For decades, dark matter and its nature and location have remained elusive to cosmologists. Recently, a team of astronomers conducted a study to locate the mysterious substance, but the results show that there is not as much dark matter as previously theorized.

“Our calculations show that it should have shown up very clearly in our measurements. But it was just not there!” Christian Moni Bidin of the Astronomy Department at la Universidad de Concepción in Chile says in the European Southern Observatory (ESO) press release. Moni Bidin also headed the study and was the lead author of the team research paper, published in The Astrophysical Journal.

Dark matter is impossible to be seen or detected. It constitutes 74% of the mass in the Universe. How it is distributed around the Universe is unknown. Astronomers believe that dark matter is what causes and exerts the gravitational force around objects made of normal matter (i.e. everything that is not dark matter or dark energy), such as planets, stars, and galaxies.

In the past, astronomers considered that one certain location of dark matter would be around galaxies: a model known as the Standard Halo Model demonstrates how galaxies form and evolve. This model also states that they rotate as quickly as they do due to dark matter, which is thought to collect around the galaxies as a halo.

Working with the 2.2-meter MPG/ESO telescope at ESO’s La Silla Observatory in Chile, the team produced a model in hopes of finding the amount, mass, density, and distribution of dark matter around the Sun (the nearest best bet for finding the substance) and our very own galaxy (the Milky Way). Utilizing a hypothesized amount of dark matter based on a past model, they measured the motions of hundreds of stars (sometimes created from the influence of dark matter) as far as 13,000 light-years away from the Sun.

But what the team observed was a lack of dark matter instead; the conjectured density was significantly lower. “The mystery of dark matter has just become even more mysterious,” Moni Bidin states.

He and his colleagues will further investigate and analyze their results. According to their paper, if matters are consistent, the distribution of dark matter would have to

“reconcile the results with the DM paradigm. The interpretation of these results is thus not straightforward. We believe that they require further investigation and analysis, both on the observational and the theoretical side, to solve the problems they present.”

“Despite the new results,” Moni Bidin continues, “the Milky Way certainly rotates much faster than the visible matter alone can account for. So, if dark matter is not present where we expected it, a new solution for the missing mass problem must be found.”

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Using BOSS (Baryon Oscillation Spectroscopic Survey), a component of the third Sloan Digital Sky Survey from the Lawrence Berkeley National Laboratory in California, scientists have produced the most accurate measurements of when dark energy arose and caused the universe to accelerate its expansion.

Martin White, of Berkeley Lab’s Physics Division states in the press release, “BOSS’s first major cosmological results establish the accurate three-dimensional positions of 327,349 massive galaxies across 3,275 square degrees of the sky, reaching as far back as redshift 0.7 – the largest sample of the universe ever surveyed at this high density.” White is a professor of physics and astronomy at the University of California at Berkeley, and chair of the BOSS science survey teams.

The notion that the universe is expanding came about in the 1920s, when American astronomer Edwin Hubble discovered that all of the galaxies whose light shift he measured had produced a red shift– they were moving away from the Earth. The universe is continuously accelerating in its expansion.

Accelerated expansion was announced only fourteen years ago. Astronomers believe that a mysterious force called dark energy is the cause of this accelerated expansion, which is believed to have first occurred seven billion years ago. Presently, dark energy makes up nearly 75% of the universe’s total mass and energy.

Since the proposal of dark energy, the idea of it and when it came about precisely remained elusive. But just last week, the group of scientists at Berkley created the most precise map of dark energy, which looks billions of years into the past.

In order to create a map of dark energy, and to determine when dark energy caused the universe to suddenly accelerate expansion, the team of scientists working with BOSS produced precise measurements of the distances between each of the hundreds of thousands of galaxies, while also analyzing the galaxies’ red shifts, which allowed them to calculate the rate of expansion. To determine the distances, BOSS used a technique known as baryon acoustic oscillation.

Baryon acoustic oscillation occurs when baryons (i.e. “ordinary” matter) cluster due to the pressure of sound waves that moved through the universe when the universe was still very young (not even 400,000 years old) and hot and having varied densities because of the mixture of light and matter.

The universe has not always been expanding; rather, the expansion has been slowing down due to the pull of gravity the universe placed on itself. While BOSS was creating the map, it was able to pinpoint when exactly dark energy suddenly “turned on,” and accelerated expansion: six billion years after the universe came into existence.

