Lisa Randall

This book, subtitled “The Astounding Interconnectedness of the Universe” sets out to explicate “our current knowledge about the Universe, the Milky Way, the Solar System, as well as what makes for a habitable zone and life on Earth.”

The author, an award-winning professor of science at Harvard, explains that there were five major mass extinctions in the past 540 million years, as well as about twenty lesser ones, in which approximately 20 percent of life-forms died out. Many people show more are familiar with the extinction of the dinosaurs, the Mesozoic species that dominated the planet for more than 100 million years. She reviews the observations of geologists and paleontologists confirming that a big object hit the Earth 66 million years ago and as a result at least 75 percent of life on the Earth died, including the dinosaurs.

The description of how scientists solved the mystery of the dinosaur extinction is fascinating. It included detecting huge amounts of the rare metal iridium in the clay of the K-Pg geologic boundary marking the period of the dinosaur extinction. The K-Pg clay layer was meticulously studied in almost 40 locations around the globe. Other rare metals in that clay layer were also found, at levels a thousand times higher than seen elsewhere on earth. Scientists also identified shocked quartz, which indicates a high-pressure origin, and crystals called spinels that point to rapid solidification after high-temperature melting. The only known sources for the state of these materials are meteoroid impacts and nuclear explosions. Obviously, there were no nuclear explosions before 1945, leaving only one "culprit" to account for the measurements.

Scientists, further investigating evidence left by the meteor impact crater at Chicxulub (pronounced CHICK-shuh-lube) in the Yucatán Peninsula in Mexico, concluded that the meteor had to have been an incredible 10-15 kilometers in diameter. An object the size and speed of that meteor “would have released an energy equivalent of up to 100 trillion tons of TNT, more than a billion times greater than that of the atom bombs that destroyed Hiroshima and Nagasaki.”

Even just a kilometer-wide meteoroid, the author points out, would do global damage, creating extreme winds, huge tsunamis, tidal waves, massive earthquakes, and trillions of tons of material ejected into the atmosphere and then rained down upon the Earth.

The only survivors would have been living creatures that could hide - through hibernation or otherwise.

The author suggests that a disk of dark matter might have been the trigger dislodging a comet from its orbit - probably in the Oort Cloud, and send it veering toward the Earth. A meteor from the comet then caused all this devastation upon impact.

In order to establish her theory, she has to take a detour to explain the composition and history of the Universe to readers. Thus she educates us about ordinary matter and how it differs from dark matter, and how we know about the existence of dark matter and dark energy. She talks about the composition of our Solar System, and how it operates within the Milky Way. She does all of this clearly and lucidly, with plenty of popular culture references and metaphors so that any reader should have no problem understanding her.

Although most of the book concerns impacts from meteoroids, the author ends with a cautionary note about a possible sixth extinction unrelated to celestial bodies:

“Many scientists today think we are currently undergoing a sixth mass extinction - of manmade origin. . . . The mammal extinction rate of the last 500 years has been about 16 times higher than normal, and in the last century the rate has been elevated by a factor of 32. Amphibians in the last century have died off at a rate nearly 100 times higher than in the past, with 41 percent currently facing the threat of extinction, while bird extinctions in this same time frame have exceeded the average rate by a factor of about 20. . . . The changes in the environment that are occurring now . . . have a disturbing resemblance to those at the time of the P-Tr extinction. [The P-Tr extinction was an event about 250 million years ago that was the most devastating known extinction in terms of the percentage of species that disappeared from the planet. While the cause of the P-Tr extinction remains the subject of controversy, massive climate change and changes in the chemistry of the atmosphere and oceans are thought to have been determinative.]”

She warns:

“Incredibly, the rate of temperature and changes in pH (which measures acidity) seems to have been comparable at that time [the P-Tr extinction] to what they are today. Human influence is almost certainly largely to blame for the recent diversity loss. . . . We are very rapidly undoing the cosmic work of millions or even billions of years.”

Evaluation: The relationship between the dinosaur extinction and the presence of dark matter unfolds like a murder mystery. It was fascinating to read about how scientists pieced together clues and evidence to solve a “cold case” - one that occurred some 66 million years in the past. show less

I put this book on the bedtime story shelf and my fourteen-year-old picked it up, which means that I read this whole thing out loud to my family. There were times when I thought that this book's structure wasn't very friendly to a read aloud format, as there was a LOT of repetition and circling back on theories which sometimes made me impatient to read so slowly. But really, it probably helped the kids, especially as we read it one chapter at a time, so it helped with the "where we left show more off..." reminders.

Okay, so there is a really interesting premise at the heart of this book, and that is: is there a cyclical nature to mass extinctions in the fossil record supporting evidence for cyclical catastrophic meteor strikes? And if so, could that cycle be linked to a structural issue in our solar system — and if so, could that structural issue be related to dark matter? Clearly, there are a LOT of interconnected features to unpack here, which means that even if at the end, you are unpersuaded by the thesis that dark matter killed the dinosaurs (which is not actually a foregone conclusion of this book), you still have learned about the fossil record, mass extinctions, meteor strikes, the structure of the solar system, dark matter, and predictive modeling. In a way, that is more FUN — a depiction of the way that science searches for connections and patterns, and that you don't have to prove your hypothesis correct in order to learn an impressive amount about the universe.

A very worthwhile adventure. show less

Admittedly, my first reaction to the title of this book was that it must be some kind of joke. It sounded, well, loony. But Lisa Randall is a brilliant, world-famous, very influential theoretical physicist and I am...none of the above, so my initial reaction was, at best, probably uninformed. Sadly, I got lost a few times when reading this, especially when the discussion turned to particle physics (see above about what Lisa Randall is and I am not), but I think I caught the main thread of show more her proposal. I'll try to summarize:
In order for the universe to behave the way it does, something that isn't ordinary, visible matter (like stars and such) must be exerting a gravitational influence. It's uncertain if this something reacts with anything else (like electromagnetism), but if it does, it's not obvious. By consensus, this unknown something is called dark matter, but no one really knows what it is. Professor Randall discusses some of the possibilities, few of which I can honestly say I fully understand. Her conjecture, based on what little data that exists, is that the dark matter may not be all one type of unknown something. Different dark matter parts may interact with other parts in ways not entirely unlike how protons and electrons of normal matter interact. Dark matter of this nature could, theoretically, form a disk that is contiguous with the plane of galaxy and exert significant gravitational influences on normal matter (like the Sun and our own lovely planet).
So where do dinosaurs come in?
Well...
Impact craters on Earth suggest that there may be some periodicity (30-35 million years) to when really big things fall out of the sky and rearrange the landscape. (This is not yet firmly established.)
Such impacts probably are not asteroids that normally hang out between Mars and Jupiter but are, instead, large comets. (Also not certain.) These comets could originate in the Oort cloud (which probably does exist, although we have no firm observational evidence).
As the Solar System travels around the disk of the galaxy, it not only goes round and round but also up and down. This takes it through the galactic plane and the hypothesized dark matter disk, possibly every 30-some million years (although this is uncertain). When it does pass through, though, the dark matter could nudge objects from their stable orbits in the Oort cloud and send them inward toward the sun and Earth. Some of those could actually hit us, and one such might be the prime suspect for whatever caused that big crater off the Yucatan peninsula and took out the dinosaurs 66 million years ago.
So you see, it's not loony. It's actually quite informative, although it is highly speculative. There are a lot of unknowns here, but some may be known better soon and the theory will stand or fall based on the evidence. That's science. show less

I reviewed this once before and a tecnical snafu ate it when I tried to up load it...

This book is dreadful: here are the many reasons why:

The material is disorganised. The book is ostensibly about extra spatial dimensions. The concepts are introduced in the first few chapters then don't re-appear until the last few chapters. The Standard Model is introduced twice.

The explanations are poor and sometimes wrong. The section on the Pauli Principle is riddled with errors and omissions that should show more embarress a good A-level chemistry student. The section on CP symmetry and CPT symmetry is so bad that I did not recognise these concepts for what they were until several chapters later. These concepts are not actually difficult to explain, even if it is hard to see why they should be true: In CP symmetry, all matter is swapped for it's antimatter equivalent and the directions left and right are reversed. When this is done, no difference can be detected between before and after the swap. This symmetry is known to work for all physical processes except those involving the weak nuclear force. In CPT symmetry, as well as swapping matter for antimatter and left for right, the direction of time is reversed. This symmetry was believed to hold for all circumstances - it could have happened five times since you started reading this review and you would never be able to tell the difference! However, very recent results have suggested that neutrinos and antinuetrinos may have different masses which would mean that CPT symmetry does not apply to them. This isn't a well established result yet, though. So, really, how hard was that to explain? Randall also offers the worst introduction to the fundamental mysteries of quantum mechanics I've ever read (and I've read quite a number).

Randall can't write: Additionally to giving bad explanations, Randall also gives us a very bad story at the beginning of each chapter. These stories have no literary merit and do not make understanding the forthcoming material any easier. They are like the dialogues from Godel, Escher, Bach by Hofstadter with all wit, literary merit and purpose removed, except they aren't dialogues, either.

Pop song wisdom: Each chapter begins with a quote from a pop song. These are not profound or witty. Many, many years ago I developed the principle, "Do not get your life wisdom from pop songs." One could also say, "Do not quote pop songs at the heads of chapters unless you want to look as if you've never read a book in your life."

Repetition: Using the same unclear explanation over and over again does not make a topic easier to understand. Since it was very difficult to understand Randall's explanations of concepts I am already familiar with repeating them isn't helpful.

Bloat: The new "physics" Randall wants to explain comes in the final two chapters of a long book which is full of digressions that are irrelevant to the main thrust. Weirdly the author includes every theoretical development of the last 20 years except the only one that has a firm experimental basis (i.e. neutrino oscillation, which I'm not going to explain here). Weirdly, this would have been useful, unlike the ones she does include, because the issue of "flavour mixing" comes up at one point. Again it took me some time to realise that this "flavour mixing" was something I knew about - neutrino oscillation!

Is there anything good about this book? Well, there's an explanation of why one theory of relativity is Special and the other is General that you won't find in many other places. Is that compensation for nearly 500p of tedious, repetitive and extremely speculative barely comprehensible explanations?

Stick to the maths, Lisa; you're good at maths. show less