Friday, 30 January 2015

Technological Civilizations --"Are Their Lifespans 200 years, 500 years or 50,000 years?" (Weekend Feature)


"We have no idea how long a technological civilization like our own can last," says University of Rochester astrophysicist Adam Frank. "Is it 200 years, 500 years or 50,000 years? Answering this question is at the root of all our concerns about the sustainability of human society. Are we the first and only technologically-intensive civilization in the entire history of the universe? If not, shouldn't we stand to learn something from the past successes and failures of other species?"

Human-caused climate change, ocean acidification and species extinctions may eventually threaten the collapse of civilization, according to some scientists, while other people argue that for political or economic reasons we should allow industrial development to continue without restrictions. In a new paper, two astrophysicists argue that these questions may soon be resolvable scientifically, thanks to new data about the Earth and about other planets in our galaxy, and by combining the earth-based science of sustainability with astrobiology.

In their paper, which appeared in fall 2014 in the journal Anthropocene, Frank and co-author Woodruff Sullivan call for creation of a new research program to answer questions about humanity's future in the broadest astronomical context. The authors explain: "The point is to see that our current situation may, in some sense, be natural or at least a natural and generic consequence of certain evolutionary pathways."

To frame these questions, Frank and Sullivan begin with the famous Drake equation, a straightforward formula used to estimate the number of intelligent societies in the universe. In their treatment of the equation, the authors concentrate on the average lifetime of a Species with Energy-Intensive Technology (SWEIT). Frank and Sullivan calculate that even if the chances of forming such a "high tech" species are 1 in a 1,000 trillion, there will still have been 1,000 occurrences of a history like own on planets across the "local" region of the Cosmos.

"That's enough to start thinking about statistics," says Frank, "like what is the average lifetime of a species that starts harvesting energy efficiently and uses it to develop high technology."

Employing dynamical systems theory, the authors map out a strategy for modeling the trajectories of various SWEITs through their evolution. The authors show how the developmental paths should be strongly tied to interactions between the species and its host planet. As the species' population grows and its energy harvesting intensifies, for example, the composition of the planet and its atmosphere may become altered for long timescales.

The image below is a schematic of two classes of trajectories in SWEIT solution space. Red line shows a trajectory representing population collapse whereby development of energy harvesting technologies allows for rapid population growth which then drives increases in planetary forcing. As planetary support systems change state the SWEIT population is unable to maintain its own internal systems and collapses. Blue line shows a trajectory representing sustainability in which population levels and energy use approach levels that do not push planetary systems into unfavorable states.


Frank and Sullivan show how habitability studies of exoplanets hold important lessons for sustaining the civilization we have developed on Earth. This "astrobiological perspective" casts sustainability as a place-specific subset of habitability, or a planet's ability to support life. While sustainability is concerned with a particular form of life on a particular planet, astrobiology asks the bigger question: what about any form of life, on any planet, at any time?

We don't yet know how these other life forms compare to the ones we are familiar with here on Earth. But for the purposes of modeling average lifetimes, Frank explains, it doesn't matter.

"If they use energy to produce work, they're generating entropy. There's no way around that, whether their human-looking Star Trek creatures with antenna on their foreheads, or they're nothing more than single-cell organisms with collective mega-intelligence. And that entropy will almost certainly have strong feedback effects on their planet's habitability, as we are already beginning to see here on Earth."

The image below is a plot of human population, total energy consumption and atmospheric CO2 concentration from 10,000 BCE to today. Note the coupled increase in all 3 quantities over the last century.


"Maybe everybody runs into this bottleneck," says Frank, adding that this could be a universal feature of life and planets. "If that's true, the question becomes whether we can learn anything by modeling the range of evolutionary pathways. Some paths will lead to collapse and others will lead to sustainability. Can we, perhaps, gain some insight into which decisions lead to which kind of path?"

As Frank and Sullivan show, studying past extinction events and using theoretical tools to model the future evolutionary trajectory of humankind--and of still unknown but plausible alien civilizations--could inform decisions that would lead to a sustainable future.

Read More

Thursday, 29 January 2015

Image of the Day: "Massive Bubbles" --New 3-D Probe Inside an Iconic Milky Way Supernova


This composite image shows two perspectives of a three-dimensional reconstruction of the Cassiopeia A supernova remnant. This new 3-D map provides the first detailed look at the distribution of stellar debris following a supernova explosion. Such 3-D reconstructions encode important information for astronomers about how massive stars actually explode. The blue-to-red colors correspond to the varying speed of the emitting gas along our line of sight. The background is a Hubble Space Telescope composite image of the supernova remnant.

Cassiopeia A, or Cas A for short, is one of the most well studied supernova remnants in our galaxy. But it still holds major surprises. Harvard-Smithsonian and Dartmouth College astronomers have generated a new 3-D map of its interior using the astronomical equivalent of a CAT scan. They found that the Cas A supernova remnant is composed of a collection of about a half dozen massive cavities - or "bubbles."

"Our three-dimensional map is a rare look at the insides of an exploded star," says Dan Milisavljevic of the Harvard-Smithsonian Center for Astrophysics (CfA). This research is being published in the Jan. 30 issue of the journal Science.

About 340 years ago a massive star exploded in the constellation Cassiopeia. As the star blew itself apart, extremely hot and radioactive matter rapidly streamed outward from the star's core, mixing and churning outer debris. The complex physics behind these explosions is difficult to model, even with state-of-the-art simulations run on some of the world's most powerful supercomputers. However, by carefully studying relatively young supernova remnants like Cas A, astronomers can investigate various key processes that drive these titanic stellar explosions.

