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    Incredible Optics Photos

    1. Lunar Halo

    The beautiful circle surrounding the moon in this image is caused by ice crystals suspended in the air. Known as a paraselenic circle, this rare phenomenon comes from moonlight reflecting in complex ways off the crystals. While the circle is commonly only seen in sections, in some cases, such as this one, it can stretch around the entire sky.

    A similar effect can occur on a chilly day with sunlight, forming a giant parhelic circle in the sky.

    Image: Adam Kraft

    2. Lightning Spectra

    In his celebrated 1704 book Opticks, Isaac Newton describes shining a white light through a prism. When the light emerged, the famous physicist was surprised to see it broken into a dazzling rainbow of colors.

    While this and other discoveries from Newton helped revolutionize the field of optics, it wasn’t until the 1800s that scientists understood how much information those rainbows contained. When passed through a prism, the light coming from a hot gas reveals its constituent elements in telltale lines of color.

    In this image, taken during a thunderstorm over Paris, the forking lightning bolt heats surrounding air to between 36,000 and 54,000 degrees Fahrenheit, breaking apart air molecules into ionized plasma. The bright lines of the spectra reveals the presence of nitrogen and hydrogen in our atmosphere.

    Image: Denis Joye