Space is something that is everywhere, all around us and a part of everything. Most of what we know is space. If we think about the universe as the Earth and outer space as the oceans, both outer space and our oceans account for 70% of the whole. Intriguing. Whenever I conceptualize space, I am always referencing outer space. But space is all around us right here! If we look at a skyscraper, like the Empire State Building as the movie below suggests, we can see that if we remove all of the space from the matter that makes up the building, we are left with actual matter that is the size of a grain of rice, weighing a massive amount of course. That is insane to think about!
“You can’t understand anything in the world unless you understand space because that’s the world, the world is space with stuff in it.” Craig Hogan, University of Chicago
Most of us claim to need more of it, in the ever popular expression “I just need some space.” Very little thought is put into that expression. But as we dive deeper into its composition, we find that we know very little about something (space) that is in fact no thing, yet at the same time it is something. The video explains how humanity has evolved its understanding of space. Back in Newton’s time, space was just the container; it didn’t do anything at all. Then, through Einstein, space begins to effect how objects move. Then, with Casimir, literally objects can be pushed by the activity even in empty space. And now, through the ideas of Higgs and dark energy, the very expansion of the universe may be coming from the energy of space itself. Our understanding of space is so miniscule that it is similar to how we once viewed the Earth, as a flat surface.
Atoms make up everything that we know, from the chair we sit on, to the clothes we wear, and even our bodies. We can split atoms to make even more atoms going from a macro to a micro perspective. Let us then visualize the entire universe as one large atom, with galaxies and planets being the protons, neutrons and electrons within the atom, or universe. What if the atoms, that are the building blocks of everything, are each another universe, with planets and other life living within? This is a thought I was confronted with as I watched this video. If this is a possibility, would blasting my music as I clean my apartment wreak havoc on life within the atoms that make up the couch? When I use bleach to clean my floors, does that create mass pollution or even extinction of life residing in the atoms that make up my floor tiles? Is the atom that I am living in a part of the toilet of some other being? The possibilities are endless.
The end of the movie begins to unveil the new direction our knowledge of space is heading in; black holes. This begins to delve into a controversial topic because the closest black hole is said to be thousands of light years away, however it is mostly speculative. We understand black holes to occur when a sun is in the last stages of its life span. Once in its final stage, it collapses under the weight of its own gravity. Discovering them, however, has been another story. One way scientists claim that they can discover a black hole is through the use of radio telescopes that observe radioactive emission of matter which falls into a black hole. The nearest black hole is said to be in the Sagittarius constellation. The discovery came about as the illumination of a star, referred to as V4641 Sgr, increased in intensity by a factor of more than 1,000 in seven hours, then dropped by a factor of 100 in two hours. This star is referred to as a micro quasar due to the smaller scale of size.
“The information content of all the stuff that fell into that black hole can be expressed entirely in terms of just the outside of the black hole. The idea then is that you can capture what’s going on inside the black hole by referring only to the outside.” Clifford Johnson, Univ. of Southern California
Black holes open up a new possibility and a myriad of questions. One of those questions stems from the movie Matrix. What if our reality and everything that we know is just a holographic projection emanating from a two dimensional disk, broadcasted throughout what we know of as the universe? The information about black holes seems to tell us this; if something were to pass through a black hole, hypothetically what happens is that the object itself passes through. The other part is that, before it is passed through, the components of the object’s make up is smeared onto the surface of the black hole and copied into a two dimensional sequence where the information is then stored right at the surface. The object is then in two places at once, on the other side of the black hole in a three dimensional state, and stored at the surface of the black hole in a two dimensional state.
Wouldn’t this suggest that there are parallel universes? On both sides of the black hole is a projection of the information that is stored on the surface, only the information differs depending on the side that you are on. On side A, I am writing this blog post right now. The information is then copied onto the surface, and then projected onto side B. But what is being projected? Is it the choices that I am making, the life I am currently living, or is it the choices that I am not making and passing up? We have not yet been able to test any of these ideas and our knowledge of black holes is mostly theoretical. Much like the evolution of our conception of the Earth, so too is the evolution of our conception of space. Check out the video below and discover it for yourself! The video starts at 3:35.
“If an object inside a black hole can be described by information on the black hole’s surface, then it might be that everything in the universe, from galaxies and stars, to you and me, even space itself is just a projection of information stored on some distant, two dimensional surface that surrounds us. In other words, what we experience as reality may be something like a hologram.” Brian Greene, Columbia University
What is space?
