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.

Studying How Galaxy Collisions Affect Star Production

The International Centre for Radio Astronomy Research (ICRAR) is studying the relationship between colliding galaxies and star formation.

Looking beyond the common belief, that star production is faster when two galaxies collide, scientists at ICRAR believe that this is only true if the two galaxies are of similar mass. They theorize that if one galaxy is more massive than the other, the smaller of the galaxies generate less stars while the other has an increase production of it.

They explain that the reason for the unequal production of stars from two galaxies of different mass is because the bigger galaxy strips away its smaller galaxy's gas from its gas clouds which is a primary component for star production.

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.

Galaxy Eater NGC 1316 in the Fornax Constellation Captured By ESO Telescope

In the Fornax constellation, there are two galaxies that are close to one another; NGC 1316 and NGC 1317. These two are quite close to one another but have two opposing histories. NGC 1317 has a quiet and silent past while NGC 1316 is a turbulent one.

NGC 1316 which is about 60 million light years away from Earth, has shown signs that is has eaten up and swallowed other galaxies in the past and may be still doing it up to now. Faint dust trails and tidal tails left over from its feast surround the galaxy giving evidence of its violent background.

The image captured by the European Southern Observatory's MPG/ESO 2.2-metre telescope shows the two galaxies in close proximity to each other. The small spiral NGC 1317 has led an uneventful life, but NGC 1316 has engulfed several other galaxies in its violent history and shows the battle scars.

Solving the Mystery of the Formation of Supermassive Galaxies (SMG)

Three billion years after the Big Bang, super massive galaxies (SMG) formed which is a mystery to scientists since most massive galaxies took most of the history of the universe to take shape.

These old galaxies are no longer forming new stars. But the stars inside these galaxies are compacted in a very small area making the size of these SMGs around three times smaller than similar mass galaxies today. They also are not flattened like current spiral galaxies with a center but they are elliptical.

Researchers from the Niels Bohr Institute believe that they might have solved this mystery. They explain that these massive galaxies were formed by colliding galaxies that initiated star formation a few billion years after the Big Bang.

1 to 2 billion years after the Big Bang, they theorize that gas from early galaxies where driven into the center of the galaxy system which ignited to form new stars in the center making it compact. And because of the number of stars formed so quickly, the gas needed to form new stars are used up making it a dead galaxy.

In the image above, an extremely compact dead galaxy is compared to the size of the Milky Way. The two have about the same amounts of stars, which meant that the density of stars in the compact galaxies is more that 10 times higher than the stars in the Milky way.

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.