Ask the Space Scientist

Conducted by Dr. Sten Odenwald

Additional questions about space can be found at Ask the Astronomer.


Transit of Venus:

  1. Why do transits happen?
  2. How often do they happen?
  3. How many transits have been observed by humans?
  4. What is a Black Drop?
  5. Why were scientists so excited by transits of Venus?
  6. Who discovered the atmosphere of Venus?
  7. What is an Astronomical Unit?
  8. Who observed the first transit?
  9. Why did John Philip Sousa write the Transit of Venus March in 1883?
  10. How long does a transit of Venus last?
  11. Are astronomers still interested in the transit of Venus?
  12. Could ancient Chinese sunspot observers have seen a transit of Venus?
  13. Why did Kepler not know about the 1639 transit?
  14. How was the transit used to determine the distance from Earth to the Sun?



  1. What are the two theories accounting for the surface of Venus?
  2. What is the daytime nighttime temperature variation on Venus?
  3. Why is the atmospheric pressure so high on Venus?
  4. What is the interior of Venus like?
  5. Why doesn't Venus have a magnetic field?
  6. Would you see aurora on Venus?
  7. What does the solar wind do to the atmosphere of Venus?



  1. How old is the Earth?
  2. What is the distance from the Sun to the Earth for each month of the year?
  3. How much energy would it take to explode the Earth?
  4. Why is the Earth tectonically active and not Mars or Venus?
  5. Why are the atmospheres of Venus and Earth so different?
  6. When the Earth's magnetic field reverses, does its rotation also switch?
  7. Is the Earth's magnetic field changing?
  8. Why does the Earth have radiation belts?
  9. Why does the magnetic pole of the Earth flip?
  10. Where is the geomagnetic pole currently located?
  11. How long will the Earth remain habitable?
  12. Do planetary conjunctions have any effect on the Earth?
  13. What is the ionosphere composed of?
  14. Where are the Van Allen radiation belts and are they important to life?



  1. What is the evidence for water on Mars?
  2. What is the typical temperature on Mars?
  3. How long would a trip to Mars take?
  4. If you dropped a dead body on Mars, would it start life there?
  5. Why is Mars red?
  6. Has life existed on Mars before?



  1. How is the solar magnetic field generated?
  2. What is the rate of mass loss by the Sun from the solar wind?
  3. Does water exist on the Sun?
  4. How much mass does the Sun convert to energy each hour?
  5. Is the Sun shrinking in size?
  6. Why are sunspots dark?
  7. Is there a safe, inexpensive way to view Sunspots?
  8. Where can I get the yearly sun spot numbers from 1700 to the present?
  9. How does the solar wind affect the Earth?
  10. How was the Sun formed?
  11. How long does it take light to get out from the inside of the Sun?
  12. What is the composition of the Sun?


Solar System:

  1. What are the atmospheric constituents of the outer planets?
  2. How do astronomers weigh the planets?
  3. How are planetary magnetic fields produced?
  4. Which planet is hottest, Venus or Mercury?
  5. Why are the atmospheres of Venus, Earth and Mars so different?
  6. What are the mean surface temperatures of the planets?
  7. Why don't Mercury and Venus have moons?
  8. How fast does light travel from the Sun to each of the planets?
  9. How was the solar system formed? (Part I)
  10. Why do the planets orbit the Sun in the same plane?
  11. Do all the planets have magnetic poles like the Earth?
  12. When the Sun becomes a red giant star, what will happen to the outer planets and their satellites?
  13. Just how crowded is the asteroid belt?