Wisps of glowing space gas reveal the ‘cosmic web’

The ‘cosmic web’ that stretches through the universe and gives birth to new galaxies and black holes is mapped for the first time

  • The network of gas is thought to produce new galaxies when streams cross
  • The ‘cosmic web’ is gigantic and spreads more than 3m light years across
  • Researchers said it presents a new theory of galaxy formation  

Faint glowing wisps of space gas in the universe have given scientists a glimpse of how galaxies could be formed.

The gigantic network of gases, which stretches at least three million light years across and further than the scientists could see, form a ‘cosmic web’.

When these streams of gas cross paths, the researchers believe, dense accumulations of matter form new galaxies and black holes.

Scientists used a simulator to produce a map of how the gas looks, with galaxies scattered throughout it as bright white dots

Cosmological simulations predict that more than 60 per cent of the hydrogen created during the Big Bang is distributed as long filaments. 

And the gases stretch all through the universe.

Scientists had originally thought galaxies formed spontaneously then clustered in certain areas. 

But they now suggest the clusters of matter could exist first – within the gas streams – and then develop into galaxies.

The findings were revealed in a paper by the RIKEN Cluster for Pioneering Research and the University of Tokyo.  

Dr Hideki Umehata said: ‘The presence of such intense radiation suggests very strongly that gas falling along the filaments under the force of gravity triggers the formation of many starbursting galaxies and supermassive black holes, ultimately giving the universe the structure that we see today.

‘Previous observations have shown similar emission from blobs of gas extending beyond galaxies.

‘But now we have been able to clearly show that these filaments stretch to much larger distances, going even beyond the edge of the field that we viewed.

‘This adds credence to the idea that these filaments are actually powering the intense activity that we see in galaxies within large structures assembling in the early universe.’

Using the European Southern Observatory’s Very Large Telescope, Dr Umehata and colleagues detected and mapped the light emitted by hydrogen irradiated by a group of galaxies.

The results show the gas is arranged into long filaments, or strands, providing fuel for intense formation of stars and for the growth of supermassive black holes. 

According to the study published in the journal Science, the detected filaments contained a significant reservoir of gas, which will help to fuel the continued growth of galaxies in this region.

Computer simulations, such as those carried out by Durham’s Institute for Computational Cosmology (ICC), indicate that the cosmic web forms the scaffolding of the cosmos, providing the framework for galaxies and clusters to form and evolve.

Co-author of the research, Professor Michele Fumagalli, at Durham University, said: ‘It is very exciting to clearly see for the first time multiple and extended filaments of gas connecting galaxies in the early universe.

‘We finally have a way to map this cosmic web directly, and to understand in detail its role in regulating the formation of supermassive black holes and galaxies.’

Calvin Sykes, a PhD student in the ICC who contributed to the study, said: ‘These observations represent a very important step in validating our theory of the assembly of galaxies, adding a key piece of the puzzle.’ 

WHAT IS THE COSMIC WEB OF FILAMENTS THAT THE UNIVERSE IS MADE UP OF?

‘Ordinary’ matter, which makes up everything we can see, corresponds to only five per cent of the known universe. The rest is made up of so-called ‘dark matter.’

For decades, at least half of this regular matter had eluded detection, but scientists have in recent years made the first direct observations of a ‘cosmic web’ of filaments spanning between galaxies.

These filaments are made up of gas at temperatures between 100,000°C (180,032 °F) and 10 million°C (50 million°F) and the experts believe these structures may account for the ‘missing’ ordinary matter.

Studies have estimated that around 95 per cent of the universe is made of a mixture of ‘dark matter’ and ‘dark energy’, which only makes its presence felt by its gravitational pull, but has never been seen directly.

What is less widely known, however, is that around half of the regular matter is also missing.

In 2015, a team led by University of Geneva scientist Dominique Eckert claimed that these ‘missing baryons’ – subatomic particles made up of three quarks – were detected because of their X-ray signature in a massive cluster of galaxies known as Abell 2744.

Using the XMM-Newton space telescope, the researchers found matter concentrated into a network of knots and links connected through vast filaments, known as the ‘cosmic web’.

Large-scale galaxy surveys have shown that the distribution of ordinary matter in the universe is not homogeneous.

Instead, under the action of gravity, matter is concentrated into so-called filamentary structures, forming a network of knots and links called the ‘cosmic web’.

The regions experiencing the highest gravitational force collapse and form the knots of the network, such as Abell 2744.

Researchers focused on Abell 2744 – a massive cluster of galaxies with a complex distribution of dark and luminous matter at its centre – to make their finding.

Comparable to neural networks, these knots then connect to one another through filaments, where the researchers identified the presence of gas, and consequently, the missing ordinary matter thought to make up the universe.

Source: Read Full Article