Narrator: We think of our world as filled with stuff, like buildings and cars, busses and people, and nowhere does that seem more apparent than in a crowded city, like New York. Yet, all around the stuff that makes up our everyday world is something just as important but far more mysterious; the space in which all this stuff exists. To get a feel for what I’m talking about, let’s stop for a moment and imagine…
What if you took all this stuff away? I mean all of it, the people, the cars and buildings, and not just the stuff here on earth, but the Earth itself. What if you took away all of the planets and stars and galaxies, and not just the big stuff; the tiny things, down to the very last atoms of gas and dust? What if you took it all away? What would be left?
Most of us would say nothing and we’d be right. But, strangely, we’d also be wrong. What’s left is empty space and, as it turns out, empty space is not nothing. It’s something, something with hidden characteristics as real as all of the stuff in our everyday lives. In fact, space is so real that it can bend, space can twist, and it can ripple. So real, that empty space itself helps shape everything in the world around us and forms the very fabric of the cosmos.
Craig Hogan, University of Chicago: You can’t understand anything in the world unless you understand space because that’s the world, the world is space with stuff in it.
S. James Gates, JR. University of Maryland: We’re not usually very conscious of space, but then again, I tell people fish are probably not conscious of water either yet they’re in it all the time.
Joseph Lykken, Fermilab: Space is not really nothing, it actually has a lot going on inside.
Narrator (Brian Greene, Columbia University): When most of us picture space, we think of outer space, a place that’s far, far away. But space is actually everywhere. You could say it’s the most abundant thing in the universe. Even the tiniest of things, like atoms, the basic ingredient in you, and me, and everything else we see in the world around us, even they are almost entirely empty space. In fact, if you removed all of the space inside all of the atoms making up the stone glass and steel of the Empire State Building, you’d be left with a little lump about the size of a grain of rice but weighing hundreds of millions of pounds. The rest is only empty space.
But what exactly is space? I can show you a picture of Spain, of Napoleon, of my uncle Harold, but space, it looks like this; nothing. So, how do you make sense of something that looks like nothing?
Leonard Susskind, Stanford University: Why is this space rather than no space? Why is space three dimensional? Why is space big? We have a lot of room to move around in. How come it’s not tiny? We have no consensus about these things.
Alex Filippenko, UC Berkeley: What is space? We actually still don’t really know.
S. James Gates, JR. University of Maryland: It is one of the deepest mysteries in physics.
Narrator: Fortunately, we’re not completely in the dark. We’ve been gathering clues about space for centuries. Some of the earliest came from thinking about how objects move through space. To get a feel for this, take a look at that skater. As she glides across the rink, she’s moving in relation to everything around her, like the ice, and when she goes into a spin, not only can she see that she’s spinning, she can also feel it because as she spins, she feels her arms pulled outward. But now let’s imagine that you could take away all of the stuff that’s around her, from the rink to the most distant galaxies, so the only thing left is the skater spinning in completely empty space. If the skater still feels her arms pulled outward, she’ll know she’s spinning. But if empty space is nothing, what is she spinning in relation to? Imagine you’re that skater. When you look out, you don’t see anything, it’s just uniform still blackness all around you, and yet, your arms are being pulled outwards. So you say to yourself, what could I be spinning with respect to? Is there something out there that I’m not seeing? Trying to answer questions, like these, scientists came up with a bold new picture of space, and the key was to make something out of nothing.
When you go to the theatre, you watch the actors, the scenery, the story. But there’s something important here that you won’t find mentioned in the play at all, something we hardly ever notice; the stage. It’s an absolutely vital part of the show, and yet ,most of us, we don’t even give it a second thought. But Isaac Newton, he did. This is how the father of modern science pictured space, as an empty stage. To Newton, space was the framework for everything that happens in the cosmos; the arena, within which the drama of the universe plays out. Newton’s stage was passive, absolute, eternal, and unchanging. The action couldn’t effect the stage and the stage couldn’t effect the action.
