Extraterrestrial life may have purple tint

Extraterrestrial life may be purple, not green, as it is firmly rooted in our minds? To such conclusion scientists have come, declaring publicly that the first organisms on Earth could not be green, and lavender shade. Astrobiologists and microbiologists, after a joint study concluded: even long before the green plant have started to use the sun's energy for growth and development, as did tiny purple bacteria.

Also, according to them, alien life could develop in similar ways. Astronomers have recently discovered thousands of new planets outside the Solar system. Our ability to capture the surface of biosignals in the light reflected from these planets, more improved. Thanks to this progress, today there are effective ways to detect green life from space. But now, scientists may also have to track and "purple" signs of life.

The idea that originally the Earth was purple, not new. Scientists have put forward this theory back in 2007. Their thoughts were moving in the following direction: plants and photosynthetic algae use chlorophyll to absorb solar energy, but they can not afford to absorb the green light. It sounds strange since green is the most energy-rich. So maybe, the researchers reasoned that something else was using that part of the spectrum even before the evolution of photosynthesis of chlorophyll.

This "something else" could be the simplest organisms that absorb sunlight, due to retinal molecules. They are not as effective as the chlorophylls in the absorption of solar energy, but their effect is much easier.

Retinal absorption of light and energy is still widespread among bacteria and single-celled organisms called archaea. These organisms are purple hue was discovered everywhere, from oceans to a snow-free valleys of Antarctica, including the surface of each leaf. Retinal pigments are also found in the visual system of more complex organisms. The researchers concluded from this that, perhaps, they evolved very early, and their ancestors were common to many other "branches" of the tree of life.

There is also some evidence that modern-purple-pigmented halophilic micro-organisms that can not live without salt, are associated with the first living beings on Earth. Because life at that time was concentrated around deposits of methane in the ocean.

Regardless of whether the first life on Earth is purple, it is clear that this shade would fit perfectly for some organisms. This means that aliens could develop along the same path. And if they also used the retinal pigments to absorb energy, astrobiologists can find them by searching for specific light signatures. Chlorophyll absorbs mostly red and blue light. But the spectrum reflected from a planet covered with plants, displays what the astrobiologists call the "red barrier of photosynthesis".

This sudden change of light reflection in the near infrared spectrum, where plants absorb longer wave red color, and begin to reflect them. On the other hand, fotosinteticos based on retinal absorption, have a "green barrier". They absorb light from the green part of the spectrum, and then begin to reflect long wave.

Astrobiologists have long intrigued by the possibility of discovery of extraterrestrial life, finding this "red barrier". But now they may have to consider looking for a "green barrier". Who knows – maybe this finding will help to learn more about the aliens?

Translated by «Yandex.Translator»