Year 11 Cosmic Engine Terms

Star ACCRETED gas GRAVITY force leads to high pressure E = mc2 H is fusing to heavier element Has a core with fusion, shell coating

Galaxy A system of stars Milky Way has 200 billion stars (Usually with giant black hole in center) (Bulge and disk) (Halo of globular clusters)

Gravity Force between any and every two masses

Inflation Short time after big bang (seconds to minutes) Universe expanded in an instant to zero to 10 cm to a fraction current size Hydrogen fusion stopped Explains why universe is so uniform

Luminosity Unit of power L sun = 1 L =3.8e26 W

Distance Separation of two points in m

Brightness How much light is entering telescope, measuring instrument Relative brightness – detector signal of actual star seen from earth Absolute Brightness (related to flux) amount detected if the star you are measuring was move to 32 ly from earth. (strictly speaking “brightness” is a popular term not scientific)

Flux Means flow through an area (m2) For light W m -2 ((also used in HSC for magnetic field and particles))

(magnitude) The magnitude of an object is a ratio number indicating relative brightness of a object compared to a standard (Iobject/Istandard) “ m “ is the symbol for relative magnitude of light reaching earth before the atmosphere “ M “ is the symbol for the absolute magnitude for all objects moved the same distance from earth 32 lyears ((No units, and lower “m” means brighter stars!))

Einstein E= mc2 Advance on Newton, matter curves space Assumed space is static not growing

Hubble Measured apparent brightness, knew absolute brightness to find distance Measured speed from Doppler shift in Galaxy spectra Redshift increases with distance means expansion

Friedmann Russian Theorist Show Einstein’s space was either Contracting Static Or expanding

(Eddington) Pointed out problem with Mercury orbit to Einstein Einstein created “General Relativity” to solve problem & predicted bending starlight Eddington saw stars behind sun in a solar eclipse proving Einstein right

Lifecycle Nebulae - gas Protostar – accretion Main sequence – 4H – He burning Heat puffs up star ((( magnetic bottle of star shrinks surface of star))) Red Giant H fuel gone, pressure increases He burns to carbon ((( field weak so star expands))) (Nova) Star detonates as pressure wave explodes atmosphere, implodes core White dwarf – super dense dead core cools over billions of years