NASA's James Webb telescope discovers the earliest strand of a mysterious 'cosmic web' that links galaxies

• JWST spotted ten galaxies connected by an invisible cosmic filament.
• The filament, which is millions of light years long, is the earliest ever seen.

NASA's James Webb Telescope has spotted a string of ancient galaxies connected by a cosmic filament dating back to the early days of the universe.

This is the earliest filament ever seen of the so-called "cosmic web," a mysterious network that connects the galaxies in our universe.

The filament is thought to be about three million light-years long. That is billions of times the distance from Earth to Mars.

Its discovery could shed light on how our universe formed and the invisible strings that hold it together.

"I was surprised by how long and how narrow this filament is," said Xiaohui Fan of the University of Arizona and a member of the ASPIRE consortium of researchers who made the discovery, in a press release about the finding.

"I expected to find something, but I didn't expect such a long, distinctly thin structure."

Galaxies are connected by a cosmic web

Looking at pictures of the universe, it could be tempting to think that galaxies appear randomly out of nothing.

But over the past 20 years, research has uncovered the universe is built on a sort of scaffolding, a series of filaments and clumps invisible to the naked eye.

In these clumps, dark matter and regular matter become very dense, creating the perfect conditions for the birth of stars and galaxies.

Between these clumps and filaments are "very low-density regions of the universe where there are very few galaxies and less matter," Niall Jeffrey, a cosmologist at University College London, previously told the Guardian.

Peering back into the early stages of the universe can give us a sense of how galaxies appeared within this mysterious network.

Earliest filament ever seen

The filament appeared about 830 million years after the Big Bang, very early on considering the universe is about 13 billion years old.

While the filament itself is invisible, it's possible to see how it brings galaxies together. It goes through ten galaxies that appear as tiny red dots on the picture, meaning their light comes from the earliest recesses of the universe.

A close-up of three of these galaxies is shown below.

A quasar, a luminous supermassive black hole, is thought to be anchoring the filament, researchers said. It is highlighted by the red arrow in the picture above.

The team believes that eventually the galaxies will be pulled together into a cluster, much like the nearby Coma galaxy cluster.

The ASPIRE team hopes the picture will shed more light on the cosmic web, but it is also very interested in how early quasars were formed in the universe's infancy.

"The last two decades of cosmology research have given us a robust understanding of how the cosmic web forms and evolves," said team member Joseph Hennawi of the University of California, Santa Barbara, in the press release.

"ASPIRE aims to understand how to embed the emergence of the earliest massive black holes into our current story of cosmic structure formation," he said.