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Sent: 12/11/2012 6:37:16 P.M. Eastern Standard Time
Subj: The Daily Galaxy: News from Planet Earth & Beyond
_The Daily Galaxy: News from Planet Earth & Beyond_
_"We May be Living in a Massive Computer-Generated Universe" --Physicists
Say Its Reality Can Now Be Tested_
Posted: 11 Dec 2012 07:57 AM PST
The idea that we may be living in a computer generated universe that has
been debated by the greats of philosphy, from _Plato_
(http://en.wikipedia.org/wiki/Plato) to _Descartes_ (http://en.wikipedia.org/wiki/René_Descartes)
, who speculated that the world we see around us could be generated by an
'evil demon'. Plato wrote that reality may be no more than shadows in a cave
but the human species, having never left the cave, may not be aware of
it.More recently, the concept that current humanity could possibly be living
in a computer simulation comes from a 2003 paper published in Philosophical
Quarterly by _Nick Bostrom_ (http://www.nickbostrom.com/) , a philosophy
professor at the _University of Oxford_
(http://maps.google.com/maps?ll=51.7611,-1.2534&spn=0.01,0.01&q=51.7611,-1.2534 (University%20of%20Oxford)&t=h) .
In the paper, he argued that at least one of three possibilities is true:
(1) The human species is likely to go extinct before reaching a “posthuman”
stage; (2) Any posthuman civilization is very unlikely to run a
significant number of simulations of its evolutionary history. We are almost
certainly living in a computer simulation; (3) “the belief that there is a
significant chance that we will one day become posthumans who run ancestor
simulations is false, unless we are currently living in a simulation.”
The conical (red) surface shows the relationship between energy and
momentum in special relativity, a fundamental theory concerning space and time
developed by Albert Einstein, and is the expected result if our universe is
not a simulation. The flat (blue) surface illustrates the relationship
between energy and momentum that would be expected if the universe is a
simulation with an underlying cubic lattice.
With current limitations and trends in computing, it will be decades
before researchers will be able to run even primitive simulations of the
universe. But now a team of physicists at the University of Washington has come up
with a potential test to see if the idea holds water. The team has
suggested tests that can be performed now, or in the near future, that are
sensitive to constraints imposed on future simulations by limited resources.
Currently, supercomputers using a technique called lattice quantum
chromodynamics and starting from the fundamental physical laws that govern the
universe can simulate only a very small portion of the universe, on the scale
of one 100-trillionth of a meter, a little larger than the nucleus of an
atom, said _Martin Savage_ (http://en.wikipedia.org/wiki/Martin_Savage) , a UW
Eventually, more powerful simulations will be able to model on the scale
of a molecule, then a cell and even a human being. But it will take many
generations of growth in computing power to be able to simulate a large enough
chunk of the universe to understand the constraints on physical processes
that would indicate we are living in a computer model.
However, Savage said, there are signatures of resource constraints in
present-day simulations that are likely to exist as well in simulations in the
distant future, including the imprint of an underlying lattice if one is
used to model the _space-time continuum_
The supercomputers performing lattice quantum chromodynamics calculations
essentially divide space-time into a four-dimensional grid. That allows
researchers to examine what is called the strong force, one of the four
fundamental forces of nature and the one that binds subatomic particles called
quarks and gluons together into neutrons and protons at the core of atoms.
“If you make the simulations big enough, something like our universe
should emerge,” Savage said. Then it would be a matter of looking for a “
signature” in our universe that has an analog in the current small-scale
Savage and colleagues Silas Beane of the _University of New Hampshire_
33 (University%20of%20New%20Hampshire)&t=h) , who collaborated while at
the UW’s Institute for Nuclear Theory, and Zohreh Davoudi, a UW physics
graduate student, suggest that the signature could show up as a limitation in
the energy of cosmic rays.
In a paper they have posted on _arXiv_ (http://arxiv.org/) , an online
archive for preprints of scientific papers in a number of fields, including
physics, they say that the highest-energy cosmic rays would not travel along
the edges of the lattice in the model but would travel diagonally, and they
would not interact equally in all directions as they otherwise would be
expected to do.*“This is the first testable signature of such an idea,”
If such a concept turned out to be reality, it would raise other
possibilities as well. For example, Davoudi suggests that if our universe is a
simulation, then those running it could be running other simulations as well,
essentially creating other universes parallel to our own.
“Then the question is, ‘Can you communicate with those other universes if
they are running on the same platform?’” she said.
Elsewhere this fall, Professor Silas Beane, a theoretical physicist at the
_University of Bonn_
(University%20of%20Bonn)&t=h) in Germany said that his group of scientists have developed a way to
test the 'simulation hypothesis'. If the cosmos is a numerical simulation,
there ought to be clues in the spectrum of high energy cosmic rays. Now
more than two thousand years since Plato suggested that our senses provide
only a weak reflection of objective reality, experts believe they have solved
the riddle using mathetical models known as the _lattice QCD_
(http://en.wikipedia.org/wiki/Lattice_QCD) approach in an attempt to recreate - on a
theoretical level - a simulated reality. Lattice QCD is a complex approach that
that looks at how particles known as quarks and gluons relate in three
"We consider ourselves on some level universe simulators because we
calculate the interactions of particles by basically replacing space and time by
a grid and putting it in a box," said Beane. "In doing that we face lots of
problems for instance the box and the grid size breaks _Einstein's special
theory of relativity_
(http://www.dailygalaxy.com/my_weblog/2012/10/new-math-allows-for-travel-beyond-speed-of-light.html) so we know how to fix this
in order to get physical predictions that are meaningful."
"We thought that if we make the assumption that the so-called simulators
face some of the same problems that we do in terms of finite resources and
so on then, if they are doing a simulation and even though their box size of
course is enormous and the grid size can be very small, as long as the
resources are finite then the box size will be finite, the grid size will be
finite," Beane added. "And therefore at some level for instance there would
be violations of Einstein's special theory of relativity."
According to _MIT's Technology Review,_
tion/) "using the world's most powerful supercomputers, physicists have
only managed to simulate tiny corners of the cosmos just a few femtometers
across (A femtometer is 10^-15 meters.) That may not sound like much but the
significant point is that the simulation is essentially indistinguishable
from the real thing (at least as far as we understand it)."
As _Carl Sagan_
said, extraordinary claims require extraordinary evidence.The image at the
top of the page image shows a smoothed reconstruction of the total (mostly
dark) matter distribution in the COSMOS field, created from data taken by
the NASA/ESA Hubble Space Telescope and ground-based telescopes. It was
inferred from the weak gravitational lensing distortions that are imprinted
onto the shapes of background galaxies. The colour coding indicates the
distance of the foreground mass concentrations as gathered from the weak lensing
effect. Structures shown in white, cyan, and green are typically closer to
us than those indicated in orange and red. To improve the resolution of
the map, data from galaxies both with and without redshift information were
The Daily Galaxy via _http://www.washington.edu/news_
(http://www.washington.edu/news) , _New Scientist_ (mip://0f4c67f0/www.newscientist.com) and
(http://www.dailygalaxy.com/my_weblog/2012/10/massive-cloud-set-for-close-encounter-with-milky-ways-central-black-hole-1.html) _Massive "G2" Cloud
Sucked Into Close Encounter with Milky Way's Central Black Hole_
(http://www.dailygalaxy.com/my_weblog/2012/11/monster-quasar-discovered-with-power-outflow-100-times-milky-way-galaxy.html) _Monster Quasar Discovered
with Power Outflow 100 Times Milky Way Galaxy_
_Sulfate-Feeding Microbes Active in Earth's Oceans 2.7 Billion Years Ago_
Posted: 10 Dec 2012 09:22 PM PST
Scientists probing _sulfide ore_ (http://en.wikipedia.org/wiki/Sulfide)
deposits from one of the world's richest base-metal mines confirmed that
oxygen levels were extremely low on Earth 2.7 billion years ago, but also shows
that microbes were actively feeding on sulfate in the ocean and
influencing seawater chemistry during that geological time period. The research,
reported by a team of Canadian and U.S. scientists in _Nature Geoscience_
(http://www.nature.com/ngeo/) , provides new insight into how ancient metal-ore
deposits can be used to better understand the chemistry of the ancient
oceans – and the early evolution of life._Sulfate_
(http://en.wikipedia.org/wiki/Sulfate) is the second most abundant dissolved ion in the oceans today.