By picturing space in this way, Newton was able to describe the world as no one had ever done before. His unchanging stage allowed him to understand almost all motion we can see around us, yielding laws that can predict everything, from the way apples fall from trees to the path the Earth takes around the sun. These laws work so well that we still use them for the things we do today, from launching satellites to landing airplanes. The laws all hinge on one radical idea; space is real. Even though you can’t see it or smell it or touch it, space is enough of a real physical thing to provide a bench mark for certain kinds of motion, like that skater. Newton would say that when she spins, her arms splay out because she is spinning with respect to something, and that something is space itself.
S. James Gates, JR. University of Maryland: Philosophers have been debating the nature of space for a very long time. What Newton does is change the terms of the debate, and with that, essentially modern science gets born.
Narrator: Newton’s stage was a huge hit. It enjoyed the limelight for over 200 years. In the early decades of the 20th century, a new set of ideas emerged that shook Newton’s stage to its very foundation. Ideas put forward by a young clerk working in a Swiss patent office; his name, Albert Einstein.
Einstein grew up in the late 1800s at the dawn of the age of electricity. Electric power was lighting up cities, giving rise to all kinds of technologies Newton could never have imagined. All of these developments tapped into something that had captivated Einstein since he was a child; light. Not light bulbs and street lamps but the very nature of light itself. It was his fascination with one particularly weird feature of light, its speed, that would lead Einstein to overturn Newton’s picture of space. To see how, let’s take a ride.
Right now we’re traveling at about 20 miles per hour. To go faster, all the driver needs to do is step on the gas and the cab’s speed changes. Now, you can feel that change, but you can also see it on the cab’s speedometer or on one of those radar speed signs. But now, imagine that instead of measuring the speed of the cab, you have a radar sign that measures the speed of the light coming off its headlights. That sign would measure the light traveling at an astounding 671 million miles an hour.
Now, when the cab starts moving, you’d think that the speed of the light would increase by the same amount as the car. After all, you’d think that the moving cab would give the light an extra push. Surprisingly, that’s not what happens. A radar sign, or any measurement of light speed will always detect light traveling at 671 million miles per hour, whether the cab is moving or not. How could this be? How could all measurements of light speed always come out the same?
Janna Levin, Barnard College / Columbia University: If you’re running at a wall, it’s coming at you faster than if you’re standing still, with respect to that wall, but that’s not true with light. The speed of light is the same for everybody. That’s really extraordinary!
Narrator: So, here’s how Einstein made sense of this extraordinary puzzle; knowing that speed is just a measure of the space that something travels over time, Einstein proposed a truly stunning idea that space and time could work together, constantly adjusting by exactly the right amount so that no matter how fast you might be moving when you measure the speed of light, it always comes out to be 671 million miles per hour.
Janna Levin, Barnard College / Columbia University: To respect that absolute quality about light, time had to cease to be absolute, space had to cease to be absolute, and those two had to become relative in such a way that they slosh between each other.
Narrator: If space and time being flexible sounds unfamiliar, it’s only because we don’t move fast enough in everyday life to see it in action. If this cab could move near the speed of light, the effects would no longer be hidden. For example, if you were on a street corner as I went by close to the speed of light, you would see space adjusting so that my cab would appear to be just inches long and you’d also hear my watch ticking off time very slowly. But from my perspective inside the cab, my watch would be ticking normally and space in here would appear as it always does. When I look outside the cab, I’d see space wildly adjusting all to keep the speed of light constant. So, with Einstein, time and space are no longer rigid and absolute. Instead, they meld together with motion forming the single entity that came to be called space time.
Rocky Kolb, University of Chicago: I think as we live our life every day, we live with a Newtonian picture of space and time. It’s something that we are comfortable with. Einstein was able to make reason conquer sense. That really was the genius of Einstein.
S. James Gates, JR. University of Maryland: This notion that space and time are unity, to me is one of the greatest insights that has ever occurred in science. It’s so counter intuitive to everything we’ve ever experienced as human beings.
Narrator: And in the hands of Albert Einstein, this new picture of space would solve a deep mystery having to do with the most familiar force in the cosmos; gravity. Newton knew that gravity is a force that attracts objects to each other and his laws predicted the strength of this force with fantastic precision. But how does gravity actually work? How does the Earth pull on the moon across hundreds of thousands of miles of empty space? They behave as if they’re connected by some kind of invisible rope but everyone knew that wasn’t true and Newton’s laws provided no explanation.
