Once a week.
Subscribe to our weekly newsletter.
The lost art of rest: How to relax
In her book The Art of Rest, one researcher conducted a thorough analysis of the top 10 activities we find most restful.
Even though our bodies and minds are begging for a break, modern culture has turned rest into a sin. So how can we catch a breath?
I'll start by telling my own story. It will serve as proof that I represent one of the most severe deficits of contemporary society: I don't know how to rest. However, it also shows that each of us is the best healer of our own exhaustion and can find a way to deep rest. The path is simple to walk, but hard to enter. Especially now, when an urbanized civilization forces its amped-up pace of existence upon us, along with inflated activity norms. But first, we need to escape the rocket in which we are hurling through life.
"When was the last time you went for a holiday?"
This question took me by surprise. It was a beautiful summer afternoon, golden sunshine and light wind seeped into the room. For a long time, I watched the waving lace curtain. I counted, carefully backtracking my memories. The psychiatrist waited, watching me kindly.
"Eight years ago," I said slowly, hardly believing those words. I hadn't taken any breaks between the 29th and 37th years of my life.
"Well, perhaps it's high time for some rest, then?" he said, the question floating gently in the air, light and delicate. "The more work there is in your life, the more time you should make for rest. It may sound like a paradox, but you need to maintain the balance between those two elements."
Of course, I travelled plenty over the course of those eight years; I have been to many sunny places, usually associated with kicking back and relaxing. But every one of those trips had its purpose; I went there to see something, visit someone, write about it. And since my work is also my passion and lifestyle choice, it was easy to let the lines blur. For eight years, I failed to notice that I am never resting. The doctor did, though, and very mildly, he uttered the word burnout.
I had no idea what to do with myself. How do I go somewhere for no reason? Or maybe rather: to find peace, quiet, calm waters. And where? Where could I possibly go and have nothing to do, nothing to observe, nothing to describe?
"Go to Cornwall, it's so beautiful over there!" suggested my sister.
"How do you know, have you been there?"
"No, but I've heard."
Fair enough, Cornwall it is. The first leg of the trip was easy – I took a flight to London and spent a few fun August days in a vibrant city. I visited a bunch of galleries, bookshops, parks, went to two plays and three concerts. Then I bought a ticket to Penzance and got on a train in Paddington, feeling like a lost teddy bear riding to the most faraway place where no-one was waiting. The only point of reference I had in my head was Land's End, a literal end of the world – the southernmost strip of British soil.
After years of hyperactivity, I plunged into a rural void. Even in the peak holiday season, most of the villages, towns and fields of Cornwall remain a motionless little world of their own, where time trickles slowly, and the only thing that could possibly stir one's emotions is the weather. This little piece of land, protruding far into the Atlantic, is as exposed to the forces of nature as a ship in the sea. When the sun is shining, there is nowhere to hide from its blaze, and once a rainstorm comes, it swallows everything, wiping out colours and shapes. After two days of typical city-dweller activities – thorough area inspections, museum-trodding, visiting organic farms and sampling local cuisine – there was nothing left to do. Nothing at all – and I simply could not stop. The sudden halt of my normal impetus was a shock. I couldn't sleep; I struggled with anxiety. Only in walks did I find some relief.
On the third day, I found my way outside town and came across a married couple wearing trekking boots. I asked them where they were coming from. That's how, by a complete accident, I found out about the South West Coast Path, a legendary route running along the southwestern coast of Great Britain. And it was the trail (for the most part, it is little more than a narrow, barely visible path leading across hills, slopes, swaths of shrubbery and fields of lavender) that saved me. It gave me a rhythm, allowing me to keep on moving together with my thoughts and feelings. I could walk across two landscapes at once: the gorgeous vistas around me, and the inner terrain of my mind that I finally had to face.
For the days to come, I walked the route bit by bit, without a map, led only by curiosity about the views that might emerge from behind the next turn. Whenever I wanted to rest, I walked down to the beach, and when hungry, I climbed up to the nearest village. Once the day was nearing its end, I caught a bus and went wherever it took me, just to find a place with a roof and a bed to rent. In the morning, once again I stared at waves breaking on sharp rocks, dolphin backs glistening in the sun, horses and cows grazing on meadows, bumblebees hovering over flowers. For days, I said nothing to anyone. I just walked, absorbed the nature around me, read, ate, bathed, slept. The whole trip took barely two weeks. And yet, it remained within me like it was a months-long period of metamorphosis and deep rest. It was a turning point. I didn't understand why it affected me this way until quite recently, when during another visit to London I came across a book The Art of Rest: How to Find Respite in the Modern Age by Claudia Hammond (Canongate, 2019), on the art of finding rest in the modern world.
