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Colourful Skies

Thomas Hough, Sunday October 24, 2021 - 12:02 AEDT

For many in Australia clear blue skies are a common sight, but why is it that we see it this colour, and why is it different during sunrise and sunset.

Earth's atmosphere contains air molecules and many types of particles, including ash, dust and ice crystals. As sunlight travels through the atmosphere it is scattered in all directions by these molecules and particles.

Air molecules are smaller than the wavelengths of visible light and are therefore more effective at scattering shorter wavelengths than longer wavelengths. It is important to note here that the human eye sees shorter wavelengths as greens, violets and blues, with longer wavelengths seen as yellows, oranges and reds. Therefore, when we are looking up at the sky, away from direct sunlight, blue light hits our eyes from all directions, making the sky appear blue.

At sunset and sunrise, when the sun is closer to the horizon, sunlight has to pass through more of the atmosphere before reaching our eyes. Scattering of light removes shorter wavelengths, leaving the longer wavelengths of yellow, orange and red to reach our eyes.

- Weatherzone

© Weatherzone 2021

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A very wet weekend for southeast Qld, northeast NSW

11:48 AEST A prolonged rainfall event is set to bring large totals to parts of NSW and Qld from Saturday, with possible heavy falls and flooding. A low-pressure system in the Coral Sea, a deepening coastal trough and persistent easterlies will bring moisture-laden air into southeast Qld and northeast NSW will bring days of rainfall to the region. While there is not a drop of rain on the radar over southeast Qld and Northeast NSW on Friday morning, the mass of cloud associated with a low in the Coral Sea will enhance rainfall over the weekend.