Twitter, even more than many other social media tools, can feel disconnected from the real world. But a group of students and professors at research site Floating Sheep have built a comprehensive map of some of Twitter’s most distasteful content: the racist, homophobic, or ableist slurs that can proliferate online. Called Geography of Hate, the interactive map charts ten relatively common slurs across the continental US, either by general category or individually. Looking at the whole country, you’ll often see a mass of red or what the map’s creators call a “blue smog of hate.” Zooming in, however, patches appear over individual regions or cities; some may be predictable, while others are not.
Research led at the Univ. of Strathclyde has developed a portable device to produce ultracold atoms for quantum technology and quantum information processing.
The researchers have developed technology which is far more compact than previous setups but can still cool and trap large numbers of atoms for use in portable devices. They pattern the surface of a semiconductor chip to form a diffraction grating, splitting a laser into many beams that cool the atoms.
Cell movement begins with lamellipodia. A thin sheet of actin filaments (light purple) that stretches out to the cell’s periphery, lamellipodia generate pushing forces that drive the cell forward. Microtubules (cyan) can barely penetrate this actin network, but they direct cell motility in other ways, such as controlling cell adhesion and acting as the cell’s internal compass.
Image: A human HaCat keratinocyte responds to epidermal growth factor by rapidly forming a lamellipod around most of its perimeter. The cell was fixed and processed within minutes after EGF addition. F-actin is stained with fluorescently labeled phalloidin (light purple), and microtubules are labeled with an antibody (cyan). DNA dye stains the nucleus dark purple.
On a global level, we are adding connected intelligence to both machines and objects using chips, micro sensors, and both wired and wireless networks to create a rapidly growing “Internet of things” sharing real-time data, performing diagnostics, and even making remote repairs. Many jobs will be created as we add intelligent connected sensors to bridges, roads, buildings, homes, and much more. By 2020, there will be well over a billion machines talking to each other and performing tasks without human intervention.
Think of it this way: from phones to cars to bridges, embedded technologies are increasingly making the things we use smarter every day. For example, some of the newest cars use cameras mounted in the rear to see if something is in the way when you are backing up. If there is something in the way, the car will apply the brake even if you don’t or you are slow to react. Likewise, the concrete in new bridges has embedded chips that can let engineers know when the concrete is cracking, stressed, and in need of repair before the bridge collapses. In addition, sensors on the surface of the road going over the bridge will detect ice and wirelessly communicate the information to your car. If you don’t slow down, the car will slow down to a safe speed for you.
Astronomers discover “missing link” of black holes
A composite image of our neighbouring galaxy, Andromeda, showing different views of the Ultraluminous X-ray (ULX) source. Image Credit: X-rays: ESA/M. Middleton et al., Radio: NRAO/M. Middleton et al., Optical: Aladin/STScI DSS. Click to enlarge, see below to download higher resolution.
The discovery of a bingeing black hole in our nearest neighbouring galaxy, Andromeda, has shed new light on some of the brightest X-ray sources seen in other galaxies, according to new work co-authored by astronomers from the International Centre for Radio Astronomy Research’s Curtin University node.
Using a suite of Earth-orbiting X-ray telescopes, including NASA’s Swift and the European Space Agency’s XMM-Newton satellites, a large international team of astronomers watched as the X-ray emission from the black hole – found over 2million light years away – brightened and faded over the course of six months.
The study, published in the prestigious scientific journal Nature, also shows what happens when black holes feast rapidly on the material stripped from a companion star.
It is the second Ultraluminous X-Ray source (ULX) to have been spotted in Andromeda – the Milky Way’s nearest neighboring galaxy – in the past two years.
X-ray telescopes have shown many nearby galaxies to host ULX sources, which can be bright enough to outshine an entire galaxy in X-rays.
Astronomers have spent years debating whether these are black holes just a few times the mass of the Sun which are gorging themselves on gas from an orbiting star, or whether they are more massive black holes eating more sedately.
Lead author Dr Matthew Middleton, who led the latest research while at Durham University, said the findings helped solve this debate.
Dr Middleton, now based at the University of Amsterdam, said: “The black hole we observed in Andromeda is the missing link.
