Part 2: The Birth of a Universe. Chapter 2. The First Light Paths and the Misleading Universe

From the very first moment, the universe pulls a trick on us. Not because nature wants to deceive us, but because the only messenger we have, light, always tells us only half the truth. In the previous chapter I described how our universe arose as a phase in a zero point field as a rare but natural ripple that grew into a complete spacetime. In this chapter it is about the first light paths in that new phase and about how we, billions of years later, try to reconstruct the story of the universe from those light paths. That is exactly where things go wrong.

Everything we know about the universe ultimately comes down to measuring light and other forms of radiation. We do not see “space itself”. We see photons that have travelled through that space and now land in our detectors. We read off redshift, intensity, direction, polarisation and from that we infer distances, speeds, and masses. In all those steps, one major assumption slips in, that the path the light travelled is close enough to a straight line in a neatly described spacetime. We act as if light moves like a laser beam through a reasonably smooth medium, with at most the occasional obvious lens that we account for. In my worldview that a big mistake. The universe we reconstruct from light is therefore not the same as the universe that is actually there.

To make that clear, it helps to go back to the beginning phase. As soon as our universe phase in the zero point field has inflated enough, the inside is hot, dense and opaque. Photons constantly collide with charged particles, they are absorbed and emitted again. There is not yet any free light path that can travel far, everything is scattered over short distances. Only when expansion and cooling have progressed far enough for protons and electrons to bind into neutral atoms does space become transparent. From that moment on, with some exaggeration, photons can for the first time truly move freely through spacetime. That is what we see today as the cosmic microwave background, light that was released about three hundred and eighty thousand years after the beginning of our universe phase and has travelled through the growing three sphere ever since.

Those photons are our oldest light paths. They have crossed almost the entire history of the universe, from the compact, young three sphere to the stretched out phase of today. On their journey they have passed along and through everything that has formed within the phase since then, the first condensations, proto galaxies, clusters, the cosmic web of filaments and voids, the halos of dwarf galaxies and the most massive black holes. If you really try to imagine that path, you do not see one neat line. You see a trajectory that constantly bends a little, slows down, speeds up and is reshaped by minute curvatures in spacetime. Every bit of mass and energy that formed along the way slightly deformed the shape of the field and with it the route of the photon.

Here lies the first source of misdirection. In our calculations we usually do the opposite, we measure the properties of the light that reaches us now and we assume one simple, effective geometry behind it. We say, if this photon has a certain redshift and is this bright, then the source must be this many light years away, in a space with this and that scale factor. But that is like taking the duration of a car trip over a mountain pass and using it to determine the straight line distance between two villages, without knowing that the driver kept taking detours. The time is right, the speed is right, but the route taken is not the shortest. That is how we overestimate the radial distance of sources, precisely because we ignore how winding the light paths are.

In the language of GLV, this means, the optical path is longer than the geometric distance. A photon travelling through the cosmos does not take a billiard straight route, it takes a road full of hairpin turns past gravitational wells of every kind and size, from dwarf galaxies to massive clusters. Each of those mini lenses bends the trajectory by a tiny amount, lengthens the path a little, and shifts the arrival phase by a fraction. These are small effects per encounter, but the number of encounters is enormous. The net result is that the photon, within the zero point field, has travelled a longer route than we assume when we simply divide its travel time by the speed of light. When we project that too long optical route back onto a straight map, we place the source systematically too far away. I call that error radial distance bias.

The same error shows up in almost all our cosmic measurement methods. If we use standard candles, supernovae whose intrinsic brightness we think we know, we infer a distance from the measured flux. But that distance is based on the idea of a straight path in an FRW space, not on a zero point field full of tiny lenses. If we use standard rulers, such as baryon acoustic oscillations, we interpret the measured angular size of structures as if the underlying geometry is smooth. If we link the angular position of the first peak in the background spectrum to a particular horizon length at decoupling, we do something similar. Each time we place a straight ruler next to a winding trajectory. The universe you get on paper that way looks larger, younger, or more rapidly expanding than it really has to be.

