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.

Pulsar Disappears After Space-Time Warp Measured

Scientists have measured the space-time warp in the gravity of binary pulsar system J1906 and determined the mass of its neutron star before the pulsar vanished from view.

A binary pulsar system is comprised of a pulsar that is orbiting a binary companion which is usually a white dwarf or neutron star. In the case of Binary Pulsar J1906, the scientists have measured the solar mass of the accompanying neutron star to be 1.32 solar mass with a sphere only 10 kilometers (6.21 miles) across.

J1906 is the youngest double neutron star system whose mass has been measured.

The spin axis of the pulsar wobbles like a spinning top. Since the distance of the two neutron stars in J1906 is very close and each star weighs more than the Sun, the space-time between the stars is curved which affects the pulsar's spin axis. The wobble has been so much that the pulsar's beams no longer hit the Earth, making it disappear from sight.

It is expected that the pulsar will be visible again in 160 years.

A pulsar is a neutron star that formed when a massive star's core is compressed during a supernova. The supernova collapses the star's core and forms the neutron star. Pulsars are extermely dense and highly magnetized. They rotate and emit a beam of electromagnetic radiation which is picked up as radio waves in the form of pulses. The name pulsar is abbreviated from the term "pulsating star".

Two New Habitable Planets Found By NASA Kepler Mission

Eight new Earth-like planets have been found orbiting stars at a distance where water can exist on the surface. Among the eight discovered planets, two of them are believed to most resemble the Earth. These are Kepler-438b and Kepler-442b.

Kepler-438b is located 470 light-years from Earth while the more distant Kepler-442b is 1,100 light-years away. Both stars orbit red dwarf stars which are smaller and cooler than the Sun.

The zone where exoplanets can maintain water in its surface is known as the Goldilocks zone. These planets must receive about as much sunlight as the Earth. The discovery of Kepler-438b and Kepler-442b doubles the number of small planets that are believed to be habitable.

These findings were announced today in a press conference at a meeting of the American Astronomical Society.

Distant Galaxy Collision Imaged Through Gravitational Lensing

The European Southern observatory and with the help of other agencies, has imaged a galactic collission that happened when the Universe was half its age using gravitational lensing.

Using state of the art instruments from all around the world, on the ground and in space, ESO has imaged galaxy H-ATLAS J142935.3-002836 in collision with another galaxy.

With the help of gravitational lensing which uses Einstein's theory that light can be bent given enough mass, scientists were able to study objects which would not be visible otherwise and to directly compare local galaxies with much more remote ones, seen when the Universe was significantly younger.

The image above shows the foreground galaxy that is doing the lensing, which resembles how our home galaxy, the Milky Way, would appear if seen edge-on. But around this galaxy there is an almost complete ring — the smeared out image of a star-forming galaxy merger far beyond.

In his theory of general relativity, Einstein predicted that given enough mass, light does not travel in a straight line but will be bent in a similar way to light refracted by a normal lens.”

Gravitational lensing is done with the help of galaxies and galaxy clusters which provides the mass that deflects light from objects behind them due to their strong gravity. The magnifying properties of this effect allow astronomers to study these objects.

The collision of H-ATLAS J142935.3-002836 was gathered using three ESO telescopes, the ALMA, APEX and VISTA, and with assistance of other telescopes and surveys namely: NASA/ESA Hubble Space Telescope, the Gemini South telescope, the Keck-II telescope, the NASA Spitzer Space Telescope, the Jansky Very Large Array, CARMA, IRAM and SDSS and WISE.

Binary Star Systems May Explain Formation of Mysterious Magnetars

Scientists may have found the explanation on how a magnetar is formed. Magnetars are a a type of neutron star and have a very strong magnetic field.

During a supernova explosion, stars collapse and form either a neutron star or a black hole. Neutron stars are so dense that a teaspoon of its material may weigh over a billion tons.

One such type of neutron star is a magnetar. Magnetars are the strongest magnets known in the Universe. They are millions of times more powerful than the strongest magnets on Earth.

Scientists have long believed that magnetars are formed through the interactions of two massive stars that orbit each other in a very tight binary system; an orbit comparable to the distance of the Earth to the Sun. The theory suggests that the mass transfer between the two stars created a rapid rotation of one star which resulted in a very strong magnetic field. A second mass transfer slimmed down that star to it doesn't collapse into a black hole at the moment of its death.

