Everything We Don’t Know About Time
Time is something that everyone is familiar with. 60 seconds is 1 minute, 60 minutes is 1 hour, 24 hours is 1 day, and so on. This is known as linear time and is something that everyone is familiar with and agrees upon.
But consider this: if someone came up to you on the street and asked you to draw time, what would you draw? You might draw a clock or a watch ticking every second, or you might draw a calendar with X's over each day to represent the passing of time. But that's all those drawings would be—just physical representations of the passing of time. Those drawings would just scrape the surface of the enigma that is time, something that seemingly runs our lives and is unavoidable. It can't be explained by even the smartest people on Earth, so what is time, and can we prove that time even exists?
Aristotle once said, "Time is the most unknown of all unknown things." That was nearly 2,500 years ago, and it still stands true today. If you were to go to Google and type in "What is time?" you would find that it says time is a dimension, and in many ways, it is. When you text a friend and ask them to meet for coffee, you wouldn't give them a place without a time. However, there's a flaw in that definition of time; it leaves too many doors unopened because time is also a measurement.
For example, I was born in the 1990s. That was over 20 years ago. If I were to say I was born 18 billion km in the past, that wouldn't make much sense, and people would probably look at me like I'm crazy. With spatial dimensions in the 3D world that we live in, it's very easy to go back and forth between places because these things are essentially fixed in space. If I went to the store to buy groceries and I forgot milk, I could easily go back and buy some milk. However, the time that it took to do that is unable to be retrieved; it is lost forever into the past. An object placed in 3D space will stay there almost indefinitely. If I place a bottle on the table, it will just stay there. But that bottle still falls victim to time.
See, time is like an arrow. It moves in one direction: forward. Scientists fittingly call this the arrow of time. If you one day woke up and found yourself floating in the middle of empty space, would you be able to tell which way is up, down, left, or right? Probably not. However, time is a much simpler ordeal. See, time comes from the past, originating at the Big Bang, where our history lies, and is fixed through the present, where we are essentially prods toward the unknown and turbulent future. We can remember things from the past, like how I can tell you that this morning I went to the store, bought groceries, and then forgot to buy milk.
But at the same time, I can't tell you what I ate for breakfast next Thursday. The arrow of time originated at the Big Bang and has been moving forward ever since. We use the second law of thermodynamics to represent this; it is known as entropy. Think of entropy as a measure of disorder in the universe. At the Big Bang, all the matter in the universe was compacted into an infinitely small point. This is considered a very low entropy situation—a very orderly situation. It would be similar to stuffing every sock that was ever made into one drawer. In that situation, you know with 100% certainty where your socks would be.
Ever since the Big Bang, all the matter in the universe has been expanding away from each other, making the universe a higher entropy system. Because of entropy and because of the arrow of time, we have galaxies, stars, planets, and even life. Entropy is the reason that you can tell the difference between the past and the future. It explains why every human is born and then lives and then dies—always in that order.
If there were no entropy, if there were no change in the universe, you wouldn't be able to tell the difference between the year 2017 and the year 1 billion. No matter what you do, time moves forward and doesn't stop for anyone or anything, at least on the macro scale. See, the arrow of time works and is extremely noticeable on large scales—the scales that you and I operate on every day. But at a quantum level, time operates differently.
Take the situation where you woke up in the middle of space. There you have no idea which way is up, down, left, or right. It's a very unique situation that only applies in the vastness of empty space. But if you come back to Earth, it's very easy for you to orient yourself. The arrow of time works in a similar way on a macro level. The big level, it's very easy for you to tell that the year 1900 is different from the year 2018. It's very easy to view the flow of time.
However, on a micro scale, if we look deep down into the physics that make up the universe, entropy and subsequently time isn't so obvious. If I were to record myself cracking an egg and pouring its guts into a bowl, and then I reverse the footage, you would easily be able to tell that the footage had been reversed. However, if I record a pendulum swinging back and forth for 5 minutes and then reverse the footage and show it to a random person on the street, will they be able to tell that that footage has been reversed? The answer is probably not.
See, the arrow of time seems to flow in one direction on the macro scale, but as you take parts of it away and skim it down to the bare bones of particles that make up the universe, time seems to work and flow in every direction, both forward and backward. There are no laws of physics that state the past is any different from the future. The only reason why you can think about what you want to have for dinner tomorrow as opposed to what you want to have for dinner yesterday is because of the arrow of time, because of entropy, because the universe had a beginning—or at least it seems like it.
You might be starting to see why the arrow of time and entropy are so important; they quite literally govern our lives and the universe. See, the fact that entropy is increasing is well known; it's the reason why life today is the way that it is. However, not many people are addressing the question: why was the entropy of the universe so low in the first place? Well, the answer is simple. It was lower yesterday than it was today. You can take this logic all the way back to the Big Bang. You hear that a lot: the universe came into being at the instance of the Big Bang. And for all we know, as of now, that may be true. However, it might not be true.
We have the physics of Einstein's general relativity that allow us to go back to mere seconds after the Big Bang, but after that, our equations break down. That's as far as we can go for now. There's no law of physics yet that states that there wasn't time before the Big Bang and perhaps a reversed arrow of time. We just don't have the science to look that far back yet.
In a previous video of mine entitled "The End of Our Universe," I discussed a situation that may occur in the distant, distant future. Because the universe is expanding and because entropy is increasing with time, there will eventually be a time where everything in the universe is so far apart from one another that space will essentially be empty. Everything will be too far apart to interact with one another, all the way down to the atoms that make up everything in the universe.
However, just as the temperature outside fluctuates day to day, so does the entropy in the universe, albeit very small fluctuations over small timescales such as a human life. Over unreal timescales, such as 10 to the 10 to the 10 to the 56 years, it is possible that quantum fluctuations could cause an extremely random extreme entropy decrease. This would create conditions similar to the Big Bang as we know it and could explain the arrow of time and the origin of our universe.
However, in order to answer these questions, we need to unite quantum mechanics with Einstein's general relativity. This would provide a scientific link between the quantum world of atoms with the macro world of stars, galaxies, and black holes in the universe. This is dubbed "The Theory of Everything" and is something that many scientists are working on right now. With this theory, we may be able to, for the first time, explain how and why the universe we live in came into existence and maybe even prove that the multiverse exists.
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Back to our story. Close your eyes and remember yourself as a child—playing with your friends, stressing out about spelling tests at school, coming home to snack on the table, and asking for help with your homework. What do you feel? Maybe you're suspended in a time when things felt new, fun, and exciting. Now think of similar activities as an adult: getting ready for bed, reading a book, having dinner with friends. These moments don't seem as interesting or exciting as they did when you were a child.
When we think back on our childhood, it feels like it lasted a lifetime. But now it's like we're passengers in our own life, with time merely passing us by. Time flies, and unfortunately for us humans, evolution never gave us wings. This feeling, where time seems to go faster when we're experiencing it but feels much longer when we remember it, is called the "Holiday Paradox," coined by psychology writer Claudia Hammond.
