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Nothing: A Very Short Introduction

af Frank Close

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4871350,366 (3.57)7
What is 'the void'? What remains when you take all the matter away? Can empty space - 'nothing' - exist? This text explores the science & history of the elusive void - from Aristotle's theories to black holes & quantum particles, & why our very latest discoveries about the vacuum can tell us extraordinary things about the cosmos.… (mere)
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Viser 1-5 af 13 (næste | vis alle)
Book is good. But I am not capable to wrap my head around the idea of nothingness. It gave me a headache. I need some tea. ( )
  paarth7 | May 6, 2023 |
Definitely worth reading...and may even require re-reading to grasp it all. But Frank Close has certainly given me a lot to think about and given me more of a grasp of "the Void" that I ever had before. When I was trying to explain to my friend Miles, what it was all about, he had difficulty grasping the idea that something could be a vacuum yet have "something" in it. I think the Physicists need to work on the terminology a bit because they are using the term "vacuum"to mean different things. And I recall one Physicist, Kraus...author of a world from nothing debating fiercely on TV when people pointed out to him that when he spoke of "nothing" he was still obviously talking about "Something".....be it virtual fields or aether or whatever. But he seemed to merrily dismiss all the objections and claim his vacuum had no matter (and, I think, not electromagnetic fields) so it was, indeed nothing.
I was fascinated by Close's descriptions of the void. (Sometimes his language is hard to follow. But p103: "after removing matter, fields, everything to reach a void" the emptiness that ensues [when viewed at large scale is not reflected at the] atomic scales where the void is seething with activity, energy and particles"....."Particles can radiate energy (eg in the form of photons) in apparent violation of energy conservation, so long as tht energy is reabsorbed by other particles within a short space of time". And p108, Imagine a region of vacuum, for example a cubic metre of outer space, devoid of all of the hydrogen and other particles removed. Can it really be devoid of of matter and energy? In the quantum universe the answer is no.......You might remove all matter and mass, but quantum uncertainty says there exists energy: energy cannot also be zero. To assert there is a void, containing nothing of these, violates the uncertainly principle. There is a minimum amount known as zero point energy, but that is the best you can do..... You can remove all the real particles until you reach the ground state, but quantum fluctuations will still survive. The quantum vacuum is like a medium....And something that I don't understand..."The zero point motion of electromagnetic fields is ever present in the vacuum'....and electron in flight wobbles slightly as it feels the zero point motion of the vacuum electromagnetic fields"....and something more that I didn't understand: Dirac's idea of the vacuum is of being filled with an infinite number of electrons who's individual energies occupy all levels from negatively infinite up to some maximum value. Such a deep calm sea is everywhere and unnoticeable unless it is disturbed. We call this normal state, the ground state which is our base level, relative to which all energies are defined". So is Close endorsing this view or is it just Dirac'wes view? I remain confused. If there are electrons in the vacuum ...then it has particles in it....Close says that "the energy fluctuations in the vacuum can spontaneously turn into electrons and positrons but constrained by the uncertainty principle to last for a brief moment of less than 10 to the power of minus 21". This time is so small that light would only have been able to travel about one thousandth the span of a hydrogen atom.....and it's possible to observe this "pair creation" in a bubble chamber. The two virtual particles thus becoming real.
Close suggests that the quantum vacuum is like a medium and never truly empty. It can be organised in different phases. Close uses the example of phase change in water going from liquid to ice and for magnetised iron that loses its magnetism above 900 degrees C.....though I don't really see how either of these relate to the vacuum. I guess he's just saying that we can expect the vacuum to have phases changes also. So his answer to the question..."Does nature allow a vacuum is NO (in that the void is actually filled with an infinite sea of particles together with quantum fluctuations) or YES ...there are many different types of vacuum, depending on how the quantum vacuum is organised".
The, on p136, we get the news that the favoured theory in physics is that the Higgs field pervades the vacuum and gives mass to the fundamental particles....not just to w and z bosons but to electrons quarks and other particles too. If this is true If this is true then in the absence of the Higgs field particles could never be stationary but would all travel at the speed of light. However, space is filled with the Higgs field. As you read this page you are looking through the Higgs field: photons do not interact with it and they move at the speed of light.

