Unit 07 · Cosmology & the Big Bang
This unit asks the biggest question there is: where did all of it come from? It starts with Hubble's law — every distant galaxy racing away, faster the farther it lies — and the correction it forces: the Big Bang was not an explosion in space but the expansion of space itself, with no center and no edge. From there it builds the case with the cosmic microwave background, the cooled afterglow that evidences a hot, dense beginning, uses the expansion rate to estimate the universe's age, and confronts dark energy and the possible fates it implies. Mastery means you can replace the “cosmic bomb” cartoon with the honest, evidence-backed picture of an expanding universe.
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Hubble's law & expanding space | Thinks galaxies fly through a fixed, static space. | Says the universe expands but not that space itself stretches. | States Hubble's law and explains that space itself expands, carrying galaxies apart. |
| Correcting the “explosion” picture | Pictures the Big Bang as a bomb going off at one point. | Senses the picture is wrong but cannot say why. | Corrects the misconception — the Big Bang was the expansion of space everywhere, not an explosion into pre-existing space. |
| The cosmic microwave background | Knows no evidence for the Big Bang. | Names the CMB but not what it shows. | Explains the cosmic microwave background as the cooled afterglow that evidences a hot, dense early universe. |
| Age of the universe & its fate | Has no sense of the universe's age. | Gives a number but cannot say how it is found. | Estimates the age from the expansion rate and describes dark energy and the possible fates it implies. |
| Modeling cosmic expansion | Cannot demonstrate expansion or insists there is a center. | Inflates a balloon model but calls its starting point the center. | Uses a balloon or raisin-bread model to show every point receding from every other — no center, no edge. |
| Integration (cross-domain) | Treats the science as isolated facts; makes no cross-domain connection. | Names a link to history, reading, or writing but cannot defend why it matters. | Connects the unit to its anchor across History · Reading · Writing (plus chosen electives) and defends why the connection matters. |
“Every galaxy is rushing away, and the farther one lies the faster it goes — Hubble’s law. But nothing is flying through space from a blast site; space itself is stretching, so there’s no center and no edge. The cosmic microwave background is the cooled glow of that hot, dense start, and running the expansion backward gives the universe’s age.”
“The Big Bang was a huge explosion that shot everything out from one spot. The universe is really old. I’ve heard of background radiation but not what it means.”
You demonstrate this unit by modeling cosmic expansion by hand and reasoning from the cosmic microwave background aloud — not a multiple-choice test. A criterion counts as mastered only when you can correct the “explosion in space” picture and defend the evidence for an expanding universe. Mastery is demonstrated, not awarded.
A 5-page clipboard packet — unit overview, key terms, the mastery rubric, anchor examples, and a score sheet you can print and grade against.