Dark Energy

On turning 33

Thanks for reading my newsletter! All opinions expressed here are strictly my own. Find me on X, Instagram and TikTok. I’d also love it if you shared this letter with a friend.

DARK ENERGY*

My parents would tell you that we were not the most Catholic household on the block, and they would be telling the truth. But I still know what it means to turn 33.

I was brought up within the kind of Catholicism where ritual and tradition were more important than gospel, so it did not matter that the Bible is not exact on how old Jesus was at the time of his resurrection, or that historians typically suggest a range of ages instead of one fixed number. “It’s the Jesus age,” my dad would simply say whenever someone turned 33. This made the number feel pivotal, a marker of a time when you just might change your whole life and emerge as someone new. I remember my uncle turning 33 and getting teased for still being childless and single in his Jesus year. Now, it’s up to me to find out whether the coming year will bring transformation, ascendance or just taunts from the universe .

***

On the Between the Covers podcast poet Danez Smith talks about “self-community across time,” and how the idea relates to their use of the pronoun “they.” For Smith, “they” is not just about rejecting the gender binary, but about embracing many ways of being, including those from the past and the future. It’s about acknowledging evolution and change as fundamental building blocks of personhood. You know how a caterpillar has to dissolve to become a butterfly? Listening to Smith, they didn’t sound interested in fully dissolving anything: their “they” was both the caterpillar and the butterfly as much as it was both the feminine and the masculine.

As a physicist, I was trained to always think about the future of some object. This is what many of the famous physics equations, or at least the ones named after physicists that became famous because of them, are for. You can combine Newton’s laws into an equation which you can then mathematically coax into telling you where some object, whether it be a ball rolling down a hill or a star caught in an orbit around a planet, will end up at any future time. Lagrangians, Hamiltonians, and the Schrodinger equation, which are formulas and mathematical recipes at the basis of both non-quantum and quantum physics, serve a similar purpose. Many quantum physics calculations center on finding “expectation values” of objects’ future properties. In quantum field theory you are almost always calculating something called “the propagator,” which tells you how to take a particle from the present into the future, to set it on a sort of mathematical march forward in time.

So-called time evolution is also where quantum physics breaks apart from its predecessors, and where it pulls certainty away from you. If you know that a quantum particle started at one position and having one set of properties and if you know that it ended up at another position with another set of properties, there are typically very few mathematical or experimental tools that could tell you what exactly happened in-between those points. This is not the case in the classical, or non-quantum, world where it is always possible to construct a mathematical model that will allow you to, at least on paper, turn back time, and determine every step of an object’s evolution or trajectory. Attempting to trace out the quantum particle’s history, on the other hand, leaves you with episodes of fuzziness, some of its past selves just vague possibilities.

In 1948, physicist Richard Feynman demonstrated that this property that flies in the face of what enlightenment era thinkers thought science was about, namely the possibility of rationally reasoning out anything about anything, can actually be useful. If you want to know how a quantum particle makes it from point A to point B, he reasoned, you have to perform an intricate, weighted sum over all the possible ways in which it can do so. Every path, from the very sensible straight line to the completely wacky loops and detours, must be considered and added up to find the trajectory that is closest to being the particle’s truth.

As I write in my forthcoming book, when I first learned about this method I found myself heavily empathizing with the quantum particle. Hearing Smith speak brought the image back to me: all the different me’s who took all possible paths through life trying to find a way to add up into the person that I am now. Accidentally, I have also found an awful lot of peace in “they.” But my ‘they’ has always been a place of indeterminacy, a signifier of existing in an in-between that at once feels liberatory and rebellious. Smith’s ‘they,’ on the other hand, sounded like a multitude, a comfort in being many as opposed to a comfort in rejecting all. On the podcast, they say:

“For me, there is that multiplicity within they-ness. I think that multiplicity speaks more than just to gender, even community, but a multiplicity across time as well. I am in community with my older selves that I haven’t arrived at yet. I am setting up gifts and problems for them to receive sometime in the future.”

It’s my birthday in five days and, as I often do, I am wondering whether the versions of me that existed in the past would approve of how I’ve lived while 32. The teenage me who wanted to be an important physicist probably wouldn’t. Me from ten years ago who had just begun graduate school and loved it definitely wouldn’t. The lockdown-era me who wanted to be ‘a real writer’ maybe would. Could I still be in community with them all?

I bought Bluff, Smith’s latest book of poetry, and it surprised me just how heavy with criticism of the poet’s past selves it was.

