Astrophysics - Motion and the universe - Steller evolution - Cosmology Flashcards
what is m/s squared used for
accelaration
What is the universe
A large collection of billions of galaxies
What is a galaxy
A collection of billions of stars
What galaxy is our solar system in
The milky way
Why does the gravitational field strength of things vary
The more mass an object has, the greater its gravitational field will be.
Gravitational field strength causes:
1) Moons to orbit planets
2) Artificial satellites to orbit the Earth
3) Causes planets to orbit the sun
4) Causes comets to orbit the sun
what is the difference between the orbits of comets moons and planets
A comet orbits a star in an elliptical shape whereas a moon orbits a planet in a circular orbit and a planet orbits in a slightly elliptical shape
What is the relationship between orbital speed , orbital radius and time period
Orbital speed =
2 x PIE x orbital radius
———————————
Time period
How can stars be classified by colour and what do the colours mean
hot, bright stars are blue, very small, colder or old dying stars are red.
What does a stars colour relate to
It’s surface temperature
What are the steps of the evolution of the sun and other simillair mass stars
1)Nebula
2) Star (Main Sequence)
3) Red Giant
4) White Dwarf
What are the steps of the evolution of stars that have a much larger mass than the sun
Nebula
Protostar
Main Sequence Star
Red Supergiant
Supernova
Neutron Star (or Black Hole)
What is absolute magnitude
the magnitude (brightness) of a celestial object as it would be seen at a standard distance of 10 parsecs.
Understand and be able to draw the main components on the Hertzsprung-Russel Diagram
https://www.researchgate.net/figure/A-typical-Hertzsprung-Russell-diagram-that-contains-information-about-central-stellar_fig1_363912640
What are the main arguments in favour of The Big Bang Theory
2) the Universe expanded from an extremely small, extremely hot, and extremely dense point (singularity). Since then it is still expanding and becoming less dense and cooler.
What evidence supports the Big Bang Theory
1) Red-Shift - the increase in wavelength of light waves from objects that are moving away from you causing them to appear more red.
2) Cosmic Microwave Background Radiation (CMBD) - The CMBR is the remains of the thermal energy from the Big Bang, spread thinly across the whole Universe which can be detected using specially designed detectors
If a wave source is moving towards an observer, what happens to the frequency and wave length
the frequency increases and the wavelength decreases (It compresses)
If a wave source is moving towards an observer, what happens to the frequency and wave length
The frequency increases and the wavelength decreases (It compresses)
What is the equation relating to change in wavelength, reference wavelength, velocity of a galaxy and speed
Cange in wavelength
——————————- =
Reference wavelength
velocity of a galaxy / speed
How does Red-shift vary
The further away the thing is, the more red-shifted it is
Why does Red-shift vary
As a result of the expansion of space: this means that the farther away a galaxy is from us, the more the space has expanded in the time since the light left that galaxy, so the more the light has been stretched, the more redshifted (understand this)