Alex Filippenko, UC Berkeley: Einstein found that no band aid patches would fix Newtonian gravity. He had to invent a mechanism for it. He had to understand it.
Narrator: After puzzling over this problem for more than ten years, Einstein reached a startling conclusion. The secret to gravity lay in the nature of space time. It was even more flexible than he had previously realized. It could stretch like an actual fabric. This was a truly radical break from Newton. Think of this table as space time and think of these balls as objects in space. Now if space time were nice and flat like the surface of this table, objects would travel in straight lines. But if space is like a fabric that can stretch and bend, well, this may seem a little strange, but watch what happens if I put something heavy on the stretchy space time fabric. Now if I take my shot again, the ball travels along an indentation in the fabric that the heavier object creates and this, Einstein realized, is how gravity actually works. It’s the warping of space time caused by the objects within it. In other words, gravity is the shape of space time itself. The moon is kept in orbit not because it’s pulled to the Earth by some mysterious force, but rather because it rolls along a curve in the space time fabric that the Earth creates.
Leonard Susskind, Stanford University: With Einstein, space became not only real, but flexible. So suddenly space had properties, suddenly space had curvature. Suddenly space had a flexible kind of geometry almost like a rubber sheet.
S. James Gates, JR. University of Maryland: It opens up a whole new way of thinking about reality that describe the entire universe. Einstein becomes “Einstein” because of that observation.
Narrator: Where Newton saw space as passive, Einstein saw it as dynamic. It’s interwoven with time and it dictates how things move. So, after Einstein, space can no longer be thought of as a static stage. It’s an actor, and it plays a leading role in the cosmic drama. Now, it’s one thing to think of space as dynamic, active, and flexible like a fabric, but is it really? Is this just a metaphor or does it actually describe what space is? Well, Einstein’s theory predicts that one way to find out would be to take a little journey to the edge of a black hole.
Black holes are collapsed stars, massive objects crushed to a fraction of their original size. Gravity around them is so strong that, according to Einstein’s math, a spinning black hole can literally drag space along with it, twisting it like an actual piece of cloth. The nearest black hole is trillions of miles away, making it a challenge to test this prediction. In the late 1950’s, a physicist named Leonard Schiff began searching for a way to test Einstein’s ideas about space much closer to home. Schiff was inspired by something we usually think of as a child’s toy; a gyroscope. He thought that, if space really twists like a fabric, the gyroscope might allow him to detect it. It was a strange idea and he chose a strange place to share it with the world; the faculty’s swimming pool at Stanford. Here, in 1959, Schiff met with two colleagues, William Fairbank and Bob Cannon.
He was excited about an ad that he had seen about a high tech gyroscope. Though it looked different, it basically worked the same as the child’s toy. Then and there, the three decided to launch a device like this into orbit around the Earth. Normally a gyroscope’s axis points in a fixed direction, but if Earth is actually dragging space, then the gyroscope’s axis would be dragged along with it, shifting it’s orientation in a way that could be measured. It was a brilliantly simple plan. There was just one problem; Einstein’s theories predict that the Earth’s rotation twists space by only a tiny amount, an amount so small, it would be like trying to measure the height of a penny from 62 miles away.
The team spent more than two years trying to figure out how to make such a precise measurement. They finally devised a plan to attach four freely floating gyroscopes to a telescope aimed at a distant star. If space twists, then over time, the gyroscopes would no longer point at the star since they’d get caught up in the swirl of space. In 1962, they applied to NASA for a grant requesting around one million dollars for what would come to be called Gravity Probe B. Members of the team originally thought the project would take about three years. They were just a little optimistic.
With an ever growing team, Gravity Probe B became one of the longest running experiments in history. Decade after decade was spent trying to realize the original vision, which meant launching a telescope into space, and building gyroscopes that were among the smoothest objects ever created.
Brad Parkinson, Stanford University: The technology is just frightening. It was like the carrot on the front of a mule. It was like it was always five to ten years away when we could do this, and it was five to ten years away for about 35 years.
Narrator: Consuming more than four decades and 750 million dollars, the project was nearly canceled by NASA nine times. Finally, in April of 2004, the team gathered to witness the launch. Of the three men who sat by the pool back in 1959, only one was alive to see it.
Robert Cannon, Stanford University: And there we were watching. It’s a terribly exciting moment in your life, just a thrilling experience. It was flawless. 10,000 things did not go wrong.
