These Sea Slugs Can 'Eat' Sunlight—but They're No Astroph...

What’s Happening

Breaking it down: By snatching chloroplasts from algae, animals called sacoglossans produce their own energy through photosynthesis These Sea Slugs Can Eat Sunlight—but Theyre No Astrophage.

Heres How the Project Hail Mary Antagonist Has a Real-Life Analog in Earths Oceans from algae, animals called sacoglossans produce their own energy through photosynthesis Niamh Ordner 7:30 a. Like Astrophage, the solar-radiation-eating microbes in Andy Weir s novel Project Hail Mary , some sea slugs can derive energy from sunlight. (wild, right?)

Illustration / Images via the Florida Museum Invertebrate Zoology Collection and public domain The sea slug is bright green, shaped like a leaf and doing something few animals can: harnessing the power of the sun.

The Details

Certain species of sacoglossan sea slugs can conduct photosynthesis—an exceptionally rare ability in the animal kingdom—earning them the nickname “ crawling leaves . ” They manage this feat from algae and storing them in specialized cells through a process known as “kleptoplasty,” which literally translates to “stealing plastids.

” “The sea slugs are a remarkable example of this [phenomenon], because they’re a multicellular organism—or, in particular, an animal—that’s able to do this,” says Joshua Widhalm , a horticulturist at Purdue University. From robbing algae to feasting on sunlight, this behavior sounds like science fiction.

Why This Matters

In fact, it’s not too far from the premise of Andy Weir’s 2021 novel, Project Hail Mary , and its film adaptation, which will arrive in theaters March 20. In the story, humanity faces the threat of widespread death from Astrophage—alien microbes that are growing on the surface of the sun and feeding on its energy. The presence of Astrophage reduces the sunlight that reaches Earth and risks sending the planet into another ice age.

This could have implications for future research in this area.

The Bottom Line

In reality, nothing quite like Astrophage exists. But these strange sea slugs and other extreme organisms on our planet have real-life versions of their extraordinary traits, suggesting that evolution’s possibilities may be limited only .

Thoughts? Drop them below.