Lawrence krauss a universe from nothing pdf download

Clearly, this is no ordinary star. It is a star that has just exploded, a supernova, one of the brightest fireworks displays in the universe. When a star explodes, it briefly over the course of about a month or so shines in visible light with a brightness of 1 0 billion stars.

Happily for us, stars don ' t explode that often, about once per hundred years per galaxy. But we are lucky that they do, because if they didn 't, we wouldn' t be here. Moreover, the atoms in your left hand probably came from a different star than did those in your right. We are all, literally, star children, and our bodies made of stardust. How do we know this? Well, we can extrapolate our picture of the Big Bang back to a time when the universe was about 1 second old, and we calculate that all observed matter was compressed in a dense plasma whose temperature should have been about 1 0 billion degrees Kelvin scale.

At this temperature nuclear reactions can readily take place between protons and neutrons as they bind together and then break apart from further collisions. Following this process as the universe cools, we can predict how frequently these primeval nuclear constituents will bind to form the nuclei of atoms heavier than hydrogen i. When we do so, we find that essentially no nuclei-beyond lithium, the third lightest nucleus in nature-formed during the primeval fireball that was the Big Bang.

We are confident that our calculations are correct because our predictions for the cosmic abundances of the lightest elements agree bang-on with these observations. Over this incredible range, observations and theoretical predictions agree. This is one of the most famous, significant, and successful predictions telling us the Big Bang really happened.

Only a hot Big Bang can produce the observed abundance of light elements and maintain consistency with the current observed expansion of the universe. I carry a wallet card in my back pocket showing the comparison of the predictions of the abundance of light elements and the observed abundance so that, each time I meet someone who doesn ' t believe that the Big Bang happened, I can show it to them.

I carry the card anyway and reproduce it for you later in the book. While lithium is important for some people, far more important to the rest of us are all the heavier nuclei like carbon, nitrogen, oxygen, iron, and so on. These were not made in the Big Bang. The only place they can be made is in the fiery cores of stars. And the only way they could get into your body today is if these stars were kind enough to have exploded, spewing their products into the cosmos so they could one day coalesce in and around a small blue planet located near the star we call the Sun.

Over the course of the history of our galaxy, about million stars have exploded. These myriad stars sacrificed themselves, if you wish, so that one day you could be born. I suppose that qualifies them as much as anything else for the role of saviors. It turns out a certain type of exploding star, called a Type la supernova, has been shown by careful studies performed over the 1 s to have a remarkable property: with high accuracy, those Type la supernovae that are intrinsically brighter also shine longer.

The correlation, while not fully understood theoretically, is empirically very tight. This means that these supernovae are very good "standard candles. If we observe a supernova in a distant galaxy-and we can because they are very bright-then by observing how long it shines, we can infer its intrinsic brightness. Then, by measuring its apparent brightness with our telescopes, we can accurately infer just how far away the supernova and its host galaxy are.

Then, by measuring the "redshift" of the light from the stars in the galaxy, we can determine its velocity, and thus can compare velocity with distance and infer the expansion rate of the universe. So far so good, but if supernovae explode only once every hundred years or so per galaxy, how likely are we ever to be able to see one?

After all, the last supernova in our own galaxy witnessed on Earth was seen by Johannes Kepler in 1 ! Starting out as a humble mathematics teacher in Austria, Kepler became assistant to the astronomer Tycho Brahe who himself had observed an earlier supernova in our galaxy and was given an entire island by the king of Denmark in return , and using Brahe ' s data on planetary positions in the sky taken over more than a decade, Kepler derived his famous three laws of planetary motion early in the seventeenth century: 1.

Planets move around the Sun in ellipses. A line connecting a planet and the Sun sweeps out equal areas during equal intervals of time. The square of the orbital period of a planet is directly proportional to the cube 3rd power of the semi-major axis of its orbit or, in other words, of the "semi-major axis" of the ellipse, half of the distance across the widest part of the ellipse.

These laws in turn lay the basis for Newton ' s derivation of the universal law of gravity almost a century later. Besides this remarkable contribution, Kepler successfully defended his mother in a witchcraft trial and wrote what was perhaps the first science fiction story, about a journey to the moon.

