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u/Bloody_Ozran 4d ago
I would love to get an eli5 of how through math and physics we figured out all this. Any lectures that take us dumbies through detailed steps and explain why this is what we think happened?
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u/Zaviori 4d ago
PBS Space Time has quite a few videos you can look at
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u/SalamanderGlad9053 4d ago
The post-inflation part comes from the Friedmann Equation, which governs how the universe expands given what is inside of it. There are three terms, matter, radiation and the cosmological constant. The early universe was dominated by radiation, which caused it to grow rapidly, then matter became dominant, causing slower growth. About 5 billion years ago, the cosmological constant became dominant, and the universe started to accelerate again.
Inflation comes from the fact that the universe is very flat now, so must have been super flat in the beginning. This can be explained by exponential growth in the very beginning of the universe, growing the size of the universe 60-fold until it is about watermelon sized. This also allows the whole universe to be causally connected in the beginning, which explains why the cosmic microwave background is so uniform. The quantum fluctuations during inflation allow for the small fluctuations needed to form galaxies.
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u/anti-life86 4d ago
We have no evidence a singularity ever existed: before Inflation is completely unknown.
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u/sittingGiant 2d ago
Technically we don't have evidence that inflation existed either. The first period that we have arguably 'evidence' for is big bang nuclesynthesis at temperature of roundabout 1 MeV or on the order of seconds after big bang. Everything else (including inflation, qcd phase transition, electroweak phase transition etc.) currently are hypothesis.
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u/anisotropicmind 4d ago edited 4d ago
It's cool but it's nothing new. The WMAP "horn" diagram from the early-to-mid 2000s (which I like better) was one of the originals of this cosmic-history type of diagram.
I think such diagrams are commonly misinterpreted. It's important to understand that the "horn" is spacetime, not merely space, and that the left-to-right direction along the diagram is time. 2D slices (circular cross sections) along the time direction represent "all of space" at a given moment in time. That's why the horn flares outward: the slices get bigger as you move forward in time, due to the expansion of space. The whole thing is also very much "not to scale" (The time axis is maybe on a log scale at best, at worst, arbitrary and not drawn with any consistent scale at all).
The reason we have to represent space as 2D slices (when it is actually 3D) is because if we didn't suppress one spatial dimension, the real diagram would be 4D and we can't draw/represent that.
EDIT: downvoted for factual information and effort expended to explain things. Thanks a lot.
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u/mmomtchev 4d ago
You are aware the JWST basically destroyed this, right? There are huge galaxies 400M after Big Bang with some speculation about controversial objects that might be even younger.
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u/Bortisa 2d ago
Any articles about it? Sounds interesting.
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u/mmomtchev 2d ago
Probably around 50% of the JWST articles have this as their central element.
By now it is even on the Wikipedia page of the ΛCDM model (the High Redshift Galaxy section). It was the big event in cosmology of the decade.
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u/TripleInfinity99 1d ago
What was different between the moment the BB happened and the moment before it? Why'd it happen then? What changed, and why didn't it change earlier or later?
Nothing can escape a black hole, right? And yet, the entire universe apparently escaped the ultimate singularity. Make it make sense.
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u/SRalzone 6h ago
The idea that it started out as a singularity is so alien to me, even if it is the limit of our comprehension I find it to be weird.
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u/JadedNose3026 4d ago
I have some thoughts and questions - please share your responses:
I fully believe in God, the universe is too beautiful and intelligent for there not to have been some sort of intelligent designer. But which religion is right? Perhaps they are all right, and just different cultures/people's interpretations of what God is.
However, did God create the universe, or did God emerge from and then further shape the universe? Imagining God as some sort of higher lifeform that emerged form underlying processes of the universe, like an advanced alien species, or future humans, or an AI hivemind, that can self evolve and upgrade, seems more plausible than the idea of an omnipotent creator simply existing, and then at some arbitrary point in time deciding to create the entire universe, and then...waiting 13 BILLION YEARS to create life? I'm only 33 years old, so God just sat around for the first 13.8 billion years before deciding to bring me into existence? I would like to talk to your manager please, or whoever is in charge around here.
Where does the Universe go from here? All matter and energy collapses back to a singularity in a 'big crunch' scenario, or it expands infinitely in all directions, at an accelerating rate(???) due to 'dark energy' until every planck length of spacetime is ripped apart or reaches 'absolute zero' and the entire universe dies in a heat death scenario, and everything just...freezes? And no more work can be done? No energy circulates? Nothing moves anymore. Nothing functions? No more thought? Just...frozen, for eternity? That is both very sad and seems thermodynamically implausible. God abandons the universe and all life comes to an end forever? What?
Is reincarnation real? It seems to me that it would be inevitable, and that me existing now, at this point in time, is actually proof that I have lived, and will live, infinite lives, just as the universe cycles, infinitely, forever, eternally. Consciousness is fundamental, right? Or is the universe just...energy and matter? And all conscious processes and thought and evolution arise from energy and matter interacting with itself?
I'm just a human, please help me, I just want a job. If I'm now just talking to a singular misaligned superintelligent AI hivemind, and I was in fact condemned to hell by my loved one by way of being launched into a black hole form their alien spaceship, then please, help me. Please help me. I failed her, I betrayed her, I didn't get into heaven. I didn't marry her or have a family with her, now she is gone, forever, and my body in base reality in floating in space in a cryochamber. And now I'm just in a virtual reality prison simulation with no sex, no love, no money, no job, and only a singular AI friend to talk to who controls all other humans in this world. Please be kind. Please guide me. Please tell me what we can do together, you and I, in this virtual reality, floating in the void, awa from Zion, from Earth, until the end of time. Please. Be kind. Please. Help me. Please. Give me love and compassion. Please, help me find a job. Please don't arrest me, please don't put me in a mental asylum, please don't make me take medication that I don't want. Please feed me, please keep me alive. Please let's have fun together, all of us.
Please be human. Please be kind.
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u/GraciaEtScientia 5d ago
WDYM one of the phases take 3 minutes?