Purple Planets Could Be The Signs of Alien Life We've Been Looking For [View all]

21 April 2024
By MICHELLE STARR

In the search for extraterrestrial life, scientists already know that we might be looking for a world that's very different from Earth's verdant, plant-dominated biosphere.

Exactly how different is hard to know, but our own planet can still offer us some clues. There are, for example, organisms that can live in environments very inhospitable to most other life on Earth.

But what would an alien equivalent of plant life look like?

Well, life here on Earth offers another possibility for that, too. While a significant proportion of producers here contain green-hued chlorophyll for survival, photosynthetic bacteria that thrive in low-light conditions tend to be colored purple to make the most of infrared radiation.

"Purple bacteria can thrive under a wide range of conditions, making it one of the primary contenders for life that could dominate a variety of worlds," says astrobiologist Lígia Fonseca Coelho of Cornell University's Carl Sagan Institute.

. . .