The map may produce insight into dark energy and what its nature is, and it can also help astronomers understand the structure of the universe, and its expansion rate.

“For the past 13 years, we’ve had a simple model of how dark energy works,” David Schlegel of the U.S. Department of Energy’s Lawrence Berkeley National Laboratory in California, BOSS’ principal investigator tells Space.com. “But the truth is, we only have a little bit of data, and we’re just beginning to explore the times when dark energy turned on. If there are surprises lurking out there, we expect to find them.”

Image Courtesy of   https://www.facebook.com/BerkeleyLab

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An international team of astronomers, led by astrophysicist Francesco Tombesi, at NASA’s Goddard Space Flight Center in Greenbelt, Maryland has discovered what causes galaxies to acquire large bulges in their centers: outflows from supermassive black holes that lie in the bulges.

A black hole is an invisible tiny “hole” in space. It is a former star that collapses on its own gravity, which is so strong that nothing, even light, can escape — hence the name “black hole,” coined by physicist John Wheeler in 1967. Black holes feed on objects surrounding them: nebulas, planetary objects, light — anything. Whatever enters a black hole gets spewed out eventually in the form of jets of x-rays and radiation. These jets allow astronomers to view the black hole’s spectrum, which tells them what elements the black hole swallowed and spat out.

Over the years, astronomers have learned that galaxies, even our very own Milky Way, contain supermassive black holes — black holes that are really, really big — at their centers. Surrounding the supermassive black holes are large clouds of gas, where stars are born left and right. The gravity of these black holes also attract fast moving stars, creating the galaxies’ bulges, which then grow large. As to how this is has puzzled astronomers for years.

Tombesi and his colleagues have encountered a distinct kind of “outflow” from the clouds of gas after studying the spectrographs of forty-two galaxies from the All-Sky Slew Survey Catalog from NASA’s Rossi X-Ray Timing Explorer Satellite. In spectroscopy, astronomers look at absorption spectra — essentially pictures of the electromagnetic spectrum — which present light absorbed from the light sources, such as stars, nebulas, galaxies, and, in this case, black holes. With the absorption spectra, astronomers can gauge the light source’s composition of elements by looking for any black lines that vertically cross the spectrum.

While researching the spectra of x-rays from the forty-two galaxies, Tombesi and the team learned that the supermassive black holes absorbed fluorescent iron. They then found out that 40% of these galaxies had such an outflow flow, which suggests that the outflow is common in black holes at the center of galaxies. The x-rays’ wavelengths were shorter than their normal length, indicating that the galaxies were blueshifted (i.e. moving towards us). This outflow was dubbed “ultra-fast outflows,” or UFOs, by Tombesi according to NASA.

“They have the potential to play a major role in transmitting feedback effects from a black hole into the galaxy at large,” Tombesi says in NASA’s press release.

Ultimately, he and his colleauges learned that UFOs halt supermassive black holes’ growth by taking away the mass it would potentially eat. Furthermore, UFOs can slow down or even completely discontinue star formation in the galactic centers by removing gas from the galactic bulge.

Tombesi and his team hope to further study UFOs and their development with Japan’s Astro-H X-ray telescope, which is scheduled to be launched in 2014.

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Shogo Masaki of the Department of Physics at Nagoya University and Masataka Fukugita and Naoki Yoshida of the University of Tokyo’s Institute of Physics and Mathematics of the Universe (IMPU) collaborated in an experiment to create a computer simulation that would hopefully figure out the location of dark matter. In late January, their experiment was successful.

The term intergalactic refers to the physical space between galaxies where matter is hardly distributed. Scientists previously thought that intergalactic space comprised of nothing, being only empty, and that galaxies, in contrast, have the highest concentration of matter. Masaki, Fukugita, and Yoshida, however, have discovered that these intergalactic zones are packed with clumps of dark matter.

In addition, they also learned that galaxies do not have clear, defined edges; instead, they “have long outskirts of dark matter that extend to their nearby galaxies” according to IMPU’s press release. These “outskirts” contain much of the matter – and dark matter – in the universe.

The existence of dark matter was proposed by Swiss astronomer Fritz Zwicky in the 1930s. Since then, there have been numerous experiments around the globe involving dark matter. Dark matter’s nature is still enigmatic: it is an invisible, dense substance, and it cannot even be detected by instruments. Scientists do know that dark matter takes up about 23% of the Universe, with dark energy taking up 72% and the rest (planets and stars, for example) only 4%.