I did not know it back then in Cornwall, but my instinct led me towards the best and most effective way of finding deep tranquillity and leisure. Thanks to Hammond's work – to my surprise, she turned out to be one of the very few researchers focused on relaxation, so vital to all humans – there are several facts about rest we now know for sure. Relaxation is a state every one of us achieves in their own way, due to an individually regulated alchemy of performed tasks and activities that bring us peace and repose. But rest is also something universal, brought to us by simple, easily available means. Humanity, as a whole, seems to agree on what kinds of activity allow us to rest most effectively.
Answers from 134 countries
The question: "What are the activities you find most restful?" was asked by an eclectic group of scientists and experts from Durham University in the north of England, working on The Rest Test, the first global research into this topic. Claudia Hammond, a BBC health journalist of many years, was also part of the team. The research report was published in 2018; it summarized the findings from a record 18,000 responses from 134 countries. Such a large response pool enabled the team to draw reliable conclusions on what helps us rest, regardless of our origin, financial status, or age. The report listed 10 activities that give us the deepest sense of relaxation. It did not include sleep, as the researchers were only interested in activities performed consciously. In her book The Art of Rest, Hammond conducted a thorough analysis of those top 10 activities, turning to science to explain why and in what conditions those, and not other choices, help us unwind.
Before I describe the 10 activities said to be the best stress-remedies, let me tell you the two modern favourites that didn't make it. As it turns out, spending hours online and on our smartphones do not provide solid rest, and respondents described the time spent on those activities as mostly empty and wasted. We also fail to relax when socializing and talking to our friends and loved ones, probably because it requires us to perform certain roles. We should also keep in mind that The Test Rest research focused on activities that give us a feeling of being well-rested, rather than what is most enjoyable.
Let's start from the bottom. In 10th place, there was mindfulness – a practice whose name seems difficult to translate into other languages, as it combines many practices that soothe the mind and teach us being aware and present in the here and now. In the Durham University research, the idea of mindfulness included such practices as yoga, breathing exercises, and clearing the mind. When repeated regularly, those practices help unite the body and mind. Hammond analysed various research on the actual impact of mindfulness on rest and found that too often, it is proposed as a universal cure to all problems. The efficacy of mindfulness is limited, and it seems to be helpful only to few: most mindfulness class attendees give up early on. In Hammond's opinion, the greatest advantage of mindfulness is that in its basic form, it proves quite easy to incorporate into our daily life. For example, we can just sit down with our eyes closed and follow our thoughts for a moment, letting them come and go on their own accord. This one activity alone is enough to remind us that life is constantly changing and worth being accepted this way. Opposing it will just wear you out!
The modern Valium
Watching TV turned out to be the ninth most effectively relaxing activity. Despite the common belief that it's mind-numbing, mood-lowering and harmful, research quoted in The Art of Rest shows that proportions are the most important thing about achieving a state of relaxation. Therefore, too much TV does bring down one's mood, but when it's not enough, it won't make us feel rested. Data from all over the world shows TV-watching time is gradually increasing – collectively, humanity consumes 3.5 billion hours of television content each year. In the US, a 75-year-old person has spent a total of nine years of their life solely on staring at the TV. But is it really that bad? Respondents in The Rest Test said that TV-watching requires no physical effort and allows us to lose ourselves in someone else's life for a while. And this enables us to rest.
Psychologist Mihály Csíkszentmihályi is the creator of the concept of flow, as well as the author of key research on how we like to spend our free time and what gives us joy. One of his experiments showed that subjects were more relaxed when watching television than attending sports events, going to dance clubs, eating, and even doing nothing. They confirmed that television makes them feel sleepy and passive, while also improving their mood. Hammond believes that TV seems to be today's equivalent of Valium, providing escape as well as relief. It can also be a significant factor in reducing the feeling of loneliness, not just to the elderly or people who live alone. To many of us, watching TV together can be a pleasant way to wrap up our day in an atmosphere of non-committal intimacy – we sit close to each other and watch a story unfold together without the obligation of speaking or being active. We are resting. And despite the common concern, TV doesn't mean being completely passive, either. Many of us combine watching television with other activities, such as ironing. Just like with other relaxing activities, this one also requires moderation. Excessive television-watching is addictive; it can also worsen symptoms of depression. But a little bit of mental numbness, Hammond argues, can be more helpful than we used to think.