Nowadays, one way to see a supernova is simply to assign a different graduate student to each galaxy in the sky. After all, one hundred years is not too different, in a cosmic sense at least, from the average time to do a PhD, and graduate students are cheap and abundant.

Happily, however, we don ' t have to resort to such extreme measures, for a very simple reason: the universe is big and old and, as a result, rare events happen all the time. Go out some night into the woods or desert where you can see stars and hold up your hand to the sky, making a tiny circle between your thumb and forefinger about the size of a dime.

Hold it up to a dark patch of the sky where there are no visible stars. Since supernovae explode once per hundred years per, with 1 00, galaxies in view, you should expect to see, on average, about three stars explode on a given night. Astronomers do just this.

They apply for telescope time, and some nights they might see one star explode, some nights two, and some nights it might be cloudy and they might not see any. In this way several groups have been able to determine Hubble ' s constant with an uncertainty of less than 1 0 percent. The new number, about 70 kilometers per second for galaxies on average of 3 million light-years apart, is almost a factor of 1 0 smaller than that derived by Hubble and Humason.

As a result, we infer an age of the universe of closer to 1 3 billion years, rather than 1. As I shall describe later, this too is in complete agreement with independent estimates of the age of the oldest stars in our galaxy. From Brahe to Kepler, from Lemaitre to Einstein and Hubble, and from the spectra of stars to the abundance of light elements, four hundred years of modern science have produced a remarkable and consistent picture of the expanding universe.

Everything holds together. The Big Bang picture is in good shape. These are things we know that we know. There are known unknowns. That is to say, there are things that we know we don 't know. But there are also unknown unknowns. There are things we don 't know we don 't know. During the 1 s and 1 s, it became increasingly clear from detailed measurements of the motion of stars and gas in our galaxy, as well as from the motion of galaxies in large groups of galaxies called clusters, that there was much more to the universe than meets either the eye or the telescope.

Gravity is the chief force operating on the enormous scale of galaxies, so measuring the motion of objects on these scales allows us to probe the gravitational attraction that drives this motion. Such measurements took off with the pioneering work of the American astronomer Vera Rubin and her colleagues in the early 1 s. Rubin had graduated with her doctorate from Georgetown after taking night classes while her husband waited in the car because she didn ' t know how to drive.

Rubin rose to become only the second woman ever to be awarded the Gold Medal of the Royal Astronomical Society. By observing stars and hot gas that were ever-farther from the center of our galaxy, Rubin determined that these regions were moving much faster than they should have been if the gravitational force driving their movement was due to the mass of all the observed objects within the galaxy.

Due to her work, it eventually became clear to cosmologists that the only way to explain this motion was to posit the existence of significantly more mass in our galaxy than one could account for by adding up the mass of all of this hot gas and stars. There was a problem, however, with this view. The very same calculations that so beautifully explain the observed abundance of the light elements hydrogen, helium, and lithium in the universe also tell us more or less how many protons and neutrons, the stuff of normal matter, must exist in the universe.

This is because, like any cooking recipe-in this case nuclear cooking-the amount of your final product depends upon how much of each ingredient you start out with. If you double the recipe-four eggs instead of two, for example-you get more of the end product, in this case an omelet. Yet the initial density of protons and neutrons in the universe arising out of the Big Bang, as determined by fitting to the observed abundance of hydrogen, helium, and lithium, accounts for about twice the amount of material we can see in stars and hot gas.

Where are those particles? It is easy to imagine ways to hide protons and neutrons snowballs, planets, cosmologists. However, when we add up how much "dark matter" has to exist to explain the motion of material in our galaxy, we find that the ratio of total matter to visible matter is not 2 to 1 , but closer to 1 0 to 1. If this is not a mistake, then the dark matter cannot be made of protons and neutrons.

There are just not enough of them. As a young elementary particle physicist in the early 1 s, learning of this possibility of the existence of exotic dark matter was extremely exciting to me.

It implied, literally, that the dominant particles in the universe were not good old-fashioned garden-variety neutrons and protons, but possibly some new kind of elementary particle, something that didn ' t exist on Earth today, but something mysterious that flowed between and amidst the stars and silently ran the whole gravitational show we call a galaxy.