It comes from the "rusting" of rocks by atmospheric oxygen, which creates
sulfate through chemical reactions with pyrite, the iron sulfide material
known as "fool's gold."
The researchers, led by PhD student _John Jamieson_
(http://en.wikipedia.org/wiki/John_Jamieson) of the University of Ottawa and Prof. Boswell Wing
of McGill, measured the "weight" of sulfur in samples of massive sulfide ore
from the _Kidd Creek_
copper-zinc mine in Timmins, Ontario, using a highly sensitive instrument
known as a mass spectrometer.
The weight is determined by the different amounts of isotopes of sulfur in
a sample, and the abundance of different isotopes indicates how much
seawater sulfate was incorporated into the massive sulfide ore that formed at
the bottom of ancient oceans. That ancient ore is now found on the Earth's
surface, and is particularly common in the Canadian shield.
The scientists found that much less sulfate was incorporated into the 2.7
billion-year-old ore at Kidd Creek than is incorporated into similar ore
forming at the bottom of oceans today. From these measurements, the
researchers were able to model how much sulfate must have been present in the
ancient seawater. Their conclusion: sulfate levels were about 350 times lower
than in today's ocean. Though they were extremely low, sulfate levels in the
ancient ocean still supported an active global population of microbes that
use sulfate to gain energy from organic carbon.
"The sulfide ore deposits that we looked at are widespread on Earth, with
Canada and Quebec holding the majority of them," says Wing, an associate
professor in McGill's Department of Earth and Planetary Science. "We now have
a tool for probing when and where these microbes actually came into global
"Deep within a copper-zinc mine in northern Ontario that was once a
volcanically active ancient seafloor may not be the most intuitive place one
would think to look for clues into the conditions in which the earliest
microbes thrived over 2.7 billion years ago," Jamieson adds. "However, our
increasing understanding of these ancient environments and our abilities to
analyze samples to a very high precision has opened the door to further our
understanding of the conditions under which life evolved."
For more information:
www.nature.com/ngeo/journal/vaop/ncurrent/abs/ngeo1647.html Journal reference: Nature Geoscience *
Image below shows ne of the sulfide ore samples analyzed for the study.
The bright area in the lower left, a "sulfide nodule," preserves isotopic
evidence of the presence of microbes that fed on sulfate in the ancient ocean.
The Daily Galaxy via _McGill University_
(McGill%20University)&t=h) Image credit: Mark. D. Hannington Related articles
(http://www.dailygalaxy.com/my_weblog/2012/10/first-analysis-of-14-million-year-old-antarctica-lake-fails-to-yield-microbes.html) _First Analysis of
14-Million-Year Old Antarctica Lake Fails to Yield Microbes_
_Ancient Microbial Life Found Thriving in Permanent Darkness 60 Feet Beneath
ancient ores for clues to early life_
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- Three interesting posts on The Daily Galaxy blog.Chris
Sent: 2/11/2014 6:40:22 P.M. Eastern Standard Time
Subj: The Daily Galaxy: News from Planet Earth & Beyond
- NOVA Experiment Sees 1st Neutrinos --Clues to Early Moments of the Universe
- "In the 'Blink of an Eye": Largest Mass Extinction in Earth's History --MIT Researchers
- Image of the Day --Clues Found that Liquid Water May Exist on Mars Today
Posted: 11 Feb 2014 07:29 AM PST
Scientists on the world’s longest-distance neutrino experiment announced today that they have seen their first neutrinos. The NOvA experiment consists of two huge particle detectors placed 500 miles apart, and its job is to explore the properties of an intense beam of ghostly particles called neutrinos. Neutrinos are abundant in nature, but they very rarely interact with other matter. Studying them could yield crucial information about the early moments of the universe.Different types of neutrinos have different masses, but scientists do not know how these masses compare to one another. A goal of the NOvA experiment is to determine the order of the neutrino masses, known as the mass hierarchy, which will help scientists narrow their list of possible theories about how neutrinos work.
Billions of those particles are sent through the earth every two seconds, aimed at the massive detectors. Once the experiment is fully operational, scientists will catch a precious few each day .
Neutrinos are curious particles. They come in three types, called flavors, and change between them as they travel. The two detectors of the NOvA experiment are placed so far apart to give the neutrinos the time to oscillate from one flavor to another while traveling at nearly the speed of light. Even though only a fraction of the experiment’s larger detector, called the far detector, is fully built, filled with scintillator and wired with electronics at this point, the experiment has already used it to record signals from its first neutrinos.
Scientists generate a beam of the particles for the NOvA experiment using one of the world’s largest accelerators, located at the Department of Energy’s Fermi National Accelerator Laboratory near Chicago. They aim this beam in the direction of the two particle detectors, one near the source at Fermilab and the other in Ash River, Minn., near the Canadian border. The detector in Ash River is operated by the University of Minnesota under a cooperative agreement with the Department of Energy’s Office of Science.
Once completed, NOvA’s near and far detectors will weigh 300 and 14,000 tons, respectively. Crews will put into place the last module of the far detector early this spring and will finish outfitting both detectors with electronics in the summer.
“The first neutrinos mean we’re on our way,” said Harvard physicist Gary Feldman, who has been a co-leader of the experiment from the beginning. “We started meeting more than 10 years ago to discuss how to design this experiment, so we are eager to get under way.”
The NOvA collaboration is made up of 208 scientists from 38 institutions in the United States, Brazil, the Czech Republic, Greece, India, Russia and the United Kingdom. The experiment receives funding from the U.S. Department of Energy, the National Science Foundation and other funding agencies.
The NOvA experiment is scheduled to run for six years. Because neutrinos interact with matter so rarely, scientists expect to catch just about 5,000 neutrinos or antineutrinos during that time. Scientists can study the timing, direction and energy of the particles that interact in their detectors to determine whether they came from Fermilab or elsewhere.
Fermilab creates a beam of neutrinos by smashing protons into a graphite target, which releases a variety of particles. Scientists use magnets to steer the charged particles that emerge from the energy of the collision into a beam. Some of those particles decay into neutrinos, and the scientists filter the non-neutrinos from the beam.
Fermilab started sending a beam of neutrinos through the detectors in September, after 16 months of work by about 300 people to upgrade the lab’s accelerator complex.
“Seeing neutrinos in the first modules of the detector in Minnesota is a major milestone,” said Fermilab physicist Rick Tesarek, deputy project leader for NOvA. “Now we can start doing physics.”
The image at the top of the page shows a galaxy cluster in the Early Universe that lies nearly 9 billion light-years away ... and existed at a time when the Universe was less than 5 billion years old. A measured mass of more than 200 trillion Suns makes this galaxy cluster the most massive object ever found when the Universe was so young. The cluster elemental abundances are consistent with the idea that most heavy elements were synthesized early on by massive stars, but current theories suggest that such a massive cluster should be rare in the early Universe.
The Daily Galaxy via FERMILab
Image credit: Credit: P.Rosati (ESO) et al.; X-Ray: CXC, NASA / Optical: ESO, VLT
Posted: 11 Feb 2014 08:34 AM PST
It was the greatest extinction event of all time (at least by Earth standards): Since the first organisms appeared on Earth approximately 3.8 billion years ago, life on the planet has had some close calls. In the last 500 million years, Earth has undergone five mass extinctions, including the event 66 million years ago that wiped out the dinosaurs. And while most scientists agree that a giant asteroid was responsible for that extinction, there’s much less consensus on what caused an even more devastating extinction, the end-Permian extinction, that occurred 252.2 million years ago, decimating 90 percent of marine and terrestrial species, from snails and small crustaceans to early forms of lizards and amphibians.“The Great Dying,” as it’s now known, was the most severe mass extinction in Earth’s history, and is probably the closest life has come to being completely extinguished. Possible causes include immense volcanic eruptions, rapid depletion of oxygen in the oceans, and — an unlikely option — an asteroid collision.