The eighth spot on the list of global relaxation is daydreaming, that is, letting our thoughts run uncontrolled. The uncontrolled meandering of thoughts is somewhat related to the concept of mindfulness. It allows our thoughts to flow in an uninhibited way without us focusing on any of them specifically. It's all about letting go. You needn't worry about your brain; an increasing amount of research proves it's never truly idle. When we seem to be thinking about nothing at all, our brains tend to become quite active. Unleashing one's thoughts is wonderfully beneficial to our creativity and releases our minds from the need to check on our daily to-do lists constantly. The trouble with daydreaming is that it's commonly associated with laziness, and the modern lifestyle does not approve of 'wasting time' in this way. Unless it happens in the bath…
A trip to the bathtub
The seventh-best method of deep relaxation is a hot bath. It seems to be viewed as the purest form of rest; respondents described it as something rejuvenating, safe, healing, private, priceless, uninterrupted. A bath is one of the best ways of unwinding, because we can allow ourselves it. Modern reality has whipped us into a fetishized state of being constantly busy and working. Hammond takes a closer look at our double-edged relationship with rest, showing that it often makes us feel guilty.
The negative approach to relaxation goes all the way to ancient times. Greek philosophers – as well as the Bible – taught us to consider idleness a sin, or a disease of the soul. Meanwhile, a bathtub remains one of the last spaces in which we allow ourselves to just be. It is also aided by the positive stereotype of personal hygiene rituals (I'm not lounging, I'm cleansing my body), and the scientifically-confirmed positive influence baths have on our health by reducing levels of the stress hormone cortisol, or by lowering our body temperature for a while after a bath, making it easier to fall asleep. However, Hammond warns, spending too much time in hot water has negative effects, adding that there is no decisive proof on the health benefits of winter swimming. Icy dippers might find this activity fun and relaxing, but science has no explanation for that!
The sixth place on the list is occupied by walks; much more dependable than polar bear plunges. The test confirmed what many of us feel instinctively and regularly practice: 38% of respondents listed walking as one of the three activities they find most relaxing. Even though walks require physical activity, they provide – just like lounging in a bath – the perfect conditions for doing nothing. When declaring "I'll go for a walk", we express the desire to be active, not lazy. Importantly, walking also improves our thinking. Many writers, from Thoreau to Solnit, said they came up with their best ideas while walking. Sitting down and thinking in a static position is more difficult, and in modern culture, it has become synonymous with idleness. Hammond describes walking as a perfect balance between nothingness and newness – we seem to be doing nothing special, and yet we return refreshed and rejuvenated.
Research done at Stanford University confirms that walks improve our creativity. Volunteers taking part in the study went for a walk and were then asked to come up with new applications for a simple object, such as a button. Those people were full of fresh ideas, unlike the other participants, who instead of walking ran on a treadmill or were pushed in wheelchairs. Walking is also a great opportunity to be together without commitment. The French philosopher Frédéric Gros describes it as "shared solitude" – during a walk, we don't even have to talk. Our steps fill the silence.
The correlation between walking as physical activity and its soothing impact on the mind is also interesting. 16% of the people surveyed said they feel more rested after physical exercise, and 8% found running or jogging relaxing. Why does this kind of effort help us rest? The latest neurological studies show that exercise, even of the most exhausting kind, causes brain activity to reach a state similar to that experienced during meditation.
It's easy to introduce walks to our daily routine – we can get off the bus one stop early, take a detour on our way home, or give up driving so that we can walk to a tube or tram stop instead. Claudia Hammond also points out that while reaching a state of relaxation requires balance, we can moderate this naturally when walking. It provides an ideal pace of existence, allowing us to absorb our surroundings, letting us think more clearly, and bringing us back to the natural way of experiencing time.
