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In Defense of ‘Dark Matter and the Dinosaurs’

In response to:

The Universe: ‘The Important Stuff Is Invisible’ from the March 10, 2016 issue

To the Editors:

I appreciate the review of my book Dark Matter and the Dinosaurs by Lawrence Krauss [NYR, March 10]. But I wish to take issue with his central argument, which misconstrues the main purposes of my book.

Krauss’s chief objection to my approach in Dark Matter and the Dinosaurs derives from the inaccurate view that I wrote the book in order to promote a speculative theory. However, I clearly state that the theory I present, about how a disk of dark matter in the Milky Way may lead to comet strikes, was intended as a substrate on which to hang some big ideas about the development of the cosmos. The title and research are a framing device to talk about the story of the universe and how we got here, and around which to update readers on the state of scientific knowledge about our planet and how scientific understanding advances.

The goal was to present the material accurately, but also in a way that engages the reader. My earlier book, Knocking on Heaven’s Door, wasn’t about heaven (or doors for that matter). My most recent title, though based on my research, was intended to draw in readers who might ultimately learn a lot despite initial misgivings or fears of reading about science. I agree with Krauss’s point about not selling research broadly before we understand it well, which is why, unlike some other scientists, I am so careful not to do it. Reviewers, like authors, have a responsibility to their readers, since they influence which books are actually read.

Krauss missed what is clearly laid out in the introduction and table of contents. Here is what I say in the introduction:

But these speculative ideas—as provocative as they might be—are not this book’s primary focus. At least as important to its content as the story of the dinosaur-destroying comet are the context and the science that embrace it, which include the far better established frameworks of cosmology and the science of the Solar System…. In the research that I will describe, my studies led me down a path where I started thinking more broadly about cosmology, astrophysics, geology, and even biology. The focus was still on fundamental physics. But having done more conventional particle physics all my life—the study of the building blocks of familiar matter such as the paper or screen on which you’re reading this—I’ve found it refreshing to probe into what is known—and what soon will be known—about the dark world too, as well as the implications of basic physical processes for the Solar System and for the Earth.

This was fully understood by the two well-respected scientists, an astronomer and a geologist, who wrote in their jointly authored review for Science magazine (October 2015):

The first thought that crossed both our minds when reading the title of this book was: “Oh, no, not again, another outlandish proposal for the extinction of dinosaurs….” However, we were relieved to find that, right from the start, Randall dismisses almost all connections between dark matter and the mass-extinction event that wiped out the dinosaurs. Instead, the book takes the reader on a journey through the cosmos, describing what we know about dark matter and what more we are poised to learn as new and better equipment becomes available.

I feel very strongly about the accuracy and significance of what the public is told. That’s why so much of the book concerns all the amazing things we know that are at best tangential to my research, and many ideas about dark matter too. This is the role of popular books about science—to acquaint nonspecialists with the current state of the field, both the confirmed and the theorized, so they can understand not only newer science but also how our world and our lives took their present forms.

Furthermore, though Krauss notes a low citation count for a short paper I wrote concerning the possible connection of a dark matter disk to meteoroid strikes, he neglects the larger number of citations for my research on the dark matter disk on which that short paper was based. More significantly, he fails to mention that even that research is only a small part of the more extensive introduction to dark matter and the cosmos that my book contains.

As one further example of Krauss’s inaccuracies, he implies in his review that I prefer the name “invisible matter” over “dark matter.” Fine, except that is not what I said. I wrote that the term “transparent matter” would be a better name than “dark matter,” since as with all transparent matter, light just passes through. One can only wonder whether it was my words that were invisible, as the goals of my book were certainly meant to be transparent.

Lisa Randall
Frank B. Baird Jr. Professor of Physics
Harvard University
Cambridge, Massachusetts