In my lifetime, space exploration has gone from Sputnik to multiple launches each week.

[Warpy]

1. Plus remotely exploring planets and moons in our own system

so that we know what it would look like to stand on them and look around. In addition, we're finding planets in other star systems and are able to find out what their atmospheric chemistry is like. And the Hubble gave us a clue about just how immense the observable universe is how many more galaxies there are, each with billions of stars that most likely have planets and moons.

We've also discovered organic chemistry wherever we look, although exoplanets wold be highly unlikely to produce the kind of life we'd recognize as such and none that would be compatible with ours. IOW, if you want to explore other worlds, pack a lunch.

When I was a kid, we knew about the Magellanic Clouds and Andromeda, but we couldn't tell the difference between clouds of dust and gas and other galaxies. Now we can. That is mind blowing, the universe having gotten so much bigger and we can't see beyond the point the CBR gets so dense it forms a barrier to the instruments we have now. We've gotten smaller but bigger at the same time, big enough to be a part of this immense universe looking at itself.

Even if that was all that happened in my lifetime, it would be astonishing. So ,much has changed, it would take a wall o text to list it.