Please note!

Listed below are questions submitted over the year by users of "From Stargazers to Starships" and the answers given to them. This is just a selection--of the many questions that arrive, only a few are listed. The ones included below are either of the sort that keeps coming up again and again, or else the answers make a special point, often going into details which might interest many users.

1. About asteroids hitting Earth.
2. The swirling of water in a draining tub.
3. Dispensing water at zero-g.
4. Robert Goddard and World War II.
5. Asymmetry of the Moon's orbit.
6. Measuring distance from the Sun.
7. Who owns the Moon?
8. Acceleration of a rocket.
9. Rebounding ping pong balls (re. #35)
10. Rebounding ping pong balls and gravity-assist
11. Why don't we feel the Sun's gravity pull?
12. How hot are red, white and blue (etc.) stars?
13. How does the solar wind move?
14. The shape of the orbit of Mars
15. What if the Earth's axis were tilted 90° to the ecliptic?



16. Mars and Venus
17. Where is the boundary between summer and winter?
18. The Ozone Hole
19. What keeps the Sun from blowing up?
20. Those glorious Southern Skies!
21. Should we fear big solar outbursts?
22. Planetary line-up and the sunspot cycle
23. What are comet tails made of?
24. If light speed sets the limit, why fly into space?
25. Does precession mis-align ancient monuments?
26. Why does the Earth rotate? Why is it a sphere?
27. What's so hard about reaching the Sun?



28. Where does space begin?
29. Gravity at the Earth's Center
30. Radiation hazard in space (3 queries)
31. "Danger, falling satellites"?
32. The Lagrangian L3 point
33. Distance to the Horizon on an Asteroid
34. Overtaking Planets
35. Falling Towards the Sun
36. The Polar Bear
37. Are the Sun's Rays Parallel?
38. More thrust in reverse than going forward?
39. The varying distance between Earth and Sun
40. Mission to Mars
41. Kepler's calculation
42. The Appearance (Phase) of the Moon



43. Stability of Lagrangian points
44. Can an Asteroid Impact Change the Earth's Orbit?
45. Can Gravity Increase with Depth?
46. Lightspeed, Hyperspace and Wormholes
47. Why do Rockets Spin?
48. Around What does the Sun Revolve?
49. Why are planets in nearly the same plane?
50. The Shapes of Rockets and Spacecraft
51. Space Debris
52. Teaching Nuclear Fusion
53. Contribution of different elements to Sunlight
54. Jewish Calendar
55. Spaceflight Without Escape Velocity?
56. Who first proposed a round Earth?
57. Does Precession change the Length of a Year?
58. The Analemma
59. Changes of the Polar Axis of Earth
60. Van Allen Belt and Spaceflight
61. Nearest Star Outside Our Galaxy
62. (a) Why are Satellites Launched Eastward?
          What is a "Sun Synchronous" orbit?
     (b) Why are satellites launched from near the equator?
    
63. How Tall Can People Get?
64. Gunpowder and Rockets
65. Precession
66. Solar Sails
67. (a) Distance to the Big Dipper
     (b) Big Dipper star names
    



68. Was Moon landing a hoax?
69. Clockwise or counter-clockwise?
70. Isotopes in Center of Earth
71. Density of the Sun's corona and the "Scale Height"
72. Did Tesla extract free energy from thin air?
73. What does "lapse rate" mean?
74. Motion of the Sun through space
75. Teaching about tides
76. Distance to the Horizon
77. Can geocentrist theory still be possible?
78. Can Earth's rotation reverse, like its magnetic polarity?
79. Why is the Earth round?
80. The De Laval Nozzle
81. Why 23.5 degrees?
82. What is Gravitational Collapse?
83. Can Earth capture a second moon?



84. How far does the Earth's gravity extend?
85. How far is the Moon?
86. Twinkle, twinkle little star-- How I wonder, what you are.
87. Teaching about seasons
88. Space Launches by Cannon--A
89. Space Launches by Cannon--B
90. The Southern Pole of the Sky
91. Do Astrologers use Wrong Positions for Planets?
92. Why does the Moon have bigger craters?
93. Why does Gravity Exist?
94. Atmospheric "Thermals"--Triggered by Electric Forces?
95. What would happen if Earth rotated faster?
96. Where do gravity of Earth and Sun balance?
97. The Ultimate Astronomy Tool
98. High Temperature in Cold Outer Space



99.   Refraction of sunlight and starlight by the atmosphere
100.   Advice to a would-be astronomer
101.   The effect of the Color of Light on the Output of Solar Cells
102.   What is "radiation"?
103.   Height of the Atmosphere
104.   How does the upper atmosphere get so hot?
105.   History of the use of De Laval's nozzle on rockets
106.   Why don't Space Rockets use Wings?
107. Distance of horizon on Mars
108. Stopping the rotation of Earth?
109. The equation of a parabola
110. When does Jewish Sabbath start in the far north?
111. Where is the center of the global landmass?
112. What if our Sun was a much hotter star?
113. Finding the north direction