Even more exciting, at least for me, this implied three new lines of research that could fundamentally reilluminate the nature of reality. If these particles were created in the Big Bang, like the light elements I have described, then we should be able to use ideas about the forces that govern the interactions of elementary particles instead of the interactions of nuclei relevant to determine elemental abundance to estimate the abundance of possible exotic new particles in the universe today.

It might be possible to derive the total abundance of dark matter in the universe on the basis of theoretical ideas in particle physics, or it might be possible to propose new experiments to detect dark matter-either of which could tell us how much total matter there is and hence what the geometry of our universe is.

The job of physics is not to invent things we cannot see to explain things we can see, but to figure out how to see what we cannot see-to see what was previously invisible, the known unknowns. Each new elementary particle candidate for dark matter suggests new possibilities for experiments to detect directly the dark matter particles parading throughout the galaxy by building devices on Earth to detect them as the Earth intercepts their motion through space.

If we could determine the nature of the dark matter, and its abundance, we might be able to determine how the universe will end. This last possibility seemed the most exciting of all, so I will begin with it. Indeed, I got involved in cosmology because I wanted to be the first person to know how the universe would end.

It seemed like a good idea at the time. When Einstein developed his theory of general relativity, at its heart was the possibility that space could curve in the presence of matter or energy. This theoretical idea became more than mere speculation in 1 9 1 9 when two expeditions observed starlight curving around the Sun during a solar eclipse in precisely the degree to which Einstein had predicted should happen if the presence of the Sun curved the space around it.

Einstein almost instantly became famous and a household name. Now, if space is potentially curved, then the geometry of our whole universe suddenly becomes a lot more interesting. Depending upon the total amount of matter in our universe, it could exist in one of three different types of geometries, so-called open, closed, or flat. It is hard to envisage what a curved three-dimensional space might actually look like.

Moreover, if the curvature is very small, then it is hard to imagine how one might actually detect it in everyday life, just as, during the Middle Ages at least, many people felt the Earth must be flat because from their perspective it looked flat. Curved three-dimensional universes are difficult to picture-a closed universe is like a three-dimensional sphere, which sounds pretty intimidating-but some aspects are easy to describe.

While these exotic geometries may seem amusing or impressive to talk about, operationally there is a much more important consequence of their existence. General relativity tells us unambiguously that a closed universe whose energy density is dominated by matter like stars and galaxies, and even more exotic dark matter, must one day recollapse in a process like the reverse of a Big Bang-a Big Crunch, if you will.

An open universe will continue to expand forever at a finite rate, and a flat universe is just at the boundary, slowing down, but never quite stopping. Determining the amount of dark matter, and thus the total density of mass in the universe, therefore promised to reveal the answer to the age-old question at least as old as T. Eliot anyway : Will the universe end with a bang or a whimper? The saga of determining the total abundance of dark matter goes back at least a half century, and one could write a whole book about it, which in fact I have already done, in my book Quintessence.

However, in this case, as I shall now demonstrate with both words and then a picture , it is true that a single picture is worth at least a thousand or perhaps a hundred thousand words. The largest gravitationally bound objects in the universe are called superclusters of galaxies. Such objects can contain thousands of individual galaxies or more and can stretch across tens of millions of light-years.

Most galaxies exist in such superclusters, and indeed our own galaxy is located within the Virgo supercluster of galaxies, whose center is almost 60 million light-years away from us. Since superclusters are so large and so massive, basically anything that falls into anything will fall into clusters. So if we could weigh superclusters of galaxies and then estimate the total density of such superclusters in the universe, we could then "weigh the universe, " including all the dark matter.

Then, using the equations of general relativity, we could determine whether there is enough matter to close the universe or not. So far so good, but how can we weigh objects that are tens of millions of light-years across? Use gravity. It was a kindlier, gentler time in 1 , and it is interesting to read the informal beginning of Einstein ' s paper, which after all was published in a distinguished scientific journal: " Some time ago, R.

Mandl paid me a visit and asked me to publish the results of a little calculation, which I had made at his request. This note complies with his wish.

