxies together.
What is a white dwarf?
A hot, dense white star which fades and goes cold to become black dwarf
What is a black hole?
Infinitely dense point in space
What is the Doppler Effect?
The absorption spectrum of the source of light
The absorption spectrum of a specific element is determined in a laboratory
The same spectrum is absorbed in light in another galaxy
Any differences in the observed wavelengths must be caused by relative motion between the galaxy and Earth
