| 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. This project started at a time when downloads used slow phone lines, and therefore the questions were grouped in files of 15-20 each. With any request for a particular question, only the appropriate file needed to be downloaded.
 
 By now (2009) the list has grown too long to include in every such file, and therefore most access is through this comprehensive listing. Alternatively, 
an index file listing questions by topic can be linked from here.
 
 
About asteroids hitting Earth.The swirling of water in a draining tub.Dispensing water at zero-g.Robert Goddard and World War II.Asymmetry of the Moon's orbit.Measuring distance from the Sun.Who owns the Moon?Acceleration of a rocket.Rebounding ping pong balls (re. #35)Rebounding ping pong balls and gravity-assistWhy don't we feel the Sun's gravity pull?How hot are red, white and blue (etc.) stars? How does the solar wind move? The shape of the orbit of MarsWhat if the Earth's axis were tilted 90° to the ecliptic?
 
  Mars and Venus  Where is the boundary between summer and winter? The Ozone Hole  What keeps the Sun from blowing up? Those glorious Southern Skies!Should we fear big solar outbursts?Planetary line-up and the sunspot cycleWhat are comet tails made of?If light speed sets the limit, why fly into space?Does precession mis-align ancient monuments?Why does the Earth rotate? Why is it a sphere?What's so hard about reaching the Sun?
 
 Where does space begin?Gravity at the Earth's Center Radiation hazard in space (3 queries)"Danger, falling satellites"?The Lagrangian L3 point Distance to the Horizon on an Asteroid  Overtaking Planets  Falling Towards the Sun  The Polar Bear  Are the Sun's Rays Parallel? More thrust in reverse than going forward? The varying distance between Earth and Sun  Mission to Mars Kepler's calculation The Appearance (Phase) of the Moon
 
  Stability of Lagrangian points  Can an Asteroid Impact Change the Earth's Orbit?
 Can Gravity Increase with Depth? Lightspeed, Hyperspace and Wormholes Why do Rockets Spin? Around What does the Sun Revolve?  Why are planets in nearly the same plane? The Shapes of Rockets and Spacecraft Space Debris Teaching Nuclear Fusion Contribution of different elements to Sunlight Jewish Calendar Spaceflight Without Escape Velocity?Who first proposed a round Earth? Does Precession change the Length of a Year? The Analemma Changes of the Polar Axis of Earth Van Allen Belt and Spaceflight Nearest Star Outside Our Galaxy(a) Why are Satellites Launched Eastward? 
What is a "Sun Synchronous" orbit?
 (b) Why are satellites launched from near the equator?
 
 How Tall Can People Get?  Gunpowder and Rockets  Precession  Solar Sails (a) Distance to the Big Dipper 
(b) Big Dipper star names
 
 
  Was Moon landing a hoax?  Clockwise or counter-clockwise?  Isotopes in Center of Earth  Density of the Sun's corona and the "Scale Height" Did Tesla extract free energy from thin air? What does "lapse rate" mean? Motion of the Sun through space Teaching about tides Distance to the Horizon Can  geocentrist theory still be possible? Can Earth's rotation reverse, like its magnetic polarity?  Why  is the Earth round?   The De Laval Nozzle   Why 23.5 degrees?   What is Gravitational Collapse?   Can Earth capture a second moon?
 
 How far does the Earth's gravity extend?   How far is the Moon? Twinkle, twinkle little star--
How I wonder, what you are. Teaching about seasons  Space Launches by Cannon--A  Space Launches by Cannon--B  The Southern Pole of the Sky  Do Astrologers use Wrong Positions for Planets?   Why does the Moon have bigger craters?   Why does Gravity Exist?  Atmospheric "Thermals"--Triggered by Electric Forces? What would happen if Earth rotated faster? Where do gravity of Earth and Sun balance? The Ultimate Astronomy Tool  High Temperature in Cold Outer Space 
 