While the causes of this global catastrophe are unknown, an MIT-led team of researchers established in that the end-Permian extinction was extremely rapid, triggering massive die-outs both in the oceans and on land in less than 20,000 years — the blink of an eye in geologic time. The MIT team also found that this time period coincides with a massive buildup of atmospheric carbon dioxide, which likely triggered the simultaneous collapse of species in the oceans and on land.
“We’ve got the extinction nailed in absolute time and duration,” says Sam Bowring, the Robert R. Shrock Professor of Earth and Planetary Sciences at MIT. “How do you kill 96 percent of everything that lived in the oceans in tens of thousands of years? It could be that an exceptional extinction requires an exceptional explanation.”
The research team at MIT has determined that the end-Permian extinction occurred over 60,000 years, give or take 48,000 years — practically instantaneous, from a geologic perspective. The new timescale is based on more precise dating techniques, and indicates that the most severe extinction in history may have happened more than 10 times faster than scientists had previously thought.
In addition to establishing the extinction’s duration, Bowring, graduate student Seth Burgess, and a colleague from the Nanjing Institute of Geology and Paleontology also found that, 10,000 years before the die-off, , the oceans experienced a pulse of light carbon, which likely reflects a massive addition of carbon dioxide to the atmosphere. This dramatic change may have led to widespread ocean acidification and increased sea temperatures by 10 degrees Celsius or more, killing the majority of sea life.
But what originally triggered the spike in carbon dioxide? The leading theory among geologists and paleontologists has to do with widespread, long-lasting volcanic eruptions from the Siberian Traps, a region of Russia whose steplike hills are a result of repeated eruptions of magma. To determine whether eruptions from the Siberian Traps triggered a massive increase in oceanic carbon dioxide, Burgess and Bowring are using similar dating techniques to establish a timescale for the Permian period’s volcanic eruptions that are estimated to have covered over five million cubic kilometers.
“It is clear that whatever triggered extinction must have acted very quickly,” says Burgess, the lead author of a paper that reports the results in this week’s Proceedings of the National Academy of Sciences, “fast enough to destabilize the biosphere before the majority of plant and animal life had time to adapt in an effort to survive.”
In 2006, Bowring and his students made a trip to Meishan, China, a region whose rock formations bear evidence of the end-Permian extinction; geochronologists and paleontologists have flocked to the area to look for clues in its layers of sedimentary rock. In particular, scientists have focused on a section of rock that is thought to delineate the end of the Permian, and the beginning of the Triassic, based on evidence such as the number of fossils found in surrounding rock layers.
Bowring sampled rocks from this area (above), as well as from nearby alternating layers of volcanic ash beds and fossil-bearing rocks. After analyzing the rocks in the lab, his team reported in 2011 that the end-Permian likely lasted less than 200,000 years. However, this timeframe still wasn’t precise enough to draw any conclusions about what caused the extinction.
Now, the team has revised its estimates using more accurate dating techniques based on a better understanding of uncertainties in timescale measurements.
With this knowledge, Bowring and his colleagues reanalyzed rock samples collected from five volcanic ash beds at the Permian-Triassic boundary. The researchers pulverized rocks and separated out tiny zircon crystals containing a mix of uranium and lead. They then isolated uranium from lead, and measured the ratios of both isotopes to determine the age of each rock sample.
From their measurements, the researchers determined a much more precise “age model” for the end-Permian extinction, which now appears to have lasted about 60,000 years — with an uncertainty of 48,000 years — and was immediately preceded by a sharp increase in carbon dioxide in the oceans.
The new timeline adds weight to the theory that the extinction was triggered by massive volcanic eruptions from the Siberian Traps that released volatile chemicals, including carbon dioxide, into the atmosphere and oceans. With such a short extinction timeline, Bowring says it is possible that a single, catastrophic pulse of magmatic activity triggered an almost instantaneous collapse of all global ecosystems.
Andrew Knoll, a professor of earth and planetary sciences at Harvard University, says the group’s refined timeline will give scientists an opportunity to test whether the timing of the Siberian Traps eruptions coincides with the extinction.
“Most mechanisms proposed to account for the observed pattern of extinction rely on rapid environmental change, so the sharp constraints on timing also serve as tests of these ideas,” Knoll says. “[This new timeline] bring us closer to the resolution of a major problem posed by the geologic record.”
To confirm whether the Siberian Traps are indeed the extinction’s smoking gun, Burgess and Bowring plan to determine an equally precise timeline for the Siberian Traps eruptions, and will compare it to the new extinction timeline to see where the two events overlap. The researchers will investigate additional areas in China to see if the duration of the extinction can be even more precisely determined.
“We’ve refined our approach, and now we have higher accuracy and precision,” Bowring says. “You can think of it as slowly spiraling in toward the truth.”
The Daily Galaxy via MIT
Image Credit: With thanks to the Houston Museum
Posted: 10 Feb 2014 02:26 AM PST
Researchers call these dark flows "recurring slope lineae." As a result, RSL has become one of the hottest acronyms at meetings of Mars scientists.
NASA spacecraft orbiting Mars have returned clues for understanding seasonal features that are the strongest indication of possible liquid water that may exist today on the Red Planet. The features are dark, finger-like markings that advance down some Martian slopes when temperatures rise. The new clues include corresponding seasonal changes in iron minerals on the same slopes and a survey of ground temperatures and other traits at active sites. These support a suggestion that brines with an iron-mineral antifreeze, such as ferric sulfate, may flow seasonally, though there are still other possible explanations.
"We still don't have a smoking gun for existence of water in RSL, although we're not sure how this process would take place without water," said Lujendra Ojha, a graduate student at the Georgia Institute of Technology, Atlanta, and lead author of two new reports about these flows. He originally discovered them while an undergraduate at the University of Arizona, Tucson, three years ago, in images from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter.
Ojha and Georgia Tech assistant professor James Wray more recently looked at 13 confirmed RSL sites using images from the same orbiter's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument. They searched for minerals that RSL might leave in their wake as a way of understanding the nature of these features: water-related or not?
They didn't find any spectral signature tied to water or salts. But they did find distinct and consistent spectral signatures of ferric and ferrous minerals at most of the sites. These iron-bearing minerals were more abundant or featured distinct grain sizes in RSL-related materials as compared to non-RSL slopes. These results are in a paper published in the journal Geophysical Research Letters.
Ojha said, "Just like the RSL themselves, the strength of the spectral signatures varies according to the seasons. They're stronger when it's warmer and less significant when it's colder."
One possible explanation for these changes is a sorting of grain sizes, such as removal of fine dust from the surface, which could result from either a wet process or dry one. Two other possible explanations are an increase in the more-oxidized (ferric) component of the minerals, or an overall darkening due to moisture. Either of these would point to water, even though no water was directly detected. The spectral observations might miss the presence of water, because the dark flows are much narrower than the area of ground sampled with each CRISM reading. Also, the orbital observations have been made only in afternoons and could miss morning moisture.
The leading hypothesis for these features is the flow of near-surface water, kept liquid by salts depressing the freezing point of pure water. "The flow of water, even briny water, anywhere on Mars today would be a major discovery, impacting our understanding of present climate change on Mars and possibly indicating potential habitats for life near the surface on modern Mars," said Mars Reconnaissance Orbiter Project Scientist Richard Zurek, of NASA's Jet Propulsion Laboratory, Pasadena, Calif.
