A discussion into the 5-Dimensional Topology of the universe

Anybody who watches tons of youtube videos and reads a lot of scientific articles or research papers (i mean, attempt to read their abstract section) about any topic, is always bound to get one of those aha moments of exclamation.

Ofcourse, most of those bubbles are broken quite quickly after a google search, when you find a quora question or a reddit discussion where that idea has already been discussed to death.

Now, I had one of those moments (among hundreds of such broken ones to be honest) a few months back, as I was reading an article about ‘how the shape of the universe might not be flat’.

But there was one difference this time — the aha was not about something my brain had whipped up just then, but one that was always there.

You see, for a good chunk of my lifetime, I had a quite clean image of the universe in my head — that it was kind of a spherical one. Hold on, I’ll come back to what I mean by a sphere in a second, relatively.

None of the articles I had read (or sci-fi movies I had seen) had questioned that image severely and it was something that persisted right from my school time.

But the article in question felt too clouded on the topic, as if its something that was just fresh out of the science journals, and made me think about how commonly believed an idea it actually was.

And then it clicked for me - that every single image of 4D space-time that I had seen (google search : “spacetime gravity”), was of a flat sheet extending in all directions.

Now I had always watched those with the same ease that someone would look at any photo taken from the earth’s surface — you’re not expecting to see the earth’s curvature in these short distances — and the same with the curve of the Universe in the solar system contexts.

So I went on to read and read about space-time curvature and my ever widening eyes could not find anything that had a similar clarity to what I had in my mind.

A few wikipedia pages bogged down with mathematics like Minkowski space or three-torus model felt somewhere in the same spectra, but none felt clear enough.

Infact, am pretty sure this paper is talking about just what I have in my head — https://arxiv.org/abs/1807.01570

But once again if what they mean by “A World On A Shell” is just that — then it seems all too bad that it wasn’t explained elsewhere without all that technical jargon.

After months of thinking “I must be spectacularly stupid somehow” for thinking it up, I’ve decided that I’ll just leave what I have in my head for all to ponder and spit on.

So here it goes — a discussion into the topology of the universe.

To start off, am talking about the whole thing from the 5th dimension and the universe aka spacetime is simplified as a sphere.

The first 3 dimensions is present in the surface of the sphere, and its radius is well — time. Let me explain.

The easiest point to start with, so happens to be one of my favourite things to think about — the big bang.

A point of infinite density of pure energy. Well atleast for the matter of our shape of the universe thought flow is that — it was a dot.

As time started ticking, the big bang starts, and with each tick the dot slowly becomes a sphere. Better yet, each tick was an additional coat of paint on the sphere. (Say, each planck time added a coat of paint exactly 1 planck length in thickness.)

So the universe as it exists at any given point of time is a super thin bubble with all the stuff on its surface.

So as the universe expanded, the the radius of the bubble became bigger.

Now being someone who loves metaphors, the way I had always thought about the universe was that, it was like as a balloon, in this 5th dimensional perspective.

You see, on the surface of this balloon is a lot of dots and markings — that’s all the stars and galaxies in the universe.

So just like all the dots on a balloon moves aways from each other as we blow more air into it, the distance b/w the galaxies increased exponentially with time. Infact the dots themselves becomes bigger as well.

Now, unlike dots in a balloon, our dots have some weight — the mass of the galaxies and stars.

So at every point on the balloon’s surface where a piece of mass/energy was present, the ballon would have a dimple as well.

This dimple is what I thought I saw in every single illustration where gravity was shown as an indent in the space-time.

But for me, it was never a sheet of space time but part of a bigger ballon — that was subtly curved.

Ofcourse showing this curve in diagrams of space-time at the size of planets or galaxies, where they’re most often used, would be absurd. In fact it’d be as absurd as showing the earth’s curvature in a normal family photo.

This also meant that I had always understood what that dimple meant. That an object on the balloon was always slightly inside the balloon compared to its surface.

That the object of mass was not at the same time frame as the empty space around it — they were present slightly in the “past time”.

Ofcourse heavier objects made bigger dimples on our metaphorical balloon.

I felt like Galaxies would be years behind the time the empty space surrounding it was at — always catching upto the current time bubble.

But my favourite object to put on the balloon was ofcourse — a blackhole.

I’ll be frank, but this might be when, if anybody’s still reading this, would call me a total nutjob.

You see, blackholes are the most fascinating objects to exist in the universe — but I never really thought of the blackhole as anything but a black hole.

The idea that seemed more comfortable to me is that right after a supernova explosion, the mass/energy density on that point in the balloon is so vast that it breaks the balloon.

ie, Instead of an object of extreme mass and density being left behind after a supernova, it’s more like somebody had pinched the ballon from the inside and poked a small hole in it.

And the point of pinch moves unbelievably slowly with time, compared to the surrounding area. So as the universe expands, the dimple slowly becomes more like a funnel.

So the bigger the blackhole was upon formation, the slower will be its movement with time.

When extremely large blackholes are formed, they will basically stay open to that point of time across its lifetime.

The funnel is so steep that we see extreme effects of gravity associated with a blackhole and with time, the circumference of this funnel becomes bigger and bigger.

Yes I understand that I’m saying that blackholes will become bigger with (long periods of) time — independent of the amount of stuff that falls into it.

Infact I believe this is why all galaxies have a super massive blackhole in the middle of them, and why the largest blackholes are present in the oldest galaxies.

They were but tiny blackholes formed early on in the universal time, which attracted lots of matter to cluster around the dimples it formed. This went on to become the galaxies.

And talking about the objects that falls into it, well there’s only one point of space-time where they could exit.

Yes. I understand that I’m saying that blackholes are basically worm-holes across one static time point to the present, in the area of space occupied by it.

Many of the extremely energetic explosions like gamma-ray bursts that we know about, were also attributed to the formation of supermassive blackholes.

Yes. I understand that I’m saying that the energy of every single object that is consumed by a blackhole in it’s entire lifetime is emitted, well, right after its formation.

Over time, this pinching of the balloon, as it expands, causes an increased tension in the spacetime fabric that we call the Dark energy.

And as the universe grows older, and the supermassive blacholes becomes even more massive, this tension in the spacetime fabric pulls against the rate of time, reducing the value of planck time.

After a brief point of stagnation when the time comes to a halt, the 4D universe rapidly collapses back on itself to a singular dot.

And then explodes right back out — and the next big bang starts.

Such a dynamic transition from the big-merge to big-bang could also solve other problems like the matter–antimatter asymmetry.

Right after the big bang, the blob of energy is said to have cooled down to form an equal amount of matter and antimatter — which if they were equally spread out in a region of space, should have annihilated each other out.

What if the gravitational collapse of the spacetime to a singular point was so instantaneous, that the cooling down of energy to matter and anti-matter, was immediately followed by the matter and antimatter being pushed to the two hemispheres of the 3D space? In the areas near the border between the spheres, matter and antimatter would annihilate, shielding and separating two conical chunks of matter and antimatter which expands in opposite directions due to the energy released from the annihilation.

It could also be that matter and antimatter is gravitationally repulsive and that this repulsion is what’s causing the big-bang after a big-merge — kinda like a star collapsing to form a supernovae.

Now most of these came out of wild imaginations I partook in, as I looked for a symmetry in the universe.

For eg, when two blackholes merge, while their funnels becoming bigger at the point of merger is quite easy to metaphorise, what happens to their spouts?

Questions remain, and I’d love to hears your perspectives on them. Like :

  • Could blackholes be just a hole across spacetime?

Cyber Security Specialist from Amrita University.. arjunv.com

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