I learned some new things

The meteor that hit the Earth 65 million years ago and led to the extinction of the dinosaurs left what is known as the Chicxulub crater off the coast of the Yucatan peninsula in Mexico. The crater was formed by a 10-14 kilometer wide meteor impact, and set off an ice age that ruined the dinosaurs, allowing mammals to gradually take over in dominance. I remember hearing about this extinction from my teacher when I was in the second grade and we were studying the dinosaurs.

What I don't remember ever hearing about, is a greater, more complete, extinction that took place much further back in Earth's past.

Apparently, about 250 million years ago, there was an extinction event that killed off almost all life on land and life in water in a very short period of time. Various causes have been suggested, including prolific volcanic activity and a large impact from space.

Very recently, what appears to be an enormous crater has been found in Antarctica. It is about 500 kilometers wide, and would have been caused by the impact of a meteor about 50 kilometers wide. That is a rock five times the size of the one that killed the dinosaurs.
After that enormous smash and die-out, dinosaurs gradually became dominant over the next 185 million years, until they were killed off by the lesser impact, 65 million years ago.
Primates got their chance, and started thriving 60 million years ago, but didn't start walking upright until about 6 million years ago. That was a big leap, as it left our hands free to do things other than move around; things became much more complicated. Homo Sapiens have been around for less than 250,000 years.

The Earth is estimated to be about 4.7 billion years old. Life began over 3.9 billion years ago, according the oldest fossil records, but it was single cellular. Multi cellular life didn't begin until about 1.5 billion years ago.

In about 5 billion years, our sun will have used up all of it's hydrogen and have inflated into a red giant, swallowing the inner planets, including the earth, but we've got less time than that for life as we know it. The sun is gradually heating up as it burns off it's hydrogen, and in about 1 billion years, things will be too hot for water to exist in a liquid state on this planet; bad news for us.

So.

Our kind of life form has been around for 1.5 billion years, and only has another 1 billion years to go. We're over the hump. This is Thursday in the week of perfect evolutionary conditions on this planet. It doesn't get any better than this! We're, "it", as far as this planet is concerned. I suddenly feel much more important.
I need to go to sleep now.
For all I know, tomorrow could be a very big day.