The Great Expedition Series, Book 8

A Million Whys: The Space Expedition for Curious Kids

By Crafty Clover. Published by Million Whys Press.

Why Can You See Only a Few Thousand Stars with Just Your Eyes? Why Is the Sun a Star, Not a Planet? Why Do Some Meteors Blaze Into Fireballs? This book answers 150 questions like these, one question per page, each with a short video answer. Six expeditions: Night Sky & Stars, Moon & Earth Dance, Sun & Planets, Rockets, Satellites & Astronauts, Space Rocks, Comets & Looking for Life, and Telescopes & Sky Detectives.

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All 150 questions

Tap a question to watch its video and read the answer.

Expedition 1: Night Sky & Stars

1. Why Can You See Only a Few Thousand Stars with Just Your Eyes?
2. Why Are Some Stars Brighter than Others?
3. Why Is the Night Sky Dark If There Are So Many Stars?
4. Why Do So Many Star Names, Like Altair and Aldebaran, Start with “Al-”?
5. Why Do Astronomers Agree on 88 Official Constellations?
6. Why Do the Moon and Planets Follow the Same Path Across the Sky?
7. Why Can’t You See Stars During the Day?
8. Why Can You See Different Constellations in Winter than in Summer?
9. Why Is the Milky Way a Pale Band?
10. Why Do City Lights Hide the Stars?
11. Why Do Different Cultures See Different Pictures in the Same Stars?
12. Why Do Stars Have Different Colors?
13. Why Do We Say Starlight Is Old Light?
14. Why Do Some ‘Stars’ Move Across the Sky in Minutes?
15. Why Does the Big Dipper Help Find the North Star?
16. Why Does the North Star Barely Seem to Move?
17. Why Do Southern Skies Show Different Stars?
18. Why Do Star Clusters Look Like Glitter Piles?
19. Why Do Nebulae Look Like Colorful Clouds?
20. Why Will Some Stars Someday Become Supernovas?
21. Why Do Binary Stars Orbit Each Other?
22. Why Are Black Holes Hard to See, and How Do We Find Them?
23. Why Do Galaxies Look Like Spirals, Ovals, or Blobs?
24. Why Does a Nearby Star Seem to Jump When Earth Moves?
25. Why Do People Still Stare at Stars with Just Their Eyes?

Expedition 2: Moon & Earth Dance

26. Why Does the Moon Look Upside Down in Australia?
27. Why Is There a New Moon You Can’t See?
28. Why Does a Full Moon Look So Round and Bright?
29. Why Does the Moon Seem to Follow Your Car?
30. Why Does the Moon Rise and Set?
31. Why Does Moonrise Time Change Each Day?
32. Why Are There Two High Tides a Day, Not One?
33. Why Are Some Tides Especially High (Spring Tides)?
34. Why Do Bright Streaks Spray Out From a Few Spots on the Moon?
35. Why Can You Sometimes See the Dark Part of a Crescent Moon?
36. Why Do Lunar Eclipses Turn the Moon Reddish?
37. Why Are Solar Eclipses Rarer to See From Your Town?
38. Why Does the Moon Have Craters?
39. Why Are There Dark Patches on the Moon?
40. Why Is Moon Dust So Clingy for Astronauts?
41. Why Is There Almost No Weather on the Moon?
42. Why Does Daylight on the Moon Last About Two Earth Weeks?
43. Why Did Apollo Astronauts Bounce When They Walked?
44. Why Does the Moon Help Keep Earth’s Tilt Steadier?
45. Why Can the Moon Occult (Cover) a Star or Planet?
46. Why Do Calendars Sometimes Have a ‘Blue Moon’?
47. Why Does the Moon Look Bright If Its Rock Is as Dark as Old Pavement?
48. Why Is the Moon Slowly Drifting Away From Earth?
49. Why Did People Once Think the Moon Made People ‘Loony’?
50. Why Do Future Explorers Still Want to Return to the Moon?

Expedition 3: Sun & Planets

51. Why Is the Sun a Star, Not a Planet?
52. Why Does the Sun's Middle Spin Faster than Its Top and Bottom?
53. Why Must You Never Stare at the Sun?
54. Why Are Planet Orbits Ovals, Not Perfect Circles?
55. Why Is Mercury So Extremely Hot and Cold?
56. Why Is Venus Hotter than Mercury Even Farther Out?
57. Why Is Earth Called the Goldilocks Planet?
58. Why Does the Red Planet Have Blue Sunsets?
59. Why Do Mars Rovers Need Tough Wheels and Brains?
60. Why Is Jupiter a Gas Giant?
61. Why Does Jupiter Have a Great Red Spot?
62. Why Does Titan, One of Saturn's Moons, Have Thick Orange Air?
63. Why Does Neptune Have the Fastest Winds in the Solar System?
64. Why Are Uranus and Neptune Called Ice Giants?
65. Why Does Uranus Roll on Its Side?
66. Why Is Pluto Now Called a Dwarf Planet?
67. Why Do Some Planets Have Dozens of Moons?
68. Why Is the Asteroid Belt Between Mars and Jupiter?
69. Why Do Inner Planets Take Less Time to Orbit the Sun?
70. Why Will the Sun Keep Shining for Billions of Years?
71. Why Is a Day on Venus Longer than Its Year?
72. Why Do Planets Sometimes Look Like They Go Backward?
73. Why Is the Sun’s Surface Speckled with Sunspots?
74. Why Does Solar Wind Shape a Huge Bubble Around the Planets?
75. Why Do Scientists Still Discover New Small Worlds?

