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Comment by ck2 | Hacker News Reader

It's not how many that get me excited, it's the discovery of galaxies so ancient they were formed "shortly" (300-400 million years) after the cosmic dawn

https://www.colorado.edu/ness/science/cosmic-dawn

The Milky Way in comparison was 14 BILLION years later (vs half billion)

Any life with a few billion years headstart over humans might have figured out FTL travel or at least FTL communication (massless)

adding: yup, I screwed up on Milky Way age vs cosmos age, cosmos roughly 14 billion years, Milky Way first stars roughly 1 billion years after cosmos started

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Where did you get the number? Our solar system alone formed 5 billion years ago (i.e. 9 Gy after the big bang). The milky way is thought to have formed something like 1 Gy after the big bang.

Or perhaps they all cook themselves by releasing too much energy over the course of about 300 years of exponential growth...

I could imagine that climate change is a filter for all technological civilizations. (I'm convinced that all life must be based on carbon, so that's my base assumption for the sake of this comment.) Civilizations that exist before fossil fuels had the time to form won't become technological, and all technological civilizations must keep the window from the beginning of industrialization to the ability of producing sufficient clean energy small enough to keep their planet habitable. Clean energy meaning either using only solar and wind while keeping consumption low or inventing fusion quickly enough. (Not sure about fission.)

As someone who isn't too well versed on the topic, how are you so certain in your belief that all life is carbon based?

It's the only element that is able to form complex molecules (because it can form four bonds) besides silicon. Plus, it works well with wates as a solvent, which is plentiful.

With silicon there are a bunch of issues. The bonds aren't as stable, so everything would have to be extremely cold, which makes chemical reactions very slow. Also organisms would exhale sand, which is not ideal.

Carbon and water are just uniquely qualified as a basis for life.

If you say life may be possible without complex chemistry then I'd be interested in your arguments. In my experience that line of reasoning boils down to "just because we can't imagine it doesn't mean it's impossible". Maybe, but I'm unable to discuss things neither you or me can imagine.

I think that's one scenario of the Fermi paradox.

Or maybe they couldn’t because their early galaxies lacked heavy elements. Or anything FTL is simply impossible.

My current science obsession is "how much iron is in the sun?" This is an especially fun rabbit hole to explore because the theorys range from "fractional percentages" to "the sun is the stellar remnant of an exploded star and most of it is iron".

The fractional percentage camp is based off the observed spectrum. the most of it camp is based off observed material composition in the solar system.

Here is the stellar remnant theory. I found it a bit extreme, but fun to think about.

https://arxiv.org/ftp/astro-ph/papers/0410/0410569.pdf

Personally I would bet on the sun(as it is a second generation star)having a more substantial iron core than first thought, probably a quarter of the mass, too much iron, there would be no fusion, but it does not make any sense to me that as full of iron as the inner solar system is there would be negligible amounts in the center of the sun. Perhaps there is an unknown mechanism that prevents the iron from creating photons to sus out with spectrography(my guess is the thousands of kilometers of hydrogen around the core).

The Milky Way probably formed about the same era as those galaxies, we just see it 13.7Gy older because it's 13.7Gly closer.

FTL isn't massless, massless means exactly the speed of light. Imaginary mass (as in multiples of the square root of minus one) would be FTL if such things exist.

I don’t think I’m a dumb person. There’s some complex stuff I can understand, but whenever this comes up, I just can’t wrap my head around the shape of the universe and why is it exactly that the universe started somewhere and now I can look far enough in any direction and see not only that place, but also in the time it happened. Mind boggling.

It didn't start somewhere. The Big Bang happened at all points in space. It happened "everywhere".

We’re inside an inflating balloon and the space inside is a giant gobstopper where each layer is spherical movie projector screen we can watch a movie on of different moments in time.

If we’re not literally on the edge of the balloon is someone else looking back in time at us?

That's true except also every other point in space is at the center of its own balloon. The balloon has no edge, the movies just become too dark to see past a certain distance.

Too dark and yet also too bright: the fun combination of a plasma so hot and bright it's opaque being redshifted so hard it's the darkest blackest void anyone has seen.

With these numbers I always wonder how many consider the aspect of what was around when these systems formed. As in elements. For more heavier stuff you need some stellar formations and breakdowns. So true range when technologically capable life with let's say plentiful iron and other stuff is more limited. Not to even consider building blocks for life like carbon and so on.

There weren't any elements heavier than lithium to form life with that early. (there's a compelling argument that there wasn't enough phosphorus until recently/locally, but that's another question)

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