The Holiday Paradox refers to the idea that when we go on vacation, a week or even two weeks seem to go by so quickly we can barely believe that we had a vacation at all. Yet when the vacation is over and we look back on it, it feels like it was much longer than just one week. Scientists believe that one of the reasons for this is that when we're on vacation, we have lots of new experiences in a short period. You go scuba diving for the first time, you see art, you eat interesting food. These events are outside your daily routine.
Then you return to your ordinary life, marked by routine workdays and weekends. The stimulation of that vacation seems long gone, and when you look back on it, it feels like so much happened. It feels like so much time went by, and even though when you were there, it felt incredibly short. Our experience of time changes depending on what we're doing and how we feel about those experiences. That's why you hear things like "time flies when you're having fun." I'm sure you've experienced it before too. Your favorite musician's concert is over in the blink of an eye, and at the end of a great first date, you realize you've been talking for hours, yet the conversation still feels incredibly short.
This happens because when we're immersed in an activity, we're not checking our watch to see the minutes ticking by, so we lose track of time, making it seem like time is going much faster than normal. "Immersion" is the key word here because time doesn't only go faster when we're doing something exciting or something we love to do. How many times have you told yourself you'd only spend 10 minutes on TikTok, to look up from your phone three hours later and see that the sun has gone down? Exactly—it's because of how immersive the app experience is; it keeps you busy and makes you forget about time.
These differences in perception make the holiday paradox both relatable and confusing. To help us understand the phenomenon better, we need to look at how people think about their childhood. In a 2005 survey, 499 participants between the ages of 14 to 94 were asked about the pace at which they felt their lives were moving. When asked about shorter durations like weeks and months, all the way up to a year, the participants' perception of time didn't appear to increase with age. However, when asked about longer durations, the older people were, the faster they felt like their lives were moving. People over 40 in particular felt like time went by slowly in childhood, then accelerated through their teenage years and into early adulthood, and then after that, time just flew by.
But why? Why do we feel time goes faster the older we get? Our brain has a limited storage capacity, and so to keep things running smoothly, our brain encodes new experiences into memory. It tends to skip over the more repetitive events in our lives. The more memories we have, the more things we can look back on when we're thinking retrospectively, and the more things we can remember about a period of time, the longer we feel that time period was. Think about your time in college or in high school. You remember most of that period of your life because you were absorbing so much information that your brain was forced to slow down to take it all in, creating new memories, learning new concepts.
Your brain had to store a lot of new information, and so when you think back, there's a lot of things to remember, which makes that period last longer in your memory. This is why scientists always encourage you to learn new skills, no matter how old you are, because by learning new things, you're giving your brain a reason to absorb and store new information, which in turn makes that moment last so much longer.
New experiences don't always have to be good or fun to make time slow down. If you've ever felt fear, chances are your life seemed to move in slow motion. If you're in a car crash, a bike accident, or even feel physically endangered by another person, your cognitive reality shifts. What might only be a few seconds of fear feels like minutes or even hours. In her book, Claudia Hammond talked about a study in which people with arachnophobia were asked to look at spiders for 45 seconds. When they were asked afterward, every participant thought they were looking for a much, much longer period of time. They may not have been in imminent danger, but their fear was triggered. Their world slowed down.
Desperate to get out of the situation they found themselves in. Over the years, there have been many theories about why time seems to speed up as we age. You can see that our world in general has sped up. This has caused all of us to feel like life is moving more quickly. But if you talk to a 5-year-old, chances are they don't feel the same life passing by them. Effect. There's also the Proportionality Theory, which says a year feels faster at 40 than at 10 because one year constitutes much less of your life.
When you're 10, 1 year is 10% of your life, but when you're 40, it's just 2.5%. This, though, only works when you're thinking about life in its entirety and not in the specific periods when time slows down or speeds up, like when you're dancing on your wedding night or doing a plank. The holiday paradox tells us that our perception of time is everything, and that perception is deeply affected by our age and memory. If you graduated college four years ago, you likely remember walking across that stage like yesterday. But if you think about your first day of high school, it might seem like decades have passed, even though it's only been 12 years.
Time impacts our memory, but memory also creates and shapes our experience of time. We're most likely to remember the timing of an event if it's distinctive and vivid. Some people might coast through their 50s, not creating many new memories, then that decade might seem lost to time. But if you ask someone who went through a divorce or lost a loved one in their 50s, those years might feel incredibly like the slowest decade of their life.
Lives Hond writes that time perception matters because it's the experience of time that roots us in our mental reality. The mental reality of an adult stuck in their routine, unable to take vacations or learn new skills, is much duller than that of a child experiencing the world for the first time. That adult's bank of new memories is simply running low. We learn new skills from childhood to early adulthood and find ourselves in a lot of novel situations, and because of this, our early years tend to be overrepresented in memory, making them feel like they lasted longer than our later years.
The 50-year-old divorcee finds herself in a period where time seems to slow down because she's making new memories, having new experiences, and feeling new emotions. In some ways, these midlife shifts that many of us have—for better or for worse—actually tap into the kind of mental experience we went through as kids. When you're a child, every sports game, good grade, or fight with a friend feels like the most important thing in the world. But as we get older, that feeling is much less frequent. We find ourselves always waiting for significant life moments, like a marriage or promotion, to get the same rush we got as a kid—to feel that same experience of novelty and memory-making.
And the rest of the time, we're just going through the motions, letting time pass without giving it too much thought, until we wake up one day and can't figure out where it went. As it turns out, children might actually perceive time more slowly than adults. There's evidence that from a kid's perspective, time, as they're experiencing it, is slower. That's because memory, attention, and executive function—the cognitive control of our behavior—are all under development when we're children. Kids’ neurotransmissions are physically slower than those of adults, affecting how they perceive the passage of time.
By the time we grow up, our circuits are wired to figure this out. Researchers conducted a study where participants listened to a series of tones and compared their duration. The youngest participants, about 5 years old, had the least accuracy in perceiving how long a tone lasted. They often heard short tones lasting much longer than they really did. This could explain why when we're young, things feel like they take so much time.
Even the most basic things, like eating breakfast or getting dressed, when we're adults, those same tasks feel like they go by in a flash. Often, we don't even remember we did them. Somehow, you got dressed this morning, but do you actually remember it happening? Picking out your pants and putting on your shoes every day might be so routine it's not creating any new memories for you.
The moments that we live in, but in which we don't form any new memories, are those bits of time that escape us. While time might move slowly at 5 years old, our experiences between the ages of 15 and 25 stick with us the most. This is the era of nostalgia for most of us. We remember scenes from our lives, the books we read, and the movies we saw during that time. Can you think of your favorite movie quotes or funny moments? Because chances are they're from a film that came out when you were in your late teens or early 20s.
This is when we have more new experiences than most other times in our lives. We have our first job, solo traveling experience, relationships—it's often our first time living away from home and the first time we feel we have a choice in how we spend our days. While it's happening, this period feels like it's on overdrive. But looking back at it, it feels like that part of our lives lasted forever. That's because we created so many memories, met so many new people, and saw the world in many new ways.
We feel nostalgic for that time because it felt so complete. That is the holiday paradox. If you're living in that time, enjoy it. Savor it. If you made it to your late 20s, you probably know the phenomenon of having a sudden longing for your younger self, your younger life. You've settled into a routine where stressful responsibilities often replace endless fun moments.