***

The X-Men animated series was originally supposed to end in 1995 with a four-episode arc called “Beyond Good and Evil,” which is a true showcase of 90s superhero animation that features so many characters and Easter eggs that it could put many MCU productions of recent years to shame. While X-Men movies range from fun to terrible, the animated show was consistently amusing and campy, and its fairly flat characters still regularly elicited a strong emotional response even if it was by leaning into cliches. I liked last year’s X-Men ‘97, which picks up where the original animated series ended up concluding after Fox unexpectedly commissioned an extra season, but that was a show written for nostalgic adults rather than to sell children toys, and something about that changed emotional context made me crave the less self-serious tone of the original series. It was as fun and as silly as I remembered. But I had fully forgotten just how many episodes involve time travel.

From very early on in the show’s first season, the X-Men’s future is not just looming ahead of them, but actively chasing after them in the form of various time-travelers. Characters from the future often travel to the series’ present in order to change something about their world, and present day X-Men almost never ask to travel to the future, seemingly content to not take any shortcuts in getting there. Because causality in this animated universe holds in the same way that it does in physics textbooks, many of the time-travel plot lines become hard to parse without running into a paradox, but the show is relentless in returning to them.

“Beyond Good and Evil,” which borrows its title from Nietzsche, is a prime example of this. It features a cast of time-traveling heroes, notably the X-Men called Cable and Bishop who do canonically belong to the future, and an all powerful villain aptly named Apocalypse who wants nothing less but to destroy time itself. His plan is simple: capture all psychic mutants then focus their powers, against their will, onto a special part of the universe called “The Axis of Time,” in order to break time and re-birth the cosmos with himself as its absolute ruler.

Apocalypse is generally not a compelling villain because he does not seem to have any weaknesses. X-Men do often thwart his plans, but it seems implausible that they could ever truly defeat him so he is a rather flat and self-assured kind of “big bad.” “Beyond Good and Evil,” starts with a consideration of one of the traits that make Apocalypse annoying: his immortality. Cable and his team time-travel to find the villain performing a ritual that keeps him from aging and they attempt to kill him in this moment of singular weakness. They fail, but in the process of fighting them Apocalypse has a realization. It dawns on him that despite all his superior power, he has not been able to defeat the X-Men, and that their cat-and-mouse game has unwaveringly persisted throughout all times and timelines. He ends up wanting to do battle with time itself, aiming to break the pattern of fighting not by winning the fight but by making it impossible for it to repeat.

In one dramatic moment, while trying to explain how mutants’ psychic powers relate to time he says:

“Time is motion and motion and thought are unity, two aspects of the same power.”

I paused our clunky hand-me-down TV to write the line down, trying to discern whether it was profound or simply nonsense. Over the course of dozens of episodes, this may be the first time that I really cared about Apocalypse and what he had to say.

In the past year, I kept writing about time, in my day job as a science journalist and here on Ultracold more than ever before. In my birthday card, one of my coworkers cheekily wrote “thank you for making me doubt that time is real.” I am far from an omnipotent cartoon villain, but as it turns out I had made it my daily business to fight with time, and then tell everyone about it. Maybe Apocalypse was onto something and breaking time would be an easy way out, maybe there would actually be so much relief in a still, thoughtless, never-ending now.

I think this is why I struggle with birthdays, not because I am scared of getting older, but because I am reminded that time is passing and I cannot do anything to stop it, that I can’t do anything to force it to grant me a break from moving, being and becoming.

While Bluff finds Smith scolding and negotiating with their past selves, going as far as reworking old poems, the book looks forward in time too. Smith worries about the future for all the reasons that are getting harder to ignore by the day. They write about police brutality and war, about climate change, and about all the other deleterious effects of capitalism that have rooted themselves in our environment, minds and hearts. Considering it all at once, Smith repeatedly raises the question of how fragmented our future might end up being, and who will get to imagine and design their slice of tomorrow while others have theirs forced upon them.

“Who gets to pace utopia while we build apocalypse? Who gets to live by paradise as the world closes into heat?”

they ask. Then:

“The world might end here later. I want to live. I want to live longer. I want to live longer than other people if everyone must die. Oh shit. What a simple, rich, evil want. A hunger so small and selfish. I feed it. I sign its lease.”

I recognize this too: a craving for a future of comfort, maybe even success, a small leaning into the forward march of time that can cause a transformation into someone monstrous, who also lives somewhere monstrous. Bluff captures the fraught nature of now so well, alternating between trying to deal with the poet’s past selves and this kind of pre-emptive distrust of who they may become, a scrutiny of people that they may transform into. All the while, time pushes them forward. All the while they are transforming.

In the next line of the poem, Smith is running along a river. They are in motion, in thought, tracing out a trajectory across spacetime. Even in the realm of verses and rhymes, stasis is simply not an option.