Narrator: For over a year, Gravity Probe B orbited the Earth, while the team nervously monitored its every move, trying to see if the Earth would actually twist space. Finally, the data began to trickle in and there was a problem. The gyroscopes were experiencing a tiny, unexpected wobble, and to clean up the data would cost millions. With funds running out, it looked like nearly half a century of work was about to go down the drain. Then, at almost the last possible moment, two sources of additional funding emerged. The son of original team leader, William Fairbank, made a private donation, and Turki Al Saud, a member of the Saudi royal family with a degree in aeronautics from Stanford, arranged for a large grant.
Over the next two years, the problem with the data was solved, revealing that the axis of the gyroscope shifted by almost exactly the amount predicted by Einstein’s equations.
Brad Parkinson, Stanford University: I think it’s the first time that you can actually see Einstein’s effect, his drift, with the naked eye.
Narrator: This experiment provides the most direct evidence ever found that space is something real, a physical entity, like a fabric. After all, if space were nothing, there would be nothing to twist.
But at the same time that Albert Einstein was investigating space on the largest of scales, another band of physicists was probing the universe on extremely tiny scales, and there they found a completely uncharted realm where Einstein’s picture of space, it was nowhere to be found. To see what I am talking about, imagine you could shrink billions of times smaller than your current size. This is the realm of atoms and subatomic particles, the fundamental building blocks of everything we can see. When you get down to this size, the world plays by a wildly different set of rules called quantum mechanics. According to these rules, even if you try to remove every last atom and particle, you’d find that empty space is still far from empty. In fact, it’s teaming with activity. Particles are constantly popping in and out of existence. They erupt out of nothingness, quickly annihilate each other, and disappear.
Leonard Susskind, Stanford University: In quantum mechanics, empty space is really not that empty. It’s full of fluctuating fields, full of all sorts of jittery things going on.
Raphael Bousso, UC Berkeley: It’s a place where particles are constantly fluctuating and annihilating each other and being created again and annihilating.
S. James Gates, JR. University of Maryland: It’s a place of chaos and bubbling…
Narrator: While the theory predicted this, it wasn’t until 1948 that a scientist named Hendrik Casimir suggested that, even though we can’t see these particles, they should cause empty space to do something we can see. He predicted that if you take two ordinary medal plates and place them extremely close together, say closer together than the thickness of a sheet of paper, then particles with certain energies would be excluded because, in some sense, they wouldn’t fit between the plates. With more of this frenetic activity outside the plates than inside, Casimir thought that the plates would be pushed together by what we usually think of as empty space, and some years later, when the experiment was done, Casimir was proven right. In empty space, the plates were pushed together. So, on atomic scales, empty space is not empty. It’s so flooded with activity that it can force objects to move.
Today, the quest to understand space on the smallest scale is continuing with one of the most expensive science experiments in history. This is CERN, the European organization for nuclear research in Geneva. Here, buried a few hundred feet below the ground is the large hadron collider, the world’s most powerful accelerator. With the price tag of about 10 billion dollars, it accelerates subatomic particles to more than 99.99% of the speed of light and smashes them into each other. In the showers of debris produced by these collisions, scientists at place like this have discovered a whole zoo of strange and exotic particles, and right now, they’re chasing one of the most elusive, a particle thought to be essential to shaping everything, from the atoms in our bodies to the most distant stars. If this particle is found, it will redefine our picture of space and fulfill a quest begun more than 40 years ago.
It all started in 1964, when a young English physicist named Peter Higgs suggested something about space that was so radical, it nearly ruined him.
Peter Higgs, University of Edinburgh: I was told that I was talking nonsense, that I couldn’t be right. So, they clearly hadn’t understood what I was saying.
Narrator: Higgs, and a few others, were wrestling with a puzzle that comes down to this; the fundamental particles in the universe all contain different amounts of mass which we usually think of as weight. Without mass, these particles would never combine to form the familiar atoms that make up all the stuff we see in the world around us. But what creates mass, and why do different particles have different masses? Try as they might, no one had been able to answer this perplexing question. Then, one weekend after a walk outside Edinborough, Higgs had a peculiar idea. Using mathematics, he imagined space in a new way as something like an ocean. Particles are immersed in this ocean and gain mass as they move through it. To see how this works, think of a particle’s mass like an actor’s fame, and the Higgs’ ocean is like the Paparazzi. Some particles, like unknown actors, pass through with ease. The Paparazzi simply aren’t interested in them, but other particles, like superstars, have to push and press, and the more those particles struggle to get through, the more they interact with the ocean and the more mass they gain.
