‘Slime Mold’ Helps Astronomers Map the Universe’s Dark Matter

A brainless, one-celled organism with a knack for obtaining foods is helping astronomers review the

A brainless, one-celled organism with a knack for obtaining foods is helping astronomers review the premier, most mysterious construction in the universe — the cosmic world wide web. But, initially, matters could get a little bit slimy. 

The cosmic world wide web is a large community of interconnected filaments designed of dark subject and gasoline that varieties the scaffolding the total universe is developed on. These filaments can extend hundreds of hundreds of thousands of light-many years, and they join galaxies, galaxy clusters and even galaxy superclusters. Nonetheless, because the cosmic world wide web is extremely faint — and the dark subject within just it does not interact with light — it’s very challenging to map.  

To tackle this problem, researchers at the College of California, Santa Cruz, sifted by way of archived facts for extra than 37,000 galaxies ahead of charting their positions in the sky. They then utilized a complex algorithm to map out the invisible filaments of gasoline and dark subject involving people galaxies to figure out how they are interacting with each individual other, as effectively as how the cosmic world wide web influences star development in these galaxies. 

But this wasn’t your ordinary algorithm. Instead, the researchers utilized a design influenced by slime mildew — specifically, the species Physarum polycephalum.

This algorithm mimics the mold’s foods-looking for habits, which sends out tendrils of reconnaissance mildew to hunt for close by foods. If a unique mildew thread stumbles on foods, it thrives, generating a strong link involving the foods and the rest of the colony.

So by substituting individual galaxies for the mildew-primarily based algorithm’s “food,” researchers ended up equipped to make a 3D map that signifies how the galaxy-connecting filaments of the cosmic world wide web are intertwined.

Incidentally, the gasoline involving galaxies also acts as a type of “cosmic food” that fuels star development. And at the time you know how cosmic world wide web filaments are related to a galaxy, you can hazard a guess at the rate at which the galaxy is — or isn’t — forming stars. These a prediction is primarily based on no matter whether or not a galaxy is related to the cosmic world wide web, as effectively as how tightly sure it is to other galaxies. If it’s related far too strongly, it runs the threat of drying up possibilities for star development far too loosely, and it cannot get to ample fuel. 


Scientists seeded an algorithm influenced by the foods-looking for habits of slime mildew with the positions of about 37,000 galaxies, exactly where the galaxies served as the “food.” This served them design and produce a 3D map of the cosmic world wide web connecting these galaxies. Higher than, the galaxies (or foods) are demonstrated in yellow, when the cosmic world wide web is demonstrated in purple. (Credit rating: NASA/ESA/J. Burchett and O. Elek/UC Santa Cruz)

From Slime to Place

The idea to use a slime-primarily based algorithm to map the cosmic world wide web arrived from co-creator Oskar Elek, a UC Santa Cruz computational media submit-doc. He experienced previously noticed the do the job of slime mildew algorithms, so he urged Joe Burchett — an astronomer at UC Santa Cruz and direct creator of the new paper — to apply it to his do the job on the cosmic world wide web, whose construction continues to be elusive.

“He truly sent me display pictures of the facts equipped with this remaining algorithm,” Burchett says. “What I noticed was a trace of the reconstruction of the cosmic world wide web that appealed considerably, considerably, considerably extra to my intuitive perception of what the cosmic world wide web need to look like [compared with preceding products].”

This isn’t the initially time researchers have utilized slime molds to map many constructions. Slime molds are professional filament builders, setting up elaborate underground networks that support them look for for foods and resources. These one-celled organisms do the job as just one big colony that can be up to one foot in diameter. And, oddly, their filamentary constructions demonstrate a propensity for what could be explained as dilemma-solving.

Slime molds are adept at “shortest path” issues, this sort of as obtaining the greatest way to weave by way of a maze to locate foods concealed within just. It’s been named “slime mildew computing” ahead of, and even likened to a rudimentary intelligence — while this of course arrives with its very own subset of thorny queries. 

“For a slime mildew, the globe is a blend of two fields: gradients of attractants [stuff it needs] and gradients of repellents [stuff it avoids],” Andrew Adamatzky, a professor in unconventional computing at the College of West England, wrote in an e-mail. “The slime mildew merely follows the gradients. This is how it calculates, for instance, the shortest route.”

By monitoring how the slime mildew algorithm related independent galaxies, researchers knew exactly where to look for cosmic world wide web filaments in archived observations. “Wherever we noticed a filament in our design,” Burchett explained in a assertion, “the Hubble spectra confirmed a gasoline signal, and the signal obtained more robust towards the middle of filaments exactly where the gasoline need to be denser.” This suggests the researchers not only utilized the algorithm to effectively pinpoint exactly where threads of the cosmic world wide web need to be, but also truly come across them.

“For the initially time now, we can quantify the density of the intergalactic medium from the remote outskirts of cosmic world wide web filaments to the sizzling, dense interiors of galaxy clusters,” Burchett explained. “These final results not only affirm the construction of the cosmic world wide web predicted by cosmological products, they also give us a way to increase our comprehension of galaxy evolution by connecting it with the gasoline reservoirs out of which galaxies kind.”

The new investigation was published March ten in The Astrophysical Journal Letters.