***

Space is technically not my beat, but sometimes all the space reporters are busy and the universe is breaking news. Once, researchers were opening a capsule that had travelled through space, touched an asteroid and returned to us full of its dust - and it was my job to make some frantic phone calls about it. More recently, space caught up with me when an international team of scientists used a swarm of detectors in Arizona to get a good look at how millions of galaxies formed and organised themselves into clusters over the last 11 billion years. The breaking news was that even with such a vast amount of data to be tested against, our theories of gravity still seem to match reality rather well. My editor wrote a pithy headline: “Einstein’s theories tested on the largest scale ever – he was right.” The universe had made a small nod towards our understanding of the forces and structure that shape our physical now.

While the past is almost always by default fuzzy in quantum physics, space researchers tend to delight in telling me about it in stunning detail. Our telescopes and other devices that collect and analyse radiation and light routinely afford us a surprisingly clear look into the past. This is because of one constant property of our universe: light travels through it at one unchanging and finite speed.

We only see objects once light that touches them, or that they emit, reaches us. Because light is not infinitely fast, that journey takes time. So, by the time light does reach us, the object that it’s trying to represent has changed and the light’s travel time has been added to its age. And then there’s the fact that spacetime does not stand still while light travels through it. It is constantly stretching out because of forces that we do not fully understand yet and it is curving or dimpling around and underneath massive objects. So, light picks up lots of information about regions of the universe that it travels through because it is affected by all the stretching and curving. It comes to us more red or more bent than it started and we reverse engineer the past universe that did that to it.

For instance, right after the Big Bang, our universe was a hot soup of subatomic particles, and the light that emanated from it still fills our skies. Time has changed it, it is not warm and bright anymore. Instead, it became microwave radiation, which is invisible to our eyes, but easily detected by machines. It’s like the loud cry of an infant cosmos became a low ever present whisper in the roughly 13 billion years since.

When Smith writes “i seen too much. i read the ink between the stars,” I think about this sense of a past lurking between the stars in as physical a way as possible, not a metaphor but something that a good detector will show you is essentially inescapable. (When astronomers Arno Penzias and Robert Wilson discovered this “cosmic microwave background radiation” in the 1960s, they thought that it was just some glitch in their detector, maybe even the work of pigeons that nested near the antenna that they were using to collect radiation, but evacuating the birds didn’t stop the signal.)

Stars are often mentioned in Bluff, often as a stand-in for a cosmic guide, or a higher power, but I was reminded of how stars are also remarkably reliable transformers. For most stars, you can comfortably predict how they will evolve over time and which stages of stardom they will go through. Our Sun, for instance, will become a much cooler and larger star in about 5 billion years. After a few more billion years it will shrink and become an extremely dense star called a “white dwarf.”

We know this because of the current chemical composition of the Sun and the nuclear processes that keep it burning bright. Eventually those processes, that burning, will transform enough of the Sun’s atoms into different elements and the whole star will change. The star is locked into this transformation and cannot escape it. The Sun really will have one grand moment of transformations, its own Jesus year when it dies and is then resurrected as something new.

Many stars have actually found their final transformation in becoming parts of us. They exploded, dispersing their atoms into messy clouds where gravity made them cluster together and form new structures. Gravity’s one function is to pull objects closer to each other so these tiny clusters also clustered and eventually formed structures as large as planets, where chemistry gave rise to life. As Carl Sagan famously said, “We are made of star-stuff.” The stars are then part of that time-spanning “they.” In fact, the remnants of them that still exist within me might just be the parts of my “they” that have lived the longest and transformed the most. In my self-community across time, I hope they can hold the hands of all those less mature versions of me that get so scared about what may come next.

***

A few weeks ago, a dear coworker gifted me a copy of their poetry zine. Printed on burnt orange paper, the poems felt familiar even though I had never read them before. This was because they drew on some of our most loopy, but also most earnest newsroom conversations about the nature of space and time. Here were the sentiments that we could not put in print, but certainly felt driven to say to each other, yelling at me.

On one page, a column of overlapping text simply read:

“HOW UPSETTING

TO LIVE IN A BODY

AND BE SUBJECT TO TIME.”

On the page opposite:

“Everything changes all the time

Which means time must be passing

Which means time exists

And I don’t know why

If I could figure out where it came from

Maybe I could turn it off

Maybe I could stay here with you forever

What do we think the big Time Switch looks like.”

I hate to tell you this but I don’t think contemporary physics supports the Big Time Switch theory.

I hate to tell this to myself but even that superpowered cartoon villain did not manage to break time. The X-Men thwarted his plans. Their present kept unraveling into the future just like at the end of any other episode. There was no grand restart, no unraveling and remaking of their cosmos, they just had to keep going at the regular pace, maintaining relationships with their past and future selves as best as they could.

On another podcast, poet Eileen Myles says:

“My purpose is to write the poem of the moment I’m in and that moment keeps changing so I wanna keep making a new poem.”

