Billions and billions linked in new telescopic view
Attempts to visualise the size and shape of the universe have boggled even history’s greatest minds, but it is getting easier.
High definition data and rendering can bring the interwoven web of galaxies onto computer screens, and researchers say they are finally learning about the environment and evolutionary processes that hold it all together.
In a new study published in the Astrophysical Journal, a team from the University of California highlights the role of the “cosmic web” - a large-scale web-like structure comprised of whole galaxies.
The web determines the evolution of galaxies, which took place in the distant universe during the first few billion years after the Big Bang.
The distribution of galaxies and matter in the universe is not random.
Galaxies are organised, even today, in a manner resembling an enormous network - the cosmic web.
This web has dense regions made up of galaxy clusters and groups, sparsely populated regions devoid of galaxies, as well as the filaments that link particularly dense regions.
“We think the cosmic web, dominated by dark matter, formed very early in the history of the universe, starting with small initial fluctuations in the primordial universe,” said Behnam Darvish, a PhD graduate student in UC Riverside’s Department of Physics and Astronomy.
“The filaments are like bridges connecting the denser regions in the cosmic web,” Darvish explained.
“Imagine threads woven into the web.”
Astronomers know that galaxies in less dense regions of space have a higher probability of actively forming stars (something our Milky Way does), while galaxies in denser regions form stars at a much lower rate.
“But the role of intermediate environments and, in particular, the role of filaments and the cosmic web in the early universe remained, until very recently, a mystery,” said co-author Professor Bahram Mobasher.
New data and analysis from surveys COSMOS and HiZELS from telescopes like Hubble, VLT, UKIRT and Subaru has shined a light on the detail of the cosmic web.
Astrophysicists have now found that galaxies residing in the cosmic web/filaments have a much higher chance of actively forming stars.
In the distant universe, galaxy evolution seems to have been accelerated in the filaments.
“We were surprised by the crucial role the filaments play in galaxy formation and evolution,” Dr Mobasher said.
“Star formation is enhanced in them. The filaments likely increase the chance of gravitational interaction between galaxies, which, in turn, results in this star-formation enhancement.
“There is evidence in our local universe that this process in filaments also continues to occur at the present time.”
“It is possible that such filaments 'pre-process' galaxies, accelerating their evolution while also funnelling them towards clusters, where they are fully processed by the dense environment of clusters and likely end up as dead galaxies,” Darvish said.
“Our results also show that such enhancement/acceleration is likely due to galaxy-galaxy interactions in the filaments.”
Next, the team plans to extend this study to other epochs in the age of the universe to study the role of the cosmic web/filaments in galaxy formation and evolution across cosmic time.
Below is one of many videos compiled from recent data to give a fly-through experience of the vastness of our cosmic neighbourhood.