EXPECTATIONS: Before we start this unit you should be very comfortable with he following:

Size & Scale:

Our solar system was formed about 5 billion years ago and it takes our fastest space ships more than 9 years to cover only half of it (From Earth to Pluto)

A light year is almost unimaginably large to us puny humans-- 6 trillion miles.

The Universe is 13.7 billion years old and is dozens of BILLIONS of light years across.

LEARNING GOALS -- At the conclusion of this part of the unit, I will be able to:

1. explain our 'critical' time periods after the Big Bang in appropriate scientific phrasing:

• Planck Time (10^-43 sec): When time/space began-- infinitely hot, infinitely dense, infinitely small

• Inflation (10^-37 - 10^-32 sec): The Universe abruptly expands MUCH more rapidly than in the periods before and after

• CMBR Created (380,000 years) Atomic nuclei capture electrons to form atoms. Light is free to roam!

• First Stars/Galaxies (~1 Billion years)

2. relate the idea of 'heat death' and The Big Freeze and why that is the leading current theory for the fate of the Universe

   • Open
   • Shape: Saddle (hyperbolic)
   • Expands forever, gets very dark, very cold, very empty

3. relate the idea of "The Modified Big Freeze" and why that is so similar to the Big Freeze theory for the fate of the Universe

   • Flat/disk shaped
   • perfect amount of mass to stop expansion
   • cools off, just like the Big Freeze but without expanding

4. relate the idea of "The Big Crunch" and why that is a mostly discredited theory for the fate of the Universe

• Closed
• Shape: Spherical

5. relate the idea of "The Big Rip" and why that is controversial theory for the fate of the Universe

• Acceleration: Shreds itself into nothingness

6. put into context the unimaginable time scales involved in the fate of the Universe.

Radiation Era

Star Era

Degenerate Era*

Black Hole Era*

Dark Era*

* Infinite Time

7. Comment on ideas developed in our readings "The Last Question", "How the Universe Will End" and the "End of the Universe" video

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"The Last Question" reading/reflection assignment is HERE

Once upon a proton assignment is HERE