Why All That Dust?

Have you ever watched, fascinated, as particles of dust danced in a ray of sunlight? Yet that same dust is the bane of housewives and scientists. Just leave a room for a few days and there will be a powder-fine layer of dust awaiting you when you return. Dust can clog a sewing machine, stop a watch, and foul a computer system. Little wonder we tend to think of dust only as a nuisance. And yet, have you ever thought about what we would lose if there were no dust at all?

Dust can also be beneficial. Did you realize that without dust in the atmosphere we would have much less rain and snowfall? Water droplets and ice crystals are formed partly because of dust particles that act as nuclei for the formation of rain and snow.

Without dust, one of the most wonderful sights on earth​—the sunset—​would not be as beautiful. As the sun dips toward the horizon, its light must then travel through the greater thickness of air near the earth. That light strikes particles of dust and other substances in the thicker air and tends to scatter. However, the shorter bluish waves of sunlight tend to scatter or be absorbed by the particles more than the longer reddish waves. Hence, the bluish colors do not reach us as much as the reddish colors. This is what helps to produce the gorgeous orange, pink, and reddish glow of sunsets.

Thus, a little dust around the place is a small price to pay for such a beautiful reward: an awe-inspiring sunset!