Question: what is you're favourite invention

Janis Aleksans answered on 11 Nov 2019:

Lasers! Lasers are quite amazing!
But if seriously, maybe not so much of an invention as of a discovery, not so long ago scientists in Antarctica extracted a very long ice core from a glacier. Ice in Antarctica hasn’t melted for a very long time and every winter, when it snows there, a new layer of ice is made. Similar to how a new ring on a tree forms every year. This has been happening for almost half a million years now. The reason why it is so amazing is that, when ice forms, it traps within it tiny bubbles of air. Meaning we now can look and study perfectly preserved air from almost half a million years ago, long before human civilization even existed. The chemical composition of air actually tells us of the past temperatures and it is the reason how we know that the Earth now is warming up very fast, like nothing we have seen before, and why we can say that concern for global warming is real.