When NASA got criticism for drawing this to depict humans:
The year was 1972 and NASA were preparing to launch the Pioneer 10 spacecraft to a mission to Jupiter. Carl Sagan (The Great) lobbied NASA to include a tiny 6 by 9 inch gold-coated aluminium plate (or aluminum, whichever side of the pond you’re from) on the craft in case it was ever found by an intelligent life-form from another planetary system.
Trouble began when NASA published the final image in different newspapers at the time. Some of the newspapers even censored the image. Numerous letters from angry prudes claimed that the images were obscene. The American media “viewed the nudity as pornographic”.
All that for a tiny image that was supposed to be hurled into space never to be seen by anybody again!! There is literally more porno in a school biology textbook! Perhaps we should have sent the images that really do depict modern humans.
What the symbols on the Pioneer plaque actually mean
For a clear reference, lets use this enhanced version of the same image.
The two circles at the top left of the plaque represents the two lowest states of the Hydrogen atom, the vertical lines with dots represent the spin of protons and electrons. The tiny vertical line in the center indicates 1 binary digit. Apart from indicating the transition period of the atom from one state to another, the binary unit was used as the basic length and time reference for the plaque drawings.
Ignore the rectangle on the right, this symbol represent the Sun’s location using 14 known directional pulsars. the binary codes along each pulsar represents the frequency for each of their electromagnetic pulse.
This image is that of the Pioneer 10 spacecraft behind the man and woman. This was drawn to scale so that the aliens can deduce the size of humans from the spacecraft they just found. Also, on the right is a binary code scale on the height of the woman.
And finally, the image found on the bottom of the plaque is a map of the solar system showing the origin of the spacecraft and its trajectory. Again, there are binary codes on each planet which symbolizes its distance from the Sun.