Skip to main content

Colliding Worlds - Simone Marchi ****

The title of this book recalls Immanuel Velikovsky’s Worlds in Collision, one of the most notorious works of pseudoscience from the 1950s, which argued that human history since Biblical times has been shaped by collisions between planets and other bodies in the Solar System. As outrageous as Velikovsky’s theories were, they contained a tiny grain of truth. On a much longer timescale – billions of years rather than millennia – the Solar System really has been shaped by collisions. And that’s what this wide-ranging new book by Simone Marchi is all about.

The planets were built by collisions – first through the aggregation of dust and pebble-sized fragments, then by the merger of larger protoplanets. Chance played a part here – computer simulations show very different outcomes depending on whether it’s a grazing collision or head-on. This could explain why Venus and Earth ended up so different, despite being similar in size and distance from the Sun. And it was another collision – with a hypothetical planet named Theia – that gave us the most obvious thing Venus lacks, namely the Moon.

Collisions were much more frequent – because there was more interplanetary debris around – four billion years ago when life first appeared on Earth. These collisions may have caused problems for newly arisen life forms – or alternatively they may have been crucial to their development. Either way, it’s well-established that subsequent asteroid impacts helped shape evolution by triggering mass extinctions, which freed up niches for new species to emerge. The best-known example is the Chicxulub event 66 million years ago, which killed off the dinosaurs and cleared the way for the eventual emergence of our own species.

In our own time, much smaller asteroid ‘collisions’ can be of great value to scientists when they result in meteorites, which are the easiest way to acquire samples of extraterrestrial material and assess their composition. They also help to establish the age of the Solar System and, in the case of material that originated on Mars, tell us something about that planet too.

Although collisions form the main thread running through the book, it’s actually wider in scope than that, covering both the history of the Solar System, and the history of our understanding of it. That includes our understanding of our own planet, and one of the eye-opening facts is how long it took the academic world to recognise the role played by collisions in geological history. Basically, the topic got lost for decades in the gap between the geology and astronomy departments.

As far as I can tell, this is Marchi’s first book, and it’s his specialist subject – he’s a space scientist at the Southwest Research Institute in Boulder, Colorado. But don’t let that put you off – the book is entirely non-technical, and written very much with the general reader in mind. Marchi’s first-hand accounts of work he was personally involved in – such as NASA’s Dawn mission to the asteroid belt – make especially fascinating reading. For anyone wanting an up-to-date account of the Solar System and the processes that shape it, this is the perfect place to start.

Hardback: 
Bookshop.org

 


Kindle 
Using these links earns us commission at no cost to you
Review by Andrew May

Comments

Popular posts from this blog

Battle of the Big Bang - Niayesh Afshordi and Phil Harper *****

It's popular science Jim, but not as we know it. There have been plenty of popular science books about the big bang and the origins of the universe (including my own Before the Big Bang ) but this is unique. In part this is because it's bang up to date (so to speak), but more so because rather than present the theories in an approachable fashion, the book dives into the (sometimes extremely heated) disputed debates between theoreticians. It's still popular science as there's no maths, but it gives a real insight into the alternative viewpoints and depth of feeling. We begin with a rapid dash through the history of cosmological ideas, passing rapidly through the steady state/big bang debate (though not covering Hoyle's modified steady state that dealt with the 'early universe' issues), then slow down as we get into the various possibilities that would emerge once inflation arrived on the scene (including, of course, the theories that do away with inflation). ...

Ctrl+Alt+Chaos - Joe Tidy ****

Anyone like me with a background in programming is likely to be fascinated (if horrified) by books that present stories of hacking and other destructive work mostly by young males, some of whom have remarkable abilities with code, but use it for unpleasant purposes. I remember reading Clifford Stoll's 1990 book The Cuckoo's Egg about the first ever network worm (the 1988 ARPANet worm, which accidentally did more damage than was intended) - the book is so engraved in my mind I could still remember who the author was decades later. This is very much in the same vein,  but brings the story into the true internet age. Joe Tidy gives us real insights into the often-teen hacking gangs, many with members from the US and UK, who have caused online chaos and real harm. These attacks seem to have mostly started as pranks, but have moved into financial extortion and attempts to destroy others' lives through doxing, swatting (sending false messages to the police resulting in a SWAT te...

Why Nobody Understands Quantum Physics - Frank Verstraete and Céline Broeckaert **

It's with a heavy heart that I have to say that I could not get on with this book. The structure is all over the place, while the content veers from childish remarks to unexplained jargon. Frank Versraete is a highly regarded physicist and knows what he’s talking about - but unfortunately, physics professors are not always the best people to explain physics to a general audience and, possibly contributed to by this being a translation, I thought this book simply doesn’t work. A small issue is that there are few historical inaccuracies, but that’s often the case when scientists write history of science, and that’s not the main part of the book so I would have overlooked it. As an example, we are told that Newton's apple story originated with Voltaire. Yet Newton himself mentioned the apple story to William Stukeley in 1726. He may have made it up - but he certainly originated it, not Voltaire. We are also told that ‘Galileo discovered the counterintuitive law behind a swinging o...