Have you ever looked up in wonder at the night sky? Astronomy is your ultimate stargazing companion, off ering helpful observing tips, gorgeous images, and much more. SPECIAL COLLECTOR’S EDITION n ever mont l issue ou ll n MARCH 2018 I y h y y ’ fi d: • Tips for locating stars, planets, and deep-sky objects. The world’s best-selling astronomy magazine • Monthly sky charts to help you locate observing targets. What Texas astronomers search for Cassini exoplanets • Stunning photos of the most beautiful celestial objects. p. 55 reveals Lowell Observatory’s about Saturn historic • Reviews of the latest telescopes and equipment. refractor • EXPLORING p. 60 the ringed planet p. 20 • Strange stories Celestron of Saturn’s moons CGX Mount p. 28 reviewed p. 64 • Huygens lands on methane- Subscribe Today! soaked Titan p. 48 • Under Cassini’s ONLINE Astronomy.com • CALL 877-246-4835 hood p. 46 Outside the United States and Canada, call 903-636-1125. PLUS Bob Berman on super celestial events p. 8 P33103 Photo Credit: NASA/JPL-Caltech/Space Science Institute ASTRONOMY EXCLUSIVE METEORITE KIT Hold A Space Rock — Or 6 Of Them — In Your Hand! This exclusive Meteorite Kit, developed by meteorite expert Dr. Mike Reynolds, is the ideal way to introduce students and astronomy enthusiasts to iron, stone, and stony-iron meteorites. • 6 meteorite samples, including fragments from Campo del Cielo and Chelyabinsk, Russia. • 3 meteorwrong samples — ordinary rocks often mistaken for meteorites. • 16-page educational booklet, plus a magnet and a lab-type magni er. The kit, packed in a divided storage case, is perfect for classroom use or astronomy enthusiasts. LIMITED QUANTITIES! P33609 #81095 $89.99 Buy now at MyScienceShop.com/MeteoriteKit Sales tax where applicable. GREATEST MYSTERIES OF THE UNIVERSE by David J. Eicher COLLECTOR’S EDITION contents PAGE PAGE A universe of limitless wonder .................. 6 26. What creates gravitational waves?.......... 54 1. How old is the universe? .................... 8 27. What happens when black holes collide? . 55 2. How big is the universe? ................... 10 28. Why does antimatter exist?................. 57 3. How did the Big Bang happen?............. 12 29. Are there other planets like Earth?.......... 58 4. What is dark matter? ....................... 14 30. Does every big galaxy have a central black hole?......................... 60 5. How did galaxies form? .................... 15 31. Does inflation theory govern the universe? . 62 6. How common are black holes? ............. 17 32. Should Pluto be considered a planet? ...... 64 7. How many planets are in the solar system? . 19 33. Why did Venus turn itself inside-out?....... 66 8. Are we alone?.............................. 21 34. How could we recognize life elsewhere 9. What is the fate of the universe?............ 23 in the cosmos?............................. 69 10. What will happen to life on Earth?.......... 24 35. What created Saturn’s rings? ............... 70 11. What is dark energy?....................... 26 36. Could a distant, dark body end life on Earth? .................................. 72 12. What are gamma-ray bursts? ............... 28 37. Do we live in a multiple universe? .......... 74 13. Will asteroids threaten life on Earth?........ 30 38. How did the Milky Way Galaxy form?....... 75 14. Is water necessary for life?.................. 32 39. How did the solar system form? ............ 77 15. Is there life on Mars, Titan, or Europa?....... 34 40. What happens when galaxies collide? ...... 78 16. Why did Mars dry out? ..................... 36 41. How do massive stars explode? ............ 80 17. How did the Moon form?................... 37 42. What will happen to the Sun? .............. 82 18. Where do meteorites come from? .......... 39 43. Did comets bring life to Earth? ............. 84 19. Can light escape from black holes? ......... 40 44. How did quasars form?..................... 85 20. Did stars, galaxies, or black holes come first?................................. 42 45. Will the Milky Way merge with another galaxy? .................................... 86 21. Where do cosmic rays come from?.......... 44 46. How many brown dwarfs exist? ............ 