American Scientist

THE COSMIC TOURIST: Visit the 100 Most Awe-Inspiring Destinations in the Universe! Brian May, Patrick Moore, and Chris Lintott. 192 pp. Carlton Books, 2012. $39.95.

For true believers in space exploration—and I count myself among them—1972 was the year when everything changed. It is best known as a time of sad retrenchment. At 10:54 p.m. GMT on December 14, the Apollo 17 crew blasted off from the Moon’s Taurus-Littrow valley and headed home. Nobody has ventured beyond Earth’s orbit since. The “giant leap for mankind” proclaimed by Neil Armstrong just three years earlier looked more like a brief, abortive excursion.

But a few months before Apollo’s anticlimactic end, a different voyage began, quietly setting space exploration on a dynamic new course. On March 3, 1972, Pioneer 10 shot into the sky over Florida aboard an Atlas-Centaur rocket. In just 11 hours, the probe had raced past the Moon’s orbit. By December of the following year it was skimming over the cloud-tops of Jupiter, providing humanity’s first up-close look at the outer Solar System. From there, the giant planet’s gravity flung Pioneer 10 free of the Sun. On January 1, 1974, NASA gave the program a new name, the Pioneer Interstellar Mission, and its spacecraft became the first directed out to the stars.

The Cosmic Tourist is a lavish celebration of that second era of adventure. We live now in an age of far-ranging virtual travel, with Pioneer 10 and its many successors acting as extensions of our otherwise Earth-bound human senses. Any scientifically curious person will have already encountered a smattering of the results radioed home by those robotic emissaries, but piecemeal news stories hardly begin to capture the grand audacity of the achievement. What the authors have done here is to sort through the whole overwhelming collection of space information and craft it into a coherent narrative. Their book is presented as a cosmic Baedeker, an invitation “to be a tourist on a scale never before imagined.”

Brian May, Patrick Moore, and Chris Lintott have convincing credentials as travel guides. May is an academic astronomer and also the guitarist from the band Queen—no stranger to connecting with the public. Moore is a doyen of the British astronomy scene, both as an academic and as a popular communicator. Lintott studies star formation at the University of Oxford and is the founder of Zooniverse, a highly successful citizen science website.

The authors treat the tourism concept as serious fun. Their itinerary begins just above Earth’s surface, overlooking the city lights of Washington, DC. From there, each turn of the page takes the reader steadily farther from home. A trip odometer tracks distances by the speed of light—light-seconds, light-minutes, light-hours, and so on—and each chapter begins with the odometer’s reading for that stop along the tour. Ptolemy, the authors’ imaginary spacecraft, keeps going until it reaches the cosmic microwave background, the relic radiation left over from the Big Bang. Located 13.8 billion light-years from Earth, the microwave background defines the outer limit of the visible universe—the end of the cosmic line.

In the course of visiting the 100 destinations promised in the book’s subtitle, The Cosmic Tourist hits many of the prime tourist spots (deserts of Mars, check; rings of Saturn, check) but also makes a delightful number of unexpected detours. The next stop after Venus is a pause to look at the enigmatic zodiacal light (10 light-minutes away), a feeble glow created by sunlight bouncing off fine dust particles scattered throughout the inner Solar System. Most of those particles are probably shed from colliding asteroids and disintegrating comets, but some of them may be blowing in from deep space. It should be possible to identify and collect the interlopers, providing a direct sample of interstellar material. May is actively exploring this possibility.

Likewise, a turn through Orion includes visits not only to the familiar Orion Nebula but also to its unsung neighbor, the Witch’s Head (900 light-years away). This enormous gas cloud looks like wisps of wood smoke, lit eerily by the bluish glare of the nearby supergiant star Rigel. Later in the voyage, after passing the Magellanic Clouds, Ptolemy takes another zig and lingers at NGC 2419 (300,000 light-years away), a globular cluster of stars situated in the lonely gulf between our galaxy and its giant neighbor, the Andromeda Galaxy. I thought I knew a lot about globular clusters, but I had never heard about this solitary stellar outpost, which is so loosely bound to the Milky Way that it takes 3 billion years to complete a single orbit. “NGC 2419 serves as a reminder that, embedded within the Milky Way, we are in a privileged position,” the authors write. “Most of space is extremely empty indeed.”

The quirkiness of The Cosmic Tourist extends to its format, and there the eccentricities are less charming. Although the book’s cosmic journey is based on findings from numerous interplanetary probes and space-based observatories, all of them masterpieces of engineering, the missions themselves get glancing mentions at most. Pioneer 10 doesn’t make an appearance at all (although Voyagers 1 and 2, its more famous successors, do get their props), and no researchers are cited by name.

The authors’ streamlined style also means there are no references, making for a strangely static view of the universe at a time when the pace of astronomical discovery is moving faster than ever. Don’t look for any details about the five moons of Pluto, evidence of water on Mars from the Curiosity rover, or the planet orbiting Alpha Centauri B. These discoveries are all too new. Even the estimated age of the universe has changed since The Cosmic Tourist hit the printing press, increasing from 13.7 to 13.8 billion years—a tribute to precision measurements from European Space Agency’s Planck satellite.

Clearly The Cosmic Tourist cannot match wits with the Internet for timeliness or scope, nor is it intended to. It is designed to draw in the novice space enthusiast, to show how far the human intellect has reached even as the human body has stayed put. At the end of the trip I found myself Googling around to find more destinations, more images, the latest astronomical news. For Ptolemy, and for the authors who conjured it up, that means the expedition was a resounding success.

Corey S. Powell is the interim editor of American Scientist and former editor of Discover magazine. His blog, Out There, appears at http://blogs.discovermagazine.com/outthere.