A key to interpreting the NASA plaque

Key to NASA plaque

  1. representation of hydrogen atom, most common element in the universe
  2. binary representation of the number 1, for hydrogen
  3. lines indicate the height of the woman,
  4. binary representation of the number 8, allowing calculation of the height of the women, 8 x 21 (the wavelength of hydrogen) = 168 cm.
  5. the sun (at the center of the radial pattern, indicating the sun's position relative to the center of the galaxy), with 14 lines radiating out, each with the binary representation of the wavelengths of 14 pulsars in the galaxy; the wavelengths are variable, and a calculation could allow extraterrestrials to determine when the Pioneer was launched; the differing line lengths indicate the relative distance of the pulsars to the sun.
  6. the longest of the 15 lines radiating from the center of the galaxy, extending behind the figures, represents the relative distance of the sun from the center of the galaxy
  7. schematic drawing the sun and the solar system, showing the trajectory of the Pioneer craft (actually, while Pioneer 11 carried the same plaque as Pioneer 10, its course was a bit different). The binary numbers beneath each planet allow the calculation of its distance from the sun.
  8. the silhouette of the spacecraft is drawn to the scale of the human figures, allowing aliens to calculate the size of a man and a woman
  9. the man's hand is raised in a gesture of peace; aliens may deduce the function of the opposable thumb.
  10. the woman is smaller than the man, with a more modest depiction of the genitalia, and she is positioned slightly behind the man. Apparently the astronomer Carl Sagan, who made the original sketch for the plaque, had the couple holding hands, but then changed the drawing because he thought extraterrestrials might think it represented a single creature, not two.
  11. the spacecraft is not drawn to scale here
  12. Pluto is no longer considered a planet. Could this pose a problem for interpretation?

But even if extraterrestrials could figure out the meanings of 1 - 12, they could still not understand the meaning of the plaque? What other obstacles to interpretation can you find?