114. Why not use a heat shield going up?
115. When and where can rainbows be seen?
116. The unusual rotation of the planet Venus
117. Why not use nuclear power for spaceflight?
118. "Doesn't heat rise?"
119. Have any changes been observed on the Moon?
120. Why isn't our atmosphere flung off by the Earth's rotation?
121. Can kinetic energy be reconverted to work?
122. Does any location get the same number of sunshine hours per year?
123. Speed of toy car rolling off an inclined ramp
124. Acceleration due to gravity



125. Re-entry from Space
126. Balancing a Bicycle
127. Is Absolute Zero reached on the Moon?
128. Why isn't Longitude measured from 0° to 360°? "Constellation" or "Asterism"?
129. "Position of the Stars when I was Born"
130. Rotation of the Earth's Core"
131. How hot is the Sun?
132. How much weaker is gravity higher up?
133. Eclipse of Venus?
134. The Big Bang



135. Thanks for the "Math Refresher" in Spanish
136. The Pressure of Sunlight
137. How is the instant the seasons change determined?
138. Operation of Ion Rockets
139. Physical Librations of the Moon
140. The De-Laval Nozzle
141. Why does the space shuttle rotate at take-off?
142. Cold Fusion
143. What if a Neutron Star hit the Sun?
     Why did the Moon appear Red?
144. Centrifuge for Whirling Astronauts
145. What Holds Galaxies Together?
146. View of Earth and Moon from Mars
147. Appearance of the Moon (1)
148. Appearance of the Moon (2): Does it "roll around"?
149. Altitude of the tail of the Big Dipper
150. Sudden decompression, 5 miles up



151. Do Negative Ions make you Feel Good?
152. Shape of the Earth's Orbit
153. Questions about the Solar Corona:
                   (1) Why don't its particles separate by weight?
                   (2) What accelerates the solar wind?
154. Why does the rising Sun look so big?
155. Drawing a Perpendicular Line in Rectangular Coordinates
156. Unequal Seasons
157. Is the Big Dipper visible from Viet Nam?
158. Holes in a Solar Sail
159. Consequences of no more solar X-rays
160. Science Fair Project on the Size of the Earth
161. Superposition of Waves
162. The Sun and Seasons
163. If the Earth's Rotation would   S t o p...     (1)
164. If the Earth's Rotation would   C h a n g e...     (2)
165. What if the Earth stopped in its orbit?
166. Fast Trip to Mars     (1)
167. Fast Trip to Mars     (2)



168. Spacecraft Attitude
169. What makes the Earth rotate?
170. Energy from the Earth's Rotation?
171. How were planets created?
172. Does Precession of the Equinoxes shift our Seasons?
173. "Zenial Days" on Hawaii
174. Sun's Temperature and Energy Density of Sunlight
175. Teaching about energy in 8th grade
176. About the jetstream
177. What would a breach in a space station do?
178. Gravity at the Earth's center
179. Freak waves on the ocean
180. Citation on "Bad Greenhouse" web page
181. How can radio waves carry sound?
182. Do Cosmic Rays produce lightning?
183. Star positions shifted by the atmosphere
184. The equation of time
185. Launch window of the Space Shuttle



186. No "Man in the Moon" from Australia?
187. Picturing the Sun from a different distance
188. What makes the sun shine so brightly?
189. Re-entry from orbit
190. Effects of weightlessness on one's body
191. Blimps on Mars
192. Planet Mars "huge" in the sky, in August 2005?
193. Astronomy and telescopes for ones' own children
194. Does the solar wind have escape velocity
195. Astronomy for cliff-dwellers of New York City
196. Portable star finder
197. What if the Moon was closer? (2 questions)
198. Why doesn't the Moon have an atmosphere?
199. Telling a 3-year old about the atmosphere (2 questions)
200. Three-color vision



201. Superconductors work, universe expands--with no energy input. Why?
202. Shuttle orbit and Earth rotation
203. Worrying about Wormholes and Black Holes
204. What should I study?
205. The greenhouse effect
206. Separation between lines of latitude and longitude
207. Motion of air: hot to cold, or high pressure to low?
208. Removing "Killer Asteroids"
209. Strange light seen from Hawaii
210. Is the Sun attached to another star?
211. What if the Sun turned into a black hole?
212. Do absorption lines have a Doppler shift?
213. What are "Electromagnetic Waves"?
214. Why are the two daily tides unequal?
215. Why air gets cold higher up--a wrong explanation



216. Any limits to Newton's 2nd Law
217. Gravity at the Earth's center
218. Does the Earth follow a "squiggly" orbit?
219. Third grader asks: how far to zero gravity?
220. "How does inertia affect a rolling ball"?
221. What determines the quality of a telescope?
222. Why design maps around curved lines?
223. "Drag" by the Sun on the Earth's motion
224. Does precession affect the time of summer? (2 questions)
225. Newton's law or Bernoulli's?
226. Does the universe have an axis?
227. Frictional electricity
228. Syllabus for catching up on physics
229. Parabolic reflector
230. At what distance does Earth start looking spherical?
231. Is the Sun on fire?
232. Confusion about the "Big Bang"
233. How did Tycho calibrate his instruments?



