Beyond Our Senses: What the Universe Still Hides from Us

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Major concepts

"It is absolutely possible that beyond what our senses perceive, lie unsuspected worlds." Albert Einstein (1879-1955).

The scientific revolution

Behind this quote from Einstein, one perceives the great scientific revolutions to come. New concepts will eventually align with observable facts and then be replaced by other concepts. Indeed, great scientific revolutions emerge when they go against our senses and our emotions, to the point of appearing erroneous to us.

The limits of perception

Our senses allow us to approach reality and feel the world around us. "Nothing ever becomes real until it is experienced." John Keats (1795-1821), English Romantic poet. But if our senses show us the contours of the world, they also limit reality. We see only the nectary region (the part of the flower that secretes nectar), the one that interests us most.

Fundamental concepts

The great fundamental concepts (Gravitation, Space, Time, Vacuum, Mass, Life) still seem mysterious to us. It would not be surprising if they corresponded to something other than what our senses tell us about them.

Our senses deceive us!

Gravitation

Gravitation makes all bodies fall at the same speed regardless of their mass. This law of falling bodies goes against what our senses tell us.

The Earth and its movements

The Earth is not at the center of the universe; this goes against what our senses show us. The Earth rotates on itself at 1,674 km/h while moving at 107,200 km/h around the Sun, which itself travels at 792,000 km/h, and yet our senses tell us nothing about these movements (see note).

Space and time

Space, which we consider as a passive void, can curve, twist and ripple in the presence of masses, and worse still, it can also contract, which is counter-intuitive. We thought time was absolute, but it is relative. In our daily lives we live with the Newtonian image of space and time; we do not feel this flexibility of space-time. If we traveled at the speed of light, we would see space adjust to time, contract so that the speed of light remains constant. We now know that time is space, and space is time. In astronomy, the two concepts are strongly linked; we describe a distance with time (this star is 100 light-years away). We think of a distance, but we are talking about time and speed, that of light.

The quantum vacuum

The concept of vacuum, which we consider as the absence of matter, is even more astonishing. The vacuum is not nothing; on the contrary, according to physicists, a lot happens in it. Virtual particles patiently wait for a certain energy to appear for real. Empty space is a chaotic and seething place. The waves that travel through the vacuum vary the electromagnetic field, which is why the vacuum contains energy. Everywhere in the cosmos we observe relic radiation, the cosmic microwave background.

Mass

Mass is another equally mysterious concept. Billions of dollars have been invested to make the famous Higgs Boson appear among all possible energy windows. The Higgs field is what gives mass to particles. The Higgs mechanism fills the entire universe and all space with a molasses, a field of bosons, which makes matter matter. The more particles struggle to pass through this field, the more mass they acquire. Yet we have difficulty conceiving matter without mass; the link between mass and matter is very strong in our minds. Indeed, what is an object without mass?

Life in the Universe

And what about the concept of life; it is the one that fascinates us most. Our egocentric senses tell us that we are the product of a miraculous creation, but are we really alone in the Universe? This question has been on the minds of our astronomers for a long time, and to answer it they invented the technology that allows us to "see" other planets in other worlds. Images of exoplanets are promised for the 2030s. Here again, our anthropocentric view of the world is likely to be challenged if biosignatures are discovered in the atmosphere of other planets.

N.B.:
Why do we not feel the different speeds of the Earth's movement on its orbit and in space? The accelerations and decelerations exerted on us are too weak compared to the main force, gravity, which keeps us on the Earth's surface. In other words, the centrifugal and centripetal forces that could shake us are far too weak to be felt.

What the universe still hides from our senses

So, like Einstein, we now know that it is perfectly plausible that beyond our sensory perception lie unknown realities. If relativity and quantum mechanics have already shaken our perception, the universe has much more radical surprises in store for us. Dark matter (27%) and dark energy (68%) govern the cosmos without us feeling them, while string theories evoke extra dimensions folded away from our sensory geometry. Time could be nothing more than an emergent illusion, and quantum entanglement dissolves our notion of space by instantly connecting particles separated by billions of light-years.

Consciousness: emergent illusion or fundamental reality?

The nature of our own existence could be far stranger than our senses lead us to believe. Consciousness, which we experience as a continuous and unified flow, may be a simple artifact of our memory and neural processes. More radically, some physicists and philosophers consider that consciousness is fundamental, on the same level as space and time – a hypothesis that would completely overturn our view of the world and our place in the cosmos.

Nothingness: an unstable void or a logical impossibility?

As for nothingness, it may be nothing but an empty word. Quantum physics shows us that the vacuum is teeming with energy and virtual particles; but more deeply, the very existence of the cosmos could arise from an instability of nothing, as if nothingness was doomed to produce something. And if the universe were nothing but a quantum fluctuation on a cosmic scale, our entire reality would be only a temporary accident in an ocean of absence, a breath between two nothings.

The simulation hypothesis and the holographic principle

Even more troubling concepts emerge from mathematics and cosmology. The simulation hypothesis envisions that our universe is merely a computer program running on an external platform, making our existence virtual. At the same time, the holographic principle suggests that our three-dimensional space is merely a projection of information encoded on a two-dimensional surface, like a relief image emerging from a simple screen. In this framework, our senses deceive us twice over: they do not even perceive the true nature of the reality they claim to measure.

Parallel realities and still unnamed concepts

Finally, the multiverse extends the enormity: every decision, every quantum probability could give rise to parallel realities, making our existence a tiny branch among an infinity of others. But beyond even these models, concepts not yet imagined could emerge from future scientific revolutions – phenomena that our brains, shaped by survival on a mundane planet, are not programmed to conceive. These horizons, far beyond our senses and our intuition, remind us that the greatest revolutions may be those that challenge not only what we see, but what we are.