In any case, the fact that light followed curved trajectories if space itself curved in the presence of matter was the first significant new prediction of general relativity and the discovery that led to Einstein ' s international fame, as I have mentioned. So it is perhaps not that surprising as was recently discovered that in 1 9 1 2 , well before Einstein had in fact even completed his general relativity theory, he had performed calculations-as he tried to find some observable phenomenon that would convince astronomers to test his ideas-that were essentially identical to those he published in 1 at the request of Mr.

Perhaps because he reached the same conclusion in 1 9 1 2 that he stated in his 1 paper, namely "there is no great chance of observing this phenomenon, " he never bothered to publish his earlier work. In fact, after examining his notebooks for both periods, we can ' t say for sure that he later even remembered having done the original calculations twenty-four years before.

When he calculated the predicted effects for lensing of a distant star by an intervening star in the foreground, the effect was so small that it appeared absolutely unmeasurable, which led him to make the remark mentioned above-that it was unlikely that such a phenomenon could ever be observed. As a result, Einstein figured that his paper had little practical value.

As he put it in his covering letter to the editor of Science at the time: "Let me also thank you for your cooperation with the little publication, which Mister Mandl squeezed out of me.

It is of little value, but it makes the poor guy happy. Within months of Einstein ' s publication, the brilliant Caltech astronomer Fritz Zwicky submitted a paper to the Physical Review in which he demonstrated the practicality of precisely this possibility and also indirectly put down Einstein for his ignorance regarding the possible effect of lensing by galaxies rather than stars.

Zwicky was an irascible character and way ahead of his time. As early as 1 he had analyzed the relative motion of galaxies in the Coma cluster and determined, using Newton ' s laws of motion, that the galaxies were moving so fast that they should have flown apart, destroying the cluster, unless there was far more mass in the cluster, by a factor more than , than could be accounted for by the stars alone.

He thus should properly be considered as having discovered dark matter, though at the time his inference was so remarkable that most astronomers probably felt there might be some other less exotic explanation for the result he got.

Zwicky's one-page paper in 1 was equally remarkable. Indeed, each and every suggestion he made has come to pass, and the final one is the most significant of all. Gravitational lensing of distant quasars by intervening galaxies was first observed in 1 , and in 1 , sixty-one years after Zwicky proposed weighing nebulae using gravitational lensing, the mass of a large cluster was determined by using gravitational lensing.

In this beautiful image from the Hubble Space Telescope, a spectacular example of the multiple image of a distant galaxy located another 5 billion light-years behind the cluster can be seen as highly distorted and elongated images amidst the otherwise generally rounder galaxies.

Looking at this image provides fuel for the imagination. First, every spot in the photo is a galaxy, not a star. Each galaxy contains perhaps 1 00 billion stars, along with them probably hundreds of billions of planets, and perhaps long-lost civilizations. I say long-lost because the image is 5 billion years old. The light was emitted million years before our own Sun and Earth formed.

Many of the stars in the photo no longer exist, having exhausted their nuclear fuel billions of years ago. Beyond that, the distorted images show precisely what Zwicky argued would be possible. Working backward from this image to determine the underlying mass distribution in the cluster is a complicated and complex mathematical challenge. To do so, Tyson had to build a computer model of the cluster and trace the rays from the source through the cluster in all possible different ways, using the laws of general relativity to determine the appropriate paths, until the fit they produced best matched the researchers ' observations.

When the dust settled, Tyson and collaborators obtained a graphical image that displayed precisely where the mass was located in this system pictured in the original photograph: Something strange is going on in this image. The spikes in the graph represent the location of the visible galaxies in the original image, but most of the mass of the system is located between the galaxies, in a smooth, dark distribution.

Dark matter is clearly not confined to galaxies, but also dominates the density of clusters of galaxies. Particle physicists like myself were not surprised to find that dark matter also dominates clusters.

Even though we didn ' t have a shred of direct evidence, we all hoped that the amount of dark matter was sufficient to result in a flat universe, which meant that there had to be more than 1 00 times as much dark matter as visible matter in the universe. The reason was simple: a flat universe is the only mathematically beautiful universe.