Furthermore, contrary to popular belief, dark matter is not random – it is uniform and organized. Masaki and his colleagues gathered recent observational data of 24 million galaxies from the Sloan Digital Sky Survey (SDSS) and created a large simulation of matter distribution. With their knowledge of the large density of dark matter, they used gravitational lensing to find the substance’s location.

Because dark matter is so dense, it causes space and light from stars, galaxies, and other light-emitting objects to bend, making these celestial objects appear bigger and brighter. With gravitational lensing, Masaki and his colleagues measured how the galaxies’ light was bent, allowing them to locate dark matter.

Dark matter remains as elusive as ever: although we have found exactly where dark matter is, we still do not know what it is, but scientists are closer than ever to understanding the mysterious substance’s nature. Masaki, Fukugita, and Yoshida have published a paper describing details of their experiment in The Astrophysical Journal. A PDF of the preprint version is found here.

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Interstellar Boundary Explorer (IBEX) has captured the best and most complete glimpse yet of what lies beyond the solar system. The new measurements give clues about how and where our solar system formed, the forces that physically shape our solar system, and the history of other stars in the Milky Way.

The Earth-orbiting spacecraft observed four separate types of atoms including hydrogen, oxygen, neon and helium. These interstellar atoms are the byproducts of older stars, which spread across the galaxy and fill the vast space between stars. IBEX determined the distribution of these elements outside the solar system, which are flowing charged and neutral particles that blow through the galaxy, or the so-called interstellar wind.

“IBEX is a small Explorer mission and was built with a modest investment,” said Barbara Giles, director of the Heliophysics Division at NASA Headquarters in Washington. “The science achievements though have been truly remarkable and are a testament to what can be accomplished when we give our nation’s scientists the freedom to innovate.”

In a series of science papers appearing in the Astrophysics Journal on Jan. 31, scientists report finding 74 oxygen atoms for every 20 neon atoms in the interstellar wind. In our own solar system, there are 111 oxygen atoms for every 20 neon atoms. This translates to more oxygen in any part of the solar system than in nearby interstellar space.

“Our solar system is different than the space right outside it, suggesting two possibilities,” says David McComas, IBEX principal investigator, at the Southwest Research Institute in San Antonio. “Either the solar system evolved in a separate, more oxygen-rich part of the galaxy than where we currently reside, or a great deal of critical, life-giving oxygen lies trapped in interstellar dust grains or ices, unable to move freely throughout space.”

The new results hold clues about the history of material in the universe. While the big bang initially created hydrogen and helium, only the supernovae explosions at the end of a star’s life can spread the heavier elements of oxygen and neon through the galaxy. Knowing the amounts of elements in space may help scientists map how our galaxy evolved and changed over time.

Scientists want to understand the composition of the boundary region that separates the nearest reaches of our galaxy, called the local interstellar medium, from our heliosphere. The heliosphere acts as a protective bubble that shields our solar system from most of the dangerous galactic cosmic radiation that otherwise would enter the solar system from interstellar space.

IBEX measured the interstellar wind traveling at a slower speed than previously measured by the Ulysses spacecraft, and from a different direction. The improved measurements from IBEX show a 20 percent difference in how much pressure the interstellar wind exerts on our heliosphere.

“Measuring the pressure on our heliosphere from the material in the galaxy and from the magnetic fields out there will help determine the size and shape of our solar system as it travels through the galaxy,” says Eric Christian, IBEX mission scientist, at NASA’s Goddard Space Flight Center in Greenbelt, Md.

The IBEX spacecraft was launched in October 2008. Its science objective is to discover the nature of the interactions between the solar wind and the interstellar medium at the edge of our solar system.

The Southwest Research Institute developed and leads the IBEX mission with a team of national and international partners. The spacecraft is one of NASA’s series of low-cost, rapidly developed missions in the Small Explorers Program. Goddard manages the program for the agency’s Science Mission Directorate at NASA Headquarters in Washington.

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An international team of astronomers has produced a map that covers a billion light-years worth of dark matter in the universe. Never before has dark matter been mapped on such a large scale.

