Obviously this is real subjective as to what constitutes a "wow" moment. As an example, I think that when superconductivity was shown to happen at liquid nitrogen level in new materials was a wow moment. If someone got it up to room temperature, that would another one.

In space, I think we are guaranteed within a few years to have a wow moment of finding an earth sized terrestial planet in the sweet spot habitable zone of a star. The slow approach to this inevitable event is removing some of the wow aspect from it I think. I think it is quite a ways off before we could find life off planet in the solar system (if it exists). But that would be a wow moment. Maybe it will happen in the next 20 years.

I don't think we'll have a cold fusion wow moment; I just don't think the physics is there, at least not for the forseeable future. Hot fusion always seems like it is 50 years off (for the last 50 years), and I don't see hope of any quick breakthroughs there. But if someone was to figure out how to make cheap practical fusion energy, that would be a major WOW moment.

I think the cumulative effect of stuff like improvements in batteries with nano materials, would be a wow moment if you compressed 10 years of incremental improvements into one breakthrough. Seems, like most technology is like that these days. The improvements in computers over 40 years is WOW, but any given years, it just incrementally marches on.

Maybe a wow moment wll be when someone puts together a bunch of enabled technologies in such a useful fashion that we will recognize the way we do things will be changed forever (e.g. a cheap, automated ground car, or a cheap automated flying car).

If someone suddenly made a materials breakthrough that made it obvious that a space elevator could be practically built, that would be a wow moment for me.

A sort of scary wow moment that I expect within 20 years, is when AI starts to get so good, we humans can't help but realize if we don't augment our own minds we are surpassed.

Anybody want to add their 2 cents?