Stay tuned. Whether or not the total amount of dark matter was sufficient to produce a flat universe, observations such as these obtained by gravitational lensing I remind you that gravitational lensing results from the local curvature of space around massive objects; the flatness of the universe relates to the global average curvature of space, ignoring the local ripples around massive objects and more recent observations from other areas of astronomy have confirmed that the total amount of dark matter in galaxies and clusters is far in excess of that allowed by the calculations of Big Bang nucleosynthesis.

We are now virtually certain that the dark matter-which, 1 reiterate, has been independently corroborated in a host of different astrophysical contexts, from galaxies to clusters of galaxies-must be made of something entirely new, something that doesn ' t exist normally on Earth.

This kind of stuff, which isn ' t star stuff, isn ' t Earth stuff either. But it is something! These earliest inferences of dark matter in our galaxy have spawned a whole new field of experimental physics, and 1 am happy to say that 1 have played a role in its development.

As 1 have mentioned above, dark matter particles are all around us-in the room in which 1 am typing, as well as "out there" in space. Hence we can perform experiments to look for dark matter and for the new type of elementary particle or particles of which it is comprised.

The experiments are being performed in mines and tunnels deep underground. Why underground? Because on the surface of the Earth we are regularly bombarded by all manner of cosmic rays, from the Sun and from objects much farther away.

Even if we are bombarded every day by millions of dark matter particles, most will go through us and the Earth, without even "knowing" we are here-and without our noticing. Thus, if you want to detect the effects of the very rare exceptions to this rule, dark matter particles that actually bounce off atoms of matter, you had better be prepared to detect very rare and infrequent events. Only underground are you sufficiently shielded from cosmic rays for this to be possible even in principle.

As I write this, however, an equally exciting possibility is arising. The Large Hadron Collider, outside of Geneva, Switzerland, the world ' s largest and most powerful particle accelerator, has just begun running. But we have many reasons to believe that, at the very high energies at which protons are smashed together in the device, conditions similar to those in the very early universe will be re-created, albeit over only microscopically small regions.

In such regions the same interactions that may have first produced what are now dark matter particles during the very early universe may now produce similar particles in the laboratory! There is thus a great race going on. Who will detect dark matter particles first: the experimenters deep underground or the experimentalists at the Large Hadron Collider? The good news is that, if either group wins the race, no one loses.

We all win, by learning what the ultimate stuff of matter really is. Even though the astrophysical measurements I described don 't reveal the identity of dark matter, they do tell us how much of it exists. A final, direct determination of the total amount of matter in the universe came from the beautiful inferences of gravitational lensing measurements like the one I have described combined with other observations of X-ray emissions from clusters.

Independent estimates of the clusters ' total mass is possible because the temperature of the gas in clusters that are producing the X-rays is related to the total mass of the system in which they are emitted. The results were surprising, and as I have alluded, disappointing to many of us scientists. We cannot guarantee that A Universe from Nothing book is available in the library, click Get Book button to download or read online books. Join over Internationally renowned theoretical physicist and bestselling author Lawrence Krauss offers provocative, revelatory answers to the biggest philosophical questions: Where did our universe come from?

Why does anything exist? And how is it all going to end? Today, exciting scientific advances provide new insight into this cosmological mystery: not only cansomething arise from nothing, but something willalwaysarise from nothing.

A mind-bending trip back to the beginning of the beginning, A Universe from Nothingauthoritatively presents the most recent evidence that explains how our universe evolved - and the implications for how it's going to end. It will provoke, challenge, and delight readers to look at the most basic underpinnings of existence in a whole new way. In the words of Richard Dawkins: this could potentially be the most important scientific book since Darwin's On the Origin of Species.

Bestselling author and acclaimed physicist Lawrence Krauss offers a paradigm-shifting view of how everything that exists came to be in the first place. What was there before it? The main characters of this science, non fiction story are ,.

The book has been awarded with , and many others. Krauss pdf. Please note that the tricks or techniques listed in this pdf are either fictional or claimed to work by its creator. We do not guarantee that these techniques will work for you. The contents of this blog include simple links in the public domain to contents hosted on other servers on the network, such as box. The material is made available for educational, criticism, discussion and teaching purposes only as required by Article 70 of the L.

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