Higgs was convinced he had made a great discovery, but when he submitted his idea to a journal at CERN, it was rejected. Undaunted, Higgs honed his theory further. Until he was offered the chance to present it at Einstein’s old haunt, the Institute for Advanced Study in Princeton, there, he expected his new idea would meet some of its toughest critics.
Peter Higgs, University of Edinburgh: I was happily driving up the freeway and then there was a sign to turn off for Princeton, and that really confronted me with what I was really going into. I broke out in a cold sweat and started trembling, and I had to pull off the road to recover.
Narrator: But Higgs persevered. It was the first in a series of talks that would convince colleagues far and wide that he was onto something profound.
Peter Higgs, University of Edinburgh: Eventually, I sort of wore them down. I felt I had sort of triumphed. So I enjoyed the parties which followed.
Narrator: Today, the idea Higgs pioneered, called the Higgs field, is crucial to our understanding of space.
Joseph Lykken, Fermilab: The Higgs field is everywhere. It’s something that even in the emptiest vacuum of space has an effect, it gives you mass. So I think Higgs actually deserves credit for being one of the people that said space is stuff. It has properties in it that are intrinsic, that you can’t get rid of, you can’t turn them off.
Narrator: The only problem, that there’s no physical proof that the Higgs field exists, at least, not yet. But here at CERN, scientists are attempting to smash particles together with so much energy that they will knock loose a piece of the Higgs field producing a tiny particle of its own. It’s as if they’re trying to chip off a piece of space.
Joseph Lykken, Fermilab: We think that if we knock into space hard enough with particle accelerator collisions that we can actually make a Higgs particle come out of empty space.
Leonard Susskind, Standford University: Our whole understanding of matter, as we now have it, would just fall apart if the Higgs field didn’t exist.
Raphael Bousso, UC Berkeley: I don’t think anybody seriously doubts that we will see it. Certainly if we don’t, that will be an extremely bizarre outcome.
Narrator: Finding the Higgs particle would be a major milestone, establishing that the emptiest of empty space has an impact on all of matter. But it turns out that space contains an ingredient far more elusive than anything Higgs had ever imagined, an ingredient that may hold the key to the greatest of all mysteries; the very fate of the cosmos.
It’s a mystery that began some 14 billion years ago in what we call the big bang. In a fraction of a second, the universe underwent a violent expansion, sending space hurdling outward. Space has been expanding ever since. For decades, most scientists thought that expansion should be slowing down thanks to the pull of gravity.
Alex Filippenko, UC Berkeley: When I toss an apple up, the gravity of the Earth eventually stops it and brings it back, and just like the apple slows down with time, so too the universe should have been slowing down in its expansion because of the gravitational attraction of all matter and energy for all other matter and energy.
Narrator: But that raised the question, what is the ultimate fate of the cosmos? Would space go on expanding forever or would gravity eventually stop space from expanding causing it to collapse back on itself in a big crunch. To solve this mystery, two teams of astronomers set out to measure the slowing of the expansion, using a novel tool, exploding stars called super novas.
Adam Riess, Johns Hopkins University: So a super nova is a star that ends its life in a massive explosion. They’re extremely luminous. They can be as bright as a billion suns.
Saul Perlmutter, UC Berkeley: What makes a super nova great is that they are very similar when they explode. They all get to about the same brightness and then they fade away in just about the same way.
Narrator: Because the explosions are so bright and uniform, it teens reason that these super novas would act as very precise cosmic beacons, allowing them to track how the expansion of space has slowed over time. The trouble is, super novas are extremely rare. To find enough of them, Perlmutter spent years calling astronomers around the globe begging for time on their telescopes.
Saul Perlmutter, UC Berkeley: We needed the biggest telescopes in the world. We needed perfect conditions, and in those perfect conditions, I would be calling people up at the middle of their night when they’re trying to do some serious work , and I would be saying, I know that you have a very busy schedule, but by any chance, if you could just squeeze in this half hour observation, it would really be very interesting to us.
