When was the last time you saw the Milky Way?

For thousands of years, the chance to look up at a cloudless night sky and witness the constellations belonged to the entire human race.

Then, fewer than a hundred years ago, that changed. The Milky Way, once visible every clear night, has now given way to a murky orange haze. But the effects of light pollution go beyond the aesthetic: light that is needlessly spilled into the sky every night causes hazards for our wildlife, crime prevention and our own biorhythms.

Light pollution can pose serious problems for the environment. Large buildings lit up at night can disorient migrating birds, leading to massive collisions that kill entire flocks at a time. The instincts of newly-hatched sea turtles compel them to travel toward the brightest horizon they see, which leads turtles hatched on developed coasts towards luxury hotels and starvation.

Not even plants are safe: the exposure of trees to persistent light can affect their ability to adapt to changing light conditions as seasons pass. This can shorten the lifespan of the tree — potentially grim news for our own Oak Grove.

Excessive artificial lighting has consequences for human health as well. Human circadian cycles (our “biological clocks”) aren’t adapted to the half-light of modern night.

Over millions of years, humans adapted to sleep during periods of darkness. The production of melatonin, a hormone produced by the pineal gland, commonly marketed in pill form as a sleeping aid, is triggered by these nightly periods and suppressed by exposure to artificial light. Reduced levels of melatonin are associated with higher risks for insomnia, depression, PMS and neurodegenerative disorders like Alzheimer’s.

For those of you who are worried about crime prevention, poorly designed lights are not effective for reducing crime.

In a study conducted by the Department of Justice, increased lighting was found to have no correlation with a decrease in criminal activity.

Counterintuitively, carelessly placed lights can actually dazzle natural night vision and cast starker shadows, leading to an increase in opportunities for criminals lying in wait.

Unlike most environmental issues, light pollution is easy to solve: just turn out the lights.

The characteristic “sky glow” of light pollution is generally produced by streetlights that fail to focus light where it’s needed, like the ground.

Consider the design of the orange streetlights that flank Beall Avenue: the entire bulb is translucent, top and bottom, so roughly half of each lamp’s output is shooting directly into the sky, 24/7.

Even if you don’t care about the environment, using inefficient lights isn’t cost effective. A simple reflective housing on top of each bulb to focus light downward would dramatically improve the efficacy of these lights and reduce light pollution. The lamps outside the north entrance to Gault Library are a good start.

In addition to the harm caused to our environment, light pollution also poses a risk for posterity.

Imagine how the sky must have looked like to everyone born before the Industrial Revolution. That sky was an enduring source of inspiration for millennia. Millions of children born today may never see the Milky Way where they live, and many families lack the resources to travel long distances just to see the stars.

The right to see the night sky should be a birthright to all human beings, not just those who can afford it.