![]() ![]() It does still all come back to the sun, as a ball of plasma releasing a constant stream of electrically charged particles called the solar wind. © Vitaliy Novikov via Royal Meteorological Society / Natural History Museum Freezing fog is fog that forms when the air temperature is less than 0˚C (32˚F), often depositing rime on surfaces.Īurora. The band between the two arcs, known as Alexander’s band (after Alexander of Aphrodisias, who described it in AD200) is dark, as the light is being bent away from the observer.įog is a suspension of water droplets or ice crystals in the surface layer of the atmosphere, occasionally accompanied by smoke particles, which reduces visibility to less than half a mile. They are formed when light is reflected twice within a raindrop, resulting in a second arc with the colour order reversed. The second bow appears about 10˚ above the primary bow, but fainter and nearly twice as wide. There may still be no pot of gold, but a double rainbow can be doubly rewarding and they’re not that uncommon if you know to look for them. If you’re lucky, there are times you can see two for the price of one. From a plane, the top of a mountain or with a hose in your garden, it is possible to see a full circle. When the sun is higher in the sky, we may see a shallow arc close to the horizon, but being nearer sunrise or sunset gives the best chance of seeing a full tall semi-circle. How much we see of the arc depends on where we are and how high the sun is in the sky. Every observer will see a slightly different angle of refraction, so each rainbow is unique to that person. If the angle is right, some of that light will be reflected off the internal surface of the raindrop, exiting the drop and refracting again, so that ultimately we see the rainbow with the red band on the outside. This is known as refraction - each colour with its different wavelength will bend at slightly different angles so that the light splits into its different component colours. Sunlight is made up of a spectrum of different colours that will slow down and change direction when entering water. © Cammie Czuchnicki via Royal Meteorological Society / Natural History Museum Country Life's Top 100 architects, builders, designers and gardenersĭouble Rainbow. ![]()
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