26/07/2026
A SUNSET, A FAMILY HOLIDAY AND 1,000 YEARS OF SCIENCE
One evening during our family holiday in Kuşadası, we stopped to look out across the Aegean Sea.
The Sun had disappeared below the horizon, but it seemed to have left its colours behind. A deep red band stretched across the sea, fading slowly into orange, pink, purple and finally the dark blue of the evening sky. The palm trees had become silhouettes, and the whole scene looked almost like a painting.
Everyone was admiring the view—but the scientist in me started asking:
“Why has the sky turned red?”
Sunlight looks white, but it contains all the colours of the rainbow. At sunset, the light must travel through a much greater distance of Earth’s atmosphere before it reaches us.
And the air is not empty. It contains tiny gas molecules, dust, sea salt and other particles.
As sunlight travels through this enormous atmospheric obstacle course, the shorter blue and violet light waves are scattered very easily. They bounce away in different directions. The longer red and orange waves are scattered less, so more of them continue towards our eyes.
That is why the horizon glows red.
The different colours form a smooth gradation because light coming from different parts of the sky has travelled through different amounts of atmosphere. Near the horizon, the journey is longest, producing the deepest reds. Higher in the sky, the journey is shorter, so we gradually see pink, purple and blue.
Standing there in Kuşadası, I found myself thinking about Ibn al-Haytham, the Muslim scientist who studied light around 1,000 years ago.
He did not have our modern cameras or laboratory equipment. Instead, he observed carefully, designed experiments and tested ideas about light, vision, shadows, reflection and refraction. His work helped lay the foundations of experimental optics.
Around 300 years later, another Muslim scientist, Kamal al-Din al-Farisi, continued this journey. He used a water-filled glass sphere as a model of a giant raindrop to investigate how sunlight bends and reflects to produce a rainbow.
Later, scientists including Francesco Maria Grimaldi and Lord Rayleigh helped us understand diffraction and atmospheric scattering in greater detail.
As I looked at the sunset, I realised that I was watching the same light that scientists had been questioning and investigating for centuries.
That is what I love about science.
It does not exist only inside laboratories or textbooks. It is present while we are travelling, walking beside the sea or simply enjoying a family holiday.
Sometimes the entire sky becomes the experiment.
We only need to stop, look and ask:
“Why does that happen?”
🌅🔬
—Saif