Narrator: When they finally had enough data to chart how much the pull of gravity was slowing the expansion of the universe, they were in for a surprise.
Saul Perlmutter, UC Berkeley: The results looked a little bit strange. They didn’t really show any slowing of the universe at all. Very surprising. Actually a universe that’s actually speeding up.
Adam Riess, Johns Hopkins University: It was as though space, which we really thought was nothing, actually had an inherent springiness to it, and so, space did not want to be compressed. Space actually wants to push the universe apart.
Alex Filippenko, UC Berkeley: It looked like the universe was expanding faster and faster with time, accelerating rather than decelerating.
Rocky Kolb, University of Chicago: My immediate response was, I have to figure out why this is wrong, this can’t be right.
Narrator: But it was right, and most scientists converged on one explanation. There’s something that fills space and counteracts the pull of ordinary, attractive gravity, pushing galaxies apart and stretching the very fabric of the cosmos.
This mysterious substance filling space has been dubbed dark energy, and it’s turned our picture of the universe upside down.
Alex Filippenko, UC Berkeley: Over the largest distances, dark energy dominates the contents of the universe and we don’t know what it is.
S. James Gates, JR. University of Maryland: If you do sort of a survey on all senses of energy in the universe, dark energy turns out to be about 70% of the universe, and up until a decade ago, nobody imagined such stuff even existed.
Narrator: So, in essence, the weight of empty space itself is 70% of the weight of the entire universe. That’s roughly the same percentage of Earth’s surface that’s covered by water. Imagine we didn’t know what water is. That’s where we stand with dark energy.
Joseph Lykken, Fermilab: We’re really clueless about how to explain it. We have all of this fancy scientific apparatus of quantum mechanics and relativity and particle physics that we’ve developed in the last hundred years, and none of that works to explain dark energy.
Narrator: And the discovery of dark energy held another surprise. The idea that the universe contains such an ingredient had actually been cooked up 80 years earlier. I’ll let you in on a little secret. Although he didn’t call it dark energy, long ago, Albert Einstein predicted that space itself could exert a force that would drive galaxies apart. You see, shortly after discovering his general theory of relativity, his theory of gravity, Einstein found that, according to the mathematics, the universe would either be expanding or contracting, but it couldn’t hover at a fixed size.
This was puzzling because, before they knew about the big bang, most scientists, including Einstein, pictured the universe as static, eternal, and unchanging. When Einstein’s equation suggested an expanding or contracting universe, not the static universe everyone believed in, he had a problem. So Einstein went back to his equations and modified them to allow for kind of anti gravity that would infuse space with an outward push, counteracting the usual inward pull of gravity, allowing the universe to stand still. He called the modification the cosmological constant.
Adding the cosmological constant rescued his equations. But the truth is, Einstein had no idea if this outward push, or antigravity, really existed.
Rocky Kolb, University of Chicago: The introduction of the cosmological constant by Einstein was not a very elegant solution to try to find what he was looking for, a stationary universe.
S. James Gates, JR. University of Maryland: It achieves this effect of antigravity, it says that gravity sometimes can behave in such a way not to pull things together but to push things apart.
Adam Riess, Johns Hopkins University: Like the clash of two titans, the cosmological constant and the pull of ordinary matter could hold the universe in check and keep it static.
Narrator: But about a dozen years later, the astronomer Edwin Hubble, discovered the universe is not static, it’s expanding due to the explosive force of the big bang 14 billion years ago. That meant, Einstein’s original equations no longer had to be altered, so, suddenly, the need for a cosmological constant went right out the window. Einstein has said to have called this his biggest blunder. But here’s the thing, with the recent discovery that the expansion of the universe is accelerating, scientists are convinced that there is something in space that is pushing things apart. So 70 years later, Einstein’s biggest blunder may rank among his greatest insights.
Joseph Lykken, Fermilab: It was something that nobody else was thinking about but it might be that Einstein’s cosmological constant is the key to understanding the expansion of the universe as we see it today
Narrator: Though no one knows what dark energy actually is, it raises an astounding and troubling possibility. Einstein pictured the strength of his antigravity as constant. But, is the strength of dark energy constant and what if it changes over time? The answer could overturn everything we thought we knew about the fate of the cosmos.
At the moment, everything in our world, from the molecules making up my body, to the molecules making up the moon, is held together by forces that overwhelm the outward push of dark energy, and that’s why we don’t see things expanding in our everyday lives. But that situation might not last forever.