The muse of idleness
Fifth place on the list is occupied by "not doing anything in particular", which causes us to feel so much guilt that we keep coming up with various euphemisms to describe it: taking it easy, chilling, hanging out. We are afraid of idleness and just laying down, as it is associated with wrongdoing that can drag us down. A staggering 10% of us feel guilty at the very thought of any kind of rest. Where does this come from? It stems directly from our culture, which rewards those who are constantly busy and relentlessly working, giving them high social status and portraying them as more important – after all, they are needed. In such a system of values, there is no space left for being motionless, or even for taking a break. We are becoming more and more like our smartphones: never turned off, forever on standby, endlessly updating. Such a way of living has become normal not just to those working in the City of London, but also to the stallholders in Vietnam.
This vision of a 'good life' is linked directly to capitalism. In its global kingdom that is the US, only 74% of all employees enjoy the privilege of paid vacation, and it's still much shorter than the European average. And yet, doing nothing and taking time off is a matter of life and death. In her book, Hammond quotes several research studies that prove good rest extends our lifespan. Interestingly (and practically, too), even short breaks – such as micro-rests that last just a few minutes during our daily grind – are beneficial. That's already enough to help us work more productively and feel better. So get up, leave your desk and take a look through the window, make a cup of tea, or do anything that isn't work and lets you unwind a little.
For example, try listening to your favourite music, as it's the fourth most effective way of resting. The kind of music you choose doesn't matter. If you believe in the healing properties of Mozart's masterpieces and listen to them on a loop in the hope that they will make you a genius, you can give it a break and play some Rihanna if that's how you feel. As it turns out, an eclectic music taste also supports relaxation, as it helps us choose the style that corresponds best with our needs at any given time. Since everything in life is prone to constant change, it's best to have our private playlists for any occasion. Many respondents say music 'cleanses' them, and they find it most relaxing when they are alone.
Me, myself and I
"I want to be on my own" was the third most desired way of experiencing relaxation. Why do so many of us feel most rested when alone? After all, humans are social and political animals, and we owe our evolutionary success to our ability to adapt and cooperate. Even the human brain has the qualities of a highly-socialized organ. Hammond analysed various studies to conclude that the right dose of solitude provides relief from the social functions and requirements that we face in relationships and situations in which we are required to fulfil various roles and expectations. She also provides an interesting definition of solitude, as opposed to loneliness. Thanks to new technologies, we are rarely ever truly alone with no external stimuli; almost never truly free from the impression of being always watched and judged. Still, the same technologies increase our feeling of isolation and are just a simulation of genuine relationships. Again, it's all about proportions. Referring to several psychological studies, the author points out that it's not about the number of social relationships, but rather their quality. Just a handful of close relationships are enough to make us feel satisfied and, therefore, happy to experience some solitude without anxiety.
However, Hammond points out something even more interesting: we fail to notice how much time we already spend on our own anyway. On average, we spend 29% of every day alone, including commuting to work, which we can spend on daydreaming if we take public transport. It's worth evaluating the time we spend in solitude. That's the first step towards making the most of those moments.
Nature and reading
The second most relaxing activity turns out to be spending time surrounded by nature. In this case, instinct also proves to be our most important ally – we can feel that nature soothes us; it heals the mind and calms racing thoughts. Just a brief walk among the trees and looking at the surface of a lake is enough to help us wind down. Research shows that even looking at pictures of trees for a short time improves our productivity at work. Why? We don't know, and it seems to be very difficult for scientists to really put their finger on it. The most likely answer is that nature provides good conditions for introspection, allowing us to feel part of a larger order, enabling us to view ourselves in a broader existential context. Perhaps only then can we find eudaemonia – the state of flourishing and balanced fulfilment of our needs.
We have already walked, bathed and daydreamed… What could possibly give us an even deeper sense of relaxation? Which activity did people all over the globe describe as the most relaxing? The answer is reading.
Since 1928, we have known that reading is a soothing activity. That was when Edmund Jacobson, the pioneer researcher on rest, sought the activity that is best for relaxation of the mind and muscles. However, after Jacobson, scientists paid surprisingly little attention to what most of us find so obvious – the fact that there aren't many things as lovely as losing oneself in a good book and forgetting about the whole world! A staggering 58% of The Rest Test respondents said they find reading the most relaxing of all activities. Why is this result so surprising? Mainly because reading requires a lot of cognitive effort, as it engages the brain in a way that activates many complex neural pathways.
