Not really, even intergalactic expanses have some matter in them, just not a lot.
Yes, really. Even one atom per cubic inch would be 99.9999999% empty, and intergalactic expanses are a lot emptier than that. InterPLANETARY expanses are a lot emptier than that.
But this fact isn't amazing or have any meaning really, since the matter is all going to clump together due to gravity leaving spaces between the clumps.
Well, no, it's still amazing, since the matter didn't all clump together in one big clump, or a few big clumps that were nothing but black holes, or a few more slightly smaller clumps that were just humongous stars that subsequently became black holes when they burned out and collapsed, etc. It's amazing that the clumping formed galaxies composed of stars of varying sizes about which rotated planets of various sizes and compositions at various distances. It's amazing that stars could digest the hydrogen and helium which composed the early universe, and then puke it out to become OTHER stars and planet systems instead of just burning out and going cold. It's amazing that a cloud of hydrogen and helium of sufficient size could collapse under its own gravity to the point where it became a floating nuclear furnace in the first place.
Less than 75% of it is hydrogen.. it was ~75% in the early universe (and 25% helium), and stars convert hydrogen and helium into heavier elements.
I stand corrected. 99% of the universe TODAY still consists of nothing but hydrogen and helium, so I consider myself extremely fortunate to be living on this tiny oasis of elements OTHER than hydrogen and helium. Especially since, as far as we know, hydrogen and helium are not capable of the kinds of chemistry required to kick-start (or even sustain) life.
Why? There are atoms and those atoms combine into molecules according to a set of rules. I don't see how the word amazing applies.
The fact that such rules exist is amazing to me. The fact that atoms exist is amazing to me. You're free to adopt a ho-hum attitude toward it all, but don't pretend you know why it happened.
The fact that hydrogen atoms formed is amazing, and you don't understand why that happened.
The fact that hydrogen can transform itself into oxygen using nothing but gravity and more hydrogen is amazing.
The fact that such oxygen, once formed, can OVERCOME that immense gravity and blast itself into interstellar space is amazing.
The fact that, once floating in the immense emptiness of interstellar space, oxygen molecules can find hydrogen molecules and talk them into a menage-a-trois is amazing.
But set all that aside, and just tell me the "set of rules" which would cause the O2 molecule to split into a pair of O atoms, and a pair of H2 molecules to split into 4 H atoms, and the six of them somehow arrange themselves into two water molecules, way out there in the near-vacuum of interstellar space.
Or, if that's not how you think it happened, explain how you think all those ice-drenched comets got to be ice-drenched comets. I think it's amazing.
No more amazing than other molecules being a solid rather than a liquid at such warm temperatures, and there are other things that expand when they freeze.. not many, but some. I still don't understand the use of the word amazing, why these things happen is well understood.
By you? Okay, explain to me why water is a liquid at 70
oF, but CO
2 (a much heavier molecule) is a gas. I find it amazing.
Life will use whatever substances that are both available and meet the needs of it, how abundant something is is only one factor in that, so one wouldn't expect life to reflect the ratio of elements of an entire planet.
You speak of "life" as though it's an agent recruiting members for its team. I agree, how abundant something is is only one factor, which is why I found noreligion's challenge to "list the abundance of elements in the universe/air/crust" to be not only wrongheaded (since what we end up with is very much different than the elements of life) but kind of pointless (since the raw elements are a necessary but far from sufficient condition for life to begin).
True, someday we'll probably know or at least have plausible scenarios. And I think inevitable is a closer description than anything else, given the size of even just the observable universe, but until we have a better idea (or better yet other examples of life), hard to say for sure. But I find it far harder to believe that it happened only once, that's like balancing on the edge of a knife.. far more like that if it happened once it happened many times which puts it in the inevitable category.
I disagree, but I could certainly be wrong. I think "happened only once" is a very plausible scenario.