M5 Astrophysics And Cosmology Flashcards
Define the universe
Everything that exists
Define a planet
Large object that orbits a star
Define a dwarf planet
Planet-like objects that orbit stars but are too small to be classed as a planet
Define a planetary satellite
Any object that orbits a planet, e.g. moon or artificial satellite
Define an asteroid
Chunks of mineral and rock that orbit the Sun
Define a comet
Clumps of ice, dust and rock that orbit the Sun further away than Pluto
What is one AU (Astronomical Unit)?
The mean distance between the Earth and Sun
Define 1 light year
The distance that any EM wave can travel through a vacuum in one year
What is the Chandrasekhar limit?
The maximum mass for which the electron degeneracy pressure can counteract the gravitational force.
Limit to know whether a star will become a red giant or a red super giant.
Define escape velocity
The velocity an object needs to have enough kinetic energy to escape from the gravitational field of the object it is orbiting
What is Wien’s displacement law?
Peak wavelength is inversely proportional to temperature
What is Stefan’s law?
The luminosity of a star is directly proportional to the fourth power of the star’s surface temperature and is directly proportional to the surface area.
What does the Hertzsprung-Russell diagram show?
The correlation between the luminosity of a star and the decreasing temperature of a star and how it relates to the star’s stage in its life cycle.
What is the cosmology principle?
- The laws of physics are universal.
On a large scale the universe is: - Homogenous (every part is the same as every other part)
- Isotropic (everything looks the same in every direction)
What is the Doppler effect?
As an object moves towards or away from you, the frequency and wavelength of the sound waves being produced by the object change.
As the object moves towards you, the wavelength decreases and the frequencies are higher which creates a higher-pitched sound.
As the object moves away form you, the wavelength increases and the frequencies are lower which creates a lower-pitched sound.
