Cosmologists from Durham University, publishing their results in the prestigious international academic journal, Science, suggest that the formation of the first stars depends crucially on the nature of ‘dark matter’, the strange material that makes up most of the mass in the universe.
The discovery takes scientists a step further to determining the nature of dark matter, which remains a mystery since it was first discovered more than 70 years ago. It also suggests that some of the very first stars that ever formed can still be found in the Milky Way galaxy today.
Early structure formation in the Universe involves interaction between elusive particles known as ‘dark matter’. Even though little is known about their nature, evidence for the presence of dark matter is overwhelming, from observations of galaxies, to clusters of galaxies, to the Universe as a whole.
After the Big Bang, the universe was mostly ‘smooth’, with just small ripples in the matter density. These ripples grew larger due to the gravitational forces acting on the dark matter particles contained in them. Eventually, gas was pulled into the forming structures, leading to the formation of the very first stars, about 100 million years after the Big Bang.
For their research, the team from Durham University’s Institute for Computational Cosmology carried out sophisticated computer simulations of the formation of these early stars with accepted scientific models of so-called ‘cold’ as well as ‘warm’ dark matter.
The computer model found that for slow moving ‘cold dark matter’ particles, the first stars formed in isolation, with just a single, larger mass star forming per developing spherical dark matter concentration.
In contrast, for faster-moving ‘warm dark matter’, a large number of stars of differing sizes formed at the same time in a big burst of star formation. The bursts occurred in long and thin filaments.
One of the researchers, Dr Liang Gao, who receives funding from the UK’s Science and Technologies Facilities Council, said: “These filaments would have been around 9000 light years long, which is about a quarter of the size of the Milky Way galaxy today. The very luminous star burst would have lit-up the dark universe in spectacular fashion.”
Stars forming in the cold dark matter are massive. The larger a star is, the shorter its life span, so these larger mass stars would not have survived until today. However the warm dark matter model predicts the formation of low mass stars as well as larger ones and the scientists say the low mass stars would survive until today.
The research paves the way for observational studies which could bring scientists closer to finding out more about the nature of dark matter. Co-researcher, Dr Tom Theuns, said: “A key question that astronomers often ask is ‘where are the descendants of the first stars today"’ The answer is that, if the dark matter is warm, some of these primordial stars should be lurking around our galaxy.”
The Durham University scientists also give new insights into the way that black holes could be formed. Most galaxies harbour in their centres monster black holes, some with masses more than a billion times the mass of the sun.
The team hypothesises that collisions between stars in the dense filament in the warm dark matter scenario lead to the formation of the seeds for such black holes.
Dr Theuns added: “Our results raise the exciting prospect of learning about the nature of dark matter from studying the oldest stars. Another tell-tale sign could be the gigantic black holes that live in centres of galaxies like the Milky Way. They could have formed during the collapse of the first filaments in a universe dominated by warm dark matter.”
The importance of biodiversity in forests could increase due to climate change
17.11.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig
Win-win strategies for climate and food security
02.10.2017 | International Institute for Applied Systems Analysis (IIASA)
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses