Take an armchair tour of the universe with this sightseer’s guide

30 Aug 2023

Clár-Bríd Tohill reviews Under Alien Skies: A Sightseer’s Guide to the Universe by Philip Plait

Distant wonders Philip Plait’s new book imagines what future space travellers might experience on distant exoplanets. (Courtesy: NASA/JPL)

As an astronomer, I am passionate in learning more about our place in the universe. As part of this I often give public talks and organize science outreach events. The people who come to them – no matter their age – almost always have the same wonder and awe when it comes to the cosmos. It is, after all, only human to want to learn more about the place we call home.

Since the dawn of our species, humans have looked up to the stars and wondered about these distant curiosities. Thanks to advances in astronomy, we now know a lot more about our local cosmic neighbourhood, and even beyond it. Under Alien Skies: a Sightseer’s Guide to the Universe is your ticket to these stars. With author and astronomer Philip Plait as your guide, this book will transport you across the universe, with many wonderful stops along the way.

Since the dawn of our species, humans have looked up to the stars and wondered what these distant curiosities would be like if we could see them up close

On the first stop of the tour, you will find yourself transported to our closest heavenly neighbour, the Moon. Though only a handful of people have ever been lucky enough to witness the wonder and awe of looking down on our own planet, it’s something I’m sure many of us have tried to imagine. In a series of short stories, Plait transports you to the lunar surface, explaining in great detail what you would experience as a space traveller if you were to set foot on it. From learning how to navigate microgravity to witnessing a lunar eclipse from the Moon itself, Plait brilliantly interweaves science with exploration and adventure to get your tour of the universe off to a great start.

The next leg of the book’s journey takes you to some of our most well-known (and loved) cosmic neighbours: the planets in our Solar System. Plait begins with Mars, possibly the most desirable planetary destination right now because it will likely be the next one we visit. Hopefully, Plait’s stories about what you would experience on this ruddy planet are not too far in our future, and his brilliant account of what these first visitors will experience are sure to stir the emotions next time you spot this glowing red dot in the sky.

Next up is my favourite, and the jewel of our solar system: Saturn. With its glorious ring system, this is one of the most easily recognizable planets, and has fascinated astronomers and non-astronomers alike for centuries. From soaring journeys above its icy rings to a stop-off at one of its numerous moons, Saturn is worth an entire travelogue in itself, and the things this chapter taught me have only increased my fascination with this ringed giant.

The tour of our local cosmic neighbourhood ends with Pluto. In a chapter on this now-dwarf planet, Plait explores what it would feel like to stand on the very edge of our solar system, and what you would (and wouldn’t) be able to see. Although Earth is too far away to be visible from Pluto, the physics out here are the same as back home, so we know exactly what it would feel like if, one day, we were able to visit this distant body. By explaining everything from the amount of sunlight you would receive to the freezing temperatures under your feet, Plait makes you feel like you’re already there.

While there is much to see in our solar system, we are but a drop in an ocean of other worlds. The next few chapters contain lots of interesting science about the exoplanets orbiting other stars in our galaxy. From worlds with eternal afternoons and planets with two suns (meaning you would have two shadows to accompany you), to worlds where other planets hang like moons in the sky, Plait explores what life would be like if humans ever came to call one of these distant wonders home. While this may be possible in the future, it will not happen in our lifetimes. For today’s humans, Under Alien Skies is the closest we will get to setting foot on these other worlds, and imagining what future space travellers might experience.

The final chapter is sure to draw every reader in, as the last stop of your tour of the cosmos is a black hole. Plait really did save the best for last: only discovered in the 1970s, black holes are among the weirdest and most mysterious things in our universe. While they are invisible to us, they have such incredibly strong gravity that not even light can escape – hence their name.

The unusual nature of black holes gives rise to many misconceptions. Some people I meet at outreach events, for example, think of them as monsters tearing through space and consuming everything that gets too close. While this can be true, these goliaths come in many different sizes, and this affects how they behave. Plait offers the reader a chance to experience what it would be like to get close to different types of black holes, including all the mind-bending physics involved, minus the danger. A brilliant way to end, this chapter wonderfully wraps up the story Plait tells alongside the science and leaves you with a newfound understanding and appreciation for the beauty that is our universe.2023 W W Norton 304pp £23.99hb

Clár-Bríd Tohill is a PhD student at the Centre for Astronomy and Particle Theory at the University of Nottingham, UK

FROM PHYSICSWORLD.COM   1/9/2023