So how do we slow down our lives again? The truth is, of course, that we can't slow time down, but we can do more things to create memories of the time that we have. Look for novel experiences that engage your brain. You don't need a vacation to feel excited or refreshed about your life in the world. New things are waiting around the corner if you just open your eyes and look for them. Constantly challenge yourself to learn new skills, like maybe learning a new cuisine or building a bench for your backyard. Maybe you just want to get better at meeting people—go to a neighborhood event or sit alone at a bar and talk to a stranger.
Whether big or small, let something exciting take over your brain and let you feel like a kid again. Another hack is to try to remember your day as vividly as possible. Routine can feel good, but it also doesn't allow for new memories to get imprinted on our brains. Spending time reflecting on your day makes you more likely to ingrain the memories, even the bad ones. Naturally, our memory is short-lived. It's easy to go to bed every night and not think about what happened to us during the day.
But what if you stopped and spent a few minutes to relive it? Would mundane things become important or exciting? Would you remember someone or something you saw on the street that was new or strange? Suddenly, your day might feel a bit slower. Whether you just think about it or want to write it down, try to make the moments of your life last and take up real estate in your head. That's what we're doing when we're on vacation—we're banking all sorts of new, interesting memories—memories we might look back on when we want to reminisce about how full our days felt.
Our own minds actively create the way we experience time. While we may not always have control over our time as the demands of life mount in front of us, we can control how we remember things and therefore control our perception of the time we have. Time, as we're told, is immovable. It's totally defined. A second is a second; a year is a year. And as much as we might want to change it, we're told that's the reality. But if you do think back to your childhood, a time hopefully filled with joy and novelty, a year feels so much longer.
If you've been in danger, the minutes you weren't sure you'd be safe surely couldn't have been just minutes. So yes, maybe time is immovable, but it's comforting to know that we do have some control over how we experience it. We can warp it to make it shorter or stretch it to make it feel longer. And while we might never learn how to travel in time, at least we know we have some small control over it.
When I started this YouTube channel, I became fixated on the day it would succeed. I stopped going out with friends and spent almost every waking moment working towards and dreaming about the future. When I did manage to go out with friends, I spent all my time daydreaming. I was stuck imagining a far-off future, a future that would never come. Don't get me wrong—objectively, this channel is successful, and all of you who choose to watch these videos have literally changed my whole life. But the future I dreamed of will never come because there's always something more to chase, something bigger and better to look forward to.
Many of us live life like this. We spend most of our time preoccupied with things that don't exist and very little time enjoying the things that do. When we're not fixating on the future, we're being haunted by the past. We spend our nights curled up in bed, thinking about the wrong choices we've made in the past and what we wish we had done instead. As a culture, we're obsessed with time—we're both haunted by the past and dreading the future. But the truth is that the future and the past don't exist.
We might think that the past and the future are as real as the present, but that's the illusion of time. In reality, the present is the only thing that exists or can exist. A clock tracks movement, like the rotation of the Earth in our orbit around the sun, but its measurement of time isn't objective. There is only the present, and its direction is forward. The past can be accessed by our memories or recordings, but even this access is tremendously limited. Our memory is fallible; we often misremember critical details of events and can be influenced to think we did something we never did.
Memory itself is known to get less accurate each time we think to reflect on it, and when video is available, it doesn't give you the first-person experience. It's only a tiny piece of the past that doesn't truly capture what it was like to be there or the full range of emotions you felt at the time. The past is just a previous experience of the present; it doesn't exist. The future hasn't happened yet. We might prepare for conditions like rain later in the week—many of us will make plans for a satisfying career—but these things don't exist, and there's a fair chance they won't ever exist.
The forecast is often wrong, and careers rarely go as planned. If you continue to obsess over the past and the future, you'll never truly live a full life. You'll be too busy thinking about the moments that have either already passed or are yet to come. You'll forget to be present and to take it all in. Whereas animals live primarily in the present, humans have strong memories; we combine time together. This can be helpful from a survival standpoint. Our species anticipates the future and prepares for it now. This was necessary for humans to successfully survive threats and to develop more complex societies.
Early humans carved spears to take down wooly mammoths. They realized that if they made these weapons now, they'd have a better chance of killing a giant beast tomorrow. They also anticipated that a mammoth would provide sustenance for a long time. And by preparing for the future, they significantly increased their odds of survival. This ability to plan for the future is why we're here today. But we've paid a heavy price for that practical sense of time, and that price is our happiness, our peace of mind.
We're too stuck in the future to be at ease now. We make it all seem okay by telling ourselves the big lie. According to the British philosopher Alan Watts, this notorious untruth is that we think we'll be happy in our imagined future. But it never comes. When that future does arrive, according to our current definition of time, we'll be stuck in another imagined future.
Our minds will be focused on the future until our bodies no longer have a pulse. It's like a donkey chasing a carrot on a string—we can never get closer to our meal, and our appetite will never go away. To an observer, the donkey is foolish, but from a first-person perspective, we're convinced of the illusion. We don't see the string or the stick—only the carrot and the promise that it holds. Many of us are stuck in a future when we'll be happy, healthy, and have the job of our dreams.
Our memories control our lives, and we make decisions about the present and the future based on what happened in the past. Using our memory, we limit the possibilities of the present. We assume we can't do something because we weren't able to do it in the past. We avoid going places and doing things because we've previously had poor experiences with them. Sometimes, we decline offers because they conflict with our sense of who we are, based on our past understanding of our identity.
You may think of yourself as self-sufficient, but what about those moments when you truly need help? People have died clinging to their identity as self-sufficient. And why? Because they're tied to a past that doesn't even exist. Our schools train us to always look for the next ladder to climb. The present is mostly considered beneath us, and we criticize those who live in the moment because they're not preparing for the future. They're focused on now, which by our cultural standards is often regarded as antisocial behavior.
We invent gadgets for productivity, thinking they will give us more time. It's like saying you can enjoy more moments if you buy the next piece of tech. But all we end up doing is anticipating the next upgrade or the next big innovation. That's why the most popular question that tech reviewers get is: "Should I buy this now or wait for the next one?" And when we get the new technology, we use it to escape the now rather than embrace it.
For over 15 years, we've had the ultimate tool for fleeing the present—our smartphones. We turn to our phones whenever we're idle or in any situation without something purposeful to do, and we feel a panic from the present and escape it by seeking out the past and future. On our mobiles, we make plans with text conversations or by opening up the calendar. We browse news about what's already happened or read predictions about what will happen next. Alerts are set in the reminders app, and we accept notifications to warn us about anything and everything that isn't in our present moment.
"When's the next ballgame? What are the best beach resorts? Where's the price of housing headed?" We're constantly searching for answers about the future instead of enjoying the present. On social media, we look at images of the lives of others, and we project ourselves into a future where we are on vacation like our social media connections, or we look back on the trips we've taken in the past, and with regret, we wish we'd planned things differently.
It's not so easy to live in the present. Sitting still gives us anxiety. As a survival mechanism, preparing for the future and anxiety are intrinsically connected. We're not planning for the future when we're in the moment. It can feel a bit like closing your eyes when you're driving—you're not looking at what's ahead to avoid disaster. But we've evolved beyond the point where survival needs to occupy our minds always. At least in fact, many of our jobs are only connected to survival because they provide us with an income to buy food and shelter.