I get it. I’m trying to write about the world, but the world keeps changing too. Light from the oldest and most distant corners of the universe keeps traveling towards detectors across the world and showing us how different the past was. In huge particle accelerators, researchers are smashing atoms together to alchemize new elements. On dinner-sized tables, scientists are pushing atoms around with lasers and finding new ways to cajole them into chemical reactions. And I don’t even know about all the things we can do with turning genes on and off. And all the while, the universe is expanding, relentlessly. Whether physicists understand the reasons why or not, I think it simply has to.

At work, A big chunk of December is reserved for articles that either summarize 2024 or make predictions for 2025. My coworkers and I round up everything, from the weirdest robots that debuted in the past year to sightings of northern lights. Looking for one of my pieces, I scroll past images of cool new snakes and frogs and stop, but a list of “most encouraging climate solutions and green technologies” catches my eye. In the piece, one of my colleagues writes

“Some analyses project that global emissions from energy may hit a peak in 2024 (although they said the same about 2023)”

Then segues into a list of studies that could add up to a more hopeful case for the future of our planet. The list ranges from more sustainable ways of making cement to the world’s largest sailing cargo ship successfully completing a long journey to spreading crushed rocks that absorb the greenhouse gas carbon dioxide all over farms. The first sentence admits that predicting the future is hard. The list that follows it puts forward examples of people not being discouraged by that difficulty.

I tend to be cynical about “climate tech,” and I have been a reporter for just long enough to understand that most studies never actually leave the lab and become commercially viable products. A single study rarely feels like a convincing case for optimism, and assertions that what will save us is more technology rather than a changed relationship with it almost never does. But this list still reminded me that having valid reasons for worrying about the future does not mean that we lose agency, or that we get to stop trying. Just because the forward motion of time may be pushing us towards something scary does not mean that the only solution is to break the whole thing. There are no cheat codes to existing in our universe, but the game of cosmic existence is still worth playing.

As anarchist and writer Margaret Killjoy writes:

“The future, our future, is unwritten, but we know how to write. We will write that future together. If we’re all aboard that ship, cast about by the winds, we know how to rig the tack or row the oars or whatever (again, I’m not a sailor). We sail our way through the storm by doing what we know how to do best: we take care of each other. We build and reinforce structures of mutual aid. We refuse despair.”

While the process of writing the future may transform us, there is a big difference between becoming someone new and having to fight who you were before. Journalist and author Annalee Newitz puts forward a version of the future that acknowledges the difficulties that the future may bring without tipping into despair:

“If the U.S. goes fascist, you will start dealing with even more disturbing messages from the government. These might take the form of threats to your livelihood, or promises that you’ll be the victim of violence. You might have to watch what you say, or risk retribution from the police. Your ability to travel over borders could be limited or cut off completely. You may lose your job unless you comply with orders you know are morally wrong.

You may also risk your life to protest and fight for freedom.

But you will also eat meals with friends and family, if you can. You will keep working, if you can. You won’t become a completely different person. You will be the same old you, but your life will now include a whole list of tasks related to dealing with new levels of state-authorized control and violence.

We shouldn’t normalize fascism. But we should accept that part of our everyday lives will involve fighting it – for ourselves, as well as for our friends, neighbors, and allies, in the present and future.”

I read these words once, then again, and by the third time they feel practical and reassuring in that cold no nonsense way that getting advice from a friend who loves you enough to never offer sugar when something more bitter will ultimately be more nourishing. But this is always where I end up, isn’t it?

This is my fight that repeats through time over and over again: an effort to keep replacing fear with hope, even if the fears are slightly different every time, even if they keep becoming more justified. I don’t want 33 to bring me a rebirth or a resurrection, I think I really just want to know that as time keeps going, I will also keep finding ways to not grow bitter, resigned and hopeless.

And because I am not a star constrained by nuclear reactions or a cartoon character at the mercy of screenwriters, I have some agency over who I will be in the next year. Right now, I can look at my “they,” at everyone that I have been so far and who I am now, and make room for another person that does not give up. I can close my eyes and quietly send them a warm invitation to join us, politely noting that if we’ve made it from being an atom in a dying star all the way up to here, then how could we ever think that what’s going to truly do us in is being 33.

***

As of this writing, in the past year, I reported 142 articles for New Scientist, wrote 15 editions of Ultracold, and I wrote a book manuscript that clocked in just shy of 300 pages. I made a little under 50 cakes, a few dozen loaves of bread and many, many dinners to be shared with the people I love. I went boxing and practiced yoga weekly, I also averaged between 20 and 30 miles at a comfortable running pace most weeks, though I did slack off on my strength training. My sleep schedule was horrendous and for at least half of the year I was some degree of heartbroken. I was very tired, very often. Thank you for having kept up with me through it all.

Best,

Karmela

* Dark energy is the force that is making the universe expand at a constantly increasing rate (faster and faster), but physicists do not know any details about it nor have they detected it directly. It accounts for 68% of the total energy in the present-day observable universe, which means that most energy out there is actually dark energy.