Studying Matter In The Universe

Filaments in outer space are called supercluster complexes or great walls. Galaxy filaments are the largest cosmic structures in the universe with lengths extending from 50 to 80 megaparsecs h-1.

These filaments are thread-like structures that form boundaries between large voids in the universe. Astronomers theorize that moments after the Big Bang, a bulk of the matter in the universe condensed into a web of tangled filaments connected to each other at the locations of massive galaxy clusters.

Matter known as ordinary, which makes up everything we know, corresponds to only 5% of the Universe. Approximately half of this percentage still eluded detection. Numerical simulations made it possible to predict that the rest of this ordinary matter should be located in the large-scale structures that form the 'cosmic web' at temperatures between 100,000 and 10 million degrees. A team led by a researcher from the University of Geneva (UNIGE), Switzerland, observed this phenomenon directly. The research shows that the majority of the missing ordinary matter is found in the form of a very hot gas associated with intergalactic filaments. The article reporting this discovery is published in the journal Nature.

The image above is a digital simulation of the large-scale distribution of matter, with filaments and knots.

Kilo-Degree Survey (KiDS) To Study Dark Matter

Using imaging from the European Southern Observatory's VLT Survey Telescope (VST) and its huge camera, the OmegaCAM, the Kilo-Degree Survey (KiDS) aims to study and understand the relationship between dark matter and galaxies.

Astronomers theorize that dark matter which comprises 85% of all matter in the universe is what holds galaxies together. Without dark matter, galaxies would fling themselves apart while they rotate. Dark matter keeps these galaxies together due to the constraining effect of gravity.

The best way to work out where the dark matter lies is through gravitational lensing — the distortion of the Universe's fabric by gravity, which deflects the light coming from distant galaxies far beyond the dark matter. By studying this effect it is possible to map out the places where gravity is strongest, and hence where the matter, including dark matter, resides.

The survey studies the distortion of light emitted from galaxies. This light bends as it passes through massive clumps of dark matter while reaching the Earth. From the gravitational lensing effect, these groups turn out to contain around 30 times more dark than visible matter.

The image above shows a group of galaxies mapped by KiDS. On the right side, the image shows the same area of sky as in the left, but with the invisible dark matter rendered in pink.

Dark Matter Interactions Observed in Galaxy Collision at Abell 3827

While studying the simultaneous collision of four galaxies in the galaxy cluster Abell 3827, the European Southern Observatory's VLT and NASA/ESA's Hubble Space Telescope may have, for the first time, observed dark matter interactions with other dark matter.

The nature of dark matter is still a mystery but it is believed that it comprises 85% of the Universe’s mass; the rest being "normal matter". Without dark matter, galaxies would not be able to hold itself together and would fling themselves apart while they rotate. Dark matter keeps these galaxies together due to the constraining effect of its' gravity.

Researches observed that during the collision, one clump of dark matter appeared to be lagging behind the galaxy it surrounds. The dark matter is currently 5000 light-years behind the galaxy.

Dark matter has always been observed interacting with gravity but the computer simulation of the four galaxy collision at Abell 3827 show that extra friction from the collision would slow down dark matter and that the nature of that interaction is not gravity and still is unknown. It is also uncertain how long it took for the collision to happen.The friction that slowed the dark matter could have been a very weak force acting over about a billion years, or a relatively stronger force acting for “only” 100 million years.

Measuring the Universe To One Percent Accuracy With Baryon Oscillation Spectroscopic Survey (BOSS)

The Baryon Oscillation Spectroscopic Survey (BOSS) Collaboration announced that they have measured the scale of the Universe to an accuracy of one percent, using galaxies more than six billion light years away.

BOSS mapped the locations of 1.2 million galaxies to make the measurements. The new distance measurements were presented at the meeting of the American Astronomical Society by Harvard University astronomer Daniel Eisenstein, the director of the Sloan Digital Sky Survey (SDSS-III).

In the image, the gray spheres show the pattern of the Baryon Acoustic Oscillations (BAO) from the early Universe. Galaxies today have a slight tendency to align on the spheres -- the alignment is greatly exaggerated in this illustration. By comparing the size of the spheres (white line) to the predicted value, astronomers can determine to one-percent accuracy how far away the galaxies are. This concept allowed the scientists to arrive at their measurement of the size of the Universe.

The Baryon Oscillation Spectroscopic Survey is an astronomical survey that measures the rate of expansion of the universe using the spatial distribution of Luminous Red Galaxies (LRG) and quasars. It is one of four components of the Sloan Digital Sky Survey.

SDSS-III is used to cover distant quasars at far reaches of the universe, the distribution of galaxies, the properties of stars in the Milky Way and also subjects such as dark matter and dark energy in the universe. Its instruments can make detailed measurements of 1000 galaxies at a time.

In 2012, BOSS had released their most accurate measurement yet of the distance scale of the universe during the era when dark energy activated.

Massive Galactic Filament of Dark Matter Imaged By Hubble Space Telescope In 3D

Filaments in outer space are called supercluster complexes or great walls. Galaxy filaments are the largest cosmic structures in the universe with lengths extending from 50 to 80 megaparsecs h^-1.

These filaments are thread-like structures that form boundaries between large voids in the universe. Astronomers theorize that moments after the Big Bang, a bulk of the matter in the universe condensed into a web of tangled filaments connected to each other at the locations of massive galaxy clusters.