The Geometry of The Universe

[@MogaTange]

Absolutely flabbergasted to see how underrated this video was. I hope it blows up.

[@brianelliott9861]

EXCELLENT: Clear, concise and understandable

[@jdgoodwin3136]

I interpret "almost flat" as not flat, or a limitation in current observation.

[@apitapi]

Finally something interesting in my feed. Great video!

[@cwwiss1]

A model that states the universe is expanding in some areas but not others is nonsensical and ugly.

[@OVAstronomy]

Areas which aren't expanding are gravitationally bound due to the matter they contain. Without an expanding universe model numerous observations such as redshift cannot be explained.

[@Sm1smwhere]

Can you give a visual example that explains how we see the cosmic background radiation looking at any direction in the sky while the it supposedly was emitted at the big bang (a single point in space-time)

[@tomusic8887]

The universe is not a surface, we get al this crazy theories from the equasions and math, math does not tell you how something is in reality. They believen theories own math and models and every new data from measurements gives new problems....

[@ralphclark]

I just don’t understand how it cannot be closed. If it isn’t closed then either it’s infinite, or it has a boundary. And both of those seem preposterous.

[@pmiecz]

Awesome, thx!

[@spaceinyourface]

Now I'm wondering how an empty void can expand.

[@ingvarhallstrom2306]

There's a force in every void pushing outwards in all directions. That means every void is pushing on every other void except for the things between the voids that are the filaments and large scale structures of galaxies.

[@spaceinyourface]

Really well presented. Expansion only happens in the voids between galaxy clusters .I'm sure that's the first time I've heard it put like that,,I'm a new fan . 👍

[@angelicafigueroa5685]

I have read it’s all perspective and it’s all about the view of the observer. How is it then that you can say the universe is expanding? We as observers (in mass) see indeed the expansion of space/time but in the perspective of space/time mass is shrinking. In that case you can only say the ratio mass and space/time is changing. Or what am I missing?

[@OVAstronomy]

Space is expanding about every point so an observer from anywhere in the Universe would see everywhere else receding away from them. The mass/energy content is the same throughout time, so indeed the matter density shrinks overtime.

[@angelicafigueroa5685]

I understand that space is expanding in every direction from any point of vier in space, so also between stars. My point is the same but from the standpoint of space itself. If space/time was an entity it couldn’t see it self grow. It can only look to the mass and see it shrink. I really like to understand but I don’t see the difference. It looks to me like the same coin with different sides

[@NoosaHeads]

We don't know what we don't know. One should keep _that_ in mind at all times (to prevent preconceptions leading us in the wrong direction).

[@lukassbeataddicts]

So basically dark energy is nothing. No or very little matter cause receiving phenomenon as it’s opposite to matter attracting each other.

[@OVAstronomy]

It's a mysterious substance which provides the negative pressure necessary for expansion.

[@lukassbeataddicts]

@@OVAstronomy I know, what about if it’s simply nothing, pure void. No atoms are very few. Hence we can’t detect it. I always wondered why it has to be something. In intergalactic space there is nothing hence it expands.

[@arnoldlueders7500]

No you cannot conclude this. If it was flat but on the surface of a sphere that is so large that our measurements can't properly measure then you would not know beyond what we can see or measure. We do not know at all.

[@OVAstronomy]

As I show towards the end of the video, our current best model predicts the curvature to be almost flat but with a relatively large error range which allows for the other geometries. You are correct that a 4D sphere would appear flat to us due to how large the Universe is, which is why modern cosmology is coming up with new ways to try and decrease the uncertainty on the curvature.

[@arnoldlueders7500]

@@OVAstronomy I get it but we keep trying to answer things when we have like 0.05% of the information. It is like the climate change thing. We humans think on such small scales in time and distance and have a very difficult time understand these vast distances of time AND space. I also find it completely moronic when they talk about "space time". Time is man made concept that have nothing to do with the universe, PERIOD. Effects of gravity and such on the human body has nothing to do with "time". Most of the times scientists in these fields are just wrong. How about we just observe and once we know, we know.

[@OVAstronomy]

@@arnoldlueders7500 I understand your sentiment, however modern science is best progressed when people come up with new theories and solutions to problems which can then be peer reviewed and tested. Just because we don't yet have all the technology or means to reduce errors doesn't mean we should ignore trying to find solutions to problems like the curvature of space. Also time is a physical concept which can be defined through increasing entropy (2nd law of thermodynamics), whether it is a consequence of entropy is another debate, but time is important when considering cosmic history and periods of inflation nonetheless.