5.5 - Newtonian World - Astrophysics and Cosmology Flashcards
Define a planet
Objects with mass sufficient for their own gravity, Spherical shape, cleared its orbit
Define a dwarf planet
Orbit has not been cleared
Define an asteroid
Small and uneven objects with a near circular orbit around the sun
Define a comet
Irregularly sized balls of rock, dust and ice. Orbit in elliptical shape
Define a solar system
System containing stars and orbiting objects like planets
Define a galaxy
A collection of stars, dust and gas with each containing about 100 billion stars
Define a nebulae
Gigantic clouds of dust and gas. Birthplace of stars
What is the order for medium mass stars
Nebula
Main sequence star
Red giant
Planetary nebula
White dwarf
What is the order for high mass stars
Nebula
Main sequence star
Red supergiant
Supernova
Neutron star (high mass) / Black hole (very high mass)
Are all energy level values negative
Yes
(ground state is most negative)
What is Wein’s displacement law
λmaxT = 2.9x10^-3 mK
What is a light year
The distance travelled by light in a vacuum in one year
What is the doppler effect
The change in wavelength and frequency of a wave as the source moves away from or towards the observer
What is stellar parallax
The shift in position of an object against a backdrop of distant objects due to the orbit of earth
What is a parsec
The distance from which 1 AU subtends an angle of 1 arcsecond
What is the cosmological principle
The universe is isotropic and homogenous and the laws are universal
Isotropic means that the universe is the same in all directions to every observer, no centre of edge
Homogenous means uniformly distributed
What is Hubble’s law
Velocity of receding objects is directly proportional to their distance from earth
v = Hod