Two members of the team, Catherine Heymans of the University of Edinburgh and Associate Professor Ludovic Van Waerbeke of the University of British Columbia in Vancouver, Canada, presented their findings at the 119th meeting of American Astronomical Society, held last week.

The project took place at the Canada-France-Hawaii Telescope Lensing Survey (CFHTLensS) in Hawaii and collected data from the Canada-France-Hawaii Telescope Legacy Survey. For more than five years, the team accumulated images of ten million galaxies – six billion light-years away – from four different regions in the sky during each of the seasons. Essentially peering at the universe when it was but six billions years old, they studied  how dark matter warped the light emitted by the galaxies.

The process of producing the map was completed through a method called gravitational lensing, in which bodies (e.g. galaxies, or, in this case, dark matter) are so massive that they curve space-time and distort light, making it travel in a curve, rather than in a line. By studying the distortions of the galaxies’ light, the team was able to determine the structure of the dark matter and plot its distribution.

“It is fascinating to be able to ‘see’ the dark matter using space-time distortion,” says Waerbeke at the American Astronomical society meeting. “It gives us privileged access to this mysterious mass in the Universe which cannot be observed otherwise. Knowing how dark matter is distributed is the very first step towards understanding its nature and how it fits within our current knowledge of physics.”

The universe is more or less a cosmic web of dark matter and galaxies. Dark matter is impossible to be detected by itself, making it seem invisible, though it makes its presence known through warping space-time and light. The mysterious substance makes up a whopping 23 percent of the universe, with dark energy taking up 72 percent and everything else (stars, planets, etc.) only 4 percent.

With creating such a large map of the cosmic web, astronomers and cosmologists are becoming closer to understanding the nature of dark matter and, ergo, a large portion of the universe. Dr. Heymans, a lecturer of physics and astronomy, says, “By analyzing light from the distant Universe, we can learn about what it has travelled through on its journey to reach us.

We hope that by mapping more dark matter than has been studied before, we are a step closer to understanding this material and its relationship with the galaxies in our Universe.”

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After more than three years in space, NASA’s Fermi Gamma-ray Space Telescope is extending its view of the high-energy sky into a largely unexplored electromagnetic range. On January 10, the Fermi team announced its first census of energy sources in this new realm.

Fermi’s Large Area Telescope scans the entire sky every three hours, continually deepening its portrait of the sky in gamma rays, the most energetic form of light. While the energy of visible light falls between about 2 and 3 electron volts, the LAT detects gamma rays with energies ranging from 20 million to more than 300 billion electron volts.

At higher energies, gamma rays are rare. Above 10 GeV, even Fermi’s LAT detects only one gamma ray every four months.

“Before Fermi, we knew of only four discrete sources above 10 GeV, all of them pulsars,” said David Thompson, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Md. “With the LAT, we’ve found hundreds, and we’re showing for the first time just how diverse the sky is at these high energies.”

Any object producing gamma rays at these energies is undergoing extraordinary astrophysical processes. More than half of the 496 sources in the new census are active galaxies, where matter falling into a supermassive black hole powers jets that spray out particles at nearly the speed of light.

Only about 10 percent of the known sources lie within our own galaxy. They include rapidly rotating neutron stars called pulsars, the expanding debris from supernova explosions, and in a few cases, binary systems containing massive stars.

More than a third of the sources are completely unknown, having no identified counterpart detected in other parts of the spectrum. With the new catalog, astronomers will be able to compare the behavior of different sources across a wider span of gamma-ray energies for the first time.

Just as bright infrared sources may fade to invisibility in the ultraviolet, some of the gamma-ray sources above 1 GeV vanish completely when viewed at higher, or “harder,” energies.

One example is the well-known radio galaxy NGC 1275, which is a bright, isolated source below 10 GeV. At higher energies, it fades appreciably and another nearby source begins to appear. Above 100 GeV, NGC 1275 becomes undetectable by Fermi, while the new source, the radio galaxy IC 310, shines brightly.

The Fermi hard-source list is the product of an international team led by Pascal Fortin at the Ecole Polytechnique’s Laboratoire Leprince-Ringuet in Palaiseau, France, and David Paneque at the Max Planck Institute for Physics in Munich.