234. Gases that fill balloons
235. Asian tradition on the start of winter
236. Why our year starts at January 1
237. Sticking a hand out of a window...
238. One year of continuous sunlight?
239. Shielding out radio waves
240. The way gravity changes with depth
241. The Sun's Axis
242. "Gravity Particles"?
243. A "short stay on Mars"
244. Weight and mass
245. "The Moon Hoax"
246. Shuttle re-entry from space
247. Energy levels: plus or minus?
248. How can such small targets be accurately hit so far away?
249. A teacher asks about compiling lesson plans
250. Why the Moon has its phases
251. How can a spacecraft self-rotate?
252. Stability during a rocket launch
253. Boiling point of water in space



254. Konstantin Tsiolkovsky
     
255. The Color Indigo
     
256. Electromagnetic Waves and Electromagnetic Induction
     
257. Why do orbits curve?
     
258. The "Sundial Bridge" in Redding
     
259. (a) Temperature in space
       (b) Exposure to the space environment: Freeze or burn?
     
260. Remote sensing of Thunderstorms
     
261. What keeps Electrons away from the Atomic Nucleus?
     
262. The Stars on the Winter Solstice of 2012
     
263. Mars Sunset
     
264. Gravity at the Center of Earth
     
265. The Big Bang
     
266. "How Often are Stars Born?"
     
267. The Path of Lightning
     
268. Launching a Rocket from an Airplane
     
269. The Equation of Continuity
     
270. The Four Corners Monument
     
271. Which among the brightest stars is closest to N Pole?
     
272. Gravity Assist
     
273. Is the Centrifugal Force "Real"?
     
274. How do we know Earth is bigger than the Moon?
     
275. Sound Waves on the Sun?
     
276. What if we had to give up use of Satellites?
     
277. Rotation of Venus
     
278. "Proper Motion" of Stars
     
279. Doppler Shift from the Big Bang
     
280. Science Fiction scenario for a Flight to Mars
     
281. Motion of the Moon
     
     
     
282. "Iridium" flares
     
283. Discovering Planets outside the Solar System
     
284. Landing speed of airplane
     
285. The Hubble Constant
     
286. Are Summer Nights Darker?
     
287. "Space Elevator"
     
288. Black Holes
     

291a.Angle between ecliptic and Milky Way
291b.(Continuation)--About the year 2012

1. Don't use Diesel fuel in a gasoline car!
   
2. How bright is our Sun when seen from space?
   
3. What is a "field"?
   
4. Outer limits of the Solar System
   
5. Gravitational Energy
   
6. Stresses on a Railroad Bridge
   
7. The constellation of Cassiopeia
   
8. Tracking of radioactivity carried by winds
   
9. Why can't the space shuttle reenter "slowly"?
   
10. "The Standard Model of the Universe"
    
11. About the Maya Calendar
    
12. Are light sabers possible?
    
13. Can the heat of sunshine make the Earth expand?
    
    
14. About Mountains
    
15. "Will the World end in 2012?" (a,b)
    