In one scenario, dark energy will continue to push the galaxies farther and farther apart, until ultimately, they’d be pushed so far apart that the universe would become a cold, dark, and lonely place. In another scenario, the strength in dark energy might increase over time, becoming so strong that it would tear apart everything within the galaxies, from stars to planets, to matter of all kind
Alex Filippenko, UC Berkeley: If the dark energy grows with time, then ultimately even atoms will get ripped apart when there’s enough dark energy between the nuclei and the electrons to rip space apart, the big rip.
Narrator: Our picture of space has gone through a remarkable transformation. Back in Newton’s time, space was just the container; it didn’t do anything at all. Then, through Einstein, space begins to effect how objects move. Then, with Casimir, literally objects can be pushed by the activity in even in empty space. And now, through the ideas of Higgs and dark energy, the very expansion of the universe may be coming from the energy of empty space itself.
I don’t think anybody would have thought that space would have this kind of rich and profound impact on the nature of reality. But as far as we’ve come, the journey that began with Isaac Newton’s picture of space as something like a stage is not yet finished. As we examine the fabric of the cosmos ever more closely, we may well find far more surprises than anyone ever imagined.
Take me, for example, I seem real enough, don’t I? Well, yes, but surprising new clues are emerging that everything, you and I and even space itself, may actually be a kind of hologram. That is, everything we see and experience, everything we call our familiar three dimensional reality, may be a projection of information that’s stored on a thin, distant two dimensional surface, sort of the way this information from this hologram is stored on this thin piece of plastic. Now, holograms are something we’re all familiar with. From the security symbol you find on most credit cards, but the universe as a hologram, that’s one of the most drastic revisions to our picture of space and reality ever proposed. The evidence for it comes from one of the strangest realms of space; black holes.
Leonard Susskind, Stanford University: This is a real disconnect that’s very hard to get your head around. Modern ideas coming from black holes tell us that reality is two dimensional, that the three dimensional world, the full bodied three dimensional world, is a kind of image of a hologram on the boundary of the region of space.
S. James Gates, JR. University of Maryland: This is a very strange thing. Even when I was a younger physicist, I would have thought any physicist who said that was absolutely crazy.
Narrator: Here’s a way to think about this. Imagine I took my wallet and through it into a black hole. What would happen? We used to think that nothing, not even light, can escape the immense gravity of a black hole, my wallet would be lost forever. It now seems that may not be the whole story. Recently, scientists exploring the math describing black holes made a curious discovery. Even as my wallet disappears into the black hole, a copy of all of the information it contains seems to get smeared out and stored on the surface of the black hole, much the same way that information is stored in a computer. So, in the end, my wallet exists in two places. There’s a three dimensional version that’s lost forever inside the black hole, and a two dimensional version that remains on the surface as information.
Clifford Johnson, Univ. of Southern California: The information content of all the stuff that fell into that black hole can be expressed entirely in terms of just the outside of the black hole. The idea then is that you can capture what’s going on inside the black hole by referring only to the outside.
Narrator: And in theory, I could use the information on the outside of the black hole to reconstruct my wallet. And here’s the truly mind blowing part, space within a black hole plays by the same rules as space outside the black hole or anywhere else. So, if an object inside a black hole can be described by information on the black hole’s surface, then it might be that everything in the universe, from galaxies and stars, to you and me, even space itself is just a projection of information stored on some distant, two dimensional surface that surrounds us. In other words, what we experience as reality may be something like a hologram.
Leonard Susskind, Stanford University: It is the three dimensional world in illusion in the same sense that a hologram is an illusion, perhaps. I’m inclined to think that yes, that a three dimensional world is a kind of illusion, and that the ultimate precise reality is the two dimensional reality at the surface of the universe.
Narrator: This idea is so new that physicists are still struggling to understand it. But if its right, just as Newton and Einstein completely changed our picture of space, we may be on the verge of an even more dramatic revolution. For something that’s such a vital part of our everyday lives, space remains kind of like a familiar stranger. It’s all around us, but we’re still far from having unmasked its true identity. That may take a hundred years. It may take a thousand years, or it may happen tomorrow. When we solve that mystery, we’ll take a giant step toward fully understanding the fabric of the cosmos.