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Journey to the Exoplanets (for iPad) Review
Journey to the Exoplanets is a dazzling, multifaceted introduction to one of astronomy’s most exciting topics, the search for worlds orbiting other suns.
(4 out of 5)
- Stunning illustrations
- Packed with information
- Something for all ages and experience levels
- Interactive features such as “Planet Builder.” Links to numerous exoplanet information sources.
- Occasional crashes in the Planet Picker section
- News section is really the text of weekly Scientific American podcasts, much of it unrelated to exoplanets.
Exoplanets—worlds orbiting other stars—are one of the hottest topics in astronomy, as researchers close in on detecting potentially habitable Earth-like planets, while also finding exotic worlds such as “Tatooine”, which orbits a double star. iPad app Journey to the Exoplanets ($9.99) is a multifaceted, immersive introduction to the subject, complete with beautiful artists’ renditions of our best guess as to what some of these worlds might look like up close.
Journey to the Exoplanets, a collaboration between Scientific American and Farrar, Straus and Giroux, is classified in the iTunes App Store as a book. As an interactive, multimedia eBook, it’s highly impressive, rich in information and with beautiful supportive graphics (and in some cases, audio or video clips). It does well in covering even basic material in a lively, engaging way, and should be enjoyable to a wide-ranging audience, from young students to astronomy buffs, teachers, and scientists. It’s in easy pick as an Editors’ Choice as an educational app.
Upon opening the app, the user is at the controls of a starship, with different panels or buttons to access various functions. It’s a bit hokey, perhaps, but it’s as effective an interface as any. Most of the controls are duplicated in a bar at the top of the screen that contains 10 small buttons with icons—the bar remains in place no matter what section of the app you navigate to. The buttons are labeled Mission Control (the Home button, by another name); What is a Planet?; Exoplanet Timeline; What is A Star; Radiation And Space Travel; Finding Exoplanets; Exoplanet Gallery; Planet Builder; Filtering Starlight; and Little Scientist. A larger tab to the right, Planet Picker, lets you access specific worlds (listed by name) from the Exoplanet Gallery.
The Exoplanet Gallery is the centerpiece of this app; opening it up brings up 88 thumbnails—16 to a screen—showing beautifully illustrated artists’ renditions of alien worlds. (In the cases of Fomalhaut b and Beta Pictoris b, actual images of the star systems are shown.) At the bottom of each illustration in the Exoplanet Gallery is a dial, with the choices Info, Distance, and Discovery. Discovery gives the planet’s discovery year and month, Distance gives the system’s distance in light years, and spinning the dial to Info causes a translucent block of text with a description of the planet to pop up. For many worlds, audio files (and in one case, a video) are accessible, giving additional info. The depictions of these worlds are uniformly beautiful, and at least in part speculative, as we have limited information about many of these systems. The final 5 are largely fanciful depictions of alien life in different habitats.
Although the vast majority of the 88 graphics in the gallery were smoothly accessible through Planet Picker, maybe 3 of them—one of them being “Upsilon Andromedae System”—would not only fail to open but tapping on their names would crash the app, and I’d have to relaunch it. I had no trouble accessing the graphics in question by clicking on their thumbnails in Exoplanet Gallery.
The Lowdown on the High Up: Planets and Stars
Although some of the topics (for example, What is a Planet? and What is a Star?) may seem basic at a glance, they’re covered in some detail. It wasn’t long ago that astronomers were debating the very question of what constitutes a planet. The section on planets starts with the “wanderers” known to the ancient Babylonians, Greeks, and Romans through the discovery of asteroids (which were counted as planets until it was clear how small and numerous they are), Uranus, Neptune, and Pluto, and the eventual demotion of Pluto in 2006 along with the first formal definition of a planet, at least in our solar system.
The discovery of exoplanets has revealed new classes of planets; for example, Hot Jupiters (gas giant planets that orbit very close to their stars), Super-Earths (planets more massive than Earth but less so than ice giants like Uranus and Neptune), and Rogue Planets (worlds that wander the galaxy, unbound to any star). The app discusses these as well as hypothetical worlds such as Carbon Planets.
In addition to going into similar detail about stars, What is a Star? has a subsection called 20 Stars: a 3D representation of the 20 stars nearest the Sun, showing their locations relative to the Sun, to each other, and to the galactic center.
The Exoplanet Timeline encompasses 4,000 years of planet-related discoveries, with nearly a third of the timeline citing events since the first exoplanet discovery two decades ago. The Radiation and Space Travel section describes the danger faced by astronauts from cosmic radiation—the risk greatly compounded in long voyages such as those required to reach even the nearest stars. The section depicts possible shielding methods for spaceships, and includes an audio interview with a quantum physicist, Anton Zeilinger.
Build Your Own Planet
Planet Builder lets you create a rotating representation of a planet on screen, letting you choose the star type (temperature), the distance of the planet from the star, the planet’s size, and the age of the planet. You can see how varying any or all of these factors changes the worlds you create. You can even save the planets you create, at least in non-rotating form as a screen shot.
The Finding Exoplanets section discusses techniques astronomers have used to discover exoplanets, including radial velocity (aka Doppler) technique, the transit method, direct imaging, gravitational microlensing, and pulsar (and eclipsing binary) timing. It describes the missions of the spaceborne exoplanet hunting missions, Kepler and COROT, and the prosaic naming convention for exoplanets (star name + lowercase letter, beginning with b) that, officially at least, gives us star names like HD 216770b and OGLE-2005-BLG-390Lb rather than the likes of Vulcan or Gallifrey.
Filtering Starlight explores how light from stars of different spectral types might be filtered by a hypothetical planet’s atmosphere and oceans, and its implications for possible life on such a world (including the color of plants). Astronomers have already confirmed the presence of water vapor in the atmospheres of several exoplanets, and photosynthesis and other processes could produce conspicuous biosignatures in planetary spectra potentially detectable with a new generation of telescopes.
The Little Scientist section offers instructions for a series of (for the most part simple) astronomy experiments, on topics ranging from gravity to orbits to spectroscopy. They include building a solar projector, tracing elliptical orbits, measuring the Sun’s diameter, and building a simple spectroscope. Although they’re not exoplanet-specific, the experiments give a budding researcher some first-hand grounding in astronomical concepts related to the app’s subject matter.
The app is self-contained, and doesn’t require an Internet connection to function, although you do need one to update the News section. The News section is really just the text of weekly Scientific American astronomy podcasts, many of them unrelated to exoplanets. For those interested in further information on exoplanetology, the Credits section provides an extensive list of links to online sources, including general exoplanet sites as well as sources for further reading on specific topics covered in the app.
Other exoplanet-related apps are available for the iPad, specifically an app named Exoplanet (and a similar app for the Kepler project). While Exoplanet includes some nifty features such as a database with information on all confirmed exoplanets as well as 3D graphical depictions of the planets in orbit, it lacks the breadth of the app reviewed here, being informational more than educational. Nonetheless, Exoplanet itself is well worth downloading—and it’s free.
A few bugs aside, Journey to the Exoplanets (for iPad) is everything an educational eBook app should be: informational, immersive, reasonably comprehensive, and visually stunning, while encouraging the user to further study the subject. It’s an easy pick for Editors’ Choice.
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By Tony Hoffman, PCMag