The irony is that we already recognise part of that misdirection in gravitational lensing itself. We know that massive clusters distort the light from background galaxies, they stretch it, they pull it into arcs. We even use that effect as a magnifying glass to look farther than our telescopes would otherwise allow. But in our mental picture it remains an exception, a few recognisable lens systems in the middle of an otherwise fairly empty space. In my worldview it is exactly the other way around. The exception is the perfectly straight light ray. The normal case is a path that constantly makes tiny kinks without us seeing them individually. We take the smeared out optical route, we smooth it, and we pretend we are drawing a straight line back. At every step, something goes wrong.

The result is a misleading universe, but the deception is not in nature, nature simply does what it does. The deception lies in our translation from light to reality. When we find that stars at the edges of a galaxy rotate faster than you would expect based on the visible mass, we conclude that there must be an extra source of gravity, dark matter. But the rotation speed is derived from light, through Doppler shifts and through a distance estimate that can be radially too large. If the effective light path wound more than we assume, then the true radius is smaller, and the required mass is smaller too. Then less “dark” is needed to support the same speed.

In clusters we see the same pattern. We measure how strongly they bend the light of galaxies that lie even farther away, and we combine that with the visible mass in gas and stars. We attribute the difference to a dark halo structure. But here too we reconstruct a lens from deviations in the light field, without fully accounting for the fact that the light has already passed through a web of smaller lenses before it even reaches the cluster. The cluster then appears to lens more strongly than it really does as a local mass, simply because we do not calculate the full lens stack along the line of sight, we attribute it to one visible object. The universe looks like a larger weak gravity lens than it actually is.

On cosmic scales the same game repeats. When we look at supernovae in distant galaxies, we see that they appear fainter than you would expect from a simply expanding universe. The standard interpretation is that the expansion of the universe is accelerating, driven by a mysterious dark energy. In the GLV picture, I question the optical route instead. If space is nowhere empty, if the zero point field has small structures everywhere, then the light cones between those supernovae and us are not pristine. Photons have followed bent routes, their optical path is longer than the shortest distance. If we convert that extra length incorrectly into “how far away the supernova is” and “how much space has grown in the meantime”, then part of what we see as accelerated expansion can be misleading geometry.

That does not mean that every deviation can be explained away with “light winds”. It is not that simple, and I do not want to make it that simple. But it does mean that you first have to take optical paths seriously, and actually calculate them, before you introduce new entities. In my GLV framework, that idea becomes concrete through an optical correction term, an extra piece in the story of the geodesic, the light path, that tells how much the radial distance has been systematically overestimated compared to a calculation that does not account for all the mini lenses. That correction grows with distance, precisely because distant photons encounter more structures and accumulate more kinks. The misleading universe does not suddenly become “honest”, but we do get a more honest map.

You could say that the first light paths of the universe carry two different stories. The first is physical, they tell us what the young phase of the zero point field looked like, how hot and how dense it was, which quantum ripples lived at the beginning. That story sits in the spectral distribution and the fine structure of the cosmic microwave background. The second story is optical, they tell us how winding the route of each photon toward us has been, which structures it passed along the way, how much extra path length was added. That story sits in subtle deviations in brightness, in small shifts of angles, in the statistics of lensing. Up to now we mostly read the first story and we act as if the second hardly matters. My claim is that you are not allowed to separate them.

So the misleading side of the universe does not arise because the zero point field is “fooling” us, it arises because we confuse one kind of information, intrinsic content, with a mixture of content and route effects. It is like trying to infer how far apart two cities are from the kilometres on a car’s odometer, without knowing that the driver took detours, sat in traffic, and drove back a little. You can measure precisely how much fuel was used and how long the engine ran, but if you ignore the shape of the route, you get a distorted map. In cosmology, light is our odometer, and the cosmic web is the hairpin turns.

In the next chapters I will unpack this misleading universe further. How, with a zero point field, a three spherical shape, and winding light paths, you can understand the behaviour of gravity without dark matter as an extra substance. How rotation curves, clusters, background radiation, and supernovae can be reread in that light. And how the combination of quantum mechanics and relativity, supplemented with an optical lens, can lead to a universe that is still complex, but less mysterious than it seems at first glance. Because if there is one lesson in these first light paths, it is this, it is not the universe that lies, it is our assumptions about how we look at it that do.