ET & City Lights

The stars of the Big Dipper (left) and city lights in Baja California, Mexico and the southwest U.S. Image from NASA's The Gateway to Astronaut Photography of Earth

A myriad of city lights illuminate the nighttime side of our home world. We light up our cities and mask the lights of the stars above.  To some this is considered a hallmark of civilization. It was recently proposed that it may it may also be a sign of extraterrestrial civilizations and that it may be possible to detect them by their city lights.

While I hope that our galaxy is home to other intelligences, I would also like to believe that they would be smart enough to have conquered the problem of light pollution.

A truly advanced civilization would not be afraid of the night as many humans are. Extraterrestrials ahead of us in technology would know that the visible suns of the universe are an inspiration that should not be blotted out. They would hopefully give more thought than humans do in how they light their cities (if they even have cities).

On Earth the vast majority of light at night is a waste.  A significant portion of these lights are poorly directed. They shine up and out instead of down where light is needed. Lights illuminate empty streets all night even if they are not in use.

Half of each day is night. Nature depends on night. Humans seem to be trying to change the cycle of day and night even though there is increasing evidence that light at night is not good for our health.


It is time for all of us to be more intelligent about doing a better job in controlling our lights. In the process we will save energy and return the night sky to its natural, star-filled beauty.