17 Astronomy Flashcards
Sun
Star that produces its own light
Shape of the orbits path of the planet
Elliptical
4 planets nearest the Sun
rocky and small
4 planets furthest from the Sun
gaseous and large
Composition of Sun
Hydrogen and Helium
average orbital speed
πr² / t
Galaxy
Consist of billions of stars
Galaxy that the Sun located
Milky Way
1 light year
distance that light travel in one year
: 9.46x10^15
(3 x 10^8) x 365 x 24 x 60 x 60
Nebula
Cloud of dust and gas pulled together by gravity
Protostar
GPE converts to thermal energy
temperature rises
Stable star (Main sequence star)
Outward : force due to high temperature in centre of star
Inward : force due to gravity
Red giant
Hydrogen begins to run out
red = surface is cool
Planetary Nebula
Small + medium size star = unstable + eject its outer layer
White draft
inner part = hot and dense solid core which will eventually disappear
Red supergiant
Big stars undergo fusion and expand
As fusion fuel is running out the star contract
Supernova
Red supergiant explode
Neutron star
the exploding leaves a very dense core
Black hole
the star is big enough to form a black hole
Red shift
Light from distance galaxies have lower frequency than it should be
Hubble constant
v = H0d
: ratio of speed of recession to distance away from observer
Equation age of universe
1 / H0
Motion of the distant galaxy
Distant galaxy is moving away from Earth
Red shift
Observed light have lower frequency or higher wavelength
Cosmic microwave background radiation (CMBR)
Electromagnetic radiation which occurs every part of universe and has wavelength in range of microwave
Theory that uses red shift and CMBR as evidence
Big bang theory