In related research, reported in a paper to be published by the journal Icarus next month, the Georgia Tech scientists and colleagues at the University of Arizona; U.S. Geological Survey, Flagstaff, Ariz.; and Polish Academy of Sciences, Warsaw, used the Mars Reconnaissance Orbiter and NASA's Mars Odyssey orbiter to look for patterns in where and when the dark seasonal flows exist on Mars. Their results indicate that many sites with slopes, latitudes and temperatures matching known RSL sites do not have any evident RSL.
They hunted for areas that were ideal locations for RSL formation: areas near the southern mid-latitudes on rocky cliffs. They found 200, but barely any of them had RSL. "Only 13 of the 200 locations had confirmed RSL," said Ojha. "The fact that RSL occur in a few sites and not others indicates additional unknown factors such as availability of water or salts may play a crucial role in RSL formation."
They compared new observations with images from previous years, revealing that RSL are much more abundant some years than others.
"NASA likes to 'follow the water' in exploring the Red Planet, so we'd like to know in advance when and where it will appear," Wray said. "RSL have rekindled our hope of accessing modern water, but forecasting wet conditions remains a challenge."
This image combines a photograph of seasonal dark flows on a Martian slope with a grid of colors based on data collected by a mineral-mapping spectrometer observing the same area. The area is at Palikir Crater in the southern hemisphere of Mars. These dark, warm-season flows are called "recurring slope lineae" or RSL. Researchers are using observations from Mars orbiters to study the possibility that RSL result from action of salty liquid water. This image was included in a paper by Lujendra Ojha of Georgia Institute of Technology, Atlanta, and co-authors in Geophysical Research Letters.
The photograph is from the High Resolution Imaging Science Experiment (HiRISE) camera. The composition information, as an image with pixels appearing as a grid of squares, is from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). Both of these instruments are on NASA's Mar Reconnaissance Orbiter. The view is oriented with north toward the bottom. The scale bar at lower left indicates 90 meters (295 feet).
The purple and pink colors of the CRISM image represent spectra with absorption of light at wavelengths of 920 nanometers and 530 nanometers. The strength of these absorption bands at this site varies seasonally -- weaker when the RSL are inactive and stronger when the RSL are active. Absorption at 530 nanometers can indicate a concentration of ferric iron, so this could be a clue that the fluctuations observed in the absorption bands of iron minerals may be related to the RSL activity. Other image products from the same Nov. 2, 2007, HiRISE observation are available at http://www.uahirise.org/PSP_005943_1380.
The Daily Galaxy via http://www.nasa.gov/mars and http://mars.jpl.nasa.gov.
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- A series of interesting posts from The Daily Galaxy blog.Chris
Sent: 11/13/2014 6:26:25 P.M. Eastern Standard Time
Subj: The Daily Galaxy: News from Planet Earth & Beyond
- A Universe of Water Planets? --"Common During the Formation of All Planetary Systems"
- Mars' Atmosphere Provides Insights into Weather on Venus, Saturn's Titan & the Gas Giants
- The Rosetta Comet Mission --"Unlocking the Secrets of Our Origins" (Today's Most Popular)
- ESA Releases First Images of Philae on Comet
- Monster Storms Sighted on Ice Giant Uranus --Hints of a Hidden Vortex
Posted: 13 Nov 2014 10:15 AM PST
The new SciFi blockbuster, Interstellar, shows astonauts from post apocalyptic earth, destroyed by what appears to be a modern dust-bowl, catapulted into the unknown of outer space in the hopes of finding a new home for the human race, only to discover an extraterrestrial tidal wave on a distant exo planet. How realistic is the premise of an alien water planet? New findings suggest it's based on solid science.
"This is an important step forward in our quest to find out if life exists on other planets," said Tim Harries, from the University of Exeter's Physics and Astronomy department, who was part of the research team. "We know that water is vital for the evolution of life on Earth, but it was possible that the Earth's water originated in the specific conditions of the early solar system, and that those circumstances might occur infrequently elsewhere. By identifying the ancient heritage of Earth's water, we can see that the way in which our solar system was formed will not be unique, and that exoplanets will form in environments with abundant water. Consequently, it raises the possibility that some exoplanets could house the right conditions, and water resources, for life to evolve."
The implication of these findings is that some of the solar system's water must have been inherited from the Sun's birth environment, and thus predate the Sun itself. If our solar system's formation was typical, this implies that water is a common ingredient during the formation of all planetary systems.
To date, the Kepler satellite has detected nearly 1,000 confirmed extrasolar planets. The widespread availability of water during the planet-formation process puts a promising outlook on the prevalence of life throughout the galaxy.
A pioneering new study has shown that water found on Earth predates the formation of the Sun – raising hopes that life could exist on exoplanets, the planets orbiting other stars in our galaxy. The ground-breaking research set out to discover the origin of the water that was deposited on the Earth as it formed.
It found that a significant fraction of water found on Earth, and across our solar system, predates the formation of the Sun. By showing that water is 'inherited' from the environment when a star is born, the international team of scientists believe other exoplanetary systems also had access to an abundance of water during their own formation.
As water is a key component for the development of life on Earth, the study has important implications for the potential for life elsewhere in the galaxy.
Scientists have previously been able to understand the conditions present when stars are formed by looking at the composition of comets and asteroids, which show which gases, dust and, most importantly, ices were circling the star at its birth.
The team of international scientists were able to use 'heavy water' ices – those with an excess of water made with the element deuterium rather than hydrogen – to determine whether the water ices formed before, or during, the solar system's formation.
By using sophisticated modelling techniques, the team were able to show that the excess of heavy water was inherited from the pre-existing environment, suggesting that many exoplanets will contain water, the key liquid necessary for life.
"There has been a long-standing question as to whether any of these ancient ices, including water, are incorporated into young planetary systems, or if all the preplanetary building blocks are reprocessed and/or locally synthesized near the star," said Cleeves.
"These two scenarios have very different consequences for the composition of planets. In the latter case, the chemical make-up of the planets, including water, would depend upon what type of star a planet ends up next to. In contrast, the former case implies that all planetary systems would form from similar starting materials, including abundant interstellar water.
Up to half of the water on Earth is likely older than the solar system itself, University of Michigan astronomers theorized in another study. The researchers' work helps to settle a debate about just how far back in galactic history our planet and our solar system's water formed. Were the molecules in comet ices and terrestrial oceans born with the system itself—in the planet-forming disk of dust and gas that circled the young sun 4.6 billion years ago? Or did the water originate even earlier—in the cold, ancient molecular cloud that spawned the sun and that planet-forming disk?
Between 30 and 50 percent came from the molecular cloud, says Cleeves, That would make it roughly a million years older than the solar system.
To arrive at that estimate, Cleeves and Ted Bergin, a professor of astronomy, simulated the chemistry that went on as our solar system formed. They focused on the ratio of two slightly different varieties of water—the common kind and a heavier version. Today, comets and Earth's oceans hold particular ratios of heavy water—higher ratios than the sun contains.
"Chemistry tells us that Earth received a contribution of water from some source that was very cold—only tens of degrees above absolute zero, while the sun being substantially hotter has erased this deuterium, or heavy water, fingerprint," Bergin said.
To start their solar system simulation, the scientists wound back the clock and zeroed out the heavy water. They hit "go" and waited to see if eons of solar system formation could lead to the ratios they see today on Earth and in comets.
"We let the chemistry evolve for a million years—the typical lifetime of a planet-forming disk—and we found that chemical processes in the disk were inefficient at making heavy water throughout the solar system," Cleeves said. "What this implies is if the planetary disk didn't make the water, it inherited it. Consequently, some fraction of the water in our solar system predates the sun."
All life on Earth depends on water. Understanding when and where it came from can help scientists estimate how common water might be throughout the galaxy.
"The implications of these findings are pretty exciting," Cleeves said. "If water formation had been a local process that occurs in individual stellar systems, the amount of water and other important chemical ingredients necessary for the formation of life might vary from system to system. But because some of the chemically rich ices from the molecular cloud are directly inherited, young planetary systems have access to these important ingredients.
