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Light gives plants the energy they need to grow.

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But what happens if plants receive too much light?

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The answer is they glow.

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This neon glow is actually happening around us all the time.

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The result of a cellular process where light from the sun is transformed and released as fluorescent light.

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A journey into the plant cell reveals how it works.

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This is a chloroplast, the energy producing organ found inside the cells of plants.

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When sunlight strikes a plant, disc-like structures within the chloroplast absorb the light and convert it into energy.

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However, a small fraction of this light, about one percent, is emitted as fluorescent light.

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The light exits the plant cell and is released into the atmosphere.

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The amount of light released can vary depending on factors like the time of day, time of year, and how much sunlight is being absorbed.

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Humans can't see this light. Our eyes just aren't that sensitive.

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To see the fluorescent light that's emitted from plants all over the world, we have to use scientific instruments that are placed on satellites.

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Earth observation satellites outfitted with special sensors are able to detect this light from space.

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After multiple orbits, scientists can construct a detailed view of the data.

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This is what plant fluorescence looks like on a global scale.

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The visualization was created from five years of satellite measurements analyzed by a team of researchers led by scientists at NASA's Goddard Space Flight Center.

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Each point of light on this globe represents fluorescent light exiting a plant cell.

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The greater the intensity of light, the brighter the color.

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By observing changes in intensity over time, scientists can distinguish stressed, dead or dormant plants from healthy and growing vegetation.

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Fluorescent measurements like these are important because they can be used to develop improved vegetation models.

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And this will lead to better predictions of how plants will interact with the Earth's environment in a changing climate.

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