– a virtual travel experience

Purple Earth

The Earth’s signature color is and has been, for millions of years, green. However, if you step back roughly 2.4 billion years, our World may have been just as purple as it is green today. This was due to a purple-tinged molecule called retinal. Prior to the Great Oxygenation Event, as a result of the rise in chlorophyll-based photosynthesis, ancient microbes used a molecule, other than chlorophyll, to harness the sun’s rays,  giving the organisms a violet hue. Retinal pigments absorb green and yellow light and reflect red and blue light, which means that whichever organisms are dependent on retinal will appear purple. Researchers have dubbed this period ‘Purple Earth’.

Retinal, found in the plum-colored membrane

of a photosynthetic microbe called halobacteria, absorbs green light and reflects back red and violet light, the combination of which appears purple. This idea may explain why, even though the sun transmits most of its energy in the green part of the visible spectrum, chlorophyll absorbs mainly blue and red wavelengths.

Chlorophyll, a key part of photosynthesis,

is used in the process of turning sunlight, carbon dioxide, and water into energy; in the form of sugar for plants. Although chlorophyll dominates today, that doesn’t mean retinal is completely gone. Retinal-based phototropic metabolisms are still prevalent throughout the world, especially in the oceans, and represent one of the most important bioenergetic processes on Earth. So although the sea has the purple hues, our land masses are teeming with gorgeous green forests, fields, and plants.

Imagine stepping back in time

and seeing our Earth through purple-coloured glasses.

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