"Based on our simulations and our growing astronomical understanding, the formation of water from hydrogen and oxygen atoms is a ubiquitous component of the early stages of stellar birth," added Bergin. "It is this water, which we know from astronomical observations forms at only 10 degrees above absolute zero before the birth of the star, that is provided to nascent stellar systems everywhere."
The Daily Galaxy via University of Exeter and University of Michigan
Posted: 13 Nov 2014 09:29 AM PST
The new study finds a three-part pattern applies to atmospheric conditions on Mars. The results also show that the sun plays a major role in determining macroweather. Weather, which changes day-to-day due to constant fluctuations in the atmosphere, and climate, which varies over decades, are familiar. More recently, a third regime, called “macroweather,” has been used to describe the relatively stable regime between weather and climate. The findings indicate that weather on Mars can be predicted with some skill up to only two days in advance, compared to Earth’s 10 days.
New research on Mars weather promises to advance scientists’ understanding of the dynamics of Earth’s own atmosphere – and could provide insights into the weather of Venus, Saturn’s moon Titan, and possibly the gas giants Jupiter, Saturn, Uranus and Neptune.
The scientists chose to study Mars for its wealth of data with which to test their theory that a transitional “macroweather” regime exists on other planets. They used information collected from Viking – a Mars lander mission during the 1970s and 1980s -- and more recent data from a satellite orbiting Mars.
By taking into account how the sun heats Mars, as well as the thickness of the planet’s atmosphere, the scientists predicted that Martian temperature and wind would fluctuate similarly to Earth’s – but that the transition from weather to macroweather would take place over 1.8 Martian days (about two Earth days), compared with a week to 10 days on Earth.
“Our analysis of the data from Mars confirmed this prediction quite accurately,” said Shaun Lovejoy, a physics professor at McGill University in Montreal and lead author of the paper. “This adds to evidence, from studies of Earth’s atmosphere and oceans, that the sun plays a central role in shaping the transition from short-term weather fluctuations to macroweather.”
Co-author Professor Jan-Peter Muller from the UCL Mullard Space Science Laboratory, said: “We’re going to have a very hard time predicting the weather on Mars beyond two days given what we have found in weather records there, which could prove tricky for the European lander and rover!”
Image at the top of the page shows the Valles Marineris - which some scientists believe may have been carved by glaciers. A growing body of evidence points to the fact that water once flowed on the planet.
S. Lovejoy, J.-P. Muller, J.P. Boisvert, “On Mars too, expect macroweather,” Geophysical Research Letters, Nov. 13, 2014. DOI: 10.1002/2014GL061861
The Daily Galaxy via McGill UNiversity
Posted: 13 Nov 2014 08:30 AM PST
The epic Philae landing will unlock hold vital clues about our solar system's history. Comets are considered primitive building blocks of the solar system that are literally frozen in time. Comets may have played a part in "seeding" Earth with water and, possibly, the basic ingredients for life."Comet impacts are thought to have been one of the principal means by which water was delivered to the early Earth, around 3.6 billion years ago, possibly contributing half the water in our oceans," says planetary scientist Professor Stanley Cowley, of the University of Leicester's Department of Physics and Astronomy,. "The other half would have come from the Earth's interior. Furthermore, the comet material is also known to contain simple organic molecules which may also have seeded Earth with the material from which life emerged."
This ESA video asks us to Imagine: with a wasteland as their canvas, a Master and his young Apprentice set about turning rubble into planets and moons, asteroids and comets. They levitate the worlds above their heads, spinning them in orbit around their symbolic Sun.
“What is the key to life on Earth?” asks the Master. The Apprentice shakes her head. The answer is obvious: water. For a long time, the origins of water, and indeed life on our planet remained an absolute mystery. So we began searching for answers beyond Earth,” the Master continues. “In time we turned to comets. One trillion celestial balls of dust, ice, complex molecules, left over from the birth of our Solar System. Once thought of as messengers of doom and destruction, and yet so enchanting. And we were to catch one: a staggeringly ambitious plan.”
Science fiction? No – science fact.As Tomek Bagiński’s short film Ambition makes clear, it is the essence of what it means to be human, to attempt difficult things, to reach for seemingly impossible goals, to learn, adapt and evolve.
And at the heart of this film is Rosetta, ESA’s real mission to rendezvous with, escort and land on a comet. A mission that began as a dream, but that after decades of planning, construction and flight through the Solar System, has arrived at its goal.
Its aim? To unlock the secrets hidden within the icy treasure chest for 4.6 billion years. To study its make-up and its history. To search for clues as to our own origins.
From 100 km distance, to 50, 30 and then, defying all expectations, to just 10 km, Rosetta continues to captivate and intrigue with every image and every data packet returned. It will rewrite the textbooks of cometary science.
But there is more, an even greater challenge, another ambitious first: to land on the comet. The stage is set. The date: 12 November 2014.
“As a science fiction writer, it’s hard to think of a more stirring theme than the origin and ultimate destiny of life in the Universe,” says Alastair Reynolds.
“With the arrival of Rosetta at 67P/Churyumov–Gerasimenko – an astonishing, audacious technical achievement, literally the stuff of science fiction – we are on the brink of a bold new chapter in our understanding of our place in the Universe.”
“Rosetta is less than 10 km from a comet, and both are racing through space at over 60 000 km/h,” says Matt Taylor, ESA’s Rosetta project scientist. “Next month, we’ll be attempting to land on the comet, and with our orbiting spacecraft, we’ll continue to keep pace with the comet for another year or more, watching how it evolves over time.
“All of this is new and unique and has never been done before. It may sound like science fiction, but it’s a reality for the teams that have dedicated their entire lives to this mission, driven to push the boundaries of our technology for the benefit of science and to seek answers to the biggest questions regarding our Solar System’s origins.”
Ambition is a collaborative project of ESA and Platige Image. Directed by Tomek Baginski and starring Aiden Gillen and Aisling Franciosi, it was shot on location in Iceland, and screened on 24 October during the British Film Institute’s celebration of Sci-Fi: Days of Fear and Wonder, at the Southbank, London.
The Daily Galaxy via ESA and http://ambitionfilm.com
Posted: 13 Nov 2014 07:58 AM PST
The combination photo of different images taken with the CIVA camera system released by the European Space Agency ESA on Thursday Nov. 13, 2014 shows Rosetta's lander Philae as it is safely on the surface of Comet 67P/Churyumov-Gerasimenko, as these first CIVA images confirm. One of the lander's three feet can be seen in the foreground. Philae became the first spacecraft to land on a comet when it touched down Wednesday on the comet, 67P/Churyumov-Gerasimenko.The lander is expected to send more images from its landing site, named Agilkia. These are the first images ever taken from a comet's surface. Philae will also drill into the surface to study the composition, and witness close up how a comet changes as its exposure to the sun varies. With its primary battery, Philae will remain active on the surface for about two-and-a-half days. Philae's mothership, the Rosetta spacecraft, will remain in orbit around the comet through 2015. The orbiter will continue detailed studies as the comet approaches the sun and then moves away.
In addition to their well-deserved reputation as beautiful cosmic objects, comets hold vital clues about our solar system's history. They are considered primitive building blocks of the solar system that are literally frozen in time. Comets may have played a part in "seeding" Earth with water and, possibly, the basic ingredients for life.
Posted: 12 Nov 2014 08:20 PM PST
The normally bland face of Uranus has become increasingly stormy, with enormous cloud systems so bright that for the first time ever, amateur astronomers are able to see details in the planet's hazy blue-green atmosphere. "The weather on Uranus is incredibly active," said Imke de Pater, professor and chair of astronomy at the University of California, Berkeley, and leader of the team that first noticed the activity when observing the planet with adaptive optics on the W. M. Keck II Telescope in Hawaii."This type of activity would have been expected in 2007, when Uranus's once every 42-year equinox occurred and the sun shined directly on the equator," noted co-investigator Heidi Hammel of the Association of Universities for Research in Astronomy. "But we predicted that such activity would have died down by now. Why we see these incredible storms now is beyond anybody's guess."