We've got free time outside of our occupations. At the very least, we should enjoy our free time by living in it. Our smartphones open a gateway to filling that time with plans for the future. Many of us will prepare our next workday or respond to emails about the past. We ignore the people around us and become more distant from them. Relationships are all about the present, and one of the ways you can tell they're not going so well is if one or both partners aren't very present.
The more we try to escape the present moment, the more we neglect our relationships. Ironically, many of our plans are intended to strengthen our relationships. We save for retirements and vacations. In other words, we're planning for a time when we can exist in the moment. But when that time comes, we'll be stuck thinking about another future instead of enjoying the one we're in.
Of course, global issues make living in the moment particularly challenging. The climate is changing due to humans creating greenhouse gas emissions—a legitimate threat to our survival. We need to do what we can to prevent catastrophes in the future, but we shouldn't let that steal the present from us. Otherwise, we'll only be saving a future that we won't even be bothered to live in.
Alan Watt was a student of Eastern philosophy. He studied Buddhism, Zen Buddhism, and Hinduism, among others. From his studies, he took away the importance of being present and methods of living in the now. The sealing of these religious concepts made him very popular in the West. He wasn't a proper scholar in the strict sense, but he wrote a lot of books on these subjects and gave many entertaining lectures. Some of his teachings are a bit dated now, but his distilled messages are still as relevant as the future continues to haunt us at every turn.
Watts had a particular interest in Zen Buddhism. It emphasizes being here and now, but also goes much deeper than that. Unlike the teachings of Buddha, Zen Buddhists believe that achieving a permanent state of enlightenment or nirvana was impossible. We can only try for fleeting moments of pure essence called "satori." These are moments when we're so perfectly in the present that we're cut off completely from the past and the future. We experience the present without our ingrained interpretation of the world around us.
We don't see chairs as chairs; we see no chairs. Words fail to capture Zen, as do logic and our schematic laws of thought in explaining Zen. That's why Zen masters often respond to questions by raising a finger. Alan Watts would hit a symbol in an attempt to demonstrate Zen. The idea isn't to murder the mind or bring it to nothingness; Zen is an affirmation. It wants to put you in direct contact with your mind in order to give you peace. Buddhists believe in the inner purity inside us and that getting closer to it should be our ultimate goal in achieving Zen.
The past and the future won't bother you as forms of structured thought. The past and future have no way to enter your mind; they don't exist. In Zen, they don't exist at all. When Watts speaks of time as an illusion, he's suggesting that we aren't doomed to live as beings stifled by time. Like the Zen Buddhist, we can live in the present, even when we aren't striving for moments of satori.
Now, to better understand how to live in the present moment, watch this video on hedonism. The year is 2019, or maybe 1600, or maybe there isn't even a calendar system in place yet. There is no BC or AD because you know it hasn't happened yet. But somehow, you've managed to travel back in time. Okay, first things first, don't panic! However you manage to do this, I'm not really sure, but nice job.
Now you're quickly going to realize how much the past actually sucks. There's no clean water, there's no Febreze to cover up the terrible smells, and all the luxuries that you took advantage of are nowhere to be found. No one understands what a laptop is, and the idea of even a light bulb is a concept as foreign as the jeans you just showed up in. You're immediately going to be drawing attention from almost everyone around you.
So what exactly do you have to do in order to get society headed in the right direction? And can you make the future a place that is better for all of humanity? First things first: language. Let's assume you're able to speak English in the modern world. English is one of the most universal languages spoken around the planet. But even if you've only gone back a couple hundred years, you're still going to struggle to make conversation with almost anyone.
If you've ever read anything by Shakespeare, you'll see how different and honestly just how confusing the language was. Invent the printing press thousands of years before it was actually invented. Take the diction you've brought with you and quickly mass-produce modern English, and there you go! You've revolutionized language, pushing us ahead thousands of years already.
Okay, also we're going to need a number system for counting and math and stuff. Written numbers first appeared over 40,000 years ago and predate written language by tens of thousands of years. But it definitely wasn't the greatest. It's pretty simple to tell that these are three circles; these are four squares. But quickly, what number is this? The answer is who cares? I don't have the time to count that—it's 53 by the way!
Instead of using this number system for tens of thousands of more years, how about we skip all of that and head straight to what we use today: Arabic numerals. Those are the numbers you're familiar with, like the number five. It's much easier than counting lines for hours on end, and there are only 10 numbers you need to memorize. One of them represents nothing—it's zero. Don't try and divide it; we've been trying forever, and you just can't do it.
There are also things like fractions and decimals and irrational numbers, but we'll let everyone else figure those out on their own. Now that we have language and numbers out of the way, and people are functioning, we need units too. First off, we've figured out that light is the fastest thing in the universe, and we've somehow managed to actually calculate its speed. And it's a pretty good thing to know; it's going to prove extremely useful when we discover some things later on.
But wait, no one knows what a meter is. Take a pendulum—wait, these haven't been invented yet either. Anyway, invent pendulums and take credit for it. Create a pendulum with a length that takes 1 second to swing from end to end, and you'll have the length of 1 meter. But we don't have the length of a second either; just for simplicity's sake for now, it's the amount of time it takes you to say "one Mississippi."
Divide the length of a meter by 100, and you have the length of 1 cm. Also, there's a thing called temperature—it's how hot or cold things are. Take some water, wait for it to get really cold, and eventually, it'll turn into a solid. You'll need to assign a number value to whatever temperature this happens at. If you choose for that to be zero, congratulations! You've just invented Celsius.
Take the same water, now frozen, and put it into a container above a fire. Eventually, it'll begin to boil. For all intents and purposes, this is 100°C. You now have pretty much every basic unit of measurement you'll need for anything you do. Civilization is much better off now and is much more efficient, but none of this matters if people aren't alive long enough to learn and make the discoveries that will push society forward.
Health is super important, and this is where you'll bring all the knowledge you have into play. Germs are a thing, you know this—everyone else doesn't. They are quite literally everywhere! So make sure people are washing their hands and bodies as frequently as they can. Getting something like a small cold thousands of years ago could be enough to kill somebody.
Fight germs with hygiene and antibiotics, but you don't have any antibiotics. Penicillin works wonders. Take some moldy bread, throw it under a microscope, and if you see this weird-looking hand thing, that's called penicillium. This can then be extracted from the mold, purified, and boom! You have penicillin. It's super effective against infections because it stops the other bacteria from reproducing, making you healthy again.
Viruses are like germs, but they can't reproduce on their own. They need a host like you to grow and spread. Viruses spread diseases like the plague. To prevent this from happening, vaccinations are necessary. Vaccines help keep the body prepared for multiple diseases that exist by building up an immunity to them beforehand. Luckily, you're in the past, and no one knows what these are, so you don't have to worry about anti-vaxxers screaming at you for trying to keep the world safe.
