The end is near, perhaps in 100 billion years. Is it too soon to start freaking out?
“There will be one last sentient being, there will be one last thought,” Barnard College cosmologist Janna Levin declares at the end of “A Trip to Infinity,” a new Netflix documentary directed by Jonathan Halperin and Drew Takahashi.
This statement breaks my heart. It is the saddest and loneliest idea there is.
“I thought he was aware and well informed of our common cosmic situation: that if what we think we know about physics and cosmology is true, then life and intelligence are doomed. I thought I had made some kind of peace of mind with that,” writes Dennis Overbye in the New York Times and continues.
But that was an angle he hadn’t considered before. At some point in the future there will be a last intelligent being somewhere in the universe. And one last thought. And that last word, however profound or trivial, will fade into silence along with the memory of Einstein and Elvis and Jesus and Buddha and Aretha and Eve, while the rest of the physical universe sails on separated by billions and billions and billions. . of lonely and silent years.
Watch the trailer for ‘A Journey to Infinity’
Could this last thought be a profound pearl of wisdom? A swear word?
How did we humans get to this position? The universe as we know it arose in an explosion of fire 13.8 billion years ago and has been disintegrating ever since. Astronomers have debated for decades whether it will continue to expand forever or one day collapse again into a “big bang.”
That all changed in 1998, when astronomers discovered that cosmic expansion is accelerating, driven by an antigravity force that is part of the fabric of space-time. The bigger the universe is, the more this “dark energy” pushes it. This new force bears a striking resemblance to the cosmological constant, a cosmic repulsion that Einstein had proposed as a falsifying factor in his equations to explain why the universe didn’t collapse, but later dismissed as a blunder.
But the cosmological constant refused to die. And now it threatens to destroy physics and the universe.
Say goodbye to the galaxies you’re missing
In the end, if this dark energy prevails, distant galaxies will eventually recede so fast that we can no longer see them. As time goes by, the less we will know about the universe. The stars will die and not be reborn. It will be like living inside an internal black hole, which will suck matter, energy and information towards the horizon, never to return.
Worse yet, because thought requires energy, eventually there won’t be enough energy in the universe to sustain a thought. In the end, there will only be subatomic particles dancing intergalactic distances apart in dark silence, billions and billions of years after light or life existed in the universe.
And then there will be untold trillions of centuries more, until finally there is no way to count the years, as Brian Greene, the popular Columbia University theorist and author, so elegantly and devastatingly described in his recent book All the Way On. next year”.
The perfection and futility of it all!
It’s hard not to want to scream at our own insignificance in the face of this. The universe as we know it now is 14 billion years old, which seems like a long time, but it’s only an infinitesimal fraction of trillion and four billion years. of the darkness to come. . This would mean that everything interesting in our universe happened in a brief instant, at the beginning. A promising start and then an eternal abyss. The perfection and futility of it all!
In short, a story full of sound and fury that means nothing. What do we do with such a universe?
It might point out that it’s too early to predict the future of the universe. New discoveries in physics could provide a way out. Maybe dark energy is not stable, maybe it will go backwards and compress the universe again.
Michael Turner, the University of Chicago cosmologist emeritus who coined the term dark energy, referring to the Greek letter for Einstein’s cosmological constant, said: “Lambda would be the most indifferent answer to the dark energy puzzle!”
But for now, this is what we have to wait for.
The planet will be baked a billion years or so from now, when the Sun boils the oceans. A few billion years later, the Sun itself will die, burning the Earth and what’s left of us.
There is no escape in space. The galaxies themselves will collapse into black holes.
And black holes will eventually release whatever they have imprisoned as a fine spray of particles and radiation, to be dispersed in the prevailing wind of dark energy that dissolves them.
And so, just as there was a first living creature somewhere, once upon a time, emerging from the bright flame of the Big Bang, there will be a last creature to die, a last thought. A final sentient being, as Dr. Levin pointed out.
“That idea stuck with me,” continues Dennis Overbye in the New York Times.
“It never occurred to me that a single being would have the last word on existence, the last chance to curse or thank. Part of the pain is that no one will know who or what had the last word, or what they thought or said. In some ways this idea made cosmic extinction more personal and I wondered what it would be like,” he writes.
Maybe as all the energy will be lost on the horizon it will be like sleeping. Or like Einstein articulating his last words in German to a nurse who didn’t know the language. Or like the computer at the end of time in Isaac Asimov’s classic story “The Last Question,” who finally discovers the secret of the universe and declares, “Let there be light.” Could this be a revelation about the nature of string theory or the ultimate secret of black holes?
I don’t want to lose him, Overbye observes.
I’d like to think my last thought would be love, gratitude, wonder, or the face of a loved one, but I’m worried it’s a curse.
People wiser than I ask, when I talk about it, why am I not complaining about the billions of years before I was born? Maybe because I didn’t know what I was missing, whereas now I had a lifetime to imagine what I would be missing.
If that worries you, here’s an encouraging metaphor straight from Einstein’s equations: When you’re inside a black hole, light pours in from the universe outside, appearing to speed up, while you appear frozen. In principle, you could see the entire future history of the galaxy or even the entire universe next to you as you fall towards the center, the singularity where space and time stand still and you die.
Maybe death is something like that, a revelation of all past and future.
In a sense, when we die, the future also dies.
The past and the future are fiction.
Rather than complain about the end of time, most physicists and astronomers say the idea is a relief. The death of the future frees them to focus on the magic of the moment.
The late great astrophysicist, philosopher, and black hole evangelist John Archibald Wheeler of Princeton used to say that the past and future are fiction, existing only in the artifacts and imaginations of the present.
According to this view, the universe ends with me and, in a sense, I have the last word, concludes Overbye.
“Nothing lasts forever” is a saying that applies as much to the stock market and the stars as it does to our lives and Buddhist sand paintings. A scent of eternity can light up a whole life, maybe even mine.
Whatever happens in the endless eons to come, at least we were here for the party, for the brief, bright strip of eternity when the universe was alive with life and light.
We will always have our Milky Way.
*Article published on nytimes.com