astronomy Flashcards
what is a universe
all that exists everywhere
what is Galileo’s discovery about the universe?
-discovered the moons of Jupiter
-proved not everything revolves around the universe
-geocentric model of the universe
what was copernicus’s discovery about the universe
proposed the heliocentric model of the universe stating that the fun, not earth is at the centre of the universe
define the term galaxy
a galazy is a collection of stars, dust, and gas held together by gravity
what is Hubble’s Law
hubbles law states that the speed of a galaxy is proportional to the galaxies distance from earth
what can a spectroscope reveal about a star
what are 3 discoveries Edwin Hubble made about the universe?
-universe is expanding in all directions
-all galaxies have taken the same amount of time to reach their current positions
-space between galaxies are expanding at different rates
explain the doppler effect
the wavelenghts of a source shortening or lenghtening as it moved towards or away from the observer
explain red shift
the lenghtening of a wavelength as moving towards to the red end of the visible spectrum
explain blue shift
shortening of the wavelenght towards the blue end of the visible spectrum
define the term “Cosmological Red Shift”
wavelenghts keep getting longer as light travels over an expanding universe
explain big bang theory
states that the universe started 13.8 billions of years ago and it started of as a tiny hot and dense volume, overtime expanded massively and cooled down
states 2 evidences to support the big bang theory
hubbles law- galaxies are moving away from each other which happened in the big bang theory
cosmic microwave background radiation- a device that detects the universe from every part of space. found out that space cooled down over time
what galaxy do we belong to
milky way
in what group does the milky way galaxy in a group of 50 belong to?
Local group
