The Universe Has No Edges, But Gravity Does
The Universe Has No Edges, But Gravity Does
How a single equation explains why dark matter disappears at galaxy centres, why the Hubble constant depends on which direction you look, and why Newton's gravity was always missing a boundary.
In the last two posts on this blog, I argued that gravity is not a force that pulls things together. Instead, everything in the universe — space, voids, and matter — is expanding, and matter simply expands a little more slowly than the space around it. What we call "gravity" is just that lag, viewed from the present moment.
This post covers four new results that came out of pushing that idea further. Each one answers a question that the previous version (v6.1) left open.
1. Dark matter was a shape problem, not a missing-mass problem
Newton's law of gravity assumes that gravitational influence spreads
out evenly in all directions — like ripples on a perfectly still pond,
spreading in a perfect circle. This gives the famous
1/r² law.
But most things in the universe are not spheres. Spiral galaxies are flat disks. Galaxy clusters are connected by long filaments. The "ripples spread in a perfect sphere" assumption is a good approximation for a star, and a terrible one for a galaxy.
4πr²), divide it by the area the
flux actually spreads through — which depends on the shape of
the object.
| Object | Effective area | Result |
|---|---|---|
| Star (sphere) | 4πr² | Newton's law, unchanged |
| Spiral galaxy (disk) | 4πH·r | Flat rotation curves — no dark matter needed |
| Cosmic filament | H² | Constant pull along the filament |
| Galaxy cluster (n filaments) | n·H² | Flux splits between filaments |
Here's the part that matters: the "missing mass" that astronomers attribute to dark matter is largest exactly where the difference between a sphere and a disk is largest — at the outer edges of a galaxy. Near the centre, where a galaxy looks roughly spherical anyway, the missing mass all but disappears.
This is exactly what observations show. Dark matter is needed at galaxy outskirts, but barely at all near galactic centres. Standard cosmology treats this as a strange coincidence about how dark matter happens to be distributed. In this framework, it isn't a coincidence — it's the signature of using the wrong shape for the wrong object.
2. Every object has a natural edge to its gravity
Here's a question Newtonian gravity cannot answer: if gravity from the Sun reaches every object in the universe, however faintly, why doesn't the universe just collapse into one giant clump? The usual answer is "dark energy" — some mysterious repulsive ingredient that pushes back against gravity at large scales.
In this framework, no such ingredient is needed, because gravity already has a built-in edge.
Close to a mass, the second term dominates — matter lags behind space, and things clump together. Far away, the first term (driven by the universe's overall expansion) takes over, and matter simply joins the general outward flow. Somewhere in between, the two terms are exactly equal. That point is a natural boundary:
Below r_balance, matter clumps. Above it, matter joins the general expansion. No extra ingredient needed.
This isn't just a nice picture — it gives numbers that check out. Plugging in the Sun's mass gives a boundary of about 1 light-year, which matches the observed outer edge of the Oort Cloud. Plugging in the Milky Way's mass gives roughly 200 kiloparsecs — right where astronomers place the galaxy's outer "virial radius."
Two predictions, zero free parameters, both correct.
3. Why do stars drift apart? (Hint: not repulsion)
If every clump of matter pulls itself together a little more as it
grows — and it does, because more mass means a deeper dip in
a_matter — then the space between clumps gets left
behind. That space isn't being pushed; it's just not being held back
anymore, so it expands more freely.
a_matter the most. Once it joins, that clump gets
slightly heavier, pulls a little harder, and attracts the next
particle a little more easily. Meanwhile, the gap between this
clump and its neighbour empties out and becomes a void —
expanding faster simply because nothing is slowing it down.
This is the same mechanism at every scale: stars separating from each other, galaxies separating from each other, galaxy clusters separating from each other. No repulsive force. Just each clump digging its own hole a little deeper, while the space between holes is left to expand.
4. The Hubble tension is two different speeds, not a crisis
For the last decade, cosmologists have been stuck on an awkward mismatch: the expansion rate of the universe measured from the early universe (the cosmic microwave background) doesn't match the rate measured locally, using nearby galaxies. The two values differ by about 8%. This is the famous "Hubble tension," and it has generated hundreds of papers proposing exotic new physics.
This framework offers a simpler explanation: voids and matter expand at different speeds, and the proportions have changed over cosmic history.
In the early universe, matter was spread out almost uniformly — voids barely existed. Measurements from that era reflect something close to a single, global expansion rate. Today, voids occupy roughly 75% of the universe's volume, and they expand faster than matter does. Local measurements — which sample today's universe — pick up this extra contribution. CMB measurements, which sample the early, near-uniform universe, don't.
The 8% tension isn't a crisis. It's a measurement of how much faster voids expand than matter, weighted by how much of the universe is now void.
This makes a testable prediction — and it's already been seen
If this is right, the local expansion rate H₀ shouldn't
be the same in every direction. Look toward a region full of voids, and
you should measure a higher H₀. Look toward a region full
of galaxy filaments, and you should measure a lower one.
H₀ of about 3%, at 3.9-sigma
significance — void-facing directions measure higher, filament-facing
directions measure lower, and the effect shrinks at greater distances
(where the universe looks more uniform).
Standard cosmology, which assumes the universe expands isotropically at all scales, has no easy explanation for this. In this framework, it's the expected signature of two-component expansion.
What's still open
I want to be upfront about what this version does not yet do.
The light-bending result from General Relativity
(4GM/bc², famously double the Newtonian prediction) can now
be understood intuitively — a star's surface approaches a passing light
ray and flattens as it expands, and these two effects turn out
to be equal in size, which is why GR's answer is exactly twice Newton's.
But a fully rigorous derivation of that equality from first principles
is still in progress.
Likewise, the origin of binding forces themselves — why matter resists expansion in the first place — remains outside the scope of this framework. We take it as given and explore its consequences.
The bigger picture
Each of these four results addresses something standard cosmology treats as a separate, unexplained puzzle: why dark matter clusters the way it does, why the universe doesn't collapse, why galaxies drift apart, and why the Hubble constant disagrees with itself. In this framework, all four come from the same equation, with no new particles, no new forces, and no free parameters.
Spacetime, in this view, is a map — a coordinate system invented by observers to track an expanding universe. Like any map of a curved surface projected onto a flat page, it distorts. Dark matter and dark energy are the cosmological equivalent of Greenland looking as big as Africa on a world map: not real objects, but artifacts of the projection.
v6.2 preprint (Zenodo) — The Expansion Freedom Principle v6.2
v6.1: The Expansion Freedom Principle v6.1
v6.0: The Expansion Freedom Principle v6.0
v4.0: Gravitational Flux Transport Networks v4.0
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