“Our observations tell us that this ultraluminous X-ray source – and by extension, many others – is just a run-of-the-mill black hole, only about ten times the mass of the Sun, that is swallowing material as fast as it can.”
Dr Middleton added: “We watched a black hole go from nibbling daintily at an appetiser to bingeing on the main course, and then gradually slowing down over dessert.”
Black holes in our own Milky Way galaxy are very rarely seen to binge, but when they do, they also launch very powerful beams of material called jets, which are blasted outwards at close to the speed of light, and can be tracked using sensitive radio telescopes.
The team trained the National Science Foundation’s Karl G. Jansky Very Large Array on the black hole, and saw extremely bright radio emission that dropped by a half in just 30 minutes.
“Discovering these radio waves from an ultraluminous X-ray source is the smoking gun, a dead giveaway that these are just normal, everyday black holes,” said co-author Dr James Miller-Jones, of the Curtin University node of the International Centre for Radio Astronomy Research in Perth, Australia.
“This tells us that the region producing radio waves is extremely small in size, no further across than the distance between Jupiter and the Sun.”
This finding was confirmed by zooming in using the world’s most eagle-eyed radio telescope, the Very Long Baseline Array.
This was the first time that radio jets had been detected from a stellar-mass black hole outside our own Milky Way galaxy.
Despite the large distance to Andromeda, the absence of dust and gas in that direction allows an unhindered view of the feast, giving scientists key new insights into how jets are produced by a binging black hole.
Co-author Dr Natasha Hurley-Walker, also from the Curtin University node of the International Centre for Radio Astronomy Research, said: “We were very lucky that this ULX appeared in our local neighbourhood; its proximity meant that we could make these radio observations and demonstrate that the black hole emitting the X-rays is fairly small.”
ICRAR is a joint venture between Curtin University and The University of Western Australia providing research excellence in the field of radio astronomy.
Original Publication: Bright radio emission from an ultraluminous stellar-mass microquasar in M31, by Middleton, MJ, et al is published in Nature. DOI: 10.1038/nature11697
TOP IMAGE….A composite image of our neighbouring galaxy, Andromeda, showing different views of the Ultraluminous X-ray (ULX) source. The background image is an optical (visible) light picture of Andromeda, with the X-ray image (bottom left) taken with the Earth-orbiting XMM-Newton X-ray telescope superimposed. Colours in the X-ray image correspond to different X-ray energies, with red being least energetic and blue being most energetic. The ULX is indicated by the cross-hairs. At the top right is the radio image of the black hole taken with the Very Long Baseline Array radio telescope, showing that the radio emission was coming from an extremely small region of space, and leading the team to infer that the extraordinary amount of X-ray emission they observed was produced by a relatively modest-sized black hole. Image Credit: X-rays: ESA/M. Middleton et al., Radio: NRAO/M. Middleton et al., Optical: Aladin/STScI DSS. LOWER IMAGE….the Ultraluminous X-ray (ULX) source brightening over time in the X-ray images. Credit: Wolfgang Pietsch, Max-Planck-Institut für extraterrestrische Physik (MPE).
Supernova remnant 1987A continues to reveal its secrets
A team of astronomers led by the International Centre for Radio Astronomy Research (ICRAR) have succeeded in observing the death throws of a giant star in unprecedented detail.
An overlay of radio emission (contours) and a Hubble space telescope image of Supernova 1987A. Credit: ICRAR (radio contours) and Hubble (image.) Click to enlarge.
In February of 1987 astronomers observing the Large Magellanic Cloud, a nearby dwarf galaxy, noticed the sudden appearance of what looked like a new star. In fact they weren’t watching the beginnings of a star but the end of one and the brightest supernova seen from Earth in the four centuries since the telescope was invented. By the next morning news of the discovery had spread across the globe and southern hemisphere stargazers began watching the aftermath of this enormous stellar explosion, known as a supernova.
In the two and a half decades since then, the remnant of Supernova 1987A has continued to be a focus for researchers around the world, providing a wealth of information about one of the Universe’s most extreme events.
In research published in the Astrophysical Journal in April, a team of astronomers in Australia and Hong Kong have succeeded in using the Australia Telescope Compact Array, a CSIRO radio telescope in northern New South Wales, to make the highest resolution radio images of the expanding supernova remnant at millimetre wavelengths.
