Science & Technology


Mysterious phenomena in a gigantic galaxy-cluster collision

© Owen et al., NRAO/AUI/NSF
Abell 2256, in a "true color" radio image made with the VLA.
Researchers using the Karl G. Jansky Very Large Array (VLA) have produced the most detailed image yet of a fascinating region where clusters of hundreds of galaxies are colliding, creating a rich variety of mysterious phenomena visible only to radio telescopes.

The scientists took advantage of new VLA capabilities to make a "true color" radio image. This image shows the region as it would appear if human eyes were sensitive to radio waves instead of light waves. In this image, red shows where longer radio waves predominate, and blue shows where shorter radio waves predominate, following the pattern we see in visible light.

The image shows a number of strange features the astronomers think are related to an ongoing collision of galaxy clusters. The region is called Abell 2256, and is about 800 million light-years from Earth and some 4 million light-years across. The image covers an area in the sky almost as large as the full moon. Studied by astronomers for more than half a century with telescopes ranging from radio to X-ray, Abell 2256 contains a fascinating variety of objects, many of whose exact origins remain unclear.


Scientists surprised by rotating cosmic dust discs withstanding hellfire in Milky Way

© HST/Spitzer composite: NASA, ESA, D.Q. Wang (UMass), JPL, S. Stolovy (Spitzer Science Center)
The star clusters „Arches“ and „Quintuplet“ in the centre of the Milky Way: Intense wind and radiation forces of massive stars in the Quintuplet excavated the dense gas clouds surrounding the cluster, as indicated by the arrows. The dust discs around smaller stars living in these clusters are exposed to the same harsh environment and should not survive for long periods of time.
A team of scientists led by astronomers at the University of Bonn discovered an unusual phenomenon in the centre of the Milky Way: They detected about 20 rotating dust and gas discs in each cluster hosting exceptionally large and hot stars. The existence of these discs in the presence of the destructive UV radiation field of their massive neighbours came as a surprise. The science team is pondering how these rotating discs are able to withstand evaporation under these extreme conditions. The results are published in the most recent edition of the journal Astronomy & Astrophysics.

The centre of the Milky Way is a nursery for young stars: In its very heart, more young stars are born in dark clouds than in any other place in the Galaxy. These stars form in rich groups such as the "Quintuplet" and "Arches" clusters which were the research focus of a science team under leadership of the University of Bonn's Argelander Institute for Astronomy. Both star clusters are merely a few million years young and contain stars as massive as 100 times the mass of the Sun. "We expected that the enormous radiative energy of these giant beasts evaporate the material around their smaller neighbours in less than one million years," says Dr. Andrea Stolte of the Argelander Institute for Astronomy at the University of Bonn.


Venus, if you will, as seen in radar with the Green Bank Telescope

© B. Campbell, Smithsonian, et al., NRAO/AUI/NSF, Arecibo
A projection of the radar data of Venus collected in 2012. Striking surface features -- like mountains and ridges -- are easily seen. The black diagonal band at the center represents areas too close to the Doppler “equator” to obtain well-resolved image data.
From earthbound optical telescopes, the surface of Venus is shrouded beneath thick clouds made mostly of carbon dioxide. To penetrate this veil, probes like NASA's Magellan spacecraft use radar to reveal remarkable features of this planet, like mountains, craters, and volcanoes.

Recently, by combining the highly sensitive receiving capabilities of the National Science Foundation's (NSF) Green Bank Telescope (GBT) and the powerful radar transmitter at the NSF's Arecibo Observatory, astronomers were able to make remarkably detailed images of the surface of this planet without ever leaving Earth.

The radar signals from Arecibo passed through both our planet's atmosphere and the atmosphere of Venus, where they hit the surface and bounced back to be received by the GBT in a process known as bistatic radar.


Star explodes 4 times in this rare phenomenon

Thanks to a rare cosmic phenomenon, astronomers were able to witness an ancient, distant star explode as a supernova not once or twice, but on four separate occasions, according to a research published online Friday in the journal Science.

According to Space Daily, the supernova occurred directly behind a cluster of large galaxies that had enough combined mass to warp space-time. This forms a cosmic magnifying glass similar to the phenomenon of gravitational lensing, but which creates multiple images of the star.