The Higgs field is indeed bizarre. Particles such as electrons travelling through space at speeds below that of light are doing so because they have mass, which they have gained as a result of interacting with the omnipresent Higgs field. Yet they continue to travel without resistance: Newton's laws work, the particles continuing to move at constant velocity as no external force appears to act on them. A partial answer to this conundrum comes if we realize that a particle's energy determines its velocity; as the Higgs field is the vacuum state of lowest energy, no energy can be transferred by the particle to or from the Higgs field, and so the particle maintains its speed. It is not possible to determine an absolute value of the velocity relative to the Higgs field.* [n the technical jargon: "The Higgs vacuum is a relativistic vacuum.']
I must confess that I find this most confusing. If an electron gets its mass by "interacting" with the Higgs field, then doesn't this mean that some sort of energy is involved because, from Einstein's equation, mass is equivalent to energy...so some external force appears to be involved ...else, why would electrons not travel at the speed of light?

Close throws in some interesting facts: the Higgs field exists only at temperatures below 10 to power 17 degrees C. (After the first trillionth of a second from big bang these conditions applied..giving masses to the fundamental particles). And as ripples in electromagnetic fields produce quantum bundles (photons) so too should the Higgs field manifest itself in Higgs bosons. And the Higgs boson itself "feels" the all pervading Higgs field and so has mass. It's been recently measured at 125 GeV.

The rule is that raising the temperature causes structure and complexity to melt away giving a 'simpler system. Water is bland; ice crystals are beautiful.

The universe today is cold; the various forces and patterns of matter are structures frozen into the fabric of the vacuum. We are far from the extreme heat in the aftermath of the Big Bang, but if we were to heat everything up, the patterns and structures would disappear. Atoms and the patterns of Mendeleev's table have meaning only at temperatures below about 10,000degrees C; above this temperature atoms are ionized into a plasma of electrons and nuclear particles as in the Sun. At even hotter temperatures, the patterns enshrined in the Standard Model of particles and forces, where the electron is in a family of leptons, with families of quarks and disparate forces, do not survive the heat. Already at energies above 100 GeV, which if ubiquitous would correspond to temperatures exceeding 10 to power 15 degrees, the electromagnetic force and the weak force that controls beta-radioactivity melt into a symmetric sameness.

In his last chapter, Close seems to indulge in various flights of fantasy...like a lot of physicists seem to with "accessible" books. He ranges over string theory, multiple universes, multiple (around ten) dimensions. Then toys around with the basic idea behind the vacuum...that positive energy within matter can be counterbalanced by the negative sink of the all pervading gravitational field such that the total energy of the universe is potentially nothing. When combined with quantum uncertainty this implies that everything is indeed some quantum fluctuation living on borrowed time. Everything may thus be a quantum fluctuation out of nothing. And then he throws in his odd bit of mysticism...."what encoded the quantum possibility into the void"? And god gets a mention. OK so he doesn't have all the answers but this is more or less the first time that he admits that. A good book in so many ways yet I'm left with the feeling that I've been conned. That Frank was going to let me into the secrets of the void and it turns out that he knows a bit ...but certainly doesn't explain to my satisfaction how the Higgs field is interacting with particles to give mass. Nor does he explain how...with all these particles bobbing on and out of existence...how do we get permanency ...for anything... are various parts of me bobbing in and out of reality?

Despite these objections I still rate it as a five star book. ( )
  booktsunami | Mar 19, 2023 |
Not the best vsi book I've read, not one I remember well, though well worth the time it took to see what Close wanted to discuss. ( )
  mykl-s | Dec 7, 2022 |
Really good book. There are a lot of gems in here, and some really good mental models for concepts that are difficult to picture in the mind's eye.

If you'll excuse a couple spoilers about the nature of the universe here, this book left me (and the author) with two big questions:

1) If the universe we know, with all of the laws of physics it contains, came from quantum fluctuations, then what coded the quantum fluctuations?

2) Was there a 'before the big bang' or does the universe just exist, with time being a concept imposed by our limited cognitive abilities?

If you're familiar the big discoveries in physics then this book may not teach you many new concepts. But the way the author describes some of the discoveries and the way he poses the remaining questions make this a really good read. ( )
  kapheine | Apr 6, 2021 |
Too short to offer a good teaser or guide but it does what it says on the cover. ( )
  Paul_S | Dec 23, 2020 |
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What is 'the void'? What remains when you take all the matter away? Can empty space - 'nothing' - exist? This text explores the science & history of the elusive void - from Aristotle's theories to black holes & quantum particles, & why our very latest discoveries about the vacuum can tell us extraordinary things about the cosmos.

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