Don't Panic

Sections

# Surf

For the time being, mainly what we have is just Liddle, Ch. 13: Direct link.

Plus some supplements/complements.

1. Liddle, Ch. 13: Direct link.
2. Limitations and Tensions of our Current Cosmological Theories
3. Inflation and Inflation Cosmology
4. The flatness problem:
```      |Ω_tot_0-1| < 0.5 at cosmic time t_0

da/dt = da/dt * Ω_tot - k is a rewritten Friedmann equation (Li-55)

|Ω_tot - 1| = |k|/(da/dt) ∝ t**(2/3) for matter era using the EdS solution
|Ω_tot - 1| = |k|/(da/dt) ∝ t for radiation era  using the EdS solution

|Ω_tot - 1|_equality < ([10**12 s]/[4*10**(17) s])**(2/3) ≅ 2**(-4) (L-102)

and the value gets vastly smaller as you go ealier.
```
The observable universe seems fine-tuned for flatness now. Is this a problem?

Well if |Ω_tot - 1| = 0 exactly as a symmetry of nature, then no.

But if you believe in some complex/chaotic/multiverse universe from which our observable universe and its unobservable surroundings (our pocket universe in multiverse jargon) arose in which curvature is NOT fixed, then a big bang pocket universe needs a flattening process.

inflation provides this.

5. The horizon problem:
6. Wikipedia: Graphical timeline from Big Bang to Heat Death but note that the left-hand vertical scale is tricky, for greater than about > 0, it is x=100*log(log(t_year)) and so t_year=10**(10**(x/100)))
7. Wikipedia: Graphical timeline of the Big Bang: Redundant to the timeline above.
8. Wikipedia: Chronology of the universe: Redundant to timeline above.
9. Images: Cosmic inflation
1. Universe-review: Old inflation versus new inflation: Actually old inflation has been long gone.
2. Time evolution from pre-inflation to now: The observable universe grew from 10**(-60) meters!
3. Thespectrum: Inflation cartoon
10. Keywords: Baryonic matter (protons, neutrons, electrons), Big Bang, Big Bang nucleosynthesis, big bang singularity, cosmic energy eras (radiation era, matter era, dark-energy era) deuteron (D or H-2), early universe, helium (He) (He-3, He-4), IOP cosmological parameters summary: bit dated, Universe in Problems: lots of solutions.
11. IAL 30: Cosmology: Inflation and Inflation Cosmology
12. The horizon problem: this the one Steven Weinberg (1933--) thinks only inflation explains (see Weinberg 2008, p. 208: This is one hard book.)

• Caption: A cartoon of the divergence of Omega.

13. A Cosmic Controversy: The old bulls get riled up in support of inflaton.

Really about definitions: See the response: "Inflation generically leads to eternal inflation and, consequently, a multiverse to infinite diversity of outcomes."

14. Livio, M. 2013, How Can We Tell If a Multiverse Exists?: With the mario livio image. The false-vacuum background universe expands I guess, because gravity and general relativity still apply and there is is no static solution if there is an overall isotropy and homogeneity aside from pocket universes.
15. Images for eternal inflation, the multiverse, and pocket universes:
16. The atomist cosmology: eternal inflation, the early view: