Micro-lesson 1
Big Bang sketch
This courtyard is the clock, not a new object in the sky. Deep sky showed the islands. This one asks how long the water between the islands has been stretching.
The Big Bang is not a bomb in an empty room.
It is the start of the clock we can measure: the universe was once extremely hot and packed. Space itself has been stretching ever since. Galaxies are not flying through a fixed warehouse. The warehouse is getting bigger.
“Where did it happen?” Everywhere that is now space. There is no empty seat outside the blast.
We do not have a backyard picture of “before.” This lesson stops at the first moment we can talk about with evidence.