John Barrow provides enjoyably readable explanations for some of the salient issues in number theory, physics and cosmology. His treatment of the history of zero (number theory) and the concept of zero-point energy of vacuum space (physics and cosmology) is informative and nicely written. It might at first be difficult to see why those two separate subjects should be encapsulated in the one book, in that just the word 'zero' seems to unite them. However, Barrow's subtext is the history of thought regarding Nature and Existence and his discussion of how zero was incorporated from the East into late medieval western numerals provides for historical backdrop. Unavailable to ancient Greeks and Romans and hence the West for most of its civilized history, zero provides for continuity between negative and positive numbers.
Science (also accounting and engineering) in the West has since mushroomed with the full set of numerals at our disposal. In physics today, the residual energy of matter below 'zero-point' is thought to be ever unavailable for exploitation, even at the coldest temperatures. Despite attempts, technology cannot exploit matter as energy source at zero-point: the residual or ground energy that is locked into matter at the coldest temperatures.
Barrow provides us with the link in ideas between ancient and modern. His large ambition and erudition duly deserves five stars but, as mentioned below, for a salient omission in his presentation, I deduct the one star.
"Not until the last half of the twentieth century would it be appreciated how the vastness of the universe is necessary for the existence of life on a single planet within it." Also, "If our universe was less of a vacuum it could not be an abode for living complexity" (pg. 121). The progress of western mathematics and cosmology parallels investigation of the vacuum. "Only a fraction of the possible patterns of mathematics are used in Nature." (p.158) Whereas, "if we believe Nature to be rational then no part of physical reality could be described by a mathematically non-existent structure." (p.162). Barrow discusses the contributions of the scientific greats, from Galileo to Einstein. As is obligatory in books of this kind, Roger Bacon and Immanuel Kant get a mention, as also do the ancient Greek luminaries.
Whereas late medieval science construed the void as comprising ether, we now know that no vacuum can be empty because of residual inherent energy at close to zero temperatures. Einstein replaced the ether in scientific thought with ubiquitous electromagnetic fields. It is electromagnetism that accounts for residual energy in matter below zero point accessibility and that fills the entirety of space - including the space between nucleus and electron orbitals in atoms. Contrary to mediaeval Christianity and also ancient Indian notions of divine nothingness, in our universe nothingness has no objective validity. Einstein's huge contribution to modern science is nicely and succinctly described by Barrow.
"The quantum vacuum with its seething mass of activity has ultimately proved to be the foundation for all our detailed understanding of the most elementary particles of matter" (pg. 226). Everywhere 'virtual' (unmeasurable except in the laboratory for the Lamb shift and Casimir effect) and real (measurable) particle-antiparticle pairings perturb space. An understanding of the physics of the vacuum has propelled cosmology, sub-atomic physics and the exploitation of superconductivity. The very small in Nature has immediate impact on our understanding of the very large. In respect of the forces of Nature, the importance of temperature in the evolution of the very early universe is discussed. Heat energy is but one very important manifestation of whatever energy actually is. With respect to black body radiation (such as the cosmic background radiation), "...'temperature' is a measure of the average value of the energy" - energy that can only be emitted in particular quanta (pg. 213).
Other readers have said that Barrow's explanations of the more difficult aspects of cosmology and physics are not entirely clear in places and I agree to some extent. In fact, he seems rather to gloss explanation in favour of description on occasion, notably when explaining black hole radiation (p.240), a controversial subject that has experts in disagreement. (The Wikipedia article on Hawking black hole radiation is likewise incomplete in explaining, almost identically to Barrow's account, the theoretical phenomenon, of just how the black hole absorption of one half of a virtual particle-antiparticle pairing gives rise to energy loss. It is by no means obvious to the general reader.)
