DESI data release, BAOs, Dark Energy evolving/weakening and possibly ELI5?
Hi everyone, kindly bear with me since English is not my first language and I am also an amateur. So I have just watched AstroKobi's 'Could the Big Bang happen again?' video and it left me with more questions than I had before watching it.
So basically DESI was able to measure the 'growth' (?) of the Barionic Acoustic Oscillations (I envision all of this kind of like a tree's trunk growth rings) and apparently the data releases (not super good Sigma tho) says there are signs of DE weakening (?) Because the imprint of those BAOs (that are remnant of sound waves resulting from the interaction of something with photons (?)) froze when the universe changed phases and became transparent (?) and align with where galaxies like to be, and then the measurements of the galaxy clusters and filaments show a growth ever so smaller with time? So this means DE is weakening and the universe expansion acceleration is slowing down? I don't even know how they trace the size of the BAOs every x amount of time, can it be observed directly?
Among the russian doll of questions within questions I have, what strikes me the most is that those BAOs have been known for a while and there's been a mantra for 25 years or more saying the expansion rate of the universe is accelerating, there has to be a strong body of work to support this even if there was no direct measurement/observation or DESI map before, right? So I don't get this 180 now. Could you guys shed some light? Appreciate.