When Galaxies Collide

Professor Lisa Harvey-Smith recently released a popular science book called When Galaxies Collide. I loved it so I reached out to her and she kindly agreed to a blog interview.


There are a lot of popular science books about astronomy, but the thing I enjoyed about When Galaxies Collide is the down-to-earth approach you have to astrophysics. Interwoven within the book are numerous anecdotes covering everything from your time at the Arecibo radio telescope in Puerto Rico (which featured in Carl Sagan’s novel/movie CONTACT) to the remote Australian Outback (and Mullewa, home of ‘the bathroom at the end of the universe’). Did you ever imagine science taking you to the far-flung corners of the planet?

Thanks – I’ve always had quite a simplistic mind I think, I get bored easily with dreary explanations so I wanted to create a book that had a really human element and capture the reality of what it is to be an astronomer. That does include a lot of travel, often to odd and remote places where we (deliberately) hide telescopes from the light and radio pollution generated by big towns and cities. I don’t think I ever expected my life to turn out so interesting when I was growing up in a small village in Essex. Travel was for ‘other people’, people with money and choices. I find it astonishing how big my life is turning out to be in terms of travel and meeting incredible people.

Einstein once said, “If you can’t explain it simply, you don’t understand it well enough.” Your book tackles complex subjects but with an air of simplicity. I loved the way you describe the spiral arms of a galaxy as a celestial traffic jam, moving as a wave rather than being any kind of actual structure—being caught in traffic is something we can relate to and now we know the cosmic version leads to star formation. Is there any one favorite fact or commonly misunderstood point you personally find fascinating that you’d like to share with us?

I think Einstein was annoyingly accurate in almost everything he said! But it’s very true that a lot of science is obscured with jargon and acronyms and complexity that need not be there. I do like explaining black holes – a lot of people think that black holes will suck everything in like a terrible pit of death. It’s not true at all, in terms of gravitational pull they simply behave as if a star were sitting there. They don’t have an unusually large gravitational pull. They are just a deep ‘hole’ so if you fall in, you can’t get out again.

It’s rare that an author admits to being a weirdo, even in jest, but you do while recounting an incident while out jogging with a wild emu running along the track ahead of you. For me, this was a Lisa moment rather than a professor moment within the book, and highlights something important about science—the need for people to relate to scientists. We live in fractured times. Sometimes, scientists are revered as high priests. At other points, they’re dismissed and ignored. Neither position is healthy, so I loved the way you gave us a glimpse into the person behind the astrophysicist. Is scicomm (science communication to the public) an important part of your role?  

Science communication is a very big part of what I do. It has evolved that way in recent years because I genuinely enjoy explaining and sharing science in a way that breaks down the barriers between a scientist as some sort of revered ‘keeper of knowledge’ and a perfectly intelligent member of the public who simply haven’t met that particular concept before.  Showing that scientists are real people with hobbies and faults is a big part of that. I like to talk about my sporting interests too – running and the like.  

Why is astronomy important in modern society? In your book you talk about the history of astronomy and the awe people from around the world share when sitting by a campfire, watching sparks rise in the air with the Milky Way shining brightly above, but today we have Netflix and Candy Crush, mortgages and careers, nightclubs and football games. Why should people care about galaxies colliding billions of light years away? 

The stars have played a huge role in all our histories, from their role as gods and guides in ancient times to their use as maps, navigation tools and even as stories that guided our moral compasses.

The night sky is an integral part of nature, but we are losing our connection. Light pollution means that most of us cannot even see the Milky Way from where we live, so it is unsurprising that most people cannot identify a single constellation in the sky. 

Aliens are always a hot topic. Given the immense distances involved and the fact that potential alien signals are easily drowned out by stars, pulsars, quasars and the like, do you think we have or could develop equipment sensitive enough to listen in on ET? Given the (literally) astronomical sizes and timescales involved, are we likely to ever hear from extraterrestrials?

The search for extraterrestrial technological civilisations is a natural one since humans are curious to know whether we are alone in this universe. The methods we employ include ‘listening’ with large radio telescopes for signals from other nearby planets that are send towards us either deliberately or as a result of them communicating with one another. It is a sensible method but unlikely to succeed for now because our telescopes are only sensitive enough to ‘see’ them if they live on planets around the closest 100 or so stars to Earth. Unless their signals are extremely bright, or we build far larger telescopes, it seems unlikely to me that this method will succeed in the next 50 years. I hope I’m wrong! 

There’s a lot of interest in astronomy at the moment, with the Juno in orbit around Jupiter, Curiosity on Mars, the Parker solar probe on its way to explore our closest star, the Sun, the TESS exoplanet finder and grand projects like the James Webb Space Telescope launching in a few years. TESS and JWST in particular might find life elsewhere, perhaps not intelligent life, but if they do find evidence for any kind of exolife how will that change our world? Do you think such knowledge will transform our perspective on life?  

I would love to see us discover extra-terrestrial life and embrace the finding as a transformational moment in our collective human consciousness. Sadly, given the way we behave to one another on Earth, I think it would probably make us retreat further into our shells and spend more on ‘defence’. 

Does the sheer size of the universe boggle your mind? You’re dealing with colliding galaxies on a daily basis, but galaxies collide over hundreds of millions of years. As you note in your book, all we get is a snapshot of galaxies in freeze frame. It’s only by collecting and ordering images from tens of thousands of observations that we get to understand what’s actually happening. Do you ever feel daunted by that?  

I don’t think the human mind is designed to take in the size of things much larger or smaller than ourselves. So when I say ‘trillion’ I know what it means mathematically, but I don’t really have any more insight than anyone else as to its true meaning. Even flying across Australia from Sydney-Perth fills me with awe at the size of a single continent. The scale of the universe will never be comprehensible to me or any other astrophysicist.

In your book, there’s a picture of you with Buzz Aldrin, one of the first men on the Moon. Would you like to go into space? It’s long been a dream in science fiction and within popular culture. Some, like Elon Musk, Jeff Bezos and Richard Branson, are trying to make spaceflight accessible, but it remains elusive. Do you think it’s a pipe dream? Or are we on the cusp of making spaceflight commonplace?  

Meeting Buzz Aldrin and spending three days with him introducing his first Australian live tour was an absolute thrill. He’s a global icon and was one of my biggest heroes when I was growing up. 

I think space will become more accessible once the price comes down sufficiently. It’s the same as air travel. ‘Make it available and they will pay for it’. Or something.

Thank you for taking the time to respond to this interview. I thoroughly enjoyed your book and rated five out of five stars. It’s beautifully written, so I was thrilled when your publisher allowed me to quote a paragraph (below). Keep up the great work making science easily accessible to the general public.

When Galaxies Collide is available in paperback and as an ebook. You can learn more at www.lisaharveysmith.com



2 thoughts on “When Galaxies Collide

  1. Peter,

    Thank you for presenting “When Galaxies Collide” and introducing Prof. Lisa. The beautiful aspect of science lies with the idea that for each question answered, ten more come to light. Lisa’s book is one of those I will just have to hold in my hands as printed pages bound into a book. I think there is still some room on the shelf near “Retrograde.”

    Thanks again!


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