88 22. How are comets and asteroids related?..... 46 47. What happens at the cores of 23. How many planets surround other galaxy clusters? ............................ 90 star systems? .............................. 48 48. Is Jupiter a failed star?...................... 92 24. How many asteroids are locked up in the Kuiper Belt?............................ 50 49. How many galaxies are in our Local Group?. 94 25. Does string theory control the universe?.... 52 50. Do neutrinos hold secrets to the cosmos?. 96 BEAUTIFUL UNIVERSE. Towering columns of cosmic gas and dust make up the famous Pillars of Creation, located in the heart of the Eagle Nebula. NASA/ESA/HUBBLE HERITAGE TEAM (STSCI/AURA) GREATEST MYSTERIES OF THE UNIVERSE COLLECTOR’S EDITION Editor David J. Eicher Art Director LuAnn Williams Belter EDITORIAL Senior Editors Michael E. Bakich, Richard Talcott Production Editor Elisa R. Neckar A universe of Associate Editors Alison Klesman, Jake Parks Copy Editors Karri Ferron, Dave Lee Editorial Assistant Amber Jorgenson I/AURA; LEFT: WILLIAM ZUBACK WILLIAM LEFT: I/AURA; ART C limitless wonder Graphic Designer Kelly Katlaps Illustrator Roen Kelly Production Specialist Jodi Jeranek We live in a golden age of astronomy. Consider the history of CONTRIBUTING EDITORS Bob Berman, Adam Block, Glenn F. Chaple, Jr., Martin George, modern humans: We struggled for 1,000 centuries to secure Tony Hallas, Phil Harrington, Korey Haynes, Jeff Hester, Liz Kruesi, Ray Jayawardhana, Alister Ling, Steve Nadis, I: FAR LEFT: NASA/ESA/STS LEFT: FAR I: Stephen James O’Meara, Tom Polakis, Martin Ratcliffe, Mike D. C food and shelter. We spent another 50 centuries forming Reynolds, Sheldon Reynolds, Erika Rix, Raymond Shubinski SCIENCE GROUP early civilizations and building cities. And in but more often relies on countless small General Manager Tim Paulson just the last century alone, technology has Executive Editor Becky Lang steps. After reading 50 Greatest Mysteries of Design Director Dan Bishop helped us unravel the mysteries of the cosmos the Universe, you’ll better understand why EDITORIAL ADVISORY BOARD in ways our ancestors could not have imag- these burning questions captivate astrono- Buzz Aldrin, Marcia Bartusiak, Timothy Ferris, Alex Filippenko, Adam Frank, John S. Gallagher lll, Daniel W. E. Green, William K. NASA/ESA/STS IMAGE: COVER ined. That's pretty humbling. Despite the fact mers, as well as grasp how researchers are Hartmann, Paul Hodge, Edward Kolb, Stephen P. Maran, that 5,000 generations of modern humans attempting to answer them. Whether you’re a Brian May, S. Alan Stern, James Trefil have pondered the heavens above, we’re seasoned observer or an armchair enthusiast, Kalmbach Media really just beginning to comprehend the story after reading this special issue, you'll have a Chief Executive Officer Dan Hickey Senior Vice President, Finance Christine Metcalf of the universe — and it’s mind-boggling. much deeper understanding of where Vice President, Content Stephen C. George Drawing on Astronomy magazine's long astronomy currently stands. Vice President, Consumer Marketing Nicole McGuire Vice President, Operations Brian J. Schmidt heritage as the leading publication in its field, But most importantly, you’ll have fun. Vice President, Human Resources Sarah A. Horner 50 Greatest Mysteries of the Universe explores Astronomical news seems to make headlines Senior Director, Advertising Sales and Events David T. Sherman Advertising Sales Director Scott Redmond the cosmos’ biggest questions. We published more often now than ever before, and Circulation Director Liz Runyon the first iteration of this special issue just over equipped with this special issue, you’ll have Art and Production Manager Michael Soliday New Business Manager Cathy Daniels a decade ago, but even in the short time everything you need to insightfully discuss the Retention Manager Kathy Steele since, the field of astronomy has marched cosmos in any situation. Did you stumble upon Single Copy Specialist Kim Redmond ADVERTISING DEPARTMENT forward faster than ever before. Because of a pop-up observing session in a park? 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