I should like to give 'Nothing' five stars but was rather dismayed by his treatment of vacuum energy in relation to dark energy expansion of space. In note 28 of Chp 6, he says that, with 95% confidence, 'the contribution of the vacuum energy (of space) is about 50% more than that of all ordinary matter in the universe' (paraphrase). This is now largely redundant physics, I understand. The relevance of vacuum energy to spatial expansion seems to be a major lacuna in cosmology today. Barrow would have known in 2000-2001 when he finished writing 'Nothing' that Weinberg (1989) had pointed out the enormous discrepancy by greater than 70 orders of magnitude in calculation that vacuum energy seems not to account for accelerating spatial expansion - nobody knows what dark energy actually comprises but that it accounts for 70% composition of universal mass-energy and its astounding anti-gravitational effect, as gauged by redshift in supernova type 1a luminosity. George Ellis points to Weinberg's noted discrepancy as a major cosmological problem in various of his more recent publications, whilst Barrow disappointingly affords it no mention whatsoever. Having consulted Wikipedia articles on vacuum energy and zero-point energy, I feel justified in making criticism here, even though those articles likewise fail to elucidate the controversy - the word 'mystery' is used in place of discussion.
Another example of gloss occurs on p.237, in respect of vacuum polarisation: we are told that "The deep symmetry of the forces that would be found at high energies (when the universe was very young and very hot) is possible only because of the contributions of the quantum vacuum." This statement comes across more as a soundbite than a summary.
In Chapter 7, Barrow explains the vacuum sea of particles and antiparticles that, virtual and real, bubble or seethe throughout all vacuum space. He explains the difference between notionally virtual and real fleeting sub-microscopic particles in relation to Heisenberg's Uncertainty principle: it appears that the principle is broken in the case of virtual particle-antiparticle pairings - 'virtual' particles are real but because they are within Planck scale cannot be directly measured. (The effects of vacuum polarization have been experimentally observed, according to Wikipedia: to quote, "virtual electron-positron pairs that change the distribution of charges and currents that generated the original electromagnetic field. It is also sometimes referred to as the self energy of the gauge boson (photon).")
With regard to the laboratory, I found Barrow's explanation of the Casimir effect particularly good in comparison to other authors I have read, as also his explanation of the Lamb shift, both due to extremely small but measurable (electromagnetic) fluctuations, such effect as was omitted from Dirac's prior ground breaking relativistic account of the electron (and his brilliant prediction of the positron).
The quantum nature of sub-microscopic physics vis-a-vis (meso-macro scale) classical physics is dealt with in the book: Barrow discusses the wavelength criteria that distinguishes quantum from classical objects - an object's size is inversely proportional to its energy wavelength such that (I deduce) quantum effects occur (for very tiny objects such as sub-atomic particles) where wavelength is greater than size. (This has curious ramifications today for evident entanglement of larger than sub-atomic objects, outside the scope of this book.)
In summary, Barrow imparts a very good account of the vacuum energy of space, if unconvincingly in respect of spatial expansion. The same is true of his book, 'The Constants of Nature,' where (p.270f) he seems to say that vacuum energy is primarily responsible for expansion. I think his book is worthy of revision today; otherwise, it is superseded by later publications on the same topic I have yet to read. Nevertheless, I am most grateful to John Barrow for his breadth and depth of exposition on the enormous subject of Nothing.
Lastly, the importance of not just the cosmic vacuum but, in general, the extremely small in Nature as regards useful explanation of the very large characterizes this book, as indeed all serious explanations of cosmology. Like other authors on cosmology and physics I have read, Barrow assumes the yet to be proven existence of the graviton and gravity waves. (Perhaps the experiment at CERN may yet qualify today's lacuna in this regard.)
Download the free Kindle app and start reading Kindle books instantly on your smartphone, tablet or computer - no Kindle device required. Learn more.
Read instantly on your browser with Kindle Cloud Reader.
Using your mobile phone camera - scan the code below and download the Kindle app.
Flip to back Flip to front
Follow the author
Something went wrong. Please try your request again later.
Customers who viewed this item also viewed
Page 1 of 1 Start overPage 1 of 1
Customers who bought this item also bought
Page 1 of 1 Start overPage 1 of 1
About the author
Follow authors to get new release updates, plus improved recommendations.