“Imaging distant astronomical objects like this at wavelengths less than 1 centimetre demands the most stable atmospheric conditions. For this telescope these are usually only possible during cooler winter conditions but even then, the humidity and low elevation of the site makes things very challenging,” said lead author, Dr Giovanna Zanardo of ICRAR, a joint venture of Curtin University and The University of Western Australia in Perth.
Unlike optical telescopes, a radio telescope can operate in the daytime and can peer through gas and dust allowing astronomers to see the inner workings of objects like supernova remnants, radio galaxies and black holes.
“Supernova remnants are like natural particle accelerators, the radio emission we observe comes from electrons spiralling along the magnetic field lines and emitting photons every time they turn. The higher the resolution of the images the more we can learn about the structure of this object,” said Professor Lister Staveley-Smith, Deputy Director of ICRAR and CAASTRO, the Centre for All-sky Astrophysics.
Scientists study the evolution of supernovae into supernova remnants to gain an insight into the dynamics of these massive explosions and the interaction of the blast wave with the surrounding medium.
“Not only have we been able to analyse the morphology of Supernova 1987A through our high resolution imaging, we have compared it to X-ray and optical data in order to model its likely history,” said Professor Bryan Gaensler, Director of CAASTRO at the University of Sydney.
The team suspects a compact source or pulsar wind nebula to be sitting in the centre of the radio emission, implying that the supernova explosion did not make the star collapse into a black hole. They will now attempt to observe further into the core and see what’s there.
TOP IMAGE….Radio (contours) (Credit: ICRAR) + Hubble (image overlay) Overlay of the 7-mm radio image observed with the ATCA (brown–yellow colour scale for shades and contours) on the Hubble Space telescope image observed during the same period. (blue–white colour scale). CENTRE IMAGE….Radio image at 7 mm. Credit: ICRAR Radio image of the remnant of SN 1987A produced from observations performed with the Australia Telescope Compact Array (ATCA). LOWER IMAGE….An RGB overlay of the supernova remnant. Credit: ICRAR A Red/Green/Blue overlay of optical, X-Ray and radio observations made by 3 different telescopes. In red are the 7-mm (44GHz) observations made with the Australian Compact Array in New South Wales, in green are the optical observations made by the Hubble Space Telescope, and in blue is an X-ray view of the remnant, observed by Nasa’s space based Chandra X-ray Observatory. BOTTOM IMAGE….Image of the remnant as seen at optical wavelengths with the Hubble Space Telescope in 2011. Credit: NASA, ESA, and P. Challis (Harvard-Smithsonian Center for Astrophysics). High resolution versions
Wandering through the evening sky, on May 4th 2008, planet Mars stood in line with Castor and Pollux, the two bright stars of the constellation Gemini. In this time exposure of the celestial alignment, Mars actually takes on a distinct yellowish hue, contrasting in color with Pollux; a giant star known to have a Jupiter-class planet, and Castor; itself a multiple star system. Though in mythology Pollux and Castor are twin brothers, the two stars are physically unrelated and are about 34 and 50 light-years distant respectively. Included in the skyview are Procyon, alpha star of Canis Minor, and famous star cluster M44 also known as the Beehive Cluster. Dust in our own solar system reflecting sunlight creates the faint band of Zodiacal light emerging from the lower right corner of the frame.
Noise, in analog video and television, is a random dot pattern of static displayed when no transmission signal is obtained by the antenna receiver of television set and other display devices. The random pattern superimposed on the picture, visible as a random flicker of “dots” or “snow”, is the result of electronic noise and radiated electromagnetic noise accidentally picked up by the antenna. This effect is most commonly seen with analog TV sets or blank VHS tapes.
There are many sources of electromagnetic noise which cause the characteristic display patterns of static. Atmospheric sources of noise are the most ubiquitous, and include electromagnetic signals prompted by cosmic microwave background radiation, or more localized radio wave noise from nearby electronic devices.
Microwaves are a low-energy form of radiation but higher in energy than radio waves. The cosmic microwave background blankets the universe and is responsible for a sizeable amount of static on your television set—well, before the days of cable. Turn your television to an “in between” channel, and part of the static you’ll see is the afterglow of the big bang.