by Jeff Foust
Monday, September 16, 2019
Fire in the Sky: Space Collisions, Deadly Asteroids and Race to Protect Earth
by Gordon L. Dilow
hardcover, 288 pages, illusion.  ISBN 978-1
There is hardly a week without an asteroid story that makes a close approach – relatively speaking – to Earth. Although these particular sites are never an immediate threat of impact, they are sometimes sometimes sensationalized on tabloids and websites in "history of terror from heaven". (This seems especially true these days in the British tabloids, perhaps to either provide some relief from Brexit stories or a desire to end the debate once and for all.)
None of these asteroids, of course, led to death and destruction in these stories, but overall the threat is very real. "The chances of an asteroid or comet of potentially catastrophic size invading Earth are exactly 1 in 1," writes author Gordon Dillou in launching Fire in the Sky his new book on the threat posed by such impacts. "The only variable is when."
|"The chances of an asteroid or comet of potentially catastrophic size invading Earth are exactly 1 in 1," writes Dillow. "The only variable is when."|
Dillou became interested in the subject when he witnessed a collision on a much smaller scale: a meteor he saw in the death hours of June 2, 2016, over his home in Arizona, which turned an asteroid close to two meters, releasing the equivalent of half a kilo of TNT. This fireball created a brief glimmer of news, but stimulated his interest in the subject so much that he decided to write a book about it, even though he knew a little about the subject before that early morning.
The following is a good introduction to a topic that will be familiar to those who already know about Chicxulub and Chelyabinsk. There is a difficult historical conclusion to much of the book, following the efforts of Daniel Barringer in the late 20th century to search for (unsuccessfully) the meteorite remnant of the Meteor Crater site and later the work of Gene Schomaker to prove that it was truly impactful created a crater. There is also a team of fathers of Luis and Walter Alvarez, who discovered a layer of material rich in iridium at the border of CT and argued that it was created by an asteroid impact that destroyed dinosaurs and many other life forms 65 million years ago These are as much character studies as historical narratives of science, enlivening these people.
Later, there was an overview of more recent developments, such as the Chelyabinsk event and efforts to seek and plan for near-Earth impacts encapsulated under the term 'planetary defense'. He spends the night with an astronomer at the Arizona Observatory looking for near-Earth asteroids and follows asteroid impact planning exercises performed by interagency groups and astronomers. (Noting that in two past simulation exercises have taken place in Pasadena, Texas and Pasadena, California, he speculates that such an exercise, scheduled for this spring at a conference outside Washington, DC, will target Pasadena, Maryland. Instead, as a bad science fiction movie, the asteroid hit New York.)
|As his book states, there is much more to be done to prevent such an impact, but the good news is that we are better aware and prepared for the threat than ever.|
Dillow argues that governments like the US should spend more on searching, exploring and preparing to deal with potentially dangerous asteroids. (He adds that companies like planetary resources and deep space industries can be a "huge help" for this, without knowing that both companies have been acquired and seem to have abandoned their ambitions for mining asteroids.) What he does not say , is: how much more money needs to go for planetary defense. NASA's field costs have risen in the last decade, from just a few million annually in support of monitoring efforts to $ 150 million in its current budget, which also funds the development of a mission called the DART (Double Asteroid Redirection Test) to help tests how kinetic impact can shift the orbit of a threatening asteroid. This level of funding appears to be stable for at least the next few years and could support the development of other missions in the coming years, such as the NEOCam Observatory for the search for near-Earth asteroids. Yes, asteroids are a threat to Earth, but so are other phenomena that have more definite short-term effects, such as climate change. What is the best use of resources?
Dillow is correct that sooner or later a large asteroid or comet will pose a risk of impact to the Earth, although so far no such object has threatened to collide with the Earth for decades, despite the historical titles in the tabloids. As his book states, there is much more to be done to prevent such an impact, but the good news is that we are more aware and prepared for the threat than ever before.
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