Hammond explains: "We read the letters. We form words from them. We take meaning from those words. We relate that meaning to what we've read before. We reach into our own memories. We create images in our minds. We mentally simulate the action, the sights and the sounds of the scenes. Meanwhile, we use what psychologists refer to as 'theory of mind' to inhabit the characters' minds in order to understand their motivations, to imagine their thoughts, to feel their feelings."
Sounds rather complicated, doesn't it? But it only confirms the conclusion that comes from examining the entire top-10 list: rest rarely means passivity. There is surprisingly little scientific research following the correlation between reading and our health and relaxation, but the available data confirms that reading aids falling asleep, as well as lowering our blood pressure and blood cortisol levels. One of the reasons why we rest better while reading than while watching a movie is the control we have over the content. It's up to us how we imagine the characters and events described, how fast we pace through the story and how much we engage in it. All this doesn't stand in opposition to the effect of deep engagement; by reading, we develop many skills, such as empathy, since it is an exercise in understanding other people and their behaviours.
Csíkszentmihályi, whom I mentioned earlier, found that people who read achieve a state of flow close to a trance. Interestingly, reading seems to have a similar effect to encountering nature: when reading, we manage to forget our own life and lose ourselves in someone else's experiences, but also, indirectly, we connect to our inner self and descend to some deeper level of self-contemplation. Neurological analyses of brain activity during reading show that it is neither resting nor fully concentrated. When we read, our thoughts start floating.
Research conducted at the University of Southern California suggests that when we read, our neural paths are busy looking for connection and meaning within the text that are linked to our past experiences or thoughts about the future. Therefore, while being present in the story we are reading, we maintain close contact with our inner self. We often think that resting is meant to clear the mind, but it seems that charging it with new stories and people makes us most relaxed instead. And here is some really good news: research on the connection between reading and longevity shows that regular contact with literature adds on average two more years to our lifespan.
The pandemonium of the pandemic
The conclusions of The Rest Test and Claudia Hammond's analyses could be – as the author jokingly says herself – considered obvious. "No shit, Sherlock!" we might say mockingly. After all, most of us can feel all those things science is trying so hard to prove; Hammond's book did not teach me anything I hadn't already learnt during my trip to Cornwall.
And yet, resting is not something we achieve easily, as confirmed by the Durham research. Relaxation is not a natural part of our lives and does not occur spontaneously. In our everyday reality that fizzes with tasks and commitments, resting requires some conscious effort and sensible promises to make some space for it. One of the most valuable points made in The Art of Rest is a simple truth about being an adult: it's this stage of life in which the to-do list is never going to end. No matter how many items you cross out, new ones keep on appearing. The wheel won't stop spinning. And what's the researcher's advice?
First, accept the reality of it. Second, don't be delusional. In half a year from now, your situation won't be radically different. Don't accept an invitation to another conference, don't take on that extra project. If you don't have time for it now, you won't have more time tomorrow.
The experience of the pandemic makes this conclusion even clearer, reminding us that rest is something that requires particular protection and care. According to Hammond, one of the most essential conditions of experiencing rest is the freedom in deciding how we spend our time. Many people have lost this freedom due to quarantine and the restrictions caused by the need for self-isolation and minimizing the risk of COVID-19 infections. In some extreme cases, isolation can lead to a disintegration of personality and cause the feeling of not existing at all.
But even the simple limitations that we've become used to during lockdown – the inability to go for a walk, spend a day outside, or simply be alone for a while after days on end spent with other household members – have seriously limited our options when it comes to rest. We no longer had to commute or drive kids to school, getting to stay at home all day. Many of us expected it to be more restful this way, but instead, we have become more frustrated: we lost access to the most relaxing activities during a time when we were constantly bombarded with existential dread. We feared for ourselves and our loved ones, worrying about our health and lives, about work and finances, and about losing the everyday reality we created with so much effort.
When we return to normal – or what the experts expect to be 'the new reality' – our instinct might lead us in one of two directions. We might feel infinite exhaustion and a need for proper deep rest. Or we might decide that our fear for survival is more important, and let it push us forward so that after a period of unprecedented deprivation of rest, we end up working harder than ever before in a desperate effort to make up for the lost time.
If we read Hammond's book carefully, we will know that we should choose the former. Even if we can't take time off work, we should try and make mini-breaks and add little pockets of relaxation to our overloaded days. And most of all, avoid taking on additional commitments. Let's not amp up our pace of life, wound-up as it already is.
"Have you found yourself a hobby? Something that helps you relax?" This time, my psychiatrist's kind voice meets me through my computer screen.