    Refraction of sunlight and starlight by the atmosphere     Advice to a would-be astronomer    The effect of the Color of Light on the Output of Solar Cells    What is "radiation"?   Height of the Atmosphere     How does the upper atmosphere get so hot?        History of the use of De Laval's nozzle on rockets    Why don't Space Rockets use Wings?   Distance of horizon on Mars Stopping the rotation of Earth?The equation of a parabolaWhen does Jewish Sabbath start in the far north?Where is the center of the global landmass?What if our Sun was a much hotter star?Finding the north direction 
 
  Why not use a heat shield going up?
When and where can rainbows be seen? The unusual rotation of the planet Venus  Why not use nuclear power for spaceflight?"Doesn't heat rise?"Have any changes been observed on the Moon? Why isn't our atmosphere flung off by the Earth's rotation?
Can kinetic energy be reconverted to work?  Does any location get the same number of sunshine hours per year? Speed of toy car rolling off an inclined ramp Acceleration due to gravity 
 
 Re-entry from Space Balancing a BicycleIs Absolute Zero reached on the Moon? Why isn't Longitude measured from 0° to 360°? "Constellation" or "Asterism"?"Position of the Stars when I was Born"Rotation of the Earth's Core"How hot is the Sun?How much weaker is gravity higher up?Eclipse of Venus?The Big Bang
 
 Thanks for the "Math Refresher" in Spanish The Pressure of SunlightHow is the instant the seasons change determined?Operation of Ion RocketsPhysical Librations of the MoonThe De-Laval NozzleWhy does the space shuttle rotate at take-off?Cold FusionWhat if a Neutron Star hit the Sun?Why did the Moon appear Red?
 Centrifuge for Whirling Astronauts What Holds Galaxies Together?View of Earth and Moon from MarsAppearance of the Moon (1)Appearance of the Moon (2): Does it "roll around"?Altitude of the tail of the Big Dipper  Sudden decompression, 5 miles up 
 
 Do Negative Ions make you Feel Good? Shape of the Earth's Orbit Questions about the Solar Corona: (1) Why don't its particles separate by weight?(2) What accelerates the solar wind?
 Why does the rising Sun look so big? Drawing a Perpendicular Line in Rectangular Coordinates Unequal Seasons Is the Big Dipper visible from Viet Nam? Holes in a Solar Sail Consequences of no more solar X-rays Science Fair Project on the Size of the EarthSuperposition of Waves The Sun and Seasons If the Earth's Rotation would   S t o p...       (1) If the Earth's Rotation would   C h a n g e...       (2) What if the Earth stopped in its orbit? Fast Trip to Mars      (1) Fast Trip to Mars      (2) 
 
 Spacecraft AttitudeWhat makes the Earth rotate?Energy from the Earth's Rotation?How were planets created?Does Precession of the Equinoxes shift our Seasons?"Zenial Days" on HawaiiSun's Temperature and Energy Density of SunlightTeaching about energy in 8th gradeAbout the jetstream What would a breach in a space station do? Gravity at the Earth's center  Freak waves on the ocean  Citation on "Bad Greenhouse" web page How can radio waves carry sound? Do Cosmic Rays produce lightning? Star positions shifted by the atmosphere  The equation of time  Launch window of the Space Shuttle 
 
 No "Man in the Moon" from Australia? Picturing the Sun from a different distance What makes the sun shine so brightly? Re-entry from orbit Effects of weightlessness on one's body Blimps on Mars Planet Mars "huge" in the sky, in August 2005? Astronomy and telescopes for ones' own children Does the solar wind have escape velocity Astronomy for cliff-dwellers of New York City  Portable star finder What if the Moon was closer? (2 questions) Why doesn't the Moon have an atmosphere? Telling a 3-year old about the atmosphere  (2 questions) 
Three-color vision 
 
 Superconductors work, universe expands--with no energy input. Why? Shuttle orbit and Earth rotation Worrying about Wormholes and Black Holes What should I study? The greenhouse effect Separation between lines of latitude and longitude Motion of air: hot to cold, or high pressure to low? Removing "Killer Asteroids" Strange light seen from Hawaii Is the Sun attached to another star? What if the Sun turned into a black hole? Do absorption lines have a Doppler shift? What are "Electromagnetic Waves"? Why are the two daily tides unequal? Why air gets cold higher up--a wrong explanation 
 
