I’d heard people mention in passing that the universe is expanding, and that the rate of expansion is increasing, but I’d never understood what that really meant (or how we know this to be true).
That’s why I really enjoyed the quick example with California, and how that shows that distances to further-away objects increasing more means the universe is expanding uniformly. It would’ve normally been something that I would’ve glossed over a bit, thinking “yeah I guess that makes sense,” without actually understanding it. But the California example really drove it home.
In general, a lot of the things we’ve covered so far (like “Why is the moon red near the horizon?” or “Why do people think dark matter exists?”) are things that I’ve heard people talk about before, but I didn’t actually understand them. I really enjoy filling knowledge gaps like that, so I’ve appreciated this class.