Salient Features of the Universe
-
Upload
trevor-camacho -
Category
Documents
-
view
32 -
download
1
description
Transcript of Salient Features of the Universe
![Page 1: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/1.jpg)
Salient Features of the Universe• Homogeneity and isotropy for 6000 Mpc > x > 100 Mpc
• Universe expanding uniformly
• ordinary matter is more abundant than ordinary antimatter
• chemical composition is roughly 75% H, 25% He, + trace
• thermal background of radiation with T~3K
• nearly scale invariant, adiabatic CMB fluctuations
• hierarchy of lumpy structure from 1 kpc to 100 Mpc scales
• matter is a minority (1/4x) of all energy
• ordinary matter is a minority (1/6x) of all matter
• universe is spatially flat
• expansion rate is accelerating
![Page 2: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/2.jpg)
![Page 3: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/3.jpg)
Best evidence: we exist !
![Page 4: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/4.jpg)
![Page 5: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/5.jpg)
![Page 6: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/6.jpg)
0)(
v
t
0)( 1
pt
vvv
G42
130
a
1vrv
a
a
13
4
rG
![Page 7: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/7.jpg)
0)(
v
t
0)( 1
pt
vvv
G42
130
a
1vrv
a
a
13
4
rG
ksclustkk kcHH )(2 22232
![Page 8: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/8.jpg)
atk ~~ 3/2
ta
aH
3
2~
Case II: If clustered matter does not dominate:
6.0~~ clustk wherea
kclustkk HH 2322
Case I: Flat, matter dominated Universe 1clust
![Page 9: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/9.jpg)
a ~ 1/1000
a ~ 1/5
~ a(t) grows by only 200
![Page 10: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/10.jpg)
![Page 11: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/11.jpg)
![Page 12: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/12.jpg)
Salient Features of the Universe• Homogeneity and isotropy for 6000 Mpc > x > 100 Mpc
• Universe expanding uniformly
• ordinary matter is more abundant than ordinary antimatter
• chemical composition is roughly 75% H, 25% He, + trace
• thermal background of radiation with T~3K
• nearly scale invariant, adiabatic CMB fluctuations
• hierarchy of lumpy structure from 1 kpc to 100 Mpc scales
• matter is a minority (1/4x) of all energy
• ordinary matter is a minority (1/6x) of all matter
• universe is spatially flat
• expansion rate is accelerating
![Page 13: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/13.jpg)
Best evidence: we exist !
![Page 14: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/14.jpg)
Ma
ss d
ensi
ty/c
ritic
al d
ensi
ty
Hubble constant (x 100 km/s/Mpc)
J. Ostriker & PJS, Nature (1995):
Compelling evidence for Low Matter Density
![Page 15: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/15.jpg)
J. Ostriker & PJS, Nature (1995):
Compelling evidence for Low Matter Density
Fluctuations in the Cosmic Microwave BackgroundAnisotropy
Compelling case for a Flat Universe
![Page 16: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/16.jpg)
J. Ostriker & PJS, Nature (1995):
Compelling evidence for Low Matter Density
Compelling case for a Flat Universe
Only possible if there is Dark Energy
![Page 17: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/17.jpg)
J. Ostriker & PJS, Nature (1995):
Compelling evidence for Low Matter Density
Compelling case for a Flat Universe
Only possible if there is Dark Energy
… but, then, the dark energy better havenegative pressure
![Page 18: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/18.jpg)
Positive pressure
time
ener
gy d
ensi
ty
![Page 19: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/19.jpg)
Negative pressure
Matter dominates
time
ener
gy d
ensi
ty
![Page 20: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/20.jpg)
J. Ostriker & PJS, Nature (1995):
Compelling evidence for Low Matter Density
Compelling case for a Flat Universe
Only possible if there is Dark Energy
… but, then, the dark energy better havenegative pressure
… but, then, the universe must be accelerating
![Page 21: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/21.jpg)
![Page 22: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/22.jpg)
Type IA Supernovae
![Page 23: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/23.jpg)
CosmologicalConstant
orQuintessence?
![Page 24: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/24.jpg)
V
V
V
V
p
p
pT
221
221
221
221
V
Vpw
221
221
w < -1/3 means KE < V/2
scalar fields
![Page 25: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/25.jpg)
atk ~~ 3/2
ta
aH
3
2~
Case II: If clustered matter does not dominate:
6.0~~ clustk wherea
kclustkk HH 2322
Case I: Flat, matter dominated Universe 1clust
![Page 26: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/26.jpg)
Steady expansion
![Page 27: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/27.jpg)
Observed Features of the Universe• Universe is homogeneous and isotropic on lengths > 100 Mpc
• Universe expanding uniformly
• ordinary matter is more abundant than ordinary antimatter
• chemical composition is roughly 75% H, 25% He, + trace
• thermal background of radiation with T~3K
• nearly scale invariant spectrum of CMB fluctuations
• hierarchy of structure from 1 kpc to 1 Mpc scales
• matter is a minority (1/4x) of all energy
• ordinary matter is a minority (1/6x) of all matter
• universe is spatially flat
• expansion rate accelerating
![Page 28: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/28.jpg)
Observed Features of the Universe• Universe is homogeneous and isotropic on lengths > 100 Mpc
• Universe expanding uniformly
• ordinary matter is more abundant than ordinary antimatter
• chemical composition is roughly 75% H, 25% He, + trace
• thermal background of radiation with T~3K
• nearly scale invariant spectrum of CMB fluctuations
• hierarchy of structure from 1 kpc to 1 Mpc scales
• matter is a minority (1/4x) of all energy
• ordinary matter is a minority (1/6x) of all matter
• universe is spatially flat
• expansion rate accelerating
![Page 29: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/29.jpg)
Observed Features of the Universe• Universe is homogeneous and isotropic on lengths > 100 Mpc
• Universe expanding uniformly
• ordinary matter is more abundant than ordinary antimatter
• chemical composition is roughly 75% H, 25% He, + trace
• thermal background of radiation with T~3K
• nearly scale invariant spectrum of CMB fluctuations
• hierarchy of structure from 1 kpc to 1 Mpc scales
• matter is a minority (1/4x) of all energy
• ordinary matter is a minority (1/6x) of all matter
• universe is spatially flat
• expansion rate accelerating
![Page 30: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/30.jpg)
Observed Features of the Universe• Universe is homogeneous and isotropic on lengths > 100 Mpc
• Universe expanding uniformly
• ordinary matter is more abundant than ordinary antimatter
• chemical composition is roughly 75% H, 25% He, + trace
• thermal background of radiation with T~3K
• nearly scale invariant spectrum of CMB fluctuations
• hierarchy of structure from 1 kpc to 1 Mpc scales
• matter is a minority (1/4x) of all energy
• ordinary matter is a minority (1/6x) of all matter
• universe is spatially flat
• expansion rate accelerating
![Page 31: Salient Features of the Universe](https://reader030.fdocuments.us/reader030/viewer/2022032414/5681338f550346895d9a99fc/html5/thumbnails/31.jpg)
Looking for some problems?
• What is the nature of dark matter?
• What is the nature of dark energy?
• What is origin of supermassive black holes?
• What role does dark energy and cosmic acceleration play?
• Why is the cosmological constant so small?
• What is the origin of matter-antimatter asymmetry?
• Is the inflationary theory correct? (or the cyclic?)
• What is the inflaton or cyclic field responsible?
• How far does space extend?
• Is the Big Bang a beginning of space and time?
• Why are there three large spatial dimensions?