The “mystery of time” permeates the cosmos and our most intimate experiences. Between the limits of physics and the body’s ability to recover, a reflection on what passes, what changes, and what we can rediscover.
There are days that seem to add years to our faces. And encounters that, on the contrary, seem to restore a forgotten lightness to us.
“You look younger,” we say to someone who has found their smile again after a difficult time.
It’s an affectionate remark, but it contains a surprising question: what has really changed? Time, the body, or the way we live our lives?
At an immense distance from human affairs, black holes challenge another of our certainties: that space and time are always comprehensible through the images of everyday experience. Bringing these two worlds together can spark a fruitful reflection, provided the connection remains a question and does not become a proof.
The boundary beyond which we cannot see
When we imagine a black hole, we often think of a gigantic cosmic drain: something that swallows matter into an unknown abyss. It is an intuitive image, but it risks suggesting that there is a hidden force,located “on the other side,” capable of sucking everything in.
A black hole, however, is a region of spacetime bounded by an event horizon: beyond that boundary, no light signal can reach an external observer. The horizon thus marks a limit to communication, not a material wall. In the description of general relativity, there is an interior, and events continue to occur there.
Deeper still, the theory leads to a singularity, where the classical description reaches its limit. This does not allow us to imagine a passage to another universe as a proven fact; rather, it indicates that our knowledge is insufficient to fully describe those extreme conditions.
This is where a philosophical question arises: when a description breaks off, does reality also break off?
Science seeks answers through models and observations. In the meantime, thought can explore the meaning of that boundary, keeping open the gap between what we know and what we imagine.
Imagining a Circular Time
Let’s suppose, as a thought experiment, that time can close in on itself. That an end could be a transformation rather than an absolute conclusion. The “let’s pretend that” approach is valuable when it makes its premise explicit.
It allows us to trace its consequences, to look for its contradictions, and to question patterns of thought that would otherwise seem inevitable.
To become a scientific hypothesis, however, an idea must also take on a precise form and be tested against evidence capable of putting it to the test.
Even research on gravity has explored models in which a collapse could be followed by a rebound, overcoming the classical singularity. These are theoretical scenarios with unresolved issues—not proof that time forms a circle or that matter reemerges elsewhere.
Their interest also lies in the question they raise: how much of our conception of time belongs to reality, and how much to the categories we use to try to understand it?
When the Body Changes Its Rhythm
Let’s now return to a more familiar realm: a person is going through a painful breakup, loses their sense of security, sleeps poorly, and struggles to recognize themselves. This distress can affect the body. The systems that enable us to cope with stress are essential for adaptation, but their persistent activation can contribute to a physiological burden that affects multiple bodily functions.
Then something changes. A meaningful relationship, a new perspective, a course of treatment, the chance to feel safe again. The person begins to regain energy and habits that seemed lost.
In everyday language, we say that they’ve “gotten back to their old self”. But that return deserves careful observation: past events remain part of their history. Recovery can bring them closer to a previous state without erasing what they’ve experienced.
A positive encounter can mark a turning point in a person’s life.
On its own, however, it does not demonstrate cellular rejuvenation, nor does it allow us to conclude that depression has been resolved.
The Years That Have Passed and Biological Indicators
Research offers concrete evidence to make this reflection less abstract. Chronological age measures the years since birth; certain indicators of biological age, on the other hand, seek to describe aspects of the body’s condition.
A study published in 2023 in Cell Metabolism, led by Jesse Poganik and colleagues, found temporary changes in biological age indicators under conditions of severe physiological stress, followed by decreases during recovery. The conditions examined included major surgeries, pregnancy, and severe COVID-19 in humans and/or animal models.
These results do not prove that the entire body becomes young again, nor can they be automatically applied to the experience of falling in love. They do, however, indicate that certain biological parameters can vary in both directions: the passage of time and the trajectory of each biological indicator do not necessarily coincide.
The Spiral of Return
To illustrate this possibility, a spiral is perhaps more fitting than a circle.
We can return to a state we have already experienced: regaining strength, confidence, and desire. But we arrive there via a new path. The body has continued to live, the calendar to advance, and experience to leave its mark. Biological recovery does not prove the circularity of physical time, nor does it explain the interior of black holes.
It does, however, invite us to reexamine a more everyday belief: that every change brought about by time must have a single direction and that every loss must be final. An enormous distance remains between the cosmic mystery and the human capacity to recover. What unites them, in this reflection, is the willingness to question what seems concluded.
Perhaps time does not restore the past to us. But life can restore to us possibilities we believed belonged only to the past.
