1. Universal Future
Name all four components of the Universe that lead to the name The Degenerate Era.
2. What are two energy sources during the Degenerate Era?
3. What causes the Milky Way’s demise in the Degenerate Era?
4. What is the primary energy source in the Black Hole Era?
5. Name three of the four waste products left in the Dark Era.
B. How long do the stars last (the end of the Stelliferous Era)?
White dwarfs dominate Degenerate Era.

2. ………………………………

3. Universal Future
Name all four components of the Universe that lead to the name The Degenerate Era.
brown dwarfs, white dwarfs, neutron stars, black holes
2. What are two energy sources during the Degenerate Era?
dark matter annihilation in white dwarfs
proton decay in white dwarfs
nuclear fusion in red dwarfs made in brown dwarf mergers
3. What causes the Milky Way’s demise in the Degenerate Era?
encounters and collisions between objects … evaporation
4. What is the primary energy source in the Black Hole Era?
Hawking radiation
5. Name three of the four waste products left in the Dark Era.
photons, neutrinos, electrons, positrons
B. How long do the stars last (the end of the Stelliferous Era)?
100 trillion years or cosmological decade 14
White dwarfs dominate Degenerate Era.

4. ………………………………

5. ?
Future Universe

6. critical density ρc = 10-29 g/cm3
Future Universe
Type depends on DENSITY of Universe
DENSITY = mass / volume
critical density ρc = g/cm3
Options closed …… bound
redshift becomes blueshift
heat death
open …… unbound
redshift forever
freeze death
both mass and volume (distance) are tough to measure

7. Open or Closed?

8. Future Universe Options closed …… bound redshift becomes blueshift
heat death
open …… unbound
redshift forever
freeze death
critical …… borderline
reshift forever

9. Future Universe But … what about dark matter? what about dark energy?
gravity is only force that matters on large scales?
Test something bright very, very far away …
Type I supernovae (white dwarfs going BOOM!)
measure distance … compare redshift
distance from standard candle and brightness … time ago
redshift measures total expansion since that time
>>> map of redshift vs time
>>> Hubble’s Law not constant
expect Universe is decelerating due to gravity
expansion would be SLOWER now
galaxies receding FASTER now

10. Accelerating Universe!
expansion FASTER now
WHAT ?!?!?
dark energy
opposes gravity
largest scales only
Observations of distant supernovae allow astronomers to measure changes in the rate of expansion of the universe. In a decelerating universe (purple and red curves), redshifts of distant objects are greater than would be predicted from Hubble's law (black curve). The reverse is true for an accelerating universe. The points showing observations of some 50 supernovae strongly suggest that the cosmic expansion is accelerating. The vertical scale shows redshift; for small velocities, redshift is just velocity divided by the speed of light. (More Precisely 24-1)
(b) The bottom frames show three supernovae (marked by arrows) that exploded in distant galaxies when the Universe was nearly half its current age. The top frames are wider views of areas around these supernovae, which were originally discovered in 1997 during a ground-based survey with the Canada-France-Hawaii Telescope on Mauna Kea. (P. Garnavich/Harvard-Smithsonian Center for Astrophysics/NASA)

11. ?
Future Universe

12. Accelerating Universe?
Accelerating Universe
closed flat open accelerating
An accelerating universe can be closed, flat, or open depending on the strength of gravity relative to the repulsive force (and when you’re looking???).
gravity +
dark
energy
gravity only

13. Future Universe Options closed …… bound redshift becomes blueshift
heat death
open …… unbound
redshift forever
freeze death
critical …… borderline
reshift forever
accelerating …… unbound
redshift forever, and changing

14. Are Type I Candles Standard?
But wait … Type I supernovae (SN)
are SN the same at all times?
SN appear to look bluer
helium fraction or metallicities change
at large z, only massive WDs have time to accrete mass to SN
“standard” candles are not perfectly standard … WD composition
is the redshifted spectrum of the SN leading to data analysis issues?
could observational errors be the problem?
SN peak brightnesses at z = 0.5 differ from coasting Universe by
only 0.14 ± 0.06 to 0.06 ± 0.04 magnitudes
must get good sampling to nail peak
must correct for underlying galaxy emission
must account for interstellar medium/reddening/dust issues
must consider gravitational lensing of SN

