Cosmology - The End of Eternity

OPENING QUESTIONS: Let's say you were an omnipotent individual (Can you say "omnipotent?" <I knew you could>) and you were able to observe the entire Universe until the end of time from the very smallest detail to the very largest.

Describe one aspect of the very distant future as if you were watching it occur at that time or during the time period in which that event was occurring.

OBJECTIVE:  I will be able describe the various "Eras" that we *think* might occur if the "Big Freeze" or "Modified Big Freeze" model for the End of the Cosmos is accurate.

CALENDAR: Unit Test on Tuesday!

WORDS FOR TODAY:

  • Planck Time ("10-43 sec after the Big Bang")
  • Dark Matter ("Invisible matter")
  • Dark Energy ("The force accelerating the Universe outwards")
  • Red shift ("objects move apart")
  • Big Freeze ("The Universe expands forever getting colder, larger, darker and emptier")
  • Modified Big Freeze (""The Universe exists forever getting colder, larger, darker and emptier"
  • Big Rip ("The Universe accelerates so fast it shreds itself out of existence")

WORK O' THE DAY: 

Please jot down the key after-the-big-bang essential time/mileposts in reverse order (from the most current to the oldest) GO!

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Let's do a quick rescan (not a re-read though) of How Will the Universe End" -- Add to your notes anything that jumps out at you after watching YESTERDAY'S VIDEO (you can also jump through that video too!)

Let's stand up -- we'll make two sets of two circles. Each with an inner circle of students and an outer. We'll brief each other!

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Was it THIS?

If we take a moment to figure out what "η" is then this gets A WHOLE LOT more readable, really, really quick. Let's do that NOW!

[A] The Radiation Dominated Era. −∞ < η < 4. This era corresponds to the usual time period in which most of the energy density of the universe is in the form of radiation.


[B] The Stelliferous Era. 6 < η < 14. Most of the energy generated in the universe arises from nuclear processes in conventional stellar evolution.


[C] The Degenerate Era. 15 < η < 37. Most of the (baryonic) mass in the universe is locked up in degenerate stellar objects: brown dwarfs, white dwarfs, and neutron stars. Energy is generated through proton decay and particle annihilation.


[D] The Black Hole Era. 38 < η < 100. After the epoch of proton decay, the only stellar-like objects remaining are black holes of widely disparate masses, which are actively evaporating during this era.


[E] The Dark Era. η > 100. At this late time, protons have decayed and black holes have evaporated. Only the waste products from these processes remain: mostly photons of colossal wavelength, neutrinos, electrons, and positrons. The seeming poverty of this distant epoch is perhaps more due to the difficulties inherent in extrapolating far enough into the future, rather than an actual dearth of physical processes.