 Any limits to Newton's 2nd Law Gravity at the Earth's center Does the Earth follow a "squiggly" orbit? Third grader asks: how far to zero gravity? "How does inertia affect a rolling ball"? What determines the quality of a telescope? Why design maps around curved lines? "Drag" by the Sun on the Earth's motion Does precession affect the time of summer? (2 questions) Newton's law or Bernoulli's? Does the universe have an axis? Frictional electricity Syllabus for catching up on physics Parabolic reflector At what distance does Earth start looking spherical? Is the Sun on fire? Confusion about the "Big Bang" How did Tycho calibrate his instruments? 
 
 Gases that fill balloons Asian tradition on the start of winter Why our year starts at January 1 Sticking a hand out of a window... One year of continuous sunlight?Shielding out radio waves The way gravity changes with depth The Sun's Axis "Gravity Particles"? A "short stay on Mars" Weight and mass "The Moon Hoax" Shuttle re-entry from space Energy levels: plus or minus? How can such small targets be accurately hit
so far away? A teacher asks about compiling lesson plans Why the Moon has its phases How can a spacecraft self-rotate? Stability during a rocket launch Boiling point of water in space 
 
 Konstantin Tsiolkovsky 
The Color Indigo 
Electromagnetic Waves and Electromagnetic Induction 
Why do orbits curve? 
The "Sundial Bridge" in Redding 
(a) Temperature in space (b) Exposure to the space environment: Freeze or burn?
 
Remote sensing of Thunderstorms 
What keeps Electrons away from the Atomic Nucleus? 
The Stars on the Winter Solstice of 2012 
Mars Sunset 
Gravity at the Center of Earth 
The Big Bang 
"How Often are Stars Born?" 
The Path of Lightning 
Launching a Rocket from an Airplane 
The Equation of Continuity 
The Four Corners Monument 
Which among the brightest stars is closest to N Pole? 
Gravity Assist 
Is the Centrifugal Force "Real"? 
How do we know Earth is bigger than the Moon? 
Sound Waves on the Sun? 
What if we had to give up use of Satellites? 
Rotation of Venus 
"Proper Motion" of Stars 
Doppler Shift from the Big Bang 
Science Fiction scenario for a Flight to Mars 
Motion of the Moon 
 
 
"Iridium" flares 
Discovering Planets outside the Solar System 
Landing speed of airplane 
The Hubble Constant 
Are Summer Nights Darker? 
"Space Elevator" 
Black Holes 
 
396A Posssibility of Asteroid Hitting Earth (1)Don't use Diesel fuel in a gasoline car! 
How bright is our Sun when seen from space? 
What is a "field"? 
 Outer limits of the Solar System  
Gravitational Energy
Stresses on a Railroad Bridge 
The constellation of Cassiopeia 
Tracking of radioactivity carried by winds 
Why can't the space shuttle reenter "slowly"? 
"The Standard Model of the Universe" 
About the Maya Calendar 
Are light sabers possible? 
Can the heat of sunshine make the Earth expand? 
 
About Mountains 
"Will the World end in 2012?" (a,b)
Advice to graduating High School Student 
Could a (heat resistant!) ship float on the Sun?
Reducing the fuel weight of the Space Shuttle?
How do Rockets Land?
The Earth's Spin reduced by Global Warming
Circumnavigation of the Sun
Are nuclear forces merely gravity at very close distance?
Changing the Earth's Rotation
Why are planetary orbits eccentric?
Forces on Comet-dwellers
Nuclear reactors and bombs
Why doesn't magnetism affect electro-magnetic waves?
Is humanity changing the climate, or is it the Sun and the Earth's magnetism?
Advice to home-schooling parent
Science of Clothing
Calculating a Collision
The Coriolis force and more
Why isn't the solar system stratified by density?
 