The catalog serves as an important roadmap for ground-based facilities called Atmospheric Cherenkov Telescopes, which have amassed about 130 gamma-ray sources with energies above 100 GeV. They include the Major Atmospheric Gamma Imaging Cherenkov telescope on La Palma in the Canary Islands, the Very Energetic Radiation Imaging Telescope Array System in Arizona, and the High Energy Stereoscopic System in Namibia.

“Our catalog will have a significant impact on ground-based facilities’ work by pointing them to the most likely places to find gamma-ray sources emitting above 100 GeV,” Paneque said.

Compared to Fermi’s LAT, these ground-based observatories have much smaller fields of view. They also make fewer observations because they cannot operate during the daytime, bad weather, or a full moon.

“As Fermi’s exposure constantly improves our view of hard sources, ground-based telescopes are becoming more sensitive to lower-energy gamma rays, allowing us to bridge these two energy regimes,” Fortin added.

NASA’s Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership. Fermi is managed by Goddard. It was developed in collaboration with the U.S. Department of Energy, with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden, and the United States.

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The Drake equation is a probability law which estimates the abundance of intelligent life in our Galaxy, the Milky Way. It is quite simple in appearance, and anyone can play with the variables in order to make their own personal estimate.

The variables encountered in the equation include the proportion of intelligent to non-intelligent life; the proportion of stars which would be capable of sustaining life in their environment to those who cannot; the number of planets a star is probable to have existing in this habitable zone, if the star were to harbour planets.

Although the scientific results of this equation are in great debate, it was developed by Prof. Frank Drake in order to open discussion on the topic for the famous meeting at the Green Bank radio observatory in 1961.

Current estimates ranging from the opinions of pessimists to optimists, are of the order of it being next to impossible to communicate with other lifeforms in our Galaxy, to a possible ten different alien civilisations who are currently in the same positions as us with appropiate technology who could be trying to communicate with us and others like us.

Hence the popularity of the SETI project (the Search for Extraterrestrial Intelligence). The equation brings many interesting topics to light such as how long intelligent civilisations may continue on living, with most estimates being of short duration. One hypothesise is that once nuclear power is developed by a civilisation, they will quickly destroy themselves through their new technology.

To date there have been 684 confirmed planets discovered orbiting a total number of 474 stars other than our Sun. With thousands more proposed from the Kepler mission awaiting comfirmation. More recently the Kepler mission has discovered the first planet known to be orbiting two stars.

The techniques involved in detecting these extra-solar (i.e. orbiting other stars than our Sun) objects favor the discovery of larger, more massive planets which have a more visible influence on their parent star. The techniques follow principles as simple as; does the parent star wobble?

If so, by how much and then knowing the distance to the parent star we can calculate the mass of the orbiting planet and orbital period, which in turn would give us the distance between the parent star and planet, using Kepler’s third law. This technique follows the principles of astrometry (basically astronomical geometry).

Then from analyzing the richness of the chemical environment of such systems through spectroscopy it is possible to say if at least one component of this system would be capable of sustaining life. Unfortunately, due to the large number of complexities which arise in the observational and analysis stages no one can say for sure if these planets are currently harbours of life.

However, all is not lost as we know already that our solar system contains life on a small out of the way planet amicably called Earth. So would it be possible for other lumps of rock in our Galaxy to host complex biological species? It is of popular opinion that yes, it is possible but due to the harsh environments in which they may exist they may not of had the possibility to evolve beyond microbial stages of evolution.

For example, if we ignore Mars for a minute and concentrate on the more probable hosts, the Gaililean satelites orbiting our local failed star Jupiter or Saturn’s Titan are good bets. It was initially thought that light was a neccessary ingredient for life to come into being. That was until the discovery of strange looking creatures living in the depths of our deepest darkest oceans close to hydrothermal vents.

This would lead a reasonable mind to believe that Europa, Ganymede or Titan may be hosts to such creatures thanks to their water ice crusts encasing their volcanic prone H2O oceans. How could we detect such life? Well as we know from studies of biological creatures back home we create a chemical diversity in our atmosphere which wouldn’t exist if we did not.

So we could look for gases such as methane trapped in ice crystals such as Clathrate Hydrates on the surface of these near by objects, with techniques such as infra-red reflection spectroscopy.

An exo-planet nicknamed ‘Snow White’ has been found to have a partially water ice surface with a possible light methane atmosphere. So in conclusion, no life has been currently detected aside from on planet Earth and it will prove difficult to find, but, we are off to a good start.

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