Without finding a companion star, this theory was hard to prove. They further suggested that the companion star may have been thrown out of orbit during the supernova explosion; a runaway star. With the magnetar found in the star cluster Westerlund 1, the theory may have sound basis as scientists discovered a runaway star, Westerlund 1-5, that could have been the partner star of the magnetar and aided in its formation.

New 3D Model Gives Insight On How Supernovas are Formed

Credit: Arnett, Meakin and Viallet/AIP Advances

A new model on how supernovas are formed was presented that can explain certain properties of supernovas that existing models cannot. The new model depicts the formation in three dimensions compared to previous one or two dimensional models.

In the new model, the material in the stars are violently mixed together which causes them to expand, contract, eject and then explode into a supernova. This 3D model is described in the article, "Chaos and turbulent nucleosynthesis prior to a supernova explosion" by David Arnett, Casey Meakin and Maxime Viallet which appears in the journal AIP Advances.

Supernovas are stars that run out of fuel or reaches critical mass and explodes. The explosion from a supernova can expel stellar materials at a rate of about 30,000 kilometers per second (10% of the speed of light). A supernova remnant is formed after the explosion and its boundaries are based on the shockwave from the exploding supernova and is made up of the ejected stellar material of dust and gas.

The Crab Nebula is the most popular and well known supernova remnant in the Universe In 1987, a supernova erupted in the Large Magellanic Cloud and afterwards formed the Supernova Remnant 1987A. It was the closest exploding star observed in modern times.

Image Caption: Three-dimensional turbulent mixing in a stratified burning oxygen shell which is four pressure scale heights deep. The yellow ashes of sulphur are being dredged up from the underlying orange core. The multi-scale structure of the turbulence is prominent. Entrained material is not particularly well mixed, but has features which trace the large scale advective flows in the convection zone. Also visible are smaller scale features, which are generated as the larger features become unstable, breaking apart to become part of the turbulent cascade. The white lines indicate the boundary of the computational domain.

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.

ALMA Telescope Finds Evidence of Newly Formed Dust Made from Supernova

Artist's impression of dustfilled supernova 1987A
Credit: Alexandra Angelich (NRAO/AUI/NSF)

Researchers have captured an image of supernova 1987A with newly formed dust that was not present when the supernova was discovered. The amount of new dust comprises about 25% of the Sun's mass.

This observation gives direct evidence to support the theory of the dust making abilities of a supernova. It can also explain why young and newly formed galaxies have a dusty, dusky appearance.

When the supernova was discovered in 1987, the closest observed supernova explosion since 1604, there was only a small amount of dust observed at the time. Using the Atacama Large Millimeter/submillimeter Array (ALMA) telescope, researchers discovered the amount of dust now in the supernova has significantly increased as well as huge amounts of newly formed carbon monoxide and silicon monoxide gas.

The artists impression above shows SN 1987A's inner regions in red where huge amounts of dust were detected and imaged by ALMA. This inner region is contrasted with the outer shell (lacy white and blue circles), where the energy from the supernova is colliding with the envelope of gas ejected from the star prior to its powerful detonation.

Supernova SN 1987 was first observed in February 1987 and achieved peak brightness in May of that year. SN 1987 is around 168,000 light-years away and is located in the Large Magellanic Cloud.

Comet Ison Outburst Increases Activity By A Factor of Ten

The European Southern Observatory through its La Silla facilities in Chile released a new view of Comet ISON (C/2012 S1) which suddenly has become more active on 01 November. First spotted on September 2012, the comet will be at its closest to the Sun by 28 November.

The comet has been getting brighter as its gets closer to the Sun. Scientists explained that the heat from the Sun is interacting with the ice in the comet making the ISON get brighter and brighter. The first outburst happened on 01 November which doubled the amount of gas emitted by the comet. The second outburst happened on 13 November making it ten times brighter.

The TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) device was used to capture the image of the comet. The image which is composed of four different 30-second exposures through blue, green, red, and near-infrared filters is the clearest made of the comet since its discovery.

If the comet is still intact after its close approach to the sun, it will be visible to the human eye in the morning sky.