In the time of the pandemic, our meetings need to be kept at a safe half-distance, provided by technology. I really don't want to let him down, so I give my hopeful answer:
"Does it count if I walk the dog while listening to audiobooks?"
I wait for the pixelated shape to regain the familiar features of my doctor's face. Here it is, smiling.
"Wonderful! As long as you don't take on too much work. Have you learned it already?"
"How to refuse. It's the first step on the path towards proper rest."
Translated from the Polish by Aga Zano
- What's better for your brain: 15 minutes of jogging or 15 minutes of ... ›
- Learn to relax and meditate - Big Think ›
Geologists discover a rhythm to major geologic events.
- It appears that Earth has a geologic "pulse," with clusters of major events occurring every 27.5 million years.
- Working with the most accurate dating methods available, the authors of the study constructed a new history of the last 260 million years.
- Exactly why these cycles occur remains unknown, but there are some interesting theories.
Our hearts beat at a resting rate of 60 to 100 beats per minute. Lots of other things pulse, too. The colors we see and the pitches we hear, for example, are due to the different wave frequencies ("pulses") of light and sound waves.
Now, a study in the journal Geoscience Frontiers finds that Earth itself has a pulse, with one "beat" every 27.5 million years. That's the rate at which major geological events have been occurring as far back as geologists can tell.
A planetary calendar has 10 dates in red
Credit: Jagoush / Adobe Stock
According to lead author and geologist Michael Rampino of New York University's Department of Biology, "Many geologists believe that geological events are random over time. But our study provides statistical evidence for a common cycle, suggesting that these geologic events are correlated and not random."
The new study is not the first time that there's been a suggestion of a planetary geologic cycle, but it's only with recent refinements in radioisotopic dating techniques that there's evidence supporting the theory. The authors of the study collected the latest, best dating for 89 known geologic events over the last 260 million years:
- 29 sea level fluctuations
- 12 marine extinctions
- 9 land-based extinctions
- 10 periods of low ocean oxygenation
- 13 gigantic flood basalt volcanic eruptions
- 8 changes in the rate of seafloor spread
- 8 times there were global pulsations in interplate magmatism
The dates provided the scientists a new timetable of Earth's geologic history.
Tick, tick, boom
Credit: New York University
Putting all the events together, the scientists performed a series of statistical analyses that revealed that events tend to cluster around 10 different dates, with peak activity occurring every 27.5 million years. Between the ten busy periods, the number of events dropped sharply, approaching zero.
Perhaps the most fascinating question that remains unanswered for now is exactly why this is happening. The authors of the study suggest two possibilities:
"The correlations and cyclicity seen in the geologic episodes may be entirely a function of global internal Earth dynamics affecting global tectonics and climate, but similar cycles in the Earth's orbit in the Solar System and in the Galaxy might be pacing these events. Whatever the origins of these cyclical episodes, their occurrences support the case for a largely periodic, coordinated, and intermittently catastrophic geologic record, which is quite different from the views held by most geologists."
Assuming the researchers' calculations are at least roughly correct — the authors note that different statistical formulas may result in further refinement of their conclusions — there's no need to worry that we're about to be thumped by another planetary heartbeat. The last occurred some seven million years ago, meaning the next won't happen for about another 20 million years.
The great theoretical physicist Steven Weinberg passed away on July 23. This is our tribute.
- The recent passing of the great theoretical physicist Steven Weinberg brought back memories of how his book got me into the study of cosmology.
- Going back in time, toward the cosmic infancy, is a spectacular effort that combines experimental and theoretical ingenuity. Modern cosmology is an experimental science.
- The cosmic story is, ultimately, our own. Our roots reach down to the earliest moments after creation.
When I was a junior in college, my electromagnetism professor had an awesome idea. Apart from the usual homework and exams, we were to give a seminar to the class on a topic of our choosing. The idea was to gauge which area of physics we would be interested in following professionally.
Professor Gilson Carneiro knew I was interested in cosmology and suggested a book by Nobel Prize Laureate Steven Weinberg: The First Three Minutes: A Modern View of the Origin of the Universe. I still have my original copy in Portuguese, from 1979, that emanates a musty tropical smell, sitting on my bookshelf side-by-side with the American version, a Bantam edition from 1979.