15. Cosmic Conclusions BIG FREEZE AHEAD Conclusions 1. Big Bang origin
2. Universe’s age is 13.7 ± 0.2 Byr
3. CMB restricts matter/radiation densities, Universe’s age
4. inflation, when/how much large scale structure
5. 4% normal matter + 23% dark matter = 27% critical
6. dark energy exists, brings density up to CRITICAL
BIG FREEZE AHEAD

16. Five Universal Eras Five Eras like geology
(8 Epochs absorbed into first two Eras)
PRIMORDIAL
STELLIFEROUS
DEGENERATE
BLACK HOLE
DARK … (and depressing)

17. Past and Now 1. PRIMORDIAL 10-50 to 105 years ENERGY …… Big Bang
radiation dominated  microwave background
matter over antimatter
H, D, He, Li
STARS START TO FORM AT 105 YEARS
2. STELLIFEROUS 106 to 1014 years (now = 1010)
ENERGY …… nuclear burning in stars
superclusters, clusters, galaxies, stars form
quasars, AGN at early times
red dwarfs last trillions of years
NO MORE GAS TO MAKE STARS AT 1014 YEARS

18. The Future is Grim 3. DEGENERATE ERA 1015 to 1039 years
normal mass in BDs, WDs, neutron stars, black holes
galaxies modify structure … heavy to center
ENERGY …… neutron  proton + electron + neutrino
proton  positron + pion
pion  photon + neutrino
electron + positron  photon + neutrino
ENERGY? …… dark matter into WDs (primarily)
white dwarfs … 400 watts (black dwarfs)
Milky Way as bright as 1 Sun
NO MORE PROTON DECAY AT 1039 YEARS
BD crash = new stars … WD crash = supernova

19. And It Gets Worse … 4. BLACK HOLE ERA 1040 to 10100 years
only black holes remain (no proton decay)
sweep up material and grow
ENERGY …… black holes evaporate
Hawking radiation
pair production at event horizon
BH with 1 Msun … 1065 years
BH with 1 Milky Way … 1098 years
NO MORE HAWKING RADIATION AT YEARS

20. The Bitter End … THERMODYNAMICS WINS OVER GRAVITY
5. DARK ERA > years
electron + positron  positronium (real!)
ENERGY …… when they annihilate each other
 neutrinos + photons
THERMODYNAMICS WINS OVER GRAVITY

21. Fade to Black …

22. End of Life on Earth
Sun will last 6 Byr more … twice as bright as today
red giant … HB star … AGB star … white dwarf … black dwarf
winds during red giant phase … 25% mass loss
Earth spirals out
Earth heating makes oceans hold less CO2 and H2O
CO2 in atmosphere causes runaway greenhouse effect
oceans evaporate in 2 Byr
no H2O … no life
Escape? 1/100,000 odds Earth booted by passing red dwarf
crosses (former) Pluto orbit in a few years
continents ice over … then oceans freeze from top down
at 77 K, N2 freezes out and rains onto ice oceans … O2 soon after
life survives along hydrothermal vents powered by radioactive decay

23. Solution?
LEAVE
EARTH

24. ………………………………

25. Cosmic Structure
The most obvious features on the high-resolution map of the microwave background shown in Figure occur on a scale of about 1°--the approximate size of the "blobs" in the inset to that figure. The graph shown here quantifies this impression by plotting the correlation (vertical axis) between different points on the map separated by a given angle (horizontal axis). In effect, the height of the graph measures the "amount" of structure seen on different angular scales. The blue curve is a theoretical prediction for a flat (Ω0 = 1) universe with the cosmological parameters quoted in the text. The excellent agreement between theory and observations is regarded by most cosmologists as strong evidence that we live in a flat, critical-density universe.