Tapping Atmospheric Electricity
Global Disaster in 2012?
What's the difference between speed and velocity?
Effect of Gravity on Electromagnetic Waves 
Why is North the reference, not South?   
The lowest 700 km of our Atmosphere 
Doomsday 2012?
Where does a Flying Bird get its Support?
Why does Sun seem to move?
 Why don't waves disturb each other?
Does the Moon's motion Change?
Big Dipper and Weather
What IS the Ecliptic?
Precession, Greenhouse and more...   
Latest Sunrise, Earliest Sunset
Falling off the Earth's Bottom?
Rolling down a slope
Pelton Wheel Efficiency
Energy loss rate of our Sun
The Sun's distance
Why does sunlight have a continuous spectrum?
 
Harry Paul Sprain's perpetual Motion Device
Can the plasma that fills space help spaceflight?
Spiral arms of our galaxy
What powers a glider? 
UFOs
Maximum speed for propeller-driven airplane?
The speed at which gravity spreads  
Layers of the Earth
Why doesn't the sky fall on us?
Imagine a non-rotating Earth
Flying east with a 1° error
US Flag on the Moon 
Rope stretched across a long lake...
About studying electronics in the USA
Publish Stargazers as a book?
Charging of Earth by lightning:    +   or   –  ?
If no stars were seen--could Earth's orbital motion be discovered?
Local Solar Time in Iceland
Is orbital motion same as free fall?
Build a straight tower in warped space?
 
 
The 2011-2 sunspot maximum
Is Earth adding mass?
Shape of a "bottle rocket"
Fantasy spaceflight vs. reality
Telling a 7-year old about stars "dying"  
(1) Why is lightning jagged?     (2) What did Tesla do?
How can the north wall of my house be in sunlight?
Heating the inside of Earth
Dawning of the Age of Aquarius
Why is hydrogen the fuel of choice?
Gamma ray bursts
Counter-clockwise swirling motion in the atmosphere
Leap years on the Jewish calendar
Earth axis tilt and climate (1)
Earth axis tilt and climate (2)
Does the Sun move?
Can the Sun interfere with the visibility of the Big Dipper?
Why can't we feel the Earth's rotation?
Is our galaxy held together by a central black hole?
Why don't gas planets just evaporate?
Source of the Sun's energy
Point of gravity equilibrium
Solar system motion through the Galaxy 
 Spaceflight by waiting for the Earth to turn?
Does Earth rotation affect size of creatures?
The year 2012
Are our galactic arms winding up or opening up?
 Advice to a home-schooling mother 
 Are all stars we see suns?
 
Newton's 3rd law
Newton's 3rd law
 396B Posssibility of Asteroid Hitting Earth (2)
 
 
Author's IQ
Global Warming caused by Sun getting nearer?
The year 2012
Empty space behind North Star?
The year 2012 and the 26,000 year cycle
"Quarter Squares"
Do Rockets need "something to push against"?
Sunrise-Sunset asymmetry
Re-entry from orbit
Earth Axis and Gravity
The year 2012
Choosing an Aerospace Career
Advice for "new" physics teacher
Paradox of Time Travel
Is 7th grade Earth science boring?
Air Resistance
Experimenting with Microwave Oven
Is the Sun losing mass?
Sun's position at noon, south of equator
Fred Hoyle's theory of the Sun's Corona
Why don't Protons and Electrons combine?
Days in a Year
Position of the Moon in the sky
 
Earth crossing Galactic Equator?
Is the geocentric theory ruled out?
Does the Southern Sky have a Pole Star?
What is the fate of starlight energy?  
Double-slit diffraction of particles 
Does the Sun overhead reduce effective weight?
 Evidence for Global Warming ?  
Distances to the Equator 
Weight on the Equator and at the Pole 
Why doesn't gravity overcome buoyancy? 
The Prime Meridian 
Is L2 in the Earth's Shadow? 
In what direction is Israel from NY?
Is the World Overpopulated?   Magnetic Energy
 
Magnetic Carnot Cycle
Defining the Equator
 
 Go to main list of questions    (by topic)
 
 
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