Inspired by Steven Weinberg
Books can change lives. They can illuminate the path ahead. In my case, there is no question that Weinberg's book blew my teenage mind. I decided, then and there, that I would become a cosmologist working on the physics of the early universe. The first three minutes of cosmic existence — what could be more exciting for a young physicist than trying to uncover the mystery of creation itself and the origin of the universe, matter, and stars? Weinberg quickly became my modern physics hero, the one I wanted to emulate professionally. Sadly, he passed away July 23rd, leaving a huge void for a generation of physicists.
What excited my young imagination was that science could actually make sense of the very early universe, meaning that theories could be validated and ideas could be tested against real data. Cosmology, as a science, only really took off after Einstein published his paper on the shape of the universe in 1917, two years after his groundbreaking paper on the theory of general relativity, the one explaining how we can interpret gravity as the curvature of spacetime. Matter doesn't "bend" time, but it affects how quickly it flows. (See last week's essay on what happens when you fall into a black hole).
The Big Bang Theory
For most of the 20th century, cosmology lived in the realm of theoretical speculation. One model proposed that the universe started from a small, hot, dense plasma billions of years ago and has been expanding ever since — the Big Bang model; another suggested that the cosmos stands still and that the changes astronomers see are mostly local — the steady state model.
Competing models are essential to science but so is data to help us discriminate among them. In the mid 1960s, a decisive discovery changed the game forever. Arno Penzias and Robert Wilson accidentally discovered the cosmic microwave background radiation (CMB), a fossil from the early universe predicted to exist by George Gamow, Ralph Alpher, and Robert Herman in their Big Bang model. (Alpher and Herman published a lovely account of the history here.) The CMB is a bath of microwave photons that permeates the whole of space, a remnant from the epoch when the first hydrogen atoms were forged, some 400,000 years after the bang.
The existence of the CMB was the smoking gun confirming the Big Bang model. From that moment on, a series of spectacular observatories and detectors, both on land and in space, have extracted huge amounts of information from the properties of the CMB, a bit like paleontologists that excavate the remains of dinosaurs and dig for more bones to get details of a past long gone.
How far back can we go?
Confirming the general outline of the Big Bang model changed our cosmic view. The universe, like you and me, has a history, a past waiting to be explored. How far back in time could we dig? Was there some ultimate wall we cannot pass?
Because matter gets hot as it gets squeezed, going back in time meant looking at matter and radiation at higher and higher temperatures. There is a simple relation that connects the age of the universe and its temperature, measured in terms of the temperature of photons (the particles of visible light and other forms of invisible radiation). The fun thing is that matter breaks down as the temperature increases. So, going back in time means looking at matter at more and more primitive states of organization. After the CMB formed 400,000 years after the bang, there were hydrogen atoms. Before, there weren't. The universe was filled with a primordial soup of particles: protons, neutrons, electrons, photons, and neutrinos, the ghostly particles that cross planets and people unscathed. Also, there were very light atomic nuclei, such as deuterium and tritium (both heavier cousins of hydrogen), helium, and lithium.
So, to study the universe after 400,000 years, we need to use atomic physics, at least until large clumps of matter aggregate due to gravity and start to collapse to form the first stars, a few millions of years after. What about earlier on? The cosmic history is broken down into chunks of time, each the realm of different kinds of physics. Before atoms form, all the way to about a second after the Big Bang, it's nuclear physics time. That's why Weinberg brilliantly titled his book The First Three Minutes. It is during the interval between one-hundredth of a second and three minutes that the light atomic nuclei (made of protons and neutrons) formed, a process called, with poetic flair, primordial nucleosynthesis. Protons collided with neutrons and, sometimes, stuck together due to the attractive strong nuclear force. Why did only a few light nuclei form then? Because the expansion of the universe made it hard for the particles to find each other.
What about the nuclei of heavier elements, like carbon, oxygen, calcium, gold? The answer is beautiful: all the elements of the periodic table after lithium were made and continue to be made in stars, the true cosmic alchemists. Hydrogen eventually becomes people if you wait long enough. At least in this universe.
In this article, we got all the way up to nucleosynthesis, the forging of the first atomic nuclei when the universe was a minute old. What about earlier on? How close to the beginning, to t = 0, can science get? Stay tuned, and we will continue next week.
To Steven Weinberg, with gratitude, for all that you taught us about the universe.
