The Universe Is Not What It Seems

In the first four layers I treated the universe as if the lensing cosmic web were a kind of quiet background. The winding route of light, the direction sensitive distortion, the scale dependent amplification, and the build up through time all describe a web that does grow, but that changes fairly gradually on cosmic timescales. Layer 5 breaks with that picture. Here the dynamics come forward, the fact that the web sometimes does not grow gently, but jolts, grinds, and explode

Until now we have acted as if δ were a kind of fixed knob. In Layer 1, δ appeared as the average shortening of radial distances, because light winds. In Layer 2, a direction dependence was added on top of that. In Layer 3, we saw that not all scales are treated equally, small structures are optically emphasised just a little more than large ones. In all those layers, however, there was still a silent assumption underneath, that δ is the same everywhere along the light cone. L

I think you only really begin to see how sophisticated the universe is in distorting our picture once you look not only at how much, and in which direction, light is deflected, but also at the scale at which that happens. Layer 1 was about an average, the winding road, summarised in δ. Layer 2 added that this winding is not the same everywhere, some directions are optically heavier than others. Layer 3 adds one more dimension to this. It says that the lens strength of the cos

Layer 2 begins with a question we rarely ask out loud, whether the universe is equally honest to us in every direction. In Layer 1 it was about an average, we discovered that light paths wind, and that we therefore systematically overestimate radial distances. We captured that in one number, δ, an average shortening of about eleven percent when you redraw the winding road as a straight line. But nothing in nature guarantees that this effect is exactly the same in every direct

The biggest mistake we make in cosmology is painfully simple. We act as if light behaves like a laser beam in a dark room, one clean line from source to detector. We measure how red the light is, how bright it is, how long it takes, and we put a straight distance and a corresponding mass next to it. Anything that deviates, we push onto missing matter, dark matter, or dark energy. Layer 1 of GLV begins exactly there. It says, wait, what if the error is not in the mass, but in

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 st

A universe does not begin the way we are used to letting stories begin. We love opening scenes with, once upon a time, in the beginning, one day. The Big Bang is often told like that too, a single point, a kind of cosmic spark, and then the whole story of space, time, matter and life unfolds. That is understandable because our brain is built on timelines and causes. Still, I believe this way of thinking misleads us as soon as we get too close to the origin of the universe. If

I think our universe has a shape that our everyday intuition does not really know. We are used to lines, planes, and spheres that you can still, in your mind, turn around and examine. A table is flat, a ball is round, the Earth is a kind of large marble that you can fly around. But as soon as you take one step further, to the question of how the universe as a whole is put together, our intuitions get stuck. We try to cram something that includes everything into the same menta

There is something that is more fundamental than everything we normally mean by “the universe”. More fundamental than stars and planets, more fundamental than particles, even more fundamental than space and time. In our everyday thinking, we place things in space, and we let them move in time, as if space and time themselves are a kind of neutral background that is simply already there. In my mind, that is reversed. Space and time are not hard, given in advance markers, they

In many popular depictions, space is the ultimate form of silence. A black void, an endless plain without air, without sound, without disturbance. If there is anything we humans like to declare empty, it is space. But imagine an astronaut floating in the International Space Station, seemingly safe inside a metal cocoon high above Earth. Outside it is night, inside it is quiet. The Earth slides blue and silent past the window. And then, suddenly, something sounds that, at leas

I believe our universe is fundamentally different from what we commonly assume. I’m not a physicist. I approach the cosmos from a philosophical perspective, and far from seeing this as a limitation, I consider it an advantage. Many of the great thinkers of antiquity were both philosophers and natural scientists, laying the foundation for what we now call physics. Philosophy and physics have always needed each other, and I believe that still holds true today. Physicists often