Category: Astronomy • Solar System • big bang
"It is all a matter of time scale. An event that would be unthinkable in a hundred years may be inevitable in a hundred million." -Carl Sagan
There's some speculation that NASA, later this week, might announce evidence for life on Saturn's moon Titan.
I'm not going to comment on the speculation, but it's worth asking the question,scientifically, "How would the Universe make life, from scratch?"
Let's start by telling you what "scratch" means. If you're familiar with the story of the Universe, one of the things you know is that things were very hot and dense in the past. So hot that you couldn't have neutral atoms, or even protons and neutrons bound to one another.
But the Universe cooled quickly, and by time it was a mere 4 minutes old, it's too cool to keep fusing elements together; all you've got at this point is a Universe that's (by number) 92% Hydrogen, 8% Helium, and less than 0.0000001% anything else. Sure, your Universe will expand and cool, but it isn't for millions of years (and more likely, tens of millions of years) that you start to change what the Universe is made out of.
Because it takes that long for gravity to pull this primitive gas into dense enough region that we can -- for the first time in the Universe -- form stars!
And these stars, like all bright stars, get their energy by fusing these light elements into heavier ones. If we could look inside the most massive of these stars, know what we would find?