5. Inflation Without Inflation
Modern cosmology includes a very early period called inflation, during which space is thought to have expanded extraordinarily rapidly.
Inflation helps explain why the observable Universe is so geometrically flat, why distant regions have nearly identical temperatures and why certain unwanted relics are absent.
Any replacement for inflation must reproduce those successes.
A cosmic ocean model might attempt to do so through a rapid pressure release.
Suppose a vast compressed region of the cosmic medium underwent an abrupt phase transition.
Water can change suddenly from liquid to vapor.
Superheated fluids can expand violently when pressure changes.
A cosmic medium might possess analogous, though far more exotic, states.
Instead of spacetime itself inflating, the medium could undergo an extremely rapid reconfiguration.
Such a process might smooth density variations across tremendous distances before ordinary matter fully condensed.
Would this actually work mathematically? That is the hard part. An analogy is easy and yet an equation is difficult.
But if the equations could reproduce the observed uniformity of the cosmic microwave background, then the idea would become worth taking seriously.
6. The Tide Goes Out
Imagine cosmic history as a tide. After a great compression, the tide moves outward.
Galaxies separate, the cosmic current carries them farther apart.
At first, matter interacts strongly enough to form clusters, galaxies, stars and planets.
As time passes, the outward current grows dominant and the distances increase. The observable Universe becomes increasingly diffuse.
This looks very much like what cosmologists currently describe as expansion. But tides do not move outward forever, eventually currents shift.
Suppose the outward flow slows.
At immense timescales, far beyond the present age of the Universe, pressure differences might change direction.
The flow could begin to converge and the tide would come back in.
Galaxies that had moved apart for hundreds of billions of years might begin, on even longer timescales, to drift together.
Matter would become concentrated and black holes would merge. The cosmic medium would grow denser.
Eventually a new compression event would occur. Then another outward tide would begin. There would be no first cycle and perhaps no final one.
Only sequence: High tide, low tide, compression, release. Forever!
7. Galaxies as Vortices
Fluids naturally produce rotation. Pour water from a basin and it may spiral.
Atmospheres produce hurricanes and oceans produce vast rotating current systems.
The cosmic ocean, if real, might produce vortices on astronomical scales.
A galaxy could be one.
The stars in a spiral galaxy already rotate around the galactic center.
In the cosmic ocean hypothesis, this rotation might be partially linked to circulation in the underlying medium.
Dark matter halos would then be regions where the vortex alters density and motion.
This leads to a possible observational test.
If galaxies are vortices in a medium, then the distribution of apparent dark matter might depend not merely on the amount of visible matter but also on the rotational structure of the surrounding flow.
Two galaxies with similar luminous mass but very different rotational histories might possess measurably different dark-matter-like profiles.
Standard dark matter models can also produce different halos, of course.
The question would be whether the fluid model predicts a distinctive pattern.
That is where speculation must meet data.
8. The Cosmic Web as Weather
On enormous scales, galaxies are not scattered randomly.
They form a structure known as the cosmic web.
There are long filaments of galaxies, enormous clusters and vast relatively empty voids.
This arrangement is normally explained through the gravitational growth of small early density fluctuations, with dark matter providing much of the underlying structure.
But consider the shape of flowing fluids.
Currents produce channels and convection produces cells.
Turbulence produces filaments and voids.
A cosmic fluid might generate similar structures.
Galaxy filaments might form along stable flow boundaries.
Voids might correspond to regions where the medium has moved outward.
Clusters might form at intersections of large-scale currents.
In that case, what astronomers call large-scale structure might partly be the fossil weather pattern of the cosmic ocean.
We may be studying cosmic meteorology without realizing it.
9. Black Holes as Deep Vortices
Black holes provide the most dramatic possibility.
Under general relativity, a black hole forms when matter becomes sufficiently concentrated that spacetime curvature creates an event horizon from which nothing can escape.
The cosmic ocean model need not reject that mathematics.
Instead, it might reinterpret what lies beneath it.
Suppose a black hole represents an extreme vortex in the cosmic medium.
The flow becomes so intense that ordinary matter, light and even the causal structure of spacetime are dragged inward.
This is not entirely alien to existing physics. Rotating black holes already exhibit frame dragging, in which spacetime itself is pulled around by the rotation of the black hole.
The cosmic ocean model would take the analogy farther.
Perhaps the inward flow does not end at a mathematical singularity.
Perhaps it feeds into another region of the medium.
Imagine a whirlpool in a three-dimensional ocean.
From the surface, water appears to vanish into it.
But the water has not ceased to exist.
It has moved somewhere the surface observer cannot see.
What if black holes do something similar? Matter and energy falling into one might be redistributed through dimensions or structures unavailable to us.
The black hole would be less like a grave and more like a deep-water drain.
This immediately suggests an even stranger possibility.
There may be outlets.
10. White Holes and Cosmic Upwelling
General relativity contains theoretical objects known as white holes, effectively time-reversed black holes from which matter could emerge but not enter.No confirmed white hole has ever been observed.
But a cosmic ocean invites the concept of upwelling.
Earth's oceans contain places where deep water rises toward the surface.
Perhaps the cosmic medium has equivalent regions.
Matter entering extreme vortices might eventually reappear elsewhere in the cosmic ocean.
Such an outflow could resemble a white hole, an energetic jet or some entirely unfamiliar phenomenon.
If cosmic cycles exist, these inward and outward flows might help recycle matter from one epoch to another.
Stars recycle atoms and galaxies recycle gas.
Perhaps black holes recycle universes.
That sentence is attractive.
It is also scientifically reckless unless we can test it.
So let us ask how.