As an astronomer, I spend much of my time working in the dark.
That might sound unusual, but in my field, darkness is not something to fear. It is what allows us to see. The faintest stars, distant galaxies, and delicate structures of the universe only become visible when unnecessary light is removed from the equation.
And increasingly, I find myself thinking about that same principle much closer to home.
In our neighbourhoods, towns, and cities, we often assume that more light makes us safer. The idea is deeply embedded in how we design public spaces. Bright streets feel secure. Floodlit areas appear open and visible.
But what if the relationship between light and safety is not that simple?
One of the least understood aspects of lighting is glare. We have all experienced it. A bright light shining directly into our eyes. Headlights on an approaching road. A floodlight mounted too high or too strong.
What we may not realise is that glare does more than cause discomfort. It reduces our ability to see.
When a bright source dominates the field of view, it forces the eye to adapt. The pupil constricts, contrast is reduced, and details beyond the light become harder to distinguish. In some cases, entire sections of a space can fall into shadow, even while the overall environment feels brightly lit.
In other words, a space can be full of light, and still difficult to read.
This matters when we think about safety.
Safe environments depend on clarity. The ability to recognise faces, detect movement, judge distance, and interpret surroundings quickly and confidently. When glare or strong contrast interrupts that ability, visibility is reduced.
In my work, even a small amount of stray light entering a telescope can obscure entire regions of the sky. The information is still there, but it is no longer accessible.
The same principle applies to our streets.
This is not an argument for reducing lighting. It is an argument for using lighting more thoughtfully.
Modern lighting design is shifting away from the idea of simply adding more light. Instead, it focuses on directing light where it is actually needed. Pathways, crossings, entrances. Places where people move, interact, and make decisions.
When lighting is targeted and controlled, it reduces glare, softens harsh contrasts, and improves visibility in a meaningful way.
It also has the added benefit of reducing light pollution, which is steadily brightening our night skies and diminishing our shared experience of the stars.
This is not a choice between safety and the environment.
It is a question of understanding how light works.
The next time you are out at night, take a moment to notice not how bright a space is, but how clearly you can see.
Those two things are not always the same.