To make vaccines, grow a small culture of the virus and then heat it up. The heat will then kill the virus, but now since it's dead, it can be used to teach your body to fight it, creating a resistance to the virus. Take the dead virus and inject it into your body. People are going to think you're insane, but in reality, you're the one preventing them from getting smallpox. So just do it! They'll thank you later.
You probably have some cows by now and have figured out that they have milk. The problem is that these germs we just learned about are still in the milk, and you definitely don't want to drink that. Take the milk, heat it up right to below its boiling point, and let it sit for a minute. You've just invented pasteurization and created clean milk for everyone to drink.
Now let's talk about science. Here's an equation that'll change the way people see the world. Isaac Newton came up with it, but no one knows that you can take credit for this too. It's an equation powerful enough to define gravity itself and can even take you to the moon. Seriously, we did that! But don't forget the basic building blocks of everything: atoms.
Atoms consist of a nucleus at the core made out of neutrally charged neutrons and positively charged protons. They're surrounded by negatively charged electrons. These are going to prove to be useful in a minute. Atoms with the same number of protons and electrons are considered electrically neutral; otherwise, they'll have a positive or negative charge. This is also most likely the first time anyone's going to hear the word "electric" in their lives, and you're about to change everything for them.
Technology is a thing, and there's a lot to cover. You're probably still using water wheels or coal to create energy, but electricity is single-handedly the one invention that is going to propel civilization into the modern era. Instead of having to live by rivers for water wheels or near mines for coal, electricity will allow you to live anywhere you want and have energy transferred to you at the speed of light.
This will cause mankind to spread at the fastest rates possible. Go to the sites of any lightning strikes and look for lodestone or look for magnetite on beaches—they're magnetic. Get something to rotate, wrap that rotating thing in coils of wire, place your magnetic stones in the middle, and you'll generate electricity! Congratulations! You just discovered electricity and AC currents at the same time.
You now have the foundation of the modern world, and you did it so quickly. Here are some more inventions that'll prove to be useful: create a magnet that can move on its own, and you've just invented the compass. You can now have directions to anywhere on the planet without having to rely on the North Star.
Take your newfound electricity and run it through tungsten—now you have light bulbs. If you run powerful electricity back and forth through a wire strong enough, you've invented radio! Transmitting radio waves at a certain frequency will allow you to send signals to and from multiple antennas, allowing for light-speed communication. You can also take high-frequency radio waves, send them out, and see how long it takes for them to bounce back to you. You've just invented radar!
There's a lot of inventions that are going to be super helpful, but there's also some that you should avoid. You introduce the world of atoms to everyone, and that's going to change a lot. Energy cannot be created or destroyed, just converted. Use this super special equation that you discovered to convert between the two: a very small amount of mass can be converted to a lot of energy.
The energy released during fission or fusion of atoms can be used for electricity and have many other positive impacts, but it can also be used for destruction. Bombarding uranium-235 with neutrons will induce a nuclear chain reaction. If you have enough uranium, this is the result—these weapons have caused the death of hundreds of thousands of people and have almost resulted in the end of humanity on multiple occasions. Do not let these weapons be made.
Most of our inventions have been made to reduce the amount of work we need to do in our daily lives. Pretty much, we work to find inventions that make life easier and in turn make us lazier. A lot of inventions throughout history have had the same effect. Why would I walk across the world when I could create a harness and use a horse? A compass is perfect for figuring out where things are without having to leave signs along the way. Light bulbs are great because we don't have to keep fires lit throughout the night.
Radio is useful so that we can communicate long distances without having to physically make that journey. But most of these are saving us physical energy. What about mental labor? Jobs where you have to perform complex mental tasks day in and day out? What if you could make a machine that could perform your work for you? Oh wait, that's what you're using right now.
Letters are used to create words in the same way logic gates are used to create computations. With enough logic gates connected in the proper way, you'll have something with enough power to do complex computations at the speed of light. We call these computers. Connect multiple of these computers together and you'll have created the internet. It took until 1903 to invent a vehicle that could fly. Being able to take to the skies is one thing that will allow you to conquer the planet.
It quickly uses airfoils that are shaped in a way that allows for air to generate an upward force—it's called lift. Attach these wings to something with an engine, and if you can move fast enough in one direction, you'll eventually start lifting off the ground and begin flying. Congratulations! You've discovered the art of flight! You can now travel to almost anywhere on Earth.
If you don't have one yet, here's a map—this is our world, and it's all we have. Unfortunately, somewhere along the way, things started to go wrong. Greenhouse gases occur naturally; we actually need them to survive to keep Earth warm enough for us to live without freezing off. But due to the past few centuries, the world is currently reaching levels that are starting to get out of hand—levels that haven't been matched in millions of years. The climate is changing faster than it ever has, and it's all our fault!
Relying on fossil fuels and other non-renewable energy sources is one of the main reasons why the cars we created and mass-manufactured have been spitting out toxic gases into our atmosphere for the past century. There's literally a hole in our ozone layer because of what we've done. Work on finding clean renewable energy sources from the start; you'll actually save the planet. If changes aren't made, then there might not be a future worth waiting for.
The thing is, people don't really care, and that sucks. You have all the resources necessary; all the knowledge we have is at your disposal. The planet today is dying, so if you're going to do anything in the past, save us from ourselves.
When someone is asked what they want to do with their life, we're used to a familiar response: "I want to change the world, and I want to make an impact." While there are certainly many people who have made extraordinary contributions to society over the course of their lives, some names stand out more than others—names that are connected to deeds or inventions that are so great or, in some cases, so horrible that it's unlikely that they'll ever be forgotten.
One of those names, without a doubt, is the physicist Albert Einstein. Einstein was born in Germany in 1879. As a young adult, Einstein moved away from his home country to Switzerland in order to attend university. His desire for more expansive and innovative learning methods had already gotten him kicked out of school in his native country. Switzerland, however, proved to be the perfect place to expand his thinking.
The only way humanity has gotten anywhere was by asking questions, and Einstein knew exactly which questions to ask to fundamentally alter the way we view reality. Soon after his move to Switzerland, he began contemplating the movement of light and questioning the very laws of physics that governed the world at the time. In 1905, Einstein had what is now known as his "Year of Miracles." In the span of a single year, he released four separate publications that changed the landscape of science forever.
While each paper is extremely important in its own right, it was its third article on the electrodynamics of moving bodies that had the most striking impact on the world. This was the birth of Einstein's special theory of relativity. Einstein's theory contradicted two of the most well-known theories of physics at the time: Isaac Newton's concepts of absolute space and time and James Clerk Maxwell's theory that the speed of light was a constant.
His paper proposed that time passes differently depending on the speed at which someone is moving relative to someone else. This theory is known today as time dilation. Time dilation says that an individual in inertial motion will experience time differently than a second inertial individual who happens to be in relative motion to the first person.
To make that a lot easier to understand, let's take a look at the example Einstein himself used to explain his theory. Picture yourself on a train; it's moving much faster than any train has moved before, and as you zoom past the surrounding landscape, you see that you're approaching a train platform where your friend is standing, waiting for you when the train passes. As far as you're both concerned, you are each standing still. The difference is, of course, that you're inside a fast-moving vehicle while your friend is on the outside of it, waiting on the platform.
