Topic #1 Flashcards
What did Aristotle believe?
(2 points)
- Geocentric Universe
- Movement of planets and stars were perfect and circular
What is gravity?
The tendancy of earth and water to sink
What is levity?
The tendancy of air and fire to rise
What is geocentric?
Copernican system
Everything in the solar system revoleved around the earth
What did Copernicus believe?
(2 points)
- Heliocentric model
- Earth roated on an axis
What did Galileo do?
(3 points)
- Built a telescope to look at the moon
- Challenegd the belief that the celestial bodies were perfect spheres
- Confirmed the Copernican model
What is heliocentric?
Ptolemaic system
Everything in the solar system revolved around the sun
What did Johannes Kepler believe?
He believed in eliptical orbits
explained strange apparent movements of the planets
What is a planet?
An astronomical body that is big enough to be rounded by its own gravity
What is a super cluster?
A collection of more than a million galaxies
What is Hubble’s law?
Hubble’s Law states that the rate at which galaxies move apart from each other is proportional to their
distance from each other.
In other words – the greater the
distance between any two
galaxies, the faster they are moving apart
What is the steady state theory?
The Universe has always existed and always will –
that the Universe has no beginning and no end
What evidence shows the big bang theory happened?
(4 points)
- Red shift/movement of celestial bodies
- Cosmic microwave background radiation
- Proportion of elements in the Universe (H, He)
- Expansion of the Universe
What is the doppler effect?
Objects moving away from Earth have their absorption lines shifted towards the red end of the spectrum.
What is redshift?
- As the galaxies move away from Earth, the wavelength of that light that it
emits get longer (stretched out). - Longer wavelengths of visible light are red
- Shorter wavelengths of visible light are blue