Did Time Start at the Big Bang?
Why Hacker News recommends it
Used as a go-to reference for cosmology questions about the beginning of time and the universe's scale.
What it is
A PBS Space Time episode asking whether time began at the Big Bang. It explains that the Big Bang is not what most people were taught and what 'start' of the universe really means.
Recommended by 1 HN commenters across 1 different months, 2020 to 2024.
What Hacker News said
Strong rec davidwf · 2021-01 · on “Ask HN: What YouTube channels do you subscribe to?”
I keep a Google Document of these to share just in case people ask about my YouTube interests. I Actually Watched All of Them I have actually watched ALL of the videos on these channels and I don’t even feel bad about it :-) I actually like new videos from some of the ones below (like NativLang, for example) but they maybe don’t hold up in the early videos. - Space Time: PBS Physics, sooo good -- [LINK] -- Great first video: [this video] - Lindsay Ellis: Really, really intelligent video essays about film and culture -- [LINK] -- Great First Video: [LINK] - Periodic Videos: Chemistry, including a video for every element -- [LINK] -- Great first video (obviously): [LINK] Other Math and Science - 3B
Cites dkersten · 2020-08 · on “Big Bounce Simulations Challenge the Big Bang”
It was my understanding that physicists have never claimed that the big bang happened. That the big bang itself isn’t really part of the theory at all and that its simply a singularity point, but that some moments before that point, ohysics as we know it breaks down, so we don’t know what happened before and therefore do ‘t know if there was a bang or not, just that after that time, things happened that we can measure. Put another way, the big bang theory doesn’t include the big bang itself (the something from nothing part) but is about the inflation and expansion of the universe. Here are some PBS Space Time videos on the subject: Why the big bang definitely happened: [LINK] Did time start
Cites bb88 · 2023-07 · on “Age of universe at 26.7B years, nearly twice as old as previously believed”
> wouldn't it make more sense that time actually stretches infinitely the further back we go, thus nullifying the concept of a beginning? Matt from PBS space time covered this here. [this video]
Cites irjustin · 2024-04 · on “Webb captures iconic Horsehead Nebula in unprecedented detail”
> Well, no. The density in the observed universe is used to extrapolate the number of galaxies in the non-observed universe. The size of that universe is extrapolated from the rate of expansion and the time since the big bang. > We may not know the exact size at the start, but we know it was infinitesimally smaller than it is today. So the size of the initial universe isn't a big factor in the equations about how big it likely is today. Weather it started as a few centimeters across or a few thousand light years across, both are functionally zero compared to the current size. Most things you're saying are correctly rooted except for what's beyond the observable universe. I'm not sure why the