This effect is known as an Einstein Cross, and the Washington Post explained that it was first predicted by Albert Einstein's General Theory of Relativity roughly a century ago. Because the cluster was located between the supernova (which was nine billion light years away) and the instrument imaging it, the same explosion showed up around the galaxy four times.


Electromagnetic memory promises faster and more energy efficient information storage

© iStock/Ninety1foto
A developing form of computer memory has the potential to store information more quickly and more cheaply, while using less energy, than what’s used today by the semiconductor industry, NYU Physics Professor Andrew Kent concludes in an analysis that appeared in the journal Nature Nanotechnology.
A developing form of computer memory has the potential to store information more quickly and more cheaply, while using less energy, than what's used today by the semiconductor industry, NYU Physics Professor Andrew Kent concludes.

In an analysis that appears in the journal Nature Nanotechnology, Kent and his colleague Daniel Worledge of the IBM Watson Research Center discuss a new type of memory, spin-transfer-torque magnetic random access memory (STT-MRAM).

STT-MRAM relies on magnetism to store information, like that used in existing hard drives. However, in contrast to hard drives, STT-MRAM is written and read electrically—that is, by applying only electric currents. It does not have moving parts like a magnetic hard drive and therefore can operate much faster than a hard drive. More significantly, STT-MRAM can operate as fast as the fastest semiconductor based random access memories, and thus be used as a computer and portable device's (e.g. smartphone) working memory—a memory that is accessed frequently.

As a result, these magnetic devices can used to improve the performance of such devices, adding speed while, at the same time, greatly reducing the amount of energy needed.


Urinicity - Electricity produced from urine enough to power lights

A toilet, conveniently situated near the Student Union Bar at the University of the West of England (UWE Bristol), is proving that urine can generate electricity.

The prototype urinal is the result of a partnership between researchers at UWE Bristol and Oxfam. It is hoped the pee-power technology will light cubicles in refugee camps, which are often dark and dangerous places particularly for women.

Students and staff are being asked to use the urinal to donate pee to fuel microbial fuel cell (MFC) stacks that generate electricity to power indoor lighting.

The research team is led by Professor Ioannis Ieropoulos, Director of the Bristol BioEnergy Centre located in the Bristol Robotics Laboratory at UWE Bristol.

Professor Ieropoulos says, "We have already proved that this way of generating electricity works. Work by the Bristol BioEnergy Centre hit the headlines in 2013 when the team demonstrated that electricity generated by microbial fuel cell stacks could power a mobile phone. This exciting project with Oxfam could have a huge impact in refugee camps.


Fastest star ever observed will escape from the galaxy

Hyperfast stars point to black hole slingshot.
The compact star US 708 hasn't had an easy life. Paired with a domineering partner, 708's mass was siphoned away, reducing it to a dense, helium-filled core.

In nearby galaxy M82, a star is exploding ... and you can see it! M82 is actually filled with stars being created and dying. Trace reports on this exploding news and tells you everything you want to know about supernovas.

But 708 didn't go quietly into the night. Instead, scientists believe the feeding frenzy ended in a supernova explosion that catapulted the ravaged remains with such force it's leaving the galaxy. Fast.

Observation by NASA's Chandra X-ray Observatory shows the emissions of G299, a type-1a supernova remnant triggered by one star dragging matter from a binary partner until it exploded.
A new study shows that the star, classified as a hot subdwarf, is blasting through the Milky Way at about 750 miles per second, faster than any other star in the galaxy.

It's also the only one of about 20 similar runaways slingshot away by a supernova explosion, research published in this week's Science shows.

The other stars traveling fast enough to leave the Milky Way's gravitational fist are believed to have been booted by the supermassive black hole lurking in the center of the galaxy.

Comment: There is no specific evidence that traces trajectories back to a central black hole, but, to date, there are no other explanations for a mechanism that would impart so much kinetic energy onto a star. The theory is a star could slingshot out of a binary star system if the stellar duo swung close to a central black hole. The hole's gravitational tidal forces would break apart the duo's gravitational coupling. One of the pair would plunge toward the black hole. The other would fly with matching velocity in the opposite direction, away from the black hole. So far, 16 of these hypervelocity stars are known, the first detected in 2005. The single giant black hole propulsion theory is supported by observations that show the stars seem spaced sequentially, like a series of fired cannonballs. It is speculated that a sun like ours, under these conditions, would carry its planetary system with it.


