Windows of Astronomy

The naked eye

What can you do with the naked eye?  When it comes to the stars and planets, not a lot.  The eye can observe the stars twinkling, a bit like the flames in a fire seen from afar.  It’s natural to infer something is burning and, feeling no heat, that they are a long way away.  They are far away but they are not burning, as we now know.  Indeed, would that we could reproduce on Earth their means of generating energy continuously.  The Sun, Moon and five ‘stars’ move relative to the rest, so they are probably nearer.  The Sun certainly influences the Earth on a daily basis; the other wanderers were assumed to as well.  Another wrong assumption, except for the Moon, but that not in the way imagined before the 17th century.  The pattern of the wanderers against the backdrop of ‘fixed stars’ could be measured approximately, the time for the wanderers to go around the sky determined.  This much astronomy was pretty well only a handmaiden to astrology.  Eclipses were seen intermittently, interrupting the daily regularity.  It's easy to see that the stars are not equally bright and a sharp eye notices that a few change their brightness but such detail was seldom mentioned.  The fixed stars provided some assistance with navigation but only as a consequence of their positions and visibility. To make matters even worse, we live at the bottom of a deep ocean of air that distorts starlight, bends it, absorbs some of it and for half the time so dazzles us with scattered sunlight that we can't see either stars or planets.

In truth, our ancestors learnt almost nothing about the stars from naked eye observation beyond the fact that they existed and the Earth was not alone.  They wove mythological stories around the patterns of stars in the sky; they imagined that deities with power over us lived in the heavens; they told creation myths for the world.  There aren’t too many options for creation myths.  Hindu cosmology involves circles of time with no beginning and no end.  This is a natural extrapolation from the cycle of days, years and the life and death of generations.  Most cosmologies seem to start with darkness or chaos before one or more deities introduce light and order.  Not a shred of observational evidence supported any of the beliefs.  This is not to say our ancestors were naive or had any choice.  Had I lived in naked eye times I would no doubt have chanted the chants, praised the deities and repeated the myths.  There were often serious consequences for not doing so.  There wasn’t much more that could be done when it came to trying to understand the universe at large.

Observing Mercury

Looking at Mercury.  Image by Sophie Desrosiers

John S. Reid WindowsTelescopes


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