Uranus is an ice giant, about four times the diameter of Earth, with an atmosphere of hydrogen and helium, with just a bit of methane to give it a blue tint. Because it is so distant - 30 times farther from the sun than Earth - astronomers were able to see little detail on its surface until adaptive optics on the Keck telescopes revealed features much like those on Jupiter.
In all, de Pater, Hammel and their team detected eight large storms on Uranus's northern hemisphere when observing the planet with the Keck Telescope on August 5 and 6. One was the brightest storm ever seen on Uranus at 2.2 microns, a wavelength that senses clouds just below the tropopause, where the pressure ranges from about 300 to 500 mbar, or half the pressure at Earth's surface. The storm accounted for 30 percent of all light reflected by the rest of the planet at this wavelength.
When amateur astronomers heard about the activity, they turned their telescopes on the planet and were amazed to see a bright blotch on the surface of a normally boring blue dot.
Below are infrared images of Uranus (1.6 and 2.2 microns) obtained on Aug. 6, 2014, with adaptive optics on the 10-meter Keck telescope. The white spot is an extremely large storm that was brighter than any feature ever recorded on the planet in the 2.2 micron band. The cloud rotating into view at the lower-right limb grew into the large storm that was seen by amateur astronomers at visible wavelengths.
French amateur astronomer Marc Delcroix processed the amateur images and confirmed the discovery of a bright spot on an image by French amateur Régis De-Bénedictis, then in others taken by fellow amateurs in September and October. He had his own chance on Oct. 3 and 4 to photograph it with the Pic du Midi one-meter telescope, where on the second night, "I caught the feature when it was transiting, and I thought, 'Yes, I got it!'" said Delcroix.
"I was thrilled to see such activity on Uranus. Getting details on Mars, Jupiter or Saturn is now routine, but seeing details on Uranus and Neptune are the new frontiers for us amateurs and I did not want to miss that," said Delcroix, who works for an auto parts supplier in Toulouse and has been observing the skies - Jupiter in particular - with his backyard telescope since 2006 and, since 2012, occasionally with the Pic du Midi telescope. "I was so happy to confirm myself these first amateur images on this bright storm on Uranus, feeling I was living a very special moment for planetary amateur astronomy."
Interestingly, the extremely bright storm seen by Keck in the near infrared is not the one seen by the amateurs, which is much deeper in the atmosphere than the one that initially caused all the excitement. De Pater's colleague Larry Sromovsky, a planetary scientist at the University of Wisconsin, Madison, identified the amateur spot as one of the few features on the Keck images from August 5 that was only seen at 1.6 microns, and not at 2.2 microns. The 1.6 micron light is emitted from deeper in the atmosphere, which means that this feature is below the uppermost cloud layer of methane-ice in Uranus's atmosphere.
"The colors and morphology of this cloud complex suggests that the storm may be tied to a vortex in the deeper atmosphere similar to two large cloud complexes seen during the equinox," Sromovsky said. Such vortices could be anchored much deeper in the atmosphere and extend over large vertical distances, as inferred from similar vortices on Jupiter, including its Great Red Spot.
An expanded team of astronomers led by Kunio M. Sayanagi, an Assistant Professor at Hampton University in Virginia, leveraged the amateur observations to activate a "Target of Opportunity" proposal on the Hubble Space Telescope, which imaged the entire planet on Oct. 14. Observing at a variety of wavelengths, HST revealed multiple storm components extending over a distance of more than 9,000 kilometers (5,760 miles) and clouds at a variety of altitudes.
De Pater, Sromovsky, Hammel and Pat Fry of the University of Wisconsin will report the details of their observations on Nov. 12 at a meeting of the American Astronomical Society's Division of Planetary Sciences in Tucson, Ariz.
De Pater and her colleagues have been following Uranus for more than a decade, charting the weather on the planet, including bands of circulating clouds, massive swirling storms and convective features at its north pole. Bright clouds are probably caused by gases such as methane rising in the atmosphere and condensing into highly reflective clouds of methane ice.
Because Uranus has no internal source of heat, its atmospheric activity was thought to be driven solely by sunlight, which is now weak in the northern hemisphere. Hence astronomers were surprised when these observations showed such intense activity.
Observations taken with the Keck telescope by Christoph Baranec, an Assistant Professor at the University of Hawaii on Manoa, revealed that the storm was still active, but had a different morphology and possibly reduced intensity.
"If indeed these features are high-altitude clouds generated by flow perturbations associated with a deeper vortex system, such drastic fluctuations in intensity would indeed be possible," Sromovsky added.
"These unexpected observations remind us keenly of how little we understand about atmospheric dynamics in outer planet atmospheres," the authors wrote in their paper.
The Daily Galaxy via University of California - Berkeley
Images credits: top of page: the Hubble Space Telescope's NICMOS camera; Imke de Pater (UC Berkeley) & Keck Observatory images.
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- 3 interesting posts from The Daily Galaxy blog.Chris
Sent: 11/18/2014 6:08:38 P.M. Eastern Standard Time
Subj: The Daily Galaxy: News from Planet Earth & Beyond
- "Gravity May Answer Last Great Unknown in Standard Model of Physics"
- China Preps for 2020 Mars' Landing
- New Way to Detect the Existence of Unknown Matter and Energy?
Posted: 18 Nov 2014 07:11 AM PST
New research investigates the last unknown parameter in the Standard Model – the interaction between the Higgs particle and gravity. “The Standard Model of particle physics, which scientists use to explain elementary particles and their interactions, has so far not provided an answer to why the universe did not collapse following the Big Bang,” explains Professor Arttu Rajantie, from the Department of Physics at Imperial College London.“Our aim is to measure the interaction between gravity and the Higgs field using cosmological data,” says Professor Rajantie. “If we are able to do that, we will have supplied the last unknown number in the Standard Model of particle physics and be closer to answering fundamental questions about how we are all here.”
Studies of the Higgs particle – discovered at CERN in 2012 and responsible for giving mass to all particles – have suggested that the production of Higgs particles during the accelerating expansion of the very early universe (inflation) should have led to instability and collapse.
Scientists have been trying to find out why this didn’t happen, leading to theories that there must be some new physics that will help explain the origins of the universe that has not yet been discovered. Physicists from Imperial College London, and the Universities of Copenhagen and Helsinki, however, believe there is a simpler explanation.
In a new study in Physical Review Letters, the team describe how the spacetime curvature – in effect, gravity – provided the stability needed for the universe to survive expansion in that early period. The team investigated the interaction between the Higgs particles and gravity, taking into account how it would vary with energy. They show that even a small interaction would have been enough to stabilise the universe against decay.
“Our research investigates the last unknown parameter in the Standard Model – the interaction between the Higgs particle and gravity. This parameter cannot be measured in particle accelerator experiments, but it has a big effect on the Higgs instability during inflation. Even a relatively small value is enough to explain the survival of the universe without any new physics!”
The team plan to continue their research using cosmological observations to look at this interaction in more detail and explain what effect it would have had on the development of the early universe. In particular, they will use data from current and future European Space Agency missions measuring cosmic microwave background radiation and gravitational waves.
The image at the top of the page shows Globular cluster Messier 15, located some 35,000 light-years away in the constellation of Pegasus (The Winged Horse). It is one of the oldest clusters known, with an age of around 12 billion years. Both very hot blue stars and cooler golden stars can be seen swarming together in the image, becoming more concentrated towards the cluster's bright center. Messier 15 is one of the densest globular clusters known, with most of its mass concentrated at its core. As well as stars, Messier 15 was the first cluster known to host a planetary nebula, and it has been found to have a rare type of black hole at its centre. This image is made up of observations from Hubble's Wide Field Camera 3 and Advanced Camera for Surveys in the ultraviolet, infrared, and optical parts of the spectrum. (NASA, ESA
The Daily Galaxy via Imperial College of London
Posted: 18 Nov 2014 07:43 AM PST
Chinese scientists are planning to launch a Mars rover "around 2020", state media reported on Tuesday, as the country pours billions into its space programme and works to catch up with the US and Europe. Although the government has not officially announced plans for a Mars mission, officials from the China National Space Administration are currently lobbying to have it put on the agenda and have begun "preliminary research", the state-run China Daily reported."We plan to conduct the Mars mission around 2020, which will include the probe's orbiting, landing and roaming," Peng Tao, a space expert with the China Academy of Space Technology, was quoted by China Daily as saying. "By contrast, other nations will need multiple missions to achieve those three steps."