20% of Sun-Stars in the Universe Contain Habitable Planets

Astronomers studying data collected by NASA's Kepler spacecraft announced that based on the analysis, one out of every five sun-like stars in the Universe have Earth-sized planets with a surface temperature conducive to life.

Habitable planets are located in an orbit around a star where the heat of the star is just the right temperature where liquid water can exist. Water is one element that is believed to be important to the existence of life. When a planet is too far, water freezes and if it is too close to the star, water vaporizes.

Although it is presumed that the presence of water is an important factor, the planet's atmosphere and surface terrain is also of importance. Without a suitable atmosphere, the planet is exposed to radiation and extreme temperatures. The surface terrain helps harbor the liquid water to sustain life.

By knowing that 20% of sun-like stars harbor a habitable planet, astronomers can start planning for a mission to take an actual picture of it. This also means that there may be habitable planets as close as 12 light years away from the Earth.

The closest exoplanet to the Earth was discovered orbiting Alpha Centauri B in the Alpha Centauri system 4.3 light years away. Although the planet has a mass similar to the Earth, its orbit around Alpha Centauri B is too close to the star that it is outside of the habitable zone.

Observation From Hubble CANDELS Survey Helps Visualize Galaxies 11 BIllion Years Ago

Galaxies are classified through a system devised by Edwin Hubble known as the Hubble Sequence. With the help of Hubble Space Telescope (named after the astronomer himself) and the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), data helped visualize the Hubble Sequence 11 billion years ago. Previous data has shown the Hubble Sequence of the Universe 8 billion years back.

The size, shape, form and even color of galaxies before are different from how it looks like today (see images at end of article). The physical formation has changed and are still changing and developing. Using two cameras aboard the Hubble Space Telescope, the Wide Field Camera 3 (WFC3) and the Advanced Camera for Surveys (ACS), CANDELS is set to explore the evolution of galaxies in the Universe and collect data that can give a glimpse of the Universe 1 billion years before the Big Bang.

Previous data were limited to the visible light spectrum which shows only the redshifted ultraviolet emission of the galaxies, which highlights star formation. By looking into the infrared spectrum of light (invisible to the human eye), the astronomers could observe how these distant galaxies appear in their visible rest frame (which is now redshifted), making it easier to compare to nearby galaxies.

Hubble Cosmos Survey Solves Mystery Behind Quenched Galaxy Growth

Image shows 20 galaxies that are no logner forming stars. Called Quenched galaxies, these have been imaged by the Hubble Cosmos Survey and can be identified by the crosshair at the center of each image.
Credit: NASA, ESA, M. Carollo (ETH Zurich)

Astronomers have recently discovered why quenched galaxies seem to be growing despite the fact that it doesn't produce stars anymore.

The previous theory for the supposed growth of quenched galaxies was that these small galaxies have merged with other smaller galaxies. By using the Hubble COSMOS observations, astronomers have found that larger galaxies switch off (stop forming new stars) at later times which gives the impression that previous quenched galaxies have grown over a duration of time.

Exoplanet HD 189733b Determined to be Color Blue Like the Earth

A planet discovered in 2005 in the constellation of Vulpecula (the Fox) was determined to be colored blue with the help of the NASA/ESA Hubble Space Telescope. The blue colored planet is similar to how the Earth's color looks like from space.

The planet, HD 189733b which is a huge gas giant similar to the planet Jupiter, is 63 light years away and is closely orbiting its host star; around 1/30 the distance the Earth orbits the Sun. Although the planet comes off with a deep cobalt blue color, its atmosphere is vastly different from that of the Earth. The HD 189733b's atmosphere has a temperature of over 1000 degrees Celsius, and it rains glass, sideways, in howling 7000 kilometre-per-hour winds. HD 189733b is slightly bigger than the planet Jupiter.

Scientists have determined that the blue color of the planet is because of silicate particles in its atmosphere which scatters blue light. These particles, along with condensates of iron and aluminium oxide dust (which the mineral sapphire is made up of), also contributes to a hazy red sunset when seen from the planet.

By measuring how much radiation is reflected, a technique known as Albedo, scientists can determine the amount of light reflected. This value ranges from 0 to 1, with 1 being perfect reflectivity and 0 being a completely black surface. The Earth has an albedo of around 0.4. HD 189733b is observed to have an albedo of 0.40 ± 0.12 at a wavelength of 290–450 nm.