Easy enough. Now imagine that just as the center of the train passes by your friend, lights at both the front and the back of the train light up. Knowing that light always moves at the same speed, and because both lit up at the exact same distance from your friend on the platform, the light would reach your friend's eyes simultaneously, and they would tell you that they witnessed them light up at the exact same time—and they would be right in saying this.
Now, if your friend saw the lights turn on at the same time, the same thing should be true for you, right? Interestingly enough, it isn't, and here's why: we know light travels at the same speed no matter what, but remember, you're on a fast-moving train. So to you, the light at the front would appear to turn on first because the train is rushing to meet it. Meanwhile, the light at the back of the train would appear to turn on just a moment later because it has to catch up to the train speeding away from it.
The thing is, you would also be correct in your point of view! But how can this be? How can you both be correct in observing the same event differently? Einstein's theory also introduced the idea of length contraction. Because we know that speed is determined by distance over time, it would follow that in order for the speed of light to remain constant, the other two factors must change to accommodate that constant.
We've already talked about how time can change depending on your movement, but distance always changes depending on the movement of each inertial figure. For example, let's put you back on that train with your friend on the platform. This time your friend got a bit stronger and is now holding up a canoe that stretches 100 ft long. Now, to your friend on the platform, it's clear that they're holding a canoe that's 100 ft long because they're standing still; it's easy to see the length. If they took a measuring tape to it, it would measure 100 ft exactly.
Now cut back to you, standing on the train as it rushes past your friend. That canoe is going to look a whole lot different to you as you pass it at an unimaginably fast speed. The canoe will appear much shorter than its actual measurement. So which is real? Well, again, the answer is both of them. The length of the canoe does actually change, but the perception of its length appears shortened or contracted to you from your position in the moving train.
The faster you move, the shorter that canoe will appear. While this sounds like an interesting experiment to conduct, the speed that humans would need to travel at to see noticeable differences is not a speed that we can realistically achieve. Einstein showed that no object with mass can ever surpass the speed of light. The heavier the mass, the harder it is for it to accelerate, so experiments like this one are going to have to be put to the side.
Now, just as with time dilation, these observations are only noticeable at speeds that move at a substantial fraction of the speed of light. So these aren't observations that you and I will be able to make in our everyday lives. However, they have been tested many times throughout the last century and still stand as some of the most important contributions to physics in history.
Remember that at the beginning of this video I mentioned that 1905 is referred to as Einstein's Year of Miracles? Well, this is because he produced one final paper that year that rose out of his special theory of relativity. This paper, which some say was actually just a note jotted down in the back of a journal, proposed that energy equals mass times the speed of light squared, or in the equation known around the world: E=mc². This equation states that energy and mass can be interchangeable, so if mass is converted completely to energy, it can wield a tremendous amount of power.
A common example of this is how an atomic bomb can be so incredibly powerful and destructive. This idea led Einstein to publish yet another groundbreaking theory in 1915, known today as the general theory of relativity. The general theory of relativity was the result of Einstein's continued thinking on how his theory of special relativity related to non-inertial frames of reference, as in areas that accelerate relative to each other.
Einstein's findings show that gravity, the force that is working constantly to pull objects towards each other, is actually warping or curving space and time. The bigger the object, the bigger the curve. And because we know that objects with mass are drawn towards each other, objects with a bigger mass always have a more powerful gravitational pull. That's exactly how we end up with orbits. Planets and stars alike fall into the curves that their bigger counterparts create.
For example, the sun is much more massive than the earth, and so it warps space-time much more, which grants it a larger gravitational pull. You can keep going with this idea and deduce that the whole universe exists within a system of these curves of the fabric of space-time. Isaac Newton more than 200 years earlier had hypothesized that an object thrown with a perfect amount of acceleration would begin to curve around our planet. With the right set of initial conditions, it could potentially remain in an endless loop spinning around the earth due to the sheer force of gravity constantly pulling it in at the perfect curve.
What he was describing essentially was orbits—the exact thing that the International Space Station is doing above our heads right now. However, Newton saw acceleration and gravity as individual entities, while Einstein's theory showed that acceleration and gravity can be interchangeable. This idea is known as the equivalence principle, and it dictates that you cannot tell the difference between the effect of gravity and the effect of being in an accelerated frame of reference.
This principle is often demonstrated by having you imagine that you're in a room with no windows or any way of knowing where you are. If you were to drop a ball in that room, you can imagine that it would fall at the rate of gravity—9.8 m/s²—but if you were to drop a ball on a rocket ship that was accelerating at exactly the same rate as gravity, it would be impossible to tell whether the ball was moving down because of the Earth's pull on the object or just because the floor of the rocket ship was rushing towards the ball due to the acceleration.
Einstein's theory of general relativity helped to explain how our universe works. Because of his contributions, we can predict the path of asteroids and the orbits of far-away stars. This theory can even be applied in some of our favorite films, as special effect engineers can calculate exactly how objects move in relation to each other, even in the most unlikely circumstances. Since the publication of Einstein's theory of general relativity, there have been many experiments conducted that have proven that his findings are, in fact, correct.
Some were done during Einstein's time, while others continue to this very day. One of the most famous confirmations was Einstein's correct prediction that Mercury's orbit would change its arc by 43 seconds each century due to the curvature of space-time. He was accurate—extremely accurate, in fact. He was actually able to prove the very thing that was predicted by Newton, but that couldn't be solved with traditional Newtonian mechanics.
In another test in 1919, an English astronomer by the name of Arthur Eddington set out to prove Einstein's prediction that light rays bend when they're close to a large body. He did this by looking at the positions of stars in relation to the sun during a solar eclipse. After looking at the positions of a certain group of stars both during the eclipse and at another time, Eddington saw that the light from the stars had been deflected by an amount directly in line with Einstein's theory.
While Einstein's papers were certainly extraordinary, it still took some years before his theories were widely accepted. However, as test after test continued to confirm his predictions, the skepticism slowly diminished. In his later life, Einstein moved to the United States, where he continued to work as a physicist, focusing predominantly on an attempt to find a unified field theory. Unfortunately, he wasn't able to complete his work before his death in 1955. But his final paper helped lay the groundwork for future physicists to complete his mission in finding a unified field theory, more commonly known as a theory of everything.
Reconciling both quantum mechanics and general relativity may turn out to be one of the most challenging feats science has ever taken on. But as always, if you give us enough time, we'll slowly chip away at the problem, week by week, year by year. And who knows? One day, in the not-so-distant future, we may just find the master key to the universe.
What happens after we unlock it? Well, only time will tell. The date is October 23rd, 1593. The governor of the Philippines had just been assassinated a few days after setting off on a journey from Manila. His ship and crew were overthrown by Chinese pirates on board. When the news of his assassination reached the Philippines, the government was shocked. In the midst of all this panic, a new governor must be chosen, so a meeting was held at the governor's palace.
While business was taking place inside, guards were stationed around the outside to ensure the safety of everyone. This included many soldiers, including one named Gil Perez. After waiting outside and guarding the palace in the heat for what felt like an eternity, Gil decided to rest for a second. Nothing crazy; he stayed at his post, leaned against the wall, and simply decided to rest his eyes for a mere second.
