Purple planets might have aliens?

By Casey Frye, CCNN Writer

purple planet
Imagine how beautiful a purple planet would look.

Astrobiologists, who study the origin, evolution, and future of life in the universe, are keeping an eye out for purple planets. Why? Because when microbial life first appeared on Earth, our planet would have looked purple from outer space!

Back during the Archean era, which was roughly three billion years ago, one of the most common forms of life was purple bacteria. These microorganisms (tiny living beings) thrived in both land and water environments. Recently, a team of astrobiologists ran some light and reflection experiments to simulate what Earth would have looked like back in ancient times, especially if purple bacteria was spread across oceans and continents.  It turns out that our planet would have indeed blazed with a grape-like glow.

So now, scientists just might be searching not for little green men, but purple ones! Lisa Kaltenegger of the Max Planck Institute for Astronomy in Heidelberg, Germany, will be using multi-color photometric (light-measuring) techniques to search for planets that are similar to an Archean Earth.  This same method could also be used to find planets that have modern Earth-like conditions, like plants and deserts. In 2018, with the launch of the James Webb Space Telescope, the hunt for Earth-colored planets can pick up some serious momentum.

Image of purple planets courtesy of Burning-Liquid on deviantART.