I'm not sure I can. Every physical analogy is going to be expanding into a medium.

It's also not really "expanding into nothing." The coordinate plane of space is itself expanding, full stop. It's not expanding into anything (or nothing).

It's a fact that you just have to decide you're ok with, without a relatable model to compare it with.

Every model has limits. The point of the balloon model here is to explain how a cosmologic event horizon can occur.

I agree with you that it's limited as a way to visualize the general idea of the expansion of the universe, since it requires the same essential leap as not using a model (i.e. that the universe isn't expanding into/through anything).

I think my comment may not have been clear enough. There was only 1 big bang. There isn't another universe expanding towards us. This is all talking about one universe.

Imagine that the universe is represented by the skin of a balloon (just the 2d skin, not the internal volume). Cover the balloon with dots and pick one to call Earth. As you blow the balloon up, all of the dots will get farther from the earth dot, but the change in distance will be smaller for the near dots than the already far dots. Now imagine there's a speed limit for moving between the dots. If the rate at which the distance to the far dots is increasing is faster than that speed limit, you can never get from the far dots to the Earth dot.

>However, it is possible that there are areas of the universe where light has not yet reached us, and we cannot observe them yet.

Depending on the cosmological model you subscribe to, there are instead areas of the universe whose light will never reach us (assuming expansion continues), and we will never be able to observe. And areas where light from the past was able to reach us, but light emitted now will never be able to reach us.

For objects beyond a certain distance, the expansion rate of the universe is such that the distance between us and the object increases at a rate greater than the speed of light, meaning that photons emitted by that object will not reach us in finite time. (This does not mean anything is moving faster than the speed of light, to be clear.)

Veneers have been used in fine furniture for centuries, and that's aside from the art of marquetry.

For example, burls look pretty, but don't make a great structural choice.

CO2 detectors (sold as indoor air quality meters) are becoming more of a thing as companies have figured out that baselessly scaring informing people about their indoor air "quality" is profitable.

CO2 Alarms are definitely not a common thing in residential buildings. I agree with you that OP almost certainly has a Carbon Monoxide alarm going off.

Command strips leave a residue which can interfere with the adhesion of the next layer of paint.

My last apartment specifically forbade them, and recommended using nails instead.