A third of humanity can't see the Milky Way because of light pollution

Photo courtesy of Randy Halverson @dakotalapse
Photo courtesy of Randy Halverson @dakotalapse

- 99% of people on Earth now live under light polluted skies with 4 out of 5 Americans and roughly one third of the planet are not able to view the Milky Way at all, even under the clearest night.  A group of scientists used a high-resolution satellite from the National Oceanic and Atmospheric Administration (NOAA) to formulate a state of the art detailed global map of light pollution.  Here, you can see the areas that are affected most by artificial lights…

The U.S. is covered by dozens of “major” cities making it nearly impossible for 80% of the population to see the majority of the night sky.  Locally, it is roughly the same percentage…

The Twin Cities show up in the biggest red and white blob, but some open areas, especially near the Lake of the Woods in northern Minnesota have almost pristine viewing of the night sky on a clear evening.  So why does light affect what we see?

Light travels through the atmosphere and gets refracted by molecules in every direction.  That’s why the Sun lights up the whole sky and not just the area around it.  A similar thing happens with city lights.  As the lights turn on, molecules refract them in every direction, giving the atmosphere a glow, and preventing us from seeing the more subtle lights coming from outer space.