Expedition 4: Rockets, Satellites & Astronauts

76. Why Do Rockets Turn and Roll Shortly After Liftoff?
77. Why Do Rockets Drop Stages as They Climb?
78. Why Do Rockets Rise Slowly at First and Then Speed Up?
79. Why Do Astronauts on the Space Station See About 16 Sunrises a Day?
80. Why Do Astronauts Grow a Little Taller in Space?
81. Why Do Satellites Stay Up Without Flapping Wings?
82. Why Are Communications Satellites Often Parked High Above the Equator?
83. Why Do GPS Satellites Need Einstein's Help?
84. Why Does the International Space Station Need Constant Boosts?
85. Why Do Astronauts Exercise Every Day in Space?
86. Why Is Space Food Sticky or Packed in Pouches?
87. Why Do Launches Pause for Weather Sometimes?
88. Why Do Heat Shields Glow on the Way Home?
89. Why Do Space Toilets Use Air Flow, Not Water Swirls?
90. Why Do Astronauts Sleep in Sleeping Bags Clipped to Walls?
91. Why Are Clean Rooms Used Before Launch?
92. Why Do Mission Control Teams Work in Shifts?
93. Why Do Spacewalkers Tether Themselves?
94. Why Do Rockets Launch Toward the East Often?
95. Why Are Reusable Rockets a Big Deal?
96. Why Do Cubesats Hitch Rides to Space?
97. Why Is Radio Delay a Problem Toward Mars?
98. Why Do Astronauts Train Underwater?
99. Why Do Spacecraft Need Many Computers and Backups?
100. Why Would a Trip to Mars Take Months?

Expedition 5: Space Rocks, Comets & Looking for Life

101. Why Do Some Meteors Blaze Into Fireballs?
102. Why Are Meteor Showers Named After Constellations?
103. Why Do Some Meteorites Make Craters on Earth?
104. Why Do Some Comets Glow Green?
105. Why Does a Comet Move Fastest When It Passes Nearest the Sun?
106. Why Do Asteroids and Comets Matter for Earth’s History?
107. Why Do Scientists Sample Asteroids with Spacecraft?
108. Why Is Liquid Water a Big Deal When Hunting Life?
109. Why Might Icy Moons Hide Oceans?
110. Why Do Europa and Enceladus Excite Astrobiologists?
111. Why Haven’t We Found Definite Alien Life Yet?
112. Why Can Astronomers Find Planets They Can’t See?
113. Why Is the Habitable Zone Different Around Other Stars?
114. Why Do SETI Projects Listen for Radio Signals?
115. Why Is Mars’s Methane a Curious Clue?
116. Why Do Biosignatures Need Careful Checking?
117. Why Clean Spacecraft Before Visiting Ocean Worlds?
118. Why Are Extremophiles on Earth Important for Space Biology?
119. Why Do Meteor Showers Feel Safer than Asteroid Movies?
120. Why Do Comets Have Nuclei That Look Dark and Lumpy?
121. Why Collect Antarctic Meteorites?
122. Why Might Organic Molecules Arrive From Space?
123. Why Do Dust Tails of Comets Sometimes Cause Meteor Showers Later?
124. Why Map Near-Earth Asteroids?
125. Why Keep Asking If We’re Alone?

Expedition 6: Telescopes & Sky Detectives

126. Why Do Big Telescopes Use Mirrors Instead of Lenses?
127. Why Are Many Top Telescopes on Mountains?
128. Why Put Telescopes in Space?
129. Why Does JWST See in Infrared?
130. Why Do Radio Telescopes Look Like Giant Dishes?
131. Why Do Astronomers Use Filters and Many Wavelengths?
132. Why Can Adaptive Optics Cancel the Twinkle of Our Air?
133. Why Do Star Parties Share Telescopes?
134. Why Do Astronomers Write Down the Date, Time, and Place of Every Sighting?
135. Why Do Planetarium Shows Help Even If They’re Not the Real Sky?
136. Why Do Your Eyes Need 20 Minutes to See the Stars Well?
137. Why Do Apps Help , But Eyes Still Matter?
138. Why Do Spectroscopy Rainbows Reveal Star Recipes?
139. Why Do Citizen Scientists Help Real Missions?
140. Why Measure the Sky in Magnitudes?
141. Why Do Many Telescopes Sit Inside Domes with a Slot That Opens?
142. Why Are Binoculars a Great First ‘Telescope’?
143. Why Align a Finderscope Before Hunting Planets?
144. Why Do Some Images Use False Color?
145. Why Collaborate Across Countries on Big Telescopes?
146. Why Can a Solar Storm Bother Satellites and Power Grids?
147. Why Teach Kids to Question Viral ‘Planet’ Photos?
148. Why Do Light Pollution Laws and Dark-Sky Parks Help?
149. Why Is Patience Part of Astronomy?
150. Why Does Every Space Answer Lead to a New Question?