astrophysics test 3

100,000 LY

100-400 billlion stars

greeks galaxies kuklos (milky circle)
then romans named: via lactea (milky way)

henrietta leavitt 1912
vary in luminosity/time

open star clusters- location within milky way
globular clusters- up to 1 million stars in tight sphere- oldest original of our MW Galaxy

disk component- all matter is confined to galaxy rotation, flattened, spiral arms 2 barred, and 3-5 arms
spherical component- matter confined to a sphere, nuclear buldge densest, 13,040 LY in diameter

Study the proper motion of stars
Vmw= 220 km/sec

13.21 Billion years

stars within disk-> spiral arms
rich in metals
circular orbits
younger, hotter, bluer

stars in nuclear buldge, halo
globular clusters
lean in metals- H, He

one spiral arm overtakes another
-gas, dust , density increases
unstable gas and dust create pillars

1. spherical cloud gas, gravity pulls in cloud denser towards the center less dense out
2. gravity starts rotation
3. giant, supergiant stars are formed + globular clusters. Remain in nuclear buldge; remain in outer halo globular clusters
4. Giants + Supergiants-> supernovae
5. Gas + dust collect in disk, rich in metal
6. New hotter, bluer stars form in disk

study of structure + evolution of the universe

Universe was created in one moment of time
further look back time, infinitely darker

big bang
-one moment in time where all baryonic matter was formed 10^-43 second
-point of singularity

13.8 BY

Temp 0k
desnity 5*10^13 g km^3

Isotropy- being uniformed in all directions
homogeneity- same in all locations
cosmological principle- universe is Isotropic+Homogenous

galaxies are slow in velocity- virtually no redshift
all galaxies have redshifts
Space is expanding
-galaxies are along for the ride
-all galaxies move away from each other

1. finite- closed
-curves back onto itself
-“sphere” 2-D surface- expanding
2. infinite open universe
-“flat”- no curvature- no edge
3. Infinite- open universe
-negative curvature
-“saddle shaped”

-Critical density= 9*10^-30 g/cm^3
-Universe>critical density-> spherical sharp positively curved
-universe=critical density-> space time is flat
-universenegatively curved

4% baryonic
95% non baryonic

Strong force- atomic bonding
weak force- radioactive decay
electro-magnetic force
gravitational force- gravity

flat model universe
-big rip

hypothetical set of finite and infinite universes including our universe

parallel universe
dimensional planes
alternative universe
other universes

2010- study of background, microwave radiation
-gravitational wave anomalies
suggest a collision with another universe

Level 1- hubble volume, chaotic inflation, infinite
Level 2- different physical constraints variant of level chaotic, inflation stretch forever, large bubbles
Level 3- Many- worlds of quantum mechanics, variant of level 1, no prediction of events
Level 4- ultimate ensemble, all universes are equally real, all described by different mathematical models

1. quilted- infinite number of space
2. inflationary- “bubble universe” various pockets collapse
3. Brane Membrane – Gravity extends through them
4. Cyclic- multiple membranes
5. landscape- string theory, energy strings
6. quantum- many worlds- level 3, different quantum
7. holographic multiverse- simulated universe
8. simulation- computer modeling
9. ultimate ensemble- every mathematical possibility

Black hole, galactic center, singularity, white hole opposite another galaxy+ universe