When he opened his eyes, he was in a place he didn't recognize. In literally the blink of an eye, he found himself in an environment that he had no knowledge of. He had no idea how he got there—wherever there was. Regardless, he continued doing his duties, watching out for anything suspicious. Except he was the suspicion. The local soldiers and citizens began giving Gil weird looks. He was wearing the palace guard's uniform that no one had ever seen before.
Gil was just a random soldier in an unknown location—unknown to him, at least. That is, until the truth of the situation was brought to light. Gil Perez was no longer in the Philippines. In what seemed like an instant, he miraculously ended up in a plaza in Mexico City, over 14,000 km away. Today, that distance could be covered in less than 24 hours, but in 1593, this voyage would have taken at least 2 to 3 months.
Still shocked, Gil continued to explain his side of the story. He explained that he was a soldier from the Philippines. He explained how the governor had just been assassinated, except, of course, no one believed him. The problem here is, in 1593, it would be months before any news of this would reach Mexico City. He was immediately arrested for desertion and thrown in jail. A few months later, a ship from the Philippines finally arrived, carrying crew members as well as the news of the governor's assassination.
And what they found out is that the story Gil provided matched up with the one the crew members aboard the ship were saying. On top of all that, several of the crew members actually recognized Gil and were able to even recall the day where he seemingly disappeared from existence. He was set free and returned to the Philippines to continue life as though nothing had happened.
There's no real explanation for the story—it's over 400 years old. Many speculate that something paranormal had taken place. Some suggest that he was just a liar. Others suggest that the story never took place and was just made up by someone. Some suggest that it was an alien abduction, but a few suggest teleportation. And that is something that I find very interesting.
Teleportation is a common part of science fiction. Characters in video games, movies, and books can travel from one point in the universe to another without ever traversing the space in between—faster than light travel, instantaneous travel. The implications of wielding a power this strong are unthinkable. But is there more to teleportation than just science fiction?
The more we learn about our universe, the more science fiction starts to look like actual science. The idea of teleportation has been talked about since before the 1800s. However, it was Charles Fort in 1931 who first coined the phrase. He combined "tele," meaning distant, and "port," meaning to carry. Decades went by as the idea laid dormant in science fiction.
That was until 1993, when physicist Charles Bennett and colleagues proposed something groundbreaking: the quantum state of one particle could be teleported to another particle on the other side of the universe without the particles themselves really moving at all. In other words, information could be transferred across vast distances in space without physically having to move to that point. The team was able to take all the information of a quantum state, destroy it, transmit that information to another location, and then recreate the same exact quantum state as before.
But before we dive into all that, let's take a step back. What are quantum particles? These are the particles at the subatomic level, and reality here is different from the reality you may know. There are many strange and honestly barely understood things that happen here. For example, particles can be at two different states at the same time. And until the particle is observed, both states are real and exist.
Once observed, a final state is taken, forcing reality to collapse into one. This is known as superposition, and its most famous example comes in the form of a cat—Schrödinger's cat. But simply, it's a thought experiment. There's a cat inside a box and some radioactive material that has a 50% chance of decaying, poisoning the cat and killing it. If the material decays, the cat obviously dies. But if it doesn't, the cat stays alive.
From a quantum approach, until the box is opened, we can't know whether or not the material has decayed or not. The cat isn't dead, but it also isn't alive at the same time. Of course, this makes no sense in the real world, but at the quantum level, reality is different. This means that quantum particles can be in multiple states, rotating clockwise and anti-clockwise at the same time until an observer forces it to decide a reality simply by observing it.
But let's say we recreated the experiment, but instead with two cats this time. Now we go from two options, the cat being dead or alive (clockwise), to four options where both cats can be alive or dead, or where one cat's alive and the other is dead, and vice versa. Quantum mechanics gives us a little bit of help here in cutting down these options. It says that there is a system where you can pretty much eliminate the options where both cats have the same outcome—either both alive or both dead.
The only ones that matter are the ones that are opposite of each other. Because of this, you can open only one box and have 100% certainty of what is in the other box—but this can only happen when the cats are in a specific state: an entangled state. We now know that quantum particles can talk to one another, but only if they have a certain property to them.
This interesting phenomenon in the quantum world is the reason that particles can theoretically be teleported if they have this special kind of link to one another. They're what we call entangled. Entanglement is caused when two quantum particles are formed at the same instance of time and point in space; hence, these particles essentially share an existence, and their connection is almost telepathic. They affect each other despite the vast distance between them.
Quantum particles have spin. This doesn't mean they're actually spinning, but they have an orientation in space as well as an angular momentum. By measuring the state of one to be spinning up, or in the cat's case, alive, it could be directly deduced that the other is dead or spinning down—the other side of the room or the other side of the universe—they're linked from birth, and when one is observed, the other one knows exactly when. Einstein called this "spooky action at a distance," and there's something fundamentally unsettling about scientific phenomena that are not entirely understood.
Recently, scientists from China launched a photon receiver satellite into orbit. This satellite can detect quantum states of photons shot to it from the ground. From this, the longest-ever distance of quantum entanglement was measured. But more importantly, this was the first time a photon was teleported from Earth into space. This works by transmitting the quantum information about one particle to its entangled pair; therefore, the second particle would quite literally become the first particle.
The research team created 4,000 entangled photon pairs per second. They shot half the pairs, 1,400 km up to the satellite, while keeping the other half of the pairs down on Earth. Over the course of one month, they sent millions of photon pairs to the satellite and found success in only 911 cases. 911 out of millions of quantum pairs sounds like a huge failure, but actually, this is a very small but important step in teleportation.
As scientists discover how quantum particles are used to make up matter, they could potentially find the keys to understand how to change these particles in order to fundamentally change the matter itself. Rather than simply sending one encoded photon, could they one day send the exact construction of all the subatomic particles of, let's say, an apple? Perhaps! But with this comes a philosophical question—the teletransportation paradox.
This dates back to 1775. The average cell in your body is on average about 10 years old. Some cells get replaced more often, while others, like the carbon-14 in your DNA, never get replaced. So considering most of your cells are not the same as they were when you were born, are you still the same person? If every single atom of a person was taken apart and reconstructed, is the resulting construction still the same person?
We humans are simply a machine where our DNA script tells us how to replace dying cells until either the script or the machine fails. But if this script of how you're constructed is downloaded and correctly transcribed, maybe it could one day be used to create new versions of you on the other side of the universe—effectively teleporting you. Wait, is this even teleportation? You're technically being recreated as opposed to actual transportation. What about if you wanted to bring your conscience with you? If you wanted to bring the thing that for sure makes you you, what if simply reconstructing you in another place doesn't cut it?
For that, we need to look at wormholes. In 1935, Albert Einstein and Nathan Rosen showed that through the use of general relativity, black holes across the universe could theoretically be linked together by a tunnel through space-time—a wormhole. Einstein's general theory of relativity states that the presence of mass or energy will warp the fabric of space-time around it.
I covered this in more detail on my dark matter video as well as some others, but I'll cover it here as well. A black hole has mass so dense that not even light can escape its strong gravitational pull. Scientists for decades have attempted to take pictures of a black hole; however, this has proven elusive because, well, light cannot escape and the lack of light makes it essentially invisible, like you're trying to take a picture of nothing.
