What If The Universe DID NOT Start With The Big Bang?

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Here’s the story we like to tell about the beginning of the universe. Space is expanding evenly everywhere, but if you rewind that expansion you find that all of space was once compacted in an infinitesimal point of infinite density—the singularity at the beginning of time. The expansion of the universe from this point is called the Big Bang. We like to tell this story because it's the correct conclusion from the description of an expanding universe that followed Einstein's general theory of relativity back in the 19-teens. But since then we've learned so much more since then. Does our modern understanding of the universe still insist on a point-like Big Bang? Recent work actually gives us a way to avoid the beginning of time.

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Written by Richard Dyer & Matt O'Dowd
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[demetriusshade]

Your channel has pi million subscribers

[thomaswarfel]

I have now officially watched every PBS Spacetime video ever made. I cannot overstate how good these videos are. It is amazing to me that this quality of content is available for free. Support PBS!

[THE-X-Force]

None of this is going to save poor Alice and Bob. Their sacrifices will never be forgotten. ☮

[Jatt]

I hope PBS Spacetime doesn't ever end since it would leave me geodesically incomplete.

[graduator]

Congratulations on 3.14 million subscribers! Celebrate with a nice pie!

[Brodie]

I feel like a dog watching TV when I watch one of these videos...

I love watching them, but have very little understanding of what's going on.

[lethargogpeterson]

If anyone else also has a some familiarity with physics and yet understood basically nothing of this but the surface words, you're not alone. Wow. I'm glad talented people look into this stuff though.

[whophd]

I fear that the mythical parallels to the Big Bang theory make it too tempting to analogise it to the start of a book. I’ve been asking for 15 years whether time is asymptotic — think about how much activity occurs in the first seconds of the universe. Surely any “observer” or “observation” back then would be more scaled to the pace of activity then.

This is the flipside to the kind of “slow time” we will see after all the stars go out, life clings to the edges of black holes, and every thought occupies trillions of years. To our eyes.

[jokwonpope]

I had the mental idea of space being a sort of tunnel.. and if you’re in the middle of a tunnel, you can look forward and backwards, but because it is so far the end of the tunnel seems like a singular point and you could get to that point and there could be so much more than what you could tell before.

So real life example.. we can see as far as what we believe to be the beginning, 46.5Billion light years away, when the universe could’ve started 100B+ light years away and we would never know because it’s too far down to the tunnel to tell and from what we see it could just look like a big bang

[smallpeople]

The origin of the universe is neither late or early, a universe materializes precisely when it means to

[OpenMicRejects]

I love the the Thursday afternoon Space Time notification! It's the big bang for the weekend!

[SuperFx]

I like that boundary-defining expressions such as "start of space-time" and "end of space-time" are used instead of time-dependent notions like creation. It's confusing to say space-time has been created. Being created implies a point in time when it didn't exist. How could there be a point in time before time was created?

[amymonroe]

It may have started with a small bang.

[mehurar]

Watching him on mute. Still understand a lot. His hand Italian is superb :)

[theemissary]

Can we reorder the last two names in the metric so the acronym would be closer to 'flower'? It just feels like FLRW is still quite a mouthful for an acronym, and it's a nice word for it I feel.

[florianp]

So just like the Penrose diagrams, will this be another win for Penrose with his cyclic cosmology model?

[Bob-]

Outstanding - like always! At our current understanding, while most things seem to point to a singularity for the birth of the Universe, one dramatic discovery could shift everything. Such as truly grasping the nature of dark energy, quantum entanglement, or any of the many mysteries we've yet to fully grasp. Then, even an expanding universe may no longer be universally true, at least from all perspectives. I'm confident that humans, math, imagination, and probably A.I. will figure out quite a bit in the next decade or so, and I'd be willing to bet that our new understanding will change everything!

[giglinsparky]

Will the pbs space time store be selling the "Take Me With You" shirt again in the future?

[philochristos]

The idea that the universe had an absolute beginning in time is kind of trippy. Of course the idea that extends infinitely into the past is also trippy.

[TarkMcCoy]

OK, truth be told it didn't start on the first pull...