Long before Alexandria became the center of Egyptian trade, there was Thônis-Heracleion. But then it sank.
Before Alexander the Great established Alexandria around 331 BCE, one of Egypt's primary ports on the Mediterranean Sea between the sixth and fourth centuries BCE was a place called Thônis-Heracleion.
Now researchers from the European Institute for Underwater Archaeology (IEASM), the same organization that first found the city in 2001, have announced the discovery of a couple of fascinating items from the city's heyday. Pinned beneath fallen temple stones is a surprisingly intact Egyptian military vessel from the second century BCE, and researchers have excavated a large cemetery from the fourth century BCE.
Thônis-Heracleion was one of the two primary access points to ancient Egypt from the Mediterranean. (The other, Canopus, was discovered in 1999.) For millennia, experts assumed Thônis-Heracleion were two different lost cities, but it's now known that Thônis is simply the city's Egyptian name, while Heracleion is its Greek name.
Thônis-Heracleion had been the stuff of legend before it was located, mentioned only in rare ancient texts and stone inscriptions. Herodotus seems to have been referring to Thônis-Heracleion's temple of Amun as the place where Heracles first arrived in Egypt. He also described a visit there by Helen with her lover Paris just before the outbreak of the Trojan War. In addition, 400 years later, geographer Strabo wrote that Heraclion, containing the temple of Heracles, had been located opposite Canopus across a branch of the Nile. Today we know Thônis-Heracleion's location as Egypt's Abu Qir Bay. The sunken port is about 6.5 kilometers from the coast and lies beneath ten meters of water.
Both Thônis-Heracleion and Canopus were wealthy in their day, and the temple was an important religious center. This all ended when the Egyptian dynasty created by Ptolemy set out to establish Alexandria as Egypt's center. Thônis-Heracleion and Canopus' trade — and thus wealth — was diverted to the new capital.
It was perhaps just as well, given that natural forces eventually destroyed Thônis-Heracleion. Located on the Mediterranean, the ground upon which it was built became saturated and eventually began to destabilize and liquefy. The temple of Amun probably collapsed around 140 BCE. A series of earthquakes sealed the cty's' fate around 800 CE, sending a 100 square-kilometer chunk of the Nile delta on which it was constructed under the waves. The Mediterranean's rising sea level over the next couple thousand years completed the drowning of Thônis-Heracleion.
Researchers have recovered a large collection of Thônis-Heracleion's treasures revealing an economically rich culture. Coins, bronze statuettes, and over 700 ancient ship anchors have been pulled from the waters. Divers have also identified over 70 shipwrecks. A giant statue of the Nile god Hapi took two and a half years to bring up.
An ancient vessel and a cemetery
Gold mask found in a submerged Greek cemetery.Credit: Egyptian Ministry of Tourism and Antiques
The newly discovered ship was found beneath 16 feet of hard clay, "thanks to cutting-edge prototype sub-bottom profiler electronic equipment," says Ayman Ashmawy of the Egyptian Ministry of Tourism and Antiques.
The military vessel had been moored in Thônis-Heracleion when the temple of Amun collapsed. The temple's enormous blocks fell onto the ship, sinking it. The boat is a rare find — only one other ship of its period has been found. As underwater archaeologist Franck Goddio, one of the scientists who found the city, puts it, "Finds of fast ships from this age are extremely rare."
At 80 feet long, the boat is six times as long as it is wide. Like its dually-named city, it's an amalgam of Greek and Egyptian ship-building techniques. According to expert Ehab Fahmy, head of the Central Department of Underwater Antiquities at IEASM, the boat has some classical construction features such as mortar and tenon joints. On the other hand, it was built to be rowed, and some of its wood was reused lumber, signature traits of Egyptian boat design. Its flat bottom suggests it was built for navigating the shallows of the Nile delta where the river flows into the Mediterranean.
Also found alongside the city's submerged northeastern entrance canal was a large Greek cemetery. The funerary is adorned with opulent remembrances, including a mask made of gold, shown above. A statement by the Egyptian Ministry of Tourism and Antiques describes its significance, as reported by Reuters:
"This discovery beautifully illustrates the presence of the Greek merchants who lived in that city. They built their own sanctuaries close to the huge temple of Amun. Those were destroyed simultaneously and their remains are found mixed with those of the Egyptian temple."
Excavation is ongoing, with more of Egypt's ancient history no doubt waiting beneath the waves.