Possible Variable Fine Structure Constant Tested On A White Dwarf Star

Scientists are using the Hubble Space Telescope and a White Dwarf Star (G191-B2B) to test if the Fine Structure Constant, or alpha (α) is not really constant.

The Fine Structure Constant is defined as the charge of an electron squared over the product of Planck's constant multiplied by the speed of light. The resulting value is 1/137 or 7.2973525698(24)×10⁻³.

This constant shows the probability of an electron absorbing a photon or simply the strength of the electromagnetic force exerted in an interaction. It relates to three important aspects of physics, electromagnetism, relativity, and quantum mechanics (through Planck's constant).

The importance of the Fine Structure Constant (α) relates to the existence of life. If the value of α is not as it is, life or intelligent life as it is now, would not exist. A 4% change in the value of α would mean that stellar fusion would not create carbon, making carbon based life impossible. If α were > 0.1, stellar fusion would be impossible and no place in the universe would be warm enough for life as we know it.

Using a white dwarf star with a gravity 30,000 times more than the Earth, scientists are measuring the strength of the electromagnetic force with the help of the Hubble Space Telescope. They will compare that value to that measured on Earth to determine if the Fine Structure Constant is really not constant and that it varies across the Universe.

Chemical Reactions In Space May Be Due To Quantum Tunnelling

Researchers at the University of Leeds School of Chemistry proposed that chemical reactions in space, particularly on how alcohols are created and destroyed, are due to a quantum mechanical phenomenon, known as 'quantum tunnelling'. Their findings are published in Nature Chemistry.

The cold temperatures in space prohibit chemical reactions to take place but scientists have seen evidence that there are reactions happening despite the sub-zero conditions. The researchers at the University of Leeds have proposed that these reactions occur due to quantum tunnelling.

Quantum tunnelling is a phenomenon in quantum mechanics where particles can pass through objects (tunnel through) to reach the other side. In classical mechanics, an object like a ball will likely bounce back when it hits a wall. Quantum tunnelling dictates that the ball, albeit a very small ball the size of an electron, has a finite probability that it can pass through the wall.

Researchers at Leeds have replicated deep space environment under laboratory conditions and have observed that methanol and hydroxyl radicals react with each other to create methoxy radicals twice as fast than at room temperature.

Black Hole Outflow From Galaxy NGC 3783 Surprises Observers

The VLTI (Very Large Telescope Interferometer) of the European Southern Observatory has observed that dust around a black hole at the NGC 3783 galaxy forms a cool wind that streams out from the black hole. This observation have surprised scientists since dust surrounding black holes have been observed to reach 700 to 1000 degrees Celsius.

The dust can be found at the torus of the black hole. The torus, which resembles a three dimensional donut (as seen on the image on the left), surrounds the black hole and is believed to be the source of high energy objects called active galactic nuclei (AGN). The supermassive black hole pulls in material from the surrounding region but it seems that the resulting radiation and energy that this produces also blows it away.

The hotter dust was mapped using the AMBER VLTI instrument at near-infrared wavelengths and the newer observations reported here used the MIDI instrument at wavelengths between 8 and 13 microns in the mid-infrared.

Black holes are regions in space where gravity is so strong that even light cannot escape its pull. Black holes are formed from stars that have exploded into a supernova and collapses into itself.

Black holes vary in size with some being 20 times more massive that the sun. Supermassive Black holes can reach a mass more than a million times than that of the Sun. Each galaxy has a supermassive black hole in its center.

The VLTI used to observe the black hole is made up of a combination of four VLT Unit Telescopes and four moveable 1.8-metre VLT Auxiliary Telescopes. It combines the light from several of these telescopes to form one observation through a process called interferometry. This process does not actually produce images but the generated measurements can be used to increase the level of detail of resulting observations.

Studying the Evolution of a Supernova Through Supernova Remnant 1987A

Astronomers are intensively studying Supernova Remnant 1987A to find out more about the inner workings of stars, supernovas, and how they interact with the surroundings.

A supernova is an astronomical event where a star runs out of fuel or reaches critical mass and explodes. The explosion from a supernova can expel stellar materials at a rate of about 30,000 kilometers per second (10% of the speed of light).