What about the light that doesn't get sucked in? What about the light that slingshots around the very edge of the black hole? This will make a light ring of sorts around the black hole, and recently, in April 2019, astronomers revealed the first-ever image of a black hole. Einstein and his theories were proven right yet again. But what happens inside this hole?
When we talk about holes on Earth, it's in the context of three dimensions, where someone walking down the road can fall downwards into an uncovered manhole, for example, which is basically a two-dimensional circle on the ground. But in space, matter can fall into a black hole from all three dimensions. Black holes are pretty much three-dimensional spheres. The shape changes a bit when supermassive black holes rotate at significant portions of the speed of light, but that's not really important.
What is important is where does this hole finish? I tend to think of them as funnel shapes, where a wide event horizon eventually tapers off into one infinitely small point—the singularity. But what if this wasn't the case? What if a singularity wasn't needed? What if a link could take place in the bulk to take you to another part of the universe? Here, Einstein and Rosen theorized that the extreme density of mass may be enough to tear space-time fabric itself and connect to another point in space—perhaps to another black hole.
Scientists are unsure of what happens or if this is even possible. If it is possible, the chance of it randomly appearing in nature is pretty much zero. The center of a black hole is perhaps the most sought after but yet least understood point in science, math, and nature itself. Here is where the laws of our universe, as we know them, begin to break. But assuming that wormholes are possible, what's going to hold them open? What will prevent them from collapsing in on themselves, crushing whatever passes through out of existence?
Math and nature. Dark energy is the reason why the universe is expanding at such an accelerated pace, and it just might be able to make wormholes much easier to create. Dark energy has an effect that is essentially like the opposite of gravity. Gravity pulls things towards objects with mass, but dark energy is a repulsive force. It has a negative pressure and tends to push.
Imagine having a headache where it feels like your head is being squeezed, but instead of the squeezing being inward, it's pushing outwards. If wormholes exist and are capable of bending space-time in such a way to essentially allow teleportation between points of space, there are still many barriers to cross.
We'd have to figure out how to stop the intense gravitational pull from completely crushing our bodies or perhaps the wormhole collapsing altogether. We'd have to figure out if a trip through a wormhole is a two-way street. If we go through, are we going to be able to come back? In 1988, physicist Kip Thorne proposed an idea where wormholes may be able to be kept open longer. He suggested that wormholes might be able to be kept open through the use of negative energy, but no one knew how to create this energy inside the wormhole in that very short amount of time that they'd be open.
In his paper, Cambridge physicist Luke Butcher says that taking advantage of the Casimir energy that exists naturally in some wormholes could do the trick. After many calculations, he found that if you have a wormhole that's much wider than it is tall—more like a worm's slide as opposed to a wormhole—the amount of Casimir energy inside just might be enough to keep the wormhole from collapsing just long enough to send a photon through.
As with most things, the more we learn and figure out how things work, the more we realize that we don't know much of anything. More doors open up, more questions pop up, and not all of them have solutions. As you approach a wormhole, you'd be looking at a portal to another world. If you thought going to the moon or Mars was scary, traversing through a wormhole is essentially a suicide mission. The quantum world is strange and fascinating as scientists uncover more about the secrets of the universe by studying its most basic levels.
There are bound to be breakthroughs and leaps in technology. Teleportation may have been science fiction decades ago, but today it may just be a point of theoretical discussion and a growing body of study. In the future, we may be reconstructing ourselves through entanglement and using wormholes as portals to explore once unexplorable parts of the universe.
All good things come from compound interest. This includes friendships, relationships, finances, and science. All of these things start out slow. When you meet someone for the first time, it can feel like time slows down, as you exchange stories and dreams. As relationships develop, they can provide a rich tapestry of experiences, allowing us to see the world in new ways and providing a sense of belonging.
As the nukes dropped on every major city around the globe, everyone sought shelter, but there was nowhere to hide. In an instant, civilization, as we knew it, was destroyed. Every server, library, and entity that stored information about who we were, what we did, and how we lived was gone. Only a handful of children worldwide survived, all kept in the deepest bunkers we could find. No adults could make it.
Everything about humanity before the blast would be lost entirely. In around five generations, sure, there are tales, mysteries, and legends, but no historical record of life before the final world war. There's no way our descendants thousands of years from now can know who we were. The story might sound a little far-fetched, but the reality is—for all we know—this could have happened already, maybe, except for the nuclear part, because no evidence suggests that man-made nuclear weapons existed before Oppenheimer.
But the rest of it could be true because there's so much we don't know about the history of our world and humans. At one point, we knew more—until the fire. In 48 BC, the Library of Alexandria, located in Alexandria in what is now Egypt, burned down. Historians estimate that at one point, the library held over half a million documents from Persia, Greece, Egypt, India, and other nations. Sadly, as the pages turned into ashes, the most significant assembly of information about the ancient world disappeared.
There are a lot of theories about who started the fire. Julius Caesar is one of the most routinely accused people. He was driving his soldiers into Egypt when an Egyptian fleet in Alexandria cut him off. Legend has it that Caesar's ships were outnumbered, so they set all the ships in the harbor to fire. This fire then spread and destroyed parts of the city, including the library.
Another theory blames the fire on one of the Muslim conquerors of Egypt. The story goes that the scrolls were burned for fuel for thousands of hot baths in the city. But there's some skepticism about why a Muslim would burn Jewish and Christian texts since they also hold the holy text in Islam. Most likely, it wasn't a dramatic fire that started in the harbor or an attempt to make fuel, but a series of events that happened over time to destroy the library, culminating in a fire.
But who burned it isn't the real question we have. What knowledge was in there that we missed out on? Is a better question. What insights did historians and philosophers have about humanity that we'll never know? These are the more essential questions—questions that we might never truly know the answer to.
Beyond the Library of Alexandria, what about all the information never written down in the first place? The reality is that most of human history has been lost to time, and as a result, so many people have come up with their own conclusions about what we were. But before discussing those, there are things we need to know about our past. Prehistoric humans might not have had tools like we do today, but what they had in abundance was a really good understanding of math and engineering. That's why structures like the Great Pyramid in the Library of Alexandria could exist in the first place.
Humans first appeared about 300,000 years ago while Earth was in the middle of the last ice age. It was a harsh environment to come into existence in; as a result, human populations were tiny and grew slowly. The Stone Age, our most ancient time, lasted until about 3,000 BC. This era was marked by the use of tools and most importantly, saw a transformation of our culture from hunting and gathering to farming and food production.
Humans in the Stone Age lived in caves or very simple huts and tepees. They learned to control fire to keep their homes warm, scare away predators, and cook their prey like woolly mammoths, deer, and bison. These early humans were also the first to leave behind art in the form of etched people, animals, and signs on the walls of caves or carved into items. With time, their tools evolved from rough, dull shapes to polished, pointed items that served as spears and arrows.
Eventually, they started settling more prominently in villages and began farming. We know this from the appearance of polished hand axes and other tools used to till farmland. As they settled, advancements were made in home construction, pottery, sewing, and weaving. As human civilization expanded, something interesting also happened: human activity reached a tipping