A new level of understanding earthquakes on a microscopic scale

© Berkeley Labs
As everyone who lives in the San Francisco Bay Area knows, the Earth moves under our feet. But what about the stresses that cause earthquakes? How much is known about them? Until now, our understanding of these stresses has been based on macroscopic approximations.

Now, the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) is reporting the successful study of stress fields along the San Andreas fault at the microscopic scale, the scale at which earthquake-triggering stresses originate.

Working with a powerful microfocused X-ray beam at Berkeley Lab's Advanced Light Source (ALS), a DOE Office of Science User Facility, researchers applied Laue X-ray microdiffraction, a technique commonly used to map stresses in electronic chips and other microscopic materials, to study a rock sample extracted from the San Andreas Fault Observatory at Depth (SAFOD). The results could one day lead to a better understanding of earthquake events.

"Stresses released during an earthquake are related to the strength of rocks and thus in turn to the rupture mechanism," says Martin Kunz, a beamline scientist with the ALS's Experimental Systems Group.

"We found that the distribution of stresses in our sample were very heterogeneous at the micron scale and much higher than what has been reported with macroscopic approximations. This suggests there are different processes at work at the microscopic and macroscopic scales."

Kunz is one of the co-authors of a paper describing this research in the journal Geology. The paper is titled "Residual stress preserved in quartz from the San Andreas Fault Observatory at Depth." Co-authors are Kai Chen, Nobumichi Tamura and Hans-Rudolf Wenk.

Most earthquakes occur when stress that builds up in rocks along active faults, such as the San Andreas, is suddenly released, sending out seismic waves that make the ground shake. The pent- up stress results from the friction caused by tectonic forces that push two plates of rock against one another.

Comment: It is possible that some some earthquakes could be caused by meteorites breaking up in the atmosphere. Read Earth Changes and the Human-Cosmic Connection by Pierre Lescaudron and Laura Knight-Jadczyk for more details.

See also:
Earthquake frequency increasing: Rate of strong quakes doubles in 2014


The red and blue planet: Mars once had massive ocean in N. hemisphere

© ESO/M. Kornmesser/N. Risinger
This artist’s impression shows how Mars may have looked about four billion years ago. The young planet Mars would have had enough water to cover its entire surface in a liquid layer about 140 meters deep, but it is more likely that the liquid would have pooled to form an ocean occupying almost half of Mars’s northern hemisphere.
Mars was once a small, wet and blue world, but over the past 4 billion years, Mars dried up and became the red dust bowl we know today.

But how much water did Mars possess? According to research published in the journal Science, the Martian northern hemisphere was likely covered in an ocean, covering a region of the approximate area as Earth's Atlantic Ocean, plunging, in some places, to 1.6 kilometers (1 mile) deep.

"Our study provides a solid estimate of how much water Mars once had, by determining how much water was lost to space," said Geronimo Villanueva, of NASA's Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the new paper, in an ESO news release. "With this work, we can better understand the history of water on Mars."

Over a 6-year period, Villanueva and his team used the ESO's Very Large Telescope (in Chile) and instruments at the W. M. Keck Observatory and the NASA Infrared Telescope Facility (both on Mauna Kea in Hawaii) to study the distribution of water molecules in the Martian atmosphere. By building a comprehensive map of water distribution and seasonal changes, they were able to arrive at this startling conclusion.


Brain ages less than previously thought

Older brains may be more similar to younger brains than previously thought.

In a new paper published in Human Brain Mapping, BBSRC-funded researchers at the University of Cambridge and Medical Research Council's Cognition and Brain Sciences Unit demonstrate that previously reported changes in the aging brain using functional magnetic resonance imaging (fMRI) may be due to vascular (or blood vessels) changes, rather than changes in neuronal activity itself.

Given the large number of fMRI studies used to assess the aging brain, this has important consequences for understanding how the brain changes with age and challenges current theories of aging.

A fundamental problem of fMRI is that it measures neural activity indirectly through changes in regional blood flow. Thus, without careful correction for age differences in vasculature reactivity, differences in fMRI signals can be erroneously regarded as neuronal differences.