After the explosion, what is left of the star is a structure called a Supernova Remnant (SNR). The boundaries of a SNR is based on the shockwave from the supernova and is made up of the ejected stellar material of dust and gas.

One of the most popular and well known supernova remnant is the Crab Nebula. Most supernova remnants are named after objects or animals they resemble. Just recently, a SNR was discovered that resembled a Florida Manatee.

In early 1987, a supernova erupted in the Large Magellanic Cloud and afterwards formed the Supernova Remnant 1987A. It was the closest exploding star observed in modern times.

Cosmic Rays Confirmed To Originate From Supernovas In Two Separate Announcements

When stars explode, the supernovas send off shock waves, which accelerate protons to cosmic-ray energies through a process known as Fermi acceleration. In this mechanism, named for Enrico Fermi who first hypothesized it, the protons gain energy from collisions with turbulent magnetic fields on either side of a shock wave. Though many details of Fermi acceleration remain unknown, new results from the Fermi Gamma-ray Space Telescope provide overwhelming evidence that the mechanism is indeed responsible for producing many of the galaxy's cosmic ray protons.
Credit: Greg Stewart, SLAC National Accelerator Laboratory

In two separate announcements (and two separate studies), the European Southern Observatory and the Kavli Institute for Particle Astrophysics and Cosmology at the Department of Energy's (DOE) SLAC National Accelerator Laboratory confirmed that cosmic rays come from exploding stars or supernovas.

Cosmic rays are high energy particles from space. These particles travel at close to the speed of light and originate from outside the Solar System. They have very high energy that they can penetrate the Earth's atmosphere and even through solid rock at the surface. Prior to the announcement, its origin and how it was formed has been a mystery.

The ESO together with the Max Planck Institute for Astronomy in Heidelberg Germany, used the VIMOS Equipment on the Very Large Telescope (VLT) to study SN 1006, a supernova first observed in the year 1006, to gather data and base their discovery of the cosmic ray mystery. Their study, An Integral View of Fast Shocks around Supernova 1006, is appearing in the 14 February 2013 issue of the journal Science.

The Kavli Institute, NASA, and Stanford University used the Large Area Telescope (LAT), which sits onboard the Fermi Gamma-ray Space Telescope to base their findings. They used the telescope to study two supernova remnants, IC 433 and W44. Both are located within the Milky Way with IC 443 5,000 light years away from Earth in the constellation Gemini, and W44 is located about 10,000 light years away, in the constellation of Aquila. Their study, Detection of the Characteristic Pion-Decay Signature in Supernova Remnants, will be appearing in the February 15 2013 issue of the journal Science.

Star Forming Molecular Cloud Lupus 3 Captured In Amazing Detail

Most interstellar clouds of dust and gas are where stars are formed. The surrounding matter start to form large masses which will eventually become stars. Planets and other objects are also formed within these regions. Clouds like Lupus 3 are called 'dark clouds' or 'molecular clouds'.

A molecular cloud is a type of star forming region where molecules, most commonly molecular hydrogen (H₂), are formed. The stars formed in the image are called Herbig Ae/Be stars (named after astronomer George Howard Herbig).

Herbig Ae/Be stars are still in their star forming space and are not yet burning hydrogen for fuel. Instead, they shine by converting gravitational potential energy into heat as they contract.

Planet Forming Disc of Gas And Dust Around Star HD 142527 Observed

Artist's impression of the disc of gas and dust forming around young star HD 142527

The European Southern Observatory's ALMA space telescope has directly observed for the first time a disc of cosmic dust and gas around a young star, HD 142527. This material is believed to further form into giant planets.

Just like stars, astronomers believe that planets are also formed when clouds of cosmic dust and gas start to clump together and gain mass. These planets form from the residual material of a newly born star.

The Atacama Large Millimeter/submillimeter Array (ALMA) telescope has helped astronomers look more closely and clearly into space by detecting near infrared light which is hard to detect and invisible to the eye. The telescope which will be fully inaugurated by March 2013, has 66 high-precision antennas, spread over distances of up to 16 kilometers.

The ALMA space telescope performs very well on these clouds of gas and dust which are dense and dark.