The statements came less than a week after prototypes for the Mars rover were debuted at the China International Aviation and Aerospace Exhibition. China's recent space efforts have been focused on exploring the moon. The nation's first lunar rover -- the Yutu, or Jade Rabbit -- was launched late last year, but it has since been beset by mechanical troubles.
The planned Mars rover will be bigger than the Yutu in order to deal with the harsher terrain, China Daily quoted space officials as saying. Scientists are now focused on sending a manned mission to the moon and returning samples safely back to Earth.
The US has landed two rovers on Mars and India successfully put a satellite into orbit around the red planet in September. The former Soviet Union and the European Space Agency have also sent missions to Mars. China's first attempt to send a satellite into Mars orbit foundered in 2011 when the Russian rocket carrying the payload failed to make it out of the Earth's orbit.
The Daily Galaxy via © 2014 AFP
Image credit: NASA/JPL
Posted: 18 Nov 2014 08:16 AM PST
Over the last years, physicists have placed detectors in underground sites a kilometer or more deep in order to detect dark matter. The idea is that dark matter is easier to detect in deep sites because there is less noise from cosmic or Earth-produced radiation that can potentially cover the dark matter signal. This approach of detecting dark matter makes sense provided that dark matter interacts only a bit with atoms as it goes underground. The scientific term for this is that dark matter is weakly interacting with its surroundings."But we don't know if dark matter is that weakly interacting. In principle dark matter particles can lose energy as they travel underground before they hit the detector due to interactions with regular atoms. And in that case they might not have enough energy left to trigger the detector once they arrive there", says Chris Kouvaris of the Centre for Particle Physics Phenomenology, at the University of Southern Denmark.
In a new research paper, a team of scientists study the possibility that dark matter can indeed interact substantially with atoms. They claim that depending on the properties of the dark matter particles, deep placed detectors can be blind because particles might have lost most of their energy before reaching the detector.
The universe consists of atoms and particles - and a whole lot more that still needs to be detected. We can only speculate about the existence of this unknown matter and energy.
"We know that approximately five percent of the universe consists of the known matter we are all made of. The rest is unknown. This unknown matter is called dark matter, and we believe that it is all around us, including here on Earth", explains Chris Kouvaris, associate professor at the Centre for Cosmology and Particle Physics Phenomenology (CP3-Origins), Department of Physics, Chemistry and Pharmacy, University of Southern Denmark.
He and his colleague from CP3-Origins, postdoc Ian Shoemaker, now suggest a new way to detect the existence of the elusive dark matter.
"In such a case, it would make more sense to look for dark matter signals on the surface of the Earth or in shallow sites", Kouvaris argues.
Placing a detector in shallow sites or on the surface ensures small energy loss for the dark matter particles but it also means a big increase in the background noise. This was after all the reason why detectors were placed in deep sites in the first place. To overcome this problem Kouvaris and Shoemaker propose - instead of trying to detect a single collision of a dark matter particle with the detector - to look for a signal that varies periodically during the day.
Because dark matter particles approach the detector from various directions, as the Earth rotates, the flux of the particles reaching the detector can vary. This causes a signal that will go from maximum to minimum in 12 hours and back to maximum again after another 12 hours. Such a pattern will make the signals from dark matter stand out clear even though the detectors also pick up cosmic noise.
"The best locations for the observation of such a modulation signal are places in the south hemisphere with latitude around 40 degrees, such as Argentina, Chile and New Zealand" says Chris Kouvaris.
The image at the top of the page is from the Dark Energy Camera of the barred spiral galaxy NGC 1365, in the Fornax cluster of galaxies. (bottom) Full Dark Energy Camera image of the Fornax cluster of galaxies. Nestled on a Chilean mountaintop, the better to take advantage of the region’s clear skies, the the Dark Every Survey (DES) is the largest galaxy survey yet undertaken, a successor to the hugely successful Sloan Digital Sky Survey. With its array of 62 charged couple device (CCD) cameras, DECam is roughly the size of a phone booth, dwarfed by the vastness of the universe.
The Daily Galaxy via University of Southern Denmark
Image credit: Dark Energy Survey Collaboration.
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- Some interesting posts from the Daily Galaxy blog.Chris
Sent: 11/19/2014 6:07:29 P.M. Eastern Standard Time
Subj: The Daily Galaxy: News from Planet Earth & Beyond
- Spooky Discovery About the Largest Structure in the Universe --"Vast Quasar Groupings Found in Astounding Alignment"
- Enigmatic Object Observed --"May be a Supermassive Black Hole Ejected Into Deep Space"
- Mystery of Missing Quasars at Galaxy Centers --"May Provide 1st Real Signal of Dark Matter"
Posted: 19 Nov 2014 09:57 AM PST
Quasars are the nuclei of galaxies from the early days of the universe that undergo brief periods of extremely high brightness that make them visible across huge distances. These periods are 'brief' in astrophysics terms but actually last 10-100 million years. Since 1982 it has been known that quasars tend to group together in clumps or 'structures' of surprisingly large sizes, forming large quasar groups. The whole of Earth’s history is equal to the time that it takes photons to travel across the vast expanse of the LQG. As the largest known structure in the universe, the LQG is so vast that it would take a spaceship traveling at the speed of light some 4 billion years to cross it.
On January 11, 2013, the discovery of a vast grouping of 73s quasars, a form of supermassive black hole active galactic nuclei, with a minimum diameter of 1.4 billion light-years, stretched over four billion light-years at its widest point was announced by the University of Central Lancashire, as the largest known structure in the universe LQGs are thought to be precursors to the sheets, walls and filaments of galaxies found in the relatively nearby universe. The existence of structures of the magnitude of large quasar clusters was believed theoretically impossible. Cosmological structures had been believed to have a size limit of approximately 1.2 billion light-years.
The LQG also challenges the Cosmological Principle, the assumption that the universe, when viewed at a sufficiently large scale, looks the same no matter where you are observing it from. The modern theory of cosmology is based on the work of Albert Einstein, and depends on the assumption of the Cosmological Principle. The Principle is assumed but has never been demonstrated observationally 'beyond reasonable doubt'.
This year, a team led by Damien Hutsemékers from the University of Liège in Belgium used the FORS instrument on the VLT to study 93 quasars that were known to form huge groupings spread over billions of light-years, seen at a time when the Universe was about one third of its current age. "The first odd thing we noticed was that some of the quasars' rotation axis were aligned with each other -- despite the fact that these quasars are separated by billions of light-years," said Hutsemékers.
"The alignments in the new data, on scales even bigger than current predictions from simulations, may be a hint that there is a missing ingredient in our current models of the cosmos," observed Dominique Sluse of the Argelander-Institut für Astronomie in Bonn, Germany and University of Liège.
The team then went further and looked to see if the rotation axes were linked, not just to each other, but also to the structure of the Universe on large scales at that time.
When astronomers look at the distribution of galaxies on scales of billions of light-years they find that they are not evenly distributed. They form a cosmic web of filaments and clumps around huge voids where galaxies are scarce. This intriguing and beautiful arrangement of material is known as large-scale structure.
The new VLT results indicate that the rotation axes of the quasars tend to be parallel to the large-scale structures in which they find themselves. So, if the quasars are in a long filament then the spins of the central black holes will point along the filament. The researchers estimate that the probability that these alignments are simply the result of chance is less than 1%.
