Comment by teleforce
17 hours ago
As a side note, it's mind boggling that overwhelming majority (more than 98%) of the visible universe's mass are only from two most lightweight of chemical elements namely Hydrogen and Helium.
17 hours ago
As a side note, it's mind boggling that overwhelming majority (more than 98%) of the visible universe's mass are only from two most lightweight of chemical elements namely Hydrogen and Helium.
> it's mind boggling that overwhelming majority
is it though? I mean literally everything has to start there and the only way get to heavier elements is via stars and many-many iterations.
it's not like heavier things popped into existence.... or did they...
There is a theory that primordial black holes formed in the very early universe. I'm not sure when this process would happen relative to the formation of atoms. But, if it actually happened, it would have been long before stars started forming.
Yes, it's a little mind boggling because the typical human context is this rocky ball of what is ultimately a very uncommon distribution of heavy elements. It's a strange feeling to know that almost everything is utterly unlike the everyday human experience. If you turn down the uhm acksshuwlly a few notches I think parent post's point is quite obvious.
The uniqueness of our state is quite interesting, arguably profound. Sol exists in the so-called "Local Bubble" which is about 1/100 of the average density of the galaxy, probably caused by multiple supernova. It's possible, if not likely, that this has helped reduce impact events such that life has only reset ~6 times rather than hundreds, and probably contributed to the relative abundance of heavy elements in our solar system.
Earth's biosphere is profoundly 'lucky' on several very disparate time-scales. And then there's the size of the moon...
The average density of matter in the universe is one proton per five cubic meters or so. We're very much the outlier!
https://xkcd.com/2640/
The alt text is on point.
Feels like most resources on the map aren’t mined yet.
And earth contains so much of heavier elements.
As I learned it long ago in school, elements up to the mass of iron are formed by stellar fusion. That's the point where fusion is no longer exothermic. Any element on earth that is heavier than iron is the product of a supernova. So we live on a ball of supernova debris.
Most of what we live on, the vast majority, is iron or lighter. So it's more that we're sprinkled with supernova debris. But we are made out of stardust, so that's something.
1 reply →
> elements up to the mass of iron are formed by stellar fusion
And elements down to the mass of iron can also be formed. But iron is at the bottom of the well.
1 reply →