As hopecore as Project Hail Mary is, I do keep circling back to humans harnessing Astrophage for our advantage and ultimately our doom.
*I haven't read the book yet, so whatever I'm about to say I'm basing it off of the movie.
**And yes this kind of ties into my theory of linking the Iron Lung universe to PHM
As SOON as the scene happened where they said they were going to use Astrophage to power the ship, I knew that there was a strong possibility of some countries in the world that would try to keep their own sample of Astrophage. Those would be countries that have space programs to get up there [USA, China, Russia, etc] and grab some for themselves, or maybe some unsavory person on the project took some because they got paid to do so and gave it to these governments.
It's much like nuclear energy. Very destructive if done wrong, but extremely powerful if done correctly. But also like nuclear anything, there's the tendency to also create weapons.
But I remember how in the 60s and 70s there was a government agency that was essentially tasked to see if we could use nuclear stuff to construct things, to clear land for construction [the Ben Gurion Canal in occupied Palestine is one example]. Ultimately, they learned that it's way too dangerous to use nuclear stuff to do that kind of thing.
Regardless, I can see a similar trajectory with Astrophage in this universe.
Especially when they had the demonstration showing how Astrophage can melt metal in the blink of an eye, and the size of the explosion at the building from just a tiny amount.
Astrophage can be used for energy, some will say. Astrophage can be used for weapons, others will say. Regardless, I can see how programs to figure it out will be in place by the time the Beatles come back with the Tau Ameoba.
All they needed the Tau Ameoba for was to make sure the sun stopped dimming. And now, with the saving grace [haha] that is the Tau Ameoba, I feel like some of the Astrophage programs feel like they can be even more reckless or push the boundaries because there's a solution for if things go wrong.
And I do imagine eventually things go wrong.
You can also see a scenario where the Tau Ameoba gets out of control, too. It's cells, it's biological life that's resistant to Nitrogen [which is in Earth's air] and can also get through xenon and who knows what else eventually.
It can eat the Astrophage, which is mostly water but also clearly something else, because you can't see through it.
I'm just thinking that if there's ever a sequel, it would have to touch on the fact that Astrophage and the Tau Ameoba can cause issues down the road as well. Because humans are mostly made of water. Earth is mostly water.
[and to tie it to the Iron Lung world if we wanted to, if it's set like 300 years into the future, all of this could lead to much of what's happening in that movie too. Like that, the future is what could happen when humans stop communicating and collaborating for what's best and make decisions based on greed and pure survival scenarios]