16. Advice to graduating High School Student
    
17. Could a (heat resistant!) ship float on the Sun?
    
18. Reducing the fuel weight of the Space Shuttle?
    
19. How do Rockets Land?
    
20. The Earth's Spin reduced by Global Warming
    
21. Circumnavigation of the Sun
    
22. Are nuclear forces merely gravity at very close distance?
    
23. Changing the Earth's Rotation
    
24. Why are planetary orbits eccentric?
    
25. Forces on Comet-dwellers
    
26. Nuclear reactors and bombs
    
27. Why doesn't magnetism affect electro-magnetic waves?
    
28. Is humanity changing the climate, or is it the Sun and the Earth's magnetism?
    
29. Advice to home-schooling parent
    
30. Science of Clothing
    
31. Calculating a Collision
    
32. The Coriolis force and more
    
33. Why isn't the solar system stratified by density?
    
    
34. Tapping Atmospheric Electricity
    
35. Global Disaster in 2012?
    
36. What's the difference between speed and velocity?
    
37. Effect of Gravity on Electromagnetic Waves
    
38. Why is North the reference, not South?
    
39. The lowest 700 km of our Atmosphere
    
40. Doomsday 2012?
    
41. Where does a Flying Bird get its Support?
    
42. Why does Sun seem to move?
    
43. Why don't waves disturb each other?
    
44. Does the Moon's motion Change?
    
45. Big Dipper and Weather
    
46. What IS the Ecliptic?
    
47. Precession, Greenhouse and more...
    
48. Latest Sunrise, Earliest Sunset
    
49. Falling off the Earth's Bottom?
    
50. Rolling down a slope
    
51. Pelton Wheel Efficiency
    
52. Energy loss rate of our Sun
    
53. The Sun's distance
    
54. Why does sunlight have a continuous spectrum?
    
    
55. Harry Paul Sprain's perpetual Motion Device
    
56. Can the plasma that fills space help spaceflight?
    
57. Spiral arms of our galaxy
    
58. What powers a glider?
    
59. UFOs
    
60. Maximum speed for propeller-driven airplane?
    
61. The speed at which gravity spreads
    
62. Layers of the Earth
    
63. Why doesn't the sky fall on us?
    
64. Imagine a non-rotating Earth
    
65. Flying east with a 1° error
    
66. US Flag on the Moon
    
67. Rope stretched across a long lake...
    
68. About studying electronics in the USA
    
69. Publish Stargazers as a book?
    
70. Charging of Earth by lightning:   +   or   –  ?
    
71. If no stars were seen--could Earth's orbital motion be discovered?
    
72. Local Solar Time in Iceland
    
73. Is orbital motion same as free fall?
    
74. Build a straight tower in warped space?
    
    
    
75. The 2011-2 sunspot maximum
    
76. Is Earth adding mass?
    
77. Shape of a "bottle rocket"
    
78. Fantasy spaceflight vs. reality
    
79. Telling a 7-year old about stars "dying"
    
80. (1) Why is lightning jagged?     (2) What did Tesla do?
    
81. How can the north wall of my house be in sunlight?
    
82. Heating the inside of Earth
    
83. Dawning of the Age of Aquarius
    
84. Why is hydrogen the fuel of choice?
    
85. Gamma ray bursts
    
86. Counter-clockwise swirling motion in the atmosphere
    
87. Leap years on the Jewish calendar
    
88. Earth axis tilt and climate (1)
    
89. Earth axis tilt and climate (2)
    
90. Does the Sun move?
    
91. Can the Sun interfere with the visibility of the Big Dipper?
    
92. Why can't we feel the Earth's rotation?
    
93. Is our galaxy held together by a central black hole?
    
94. Why don't gas planets just evaporate?
    
95. Source of the Sun's energy
    
96. Point of gravity equilibrium
    
97. Solar system motion through the Galaxy
    
98. Spaceflight by waiting for the Earth to turn?
    
99. Does Earth rotation affect size of creatures?
    
100. The year 2012
     
101. Are our galactic arms winding up or opening up?
     
102. Advice to a home-schooling mother
     
103. Are all stars we see suns?
     
     
104. Newton's 3rd law
     
105. Newton's 3rd law
     

397. Author's IQ
     
398. Global Warming caused by Sun getting nearer?
     
399. The year 2012
     
400. Empty space behind North Star?
     
401. The year 2012 and the 26,000 year cycle
     
402. "Quarter Squares"
     
403. Do Rockets need "something to push against"?
     
404. Sunrise-Sunset asymmetry
     
405. Re-entry from orbit
     
406. Earth Axis and Gravity
     
407. The year 2012
     
408. Choosing an Aerospace Career
     
409. Advice for "new" physics teacher
     
410. Paradox of Time Travel
     
411. Is 7th grade Earth science boring?
     
412. Air Resistance
     
413. Experimenting with Microwave Oven
     
414. Is the Sun losing mass?
     
415. Sun's position at noon, south of equator
     
416. Fred Hoyle's theory of the Sun's Corona
     
417. Why don't Protons and Electrons combine?
     
418. Days in a Year
     
419. Position of the Moon in the sky
     
     
420. Earth crossing Galactic Equator?
     
421. Is the geocentric theory ruled out?
     
422. Does the Southern Sky have a Pole Star?
     
423. What is the fate of starlight energy?
     
424. Double-slit diffraction of particles
     
425. Does the Sun overhead reduce effective weight?
     
426. Evidence for Global Warming ?
     
427. Distances to the Equator
     
428. Weight on the Equator and at the Pole
     
429. Why doesn't gravity overcome buoyancy?
     
430. The Prime Meridian
     
431. Is L2 in the Earth's Shadow?
     
432. In what direction is Israel from NY?
     
433. Is the World Overpopulated?
     Magnetic Energy
     
434. Magnetic Carnot Cycle
     
435. Defining the Equator