"A correlation between the orientation of quasars and the structurethey belong to is an important prediction of numerical models of evolution of our Universe. Our data provide the first observational confirmation of this effect, on scales much larger that what had been observed to date for normal galaxies," adds Sluse.
The team could not see the rotation axes or the jets of the quasars directly. Instead they measured the polarisation of the light from each quasar and, for 19 of them, found a significantly polarised signal. The direction of this polarisation, combined with other information, could be used to deduce the angle of the accretion disc and hence the direction of the spin axis of the quasar.
Whole clusters of galaxies can be 2-3 Mpc across but LQGs can be 200 Mpc or more across. Based on the Cosmological Principle and the modern theory of cosmology, calculations suggest that astrophysicists should not be able to find a structure larger than 370 Mpc. The newly discovered LQG however has a typical dimension of 500 Mpc. But because it is elongated, its longest dimension is 1200 Mpc (or 4 billion light years) - some 1600 times larger than the distance from the Milky Way to Andromeda.
"While it is difficult to fathom the scale of this LQG, we can say quite definitely it is the largest structure ever seen in the entire universe," says Dr Clowes of University of Central Lancashire'sJeremiah Horrocks Institute. "This is hugely exciting – not least because it runs counter to our current understanding of the scale of the universe. Even traveling at the speed of light, it would take 4 billion years to cross. This is significant not just because of its size but also because it challenges the Cosmological Principle, which has been widely accepted since Einstein. Our team has been looking at similar cases which add further weight to this challenge and we will be continuing to investigate these fascinating phenomena."
The team published their results in the journal Monthly Notices of the Royal Astronomical Society.
This research was presented in a paper entitled "Alignment of quasar polarizations with large-scale structures", by D. Hutsemékers et al., toappear in the journal Astronomy & Astrophysics on 19 November 2014.
The ESO team is composed of D. Hutsemékers (Institut d'Astrophysique et de Géophysique, Université de Liège, Liège, Belgium), L. Braibant (Liège), V. Pelgrims (Liège) and D. Sluse (Argelander-Institut für Astronomie, Bonn, Germany; Liège).
The Daily Galaxy via ESO
Posted: 19 Nov 2014 08:24 AM PST
Astronomers have observed a mysterious phenomenon, which could be a massive black hole that has been ejected into space located 90 million light years from Earth. This may be due to gravitational waves from the collision. Scientists have long been searching for such black holes that have been flung out of the galaxy by a recoil effect.
If two galaxies are on a collision course and eventually collide, they will merge into a single larger galaxy. At the centre of each galaxy is a massive black hole and they will also merge. But if gravitational waves have been formed in the process, spreading out into space, there might be a recoiling effect, so one of the two black holes is ejected. In some cases, the recoil effect is relatively weak and the black hole is pulled back to the centre. In other cases, the recoil effect is so strong that the black hole is flung out of the galaxy forever and remains isolated in the universe.
The black hole SDSS 1133 (small point at the bottom left in image below) is actively accreting materials from the outskirts of the nearby dwarf galaxy Markarian 177 (center) located 90 million light years away. This high resolution image was taken from the Keck telescope with adaptive optics.
An international team of researchers led by Michael Koss, Eidgenössische Technische Hochschule, ETH-Zurich, along with researchers from the University of Hawaii and Allison Man from the Dark Cosmology Centre at the Niels Bohr Institute at the University of Copenhagen, made the observations at the Keck Observatory on Hawaii. The telescope is one of the largest in the world and using a special technique called ‘adaptive optics’, which can compensate for disturbances from the atmosphere, it is possible to obtain observations with incredibly high resolution.
“The observations show that the object called SDSS1133 still has a ring of dust and gas, which it is drawing inwards and engulfing as it emits radiation. The observations clearly show that there is no orbiting galaxy. By comparing the radiation from the object with the nearby dwarf galaxy Markarian-177, it appears that the black hole once belonged to the dwarf galaxy before it was flung out,” explains Allison Man, a PhD student at the Dark Cosmology Centre at the Niels Bohr Institute, University of Copenhagen.
Another possibility is that the object could be a special type of supernova, that is, an exploding massive star. When massive stars die, they explode and can form a black hole. The astronomers found photographs of the object from the 1950s and a supernova normally only lasts a few months, but it could be a case of a special massive star with a series of explosions that occurred at least 50 years before it finally exploded as a supernova in 2001. If this is the case, it will be one of the most energy-rich and sustained explosions of a star that has ever been observed.
In order to get closer to solving the mystery, the researchers will observe the phenomenon over the next year using the Hubble Space Telescope’s Cosmic Origins Spectrograph, which can study the spectral lines of highly ionized carbon in active black holes. The spectral lines from black holes are typically broad.
In a supernova, on the other hand, ionized carbon would only be produced right after the explosion and the spectral lines would typically be very narrow.
If this is a case of a supernova, the emission of light also quickly becomes weaker. If it is a black hole that has been cast out of the galaxy, on the other hand, it will emit light for a long time – perhaps millions of years.
The image at the top of the page from NASA's Spitzer and Hubble Space Telescopes shows the collision of two spiral galaxies that has triggered a brilliant starburst, the brightest ever seen away from the centers, or nuclei, of merging galaxies. The merging galaxies, known collectively as II Zw 096, can be clearly seen at shorter wavelengths of light from Hubble (blue hues). The Spitzer's infrared view, represented in red shows the brightest glow from a tiny region that may be as small as 700 light-years across -- just a small portion of the full 50,000 light-year extent of II Zw 096. This region blasts out 80 percent of the infrared light from this galactic train wreck.
The Daily Galaxy via Niels Bohr Institute
Posted: 19 Nov 2014 07:32 AM PST
In a new paper, co-authored by University of Notre Dame astrophysicist Joseph Bramante and his colleague at the University of Chicago, Tim Linden, discusses how detecting imploding pulsars may lead to insights about the properties of dark matter and how dark matter could explain the absence of pulsars in the galactic center. Dark matter, which makes up approximately 25 percent of the matter in the universe, is a very dense type of matter that does not emit a significant amount of light. A particular kind of dark matter could destroy pulsars at the galactic center by falling into the pulsars and forming black holes that swallow them.
"It is possible that pulsars imploding into black holes may provide the first concrete signal of particulate dark matter," said study co-author Joseph Bramante, a physicist at the University of Notre Dame. “In 2013, the first pulsar at the galactic center was detected, and this observation has deepened the mystery of these stellar objects,” explained Bramante. “Prior to this detection, it was thought that pulsars at the galactic center might simply be shielded from observation by dense material in the center of the galaxy.”
“Observations of pulsars imploding into black holes could provide important clues to the properties of dark matter, specifically indicating it is asymmetric, just like visible matter,” said Bramante.
Pulsars, or pulsating stars, are rotating neutron stars that emit pulses of light visible to astronomers on Earth. Pulsars are created from the collapsing cores of supermassive stars that have exploded into supernovae. These supermassive stars, 10 to 40 times the mass of the sun, have been found at the center of the galaxy, leading astronomers to predict a certain number of pulsars should also reside there, but that predicted number of pulsars has not yet been observed.
The paper also explains how the researchers showed that the presently unknown mass and quantum couplings of dark matter could be found by determining the age at which a pulsar is swallowed by a dark matter black hole. One predictor of this pulsar-collapsing dark matter is a maximum age for pulsars, which gets higher the further away from the galactic center the pulsars are because there is less dark matter away from the center.
The next steps in this work for Bramante and his collaborators includes building and testing a model of dark matter to ensure the model meets all other cosmological and astrophysical dark matter observations.
The image at the top of the page shows galaxy, called Henize 2-10, a blob-shaped dwarf galaxy 30 million light-years away. The tiny galaxy has a colossal black hole at its center and could be a transition between young, small galaxies and massive spirals like our Milky Way, suggesting that galaxies form around central black holes, not the other way around. Astronomers suggest think that Henize 2-10 could be a nearby example of some of the first galaxies ever formed in the universe.
The Daily Galaxy via University of Notre Dame