Expanding universe without dark energy or a big bang

Hi, I want to share a theory so that someone smarter than me can explain why its not right.

An expansion on Einsteins theory of general relativity may explain how a universe measured to be expanding with expansion accellarating may infact not be. Heres how...

-we do not explain the contraction of spacetime (known as gravity) with a mysterious form of energy. So why do we need to imagine (dark) energy to explain the expansion of spacetime?.
-Gravity is not a force, its the curvature (in particular, contraction) of spacetime, Just as the perceived expansion of the universe (derived from seeing galaxies move away from us accelerating the further away they get) is not a force, but rather the curvature (expansion) of spacetime. So requires no (dark) energy.
-My theory consists of one simple speculation about natural spacetime or the shape of the fabric of the universe, that on the scale of galaxies, spacetime is not flat, but rather naturally curved in the opposite way to that of curvature from massive objects.
I will use the well known visual representation of a bowling ball on a stretched elastic sheet often used to explain the curvature of spacetime in regards to orbits to get my point across.
One observes a concave curvature of the sheet around the bowling ball.  Picture a normal sized bowling ball as a representation of our sun (or typical star), now picture the sheet many millions of killometres square representing spacetime of the whole known universe, picture a slight convex curve in that sheet in its natural form rather than completely flat, this is the natural curvature of spacetime.  Imagining spacetime in this way, we can explain why galaxies and galaxy clusters appear to move away from us relative to our position in the universe when they are actually following a straight path through convex spacetime the exact same way on a much smaller scale an object in orbit around a star or planet is following a straight line through concave spacetime.
The convex nature of spacetime is so slight, that on the scale of solar systems, it does not interfere with normal orbital mathaimatics, It MAY however have a measurable effect on the scale of galaxies.
If we can take data used to measure the speed and acceleration of galaxies away from us (that has been used to measure perceived expansion of the universe), we should then be able to measure the natural curvature of spacetime on the intergalactic scale.
Of course if this were the case, the universe may not actually be expanding, there for there is no dark energy required, No big bang and the age of the universe imesarable using this method.
This could also explain why objects such as Methuselah star, HD 140283 can be measured to be 'older than the universe'.

This is an incomplete and informal theory, I would love to hear others opinions on it. Thankyou for reading.

You could use lasers to measure the curvature of space time by making a very large triangle. If the angles add up to 180 degrees space time is flat. If it is convex the angels would add up to more than 180 degrees.

Thanks Rich, that is theoraticaly sound but wouldnt it require traveling many light years to install lasers or reflectors ?. Also over a distance like that even a narrow laser would "spread" .. would be a difficult task... i appreciate your reply..

The bigger the triangle the more precise it would be at measuring the curvature of space-time. We could conduct an experiment and it might show the curvature of space-time to be flat. That result doesn't mean space-time is perfectly flat, it just means if it is curved it is so slight it can't be detected by the instruments used. Your theory is at least in principle falsifiable. Your theory, fleshed out, should predict a certain curvature to space-time. We can measure the curvature of space-time. It may be possible to measure the curvature of space-time with enough precision to give your theory some credence by making a predicted observation or falsify it if observations do not match what your theory predicts.

www.space.com/24309-shape-of-the-universe.html

I only propose it as an alternative to expansion and big bang theory as it confuses me how we still hold onto this with more and more evidence stacking up against it. Cosmologists seem to be much more content adding so many complicated adaptions to BBT and the expanding universe to explain away more and more observations and measurements that contradict it. ☹️
I read recently that the CCACP has measured the mean temperature of the universe to be actually getting much hotter over the last 10 billion years, not colder as BBT / expansions suggests. I wonder what new radical adaption will be added to this dated and failed theory now 🙄..
The so called 'crisys in cosmology' could perhaps be solved if we let go of expansion and work on new models of the universe.
As far as 'open' or 'closed is not quite what im on about, curvature would not necesarilly lead to 'closed' if you consider spacetime finite. I only suggest that spacetimes natural curve is very slight, and in the opposite direction to curvature caused by massive objects. It would explain a lot of things allready observed over the last 100 years and may be a new way to understand hubbles constant thinking of it as a curvature and not an expansion/ acellaration , in general relativity (gravity) curvature of spacetime has much the same effect as acceleration.. The expansion of the universe may just be a much bigger and backwards version of how gravity was viewed as a 'force' before general relativity .......

HI Dylan13n,

Would it be correct to say that, in your framework, the curvature of local space around masses is 'gravitational', while on the bigger scale it is 'anti-gravitational'?

That is, over extremely large distances, masses flee from each other because maybe space curves the opposite way from what we call gravity?

Thanks for the brain toys!