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

A brainless, one-celled organism with a knack for getting foodstuff is aiding astronomers review the

A brainless, one-celled organism with a knack for getting foodstuff is aiding astronomers review the major, most mysterious construction in the universe — the cosmic world wide web. But, initial, matters could get a little bit slimy. 

The cosmic world wide web is a vast community of interconnected filaments produced of darkish make any difference and gasoline that types the scaffolding the total universe is developed on. These filaments can extend hundreds of millions of gentle-years, and they hook up galaxies, galaxy clusters and even galaxy superclusters. Even so, due to the fact the cosmic world wide web is amazingly faint — and the darkish make any difference inside of it doesn’t interact with gentle — it’s extremely tough to map.  

To deal with this obstacle, scientists at the College of California, Santa Cruz, sifted via archived knowledge for a lot more than 37,000 galaxies prior to charting their positions in the sky. They then employed a refined algorithm to map out the invisible filaments of gasoline and darkish make any difference in between those people galaxies to figure out how they are interacting with every other, as nicely as how the cosmic world wide web influences star development in these galaxies. 

But this was not your typical algorithm. Rather, the scientists employed a model influenced by slime mould — exclusively, the species Physarum polycephalum.

This algorithm mimics the mold’s foodstuff-in search of conduct, which sends out tendrils of reconnaissance mould to hunt for close by foodstuff. If a unique mould thread stumbles on foodstuff, it thrives, building a strong connection in between the foodstuff and the relaxation of the colony.

So by substituting unique galaxies for the mould-dependent algorithm’s “food,” scientists ended up in a position to generate a 3D map that implies how the galaxy-connecting filaments of the cosmic world wide web are intertwined.

Incidentally, the gasoline in between galaxies also acts as a type of “cosmic food” that fuels star development. And the moment you know how cosmic world wide web filaments are connected to a galaxy, you can hazard a guess at the rate at which the galaxy is — or is not — forming stars. These a prediction is dependent on irrespective of whether or not a galaxy is connected to the cosmic world wide web, as nicely as how tightly certain it is to other galaxies. If it’s connected much too strongly, it operates the possibility of drying up prospects for star development much too loosely, and it just cannot get to plenty of fuel. 


Researchers seeded an algorithm influenced by the foodstuff-in search of conduct of slime mould with the positions of about 37,000 galaxies, exactly where the galaxies served as the “food.” This assisted them model and build a 3D map of the cosmic world wide web connecting these galaxies. Previously mentioned, the galaxies (or foodstuff) are revealed in yellow, even though the cosmic world wide web is revealed in purple. (Credit: NASA/ESA/J. Burchett and O. Elek/UC Santa Cruz)

From Slime to Space

The notion to use a slime-dependent algorithm to map the cosmic world wide web came from co-author Oskar Elek, a UC Santa Cruz computational media submit-doc. He experienced formerly witnessed the do the job of slime mould algorithms, so he urged Joe Burchett — an astronomer at UC Santa Cruz and guide author 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 actually sent me display photographs of the knowledge equipped with this final algorithm,” Burchett suggests. “What I noticed was a trace of the reconstruction of the cosmic world wide web that appealed much, much, much a lot more to my intuitive perception of what the cosmic world wide web ought to look like [when compared with former types].”

This is not the initial time experts have employed slime molds to map a variety of constructions. Slime molds are expert filament builders, setting up sophisticated underground networks that support them search for foodstuff and means. These one-celled organisms do the job as a person significant colony that can be up to 1 foot in diameter. And, oddly, their filamentary constructions show a propensity for what could be explained as problem-fixing.

Slime molds are adept at “shortest path” challenges, such as getting the most effective way to weave via a maze to locate foodstuff hidden inside of. It is been known as “slime mould computing” prior to, and even likened to a rudimentary intelligence — though this definitely will come with its very own subset of thorny questions. 

“For a slime mould, the planet is a mixture of two fields: gradients of attractants [stuff it wishes] 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 mould merely follows the gradients. This is how it calculates, for case in point, the shortest route.”

By tracking how the slime mould algorithm connected independent galaxies, scientists realized exactly where to look for cosmic world wide web filaments in archived observations. “Wherever we noticed a filament in our model,” Burchett reported in a statement, “the Hubble spectra confirmed a gasoline signal, and the signal obtained stronger towards the center of filaments exactly where the gasoline ought to be denser.” This signifies the scientists not only employed the algorithm to successfully pinpoint exactly where threads of the cosmic world wide web ought to be, but also actually locate them.

“For the initial time now, we can quantify the density of the intergalactic medium from the distant outskirts of cosmic world wide web filaments to the incredibly hot, dense interiors of galaxy clusters,” Burchett reported. “These success not only affirm the construction of the cosmic world wide web predicted by cosmological types, they also give us a way to strengthen our knowledge of galaxy evolution by connecting it with the gasoline reservoirs out of which galaxies sort.”

The new research was printed March 10 in The Astrophysical Journal Letters.