"We're sort of like bomb squad investigators. We examine the debris to learn what blew up and how it blew up," explains Milisavljevic. "Our study represents a major step forward in our understanding of how stars actually explode."

To make the 3-D map, Milisavljevic and co-author Rob Fesen of Dartmouth College examined Cas A in near-infrared wavelengths of light using the Mayall 4-meter telescope at Kitt Peak National Observatory, southwest of Tucson, AZ. Spectroscopy allowed them to measure expansion velocities of extremely faint material in Cas A's interior, which provided the crucial third dimension.

They found that the large interior cavities appear to be connected to - and nicely explain - the previously observed large rings of debris that make up the bright and easily seen outer shell of Cas A. The two most well-defined cavities are 3 and 6 light-years in diameter, and the entire arrangement has a Swiss cheese-like structure.

The bubble-like cavities were likely created by plumes of radioactive nickel generated during the stellar explosion. Since this nickel will decay to form iron, Milisavljevic and Fesen predict that Cas A's interior bubbles should be enriched with as much as a tenth of a solar mass of iron. This enriched interior debris hasn't been detected in previous observations, however, so next-generation telescopes may be needed to find the "missing" iron and confirm the origin of the bubbles.

Image credit: D. Milisavljevic (CfA) & R. Fesen (Dartmouth). Background image: NASA, ESA, and the Hubble Heritage Team.

Read More

A Quantum View of Space (Yet Another Win for Einstein!)

Quantum-Entanglement-Science-and-God-Universe-Atoms-Particles-Hadron-Collider-Connection-Faith-Mechanics-How-It-Works-Christ-Online-Offline (1)

Ever since Einstein proposed his special theory of relativity in 1905, physics and cosmology have been based on the assumption that space looks the same in all directions -- that it's not squeezed in one direction relative to another. A new experiment by physicists used partially entangled atoms -- identical to the qubits in a quantum computer -- to demonstrate more precisely than ever before that this is true: to one part in a billion billion.

The universal quantum computer, first proposed by David Deutsch in 1985, has a marvelous property: it can simulate any physically possible environment. It is the ultimate “virtual reality” machine. Now. a new experiment by University of California, Berkeley, physicists used partially entangled atoms -- identical to the qubits in a quantum computer -- to demonstrate more precisely than ever before that this is true, to one part in a billion billion.

The classic experiment that inspired Albert Einstein was performed in Cleveland by Albert Michelson and Edward Morley in 1887 and disproved the existence of an "ether" permeating space through which light was thought to move like a wave through water. What it also proved, said Hartmut Häffner, a UC Berkeley assistant professor of physics, is that space is isotropic and that light travels at the same speed up, down and sideways.

"Michelson and Morley proved that space is not squeezed," Häffner said. "This isotropy is fundamental to all physics, including the Standard Model of physics. If you take away isotropy, the whole Standard Model will collapse. That is why people are interested in testing this."

The Standard Model of particle physics describes how all fundamental particles interact, and requires that all particles and fields be invariant under Lorentz transformations, and in particular that they behave the same no matter what direction they move.

Häffner and his team conducted an experiment analogous to the Michelson-Morley experiment, but with electrons instead of photons of light. In a vacuum chamber he and his colleagues isolated two calcium ions, partially entangled them as in a quantum computer, and then monitored the electron energies in the ions as Earth rotated over 24 hours.

If space were squeezed in one or more directions, the energy of the electrons would change with a 12-hour period. It didn't, showing that space is in fact isotropic to one part in a billion billion (1018), 100 times better than previous experiments involving electrons, and five times better than experiments like Michelson and Morley's that used light.

The results disprove at least one theory that extends the Standard Model by assuming some anisotropy of space, he said.

Häffner and his colleagues, including former graduate student Thaned Pruttivarasin, now at the Quantum Metrology Laboratory in Saitama, Japan, will report their findings in the Jan. 29 issue of the journal Nature.

Häffner came up with the idea of using entangled ions to test the isotropy of space while building quantum computers, which involve using ionized atoms as quantum bits, or qubits, entangling their electron wave functions, and forcing them to evolve to do calculations not possible with today's digital computers. It occurred to him that two entangled qubits could serve as sensitive detectors of slight disturbances in space.

"I wanted to do the experiment because I thought it was elegant and that it would be a cool thing to apply our quantum computers to a completely different field of physics," he said. "But I didn't think we would be competitive with experiments being performed by people working in this field. That was completely out of the blue."

He hopes to make more sensitive quantum computer detectors using other ions, such as ytterbium, to gain another 10,000-fold increase in the precision measurement of Lorentz symmetry. He is also exploring with colleagues future experiments to detect the spatial distortions caused by the effects of dark matter particles, which are a complete mystery despite comprising 27 percent of the mass of the universe.

"For the first time we have used tools from quantum information to perform a test of fundamental symmetries, that is, we engineered a quantum state which is immune to the prevalent noise but sensitive to the Lorentz-violating effects," Häffner said. "We were surprised the experiment just worked, and now we have a fantastic new method at hand which can be used to make very precise measurements of perturbations of space."

Read More

Wednesday, 28 January 2015

Dwarf Planet Ceres --"A Game Changer in the Solar System"

"Ceres is a 'planet' that you've probably never heard of,” said Robert Mase, Dawn project manager at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. Ceres, the largest body between Mars and Jupiter in the main asteroid belt, has a diameter of about 590 miles (950 kilometers). Some scientists believe the dwarf planet harbored a subsurface ocean in the past and liquid water may still be lurking under its icy mantle.

Ceres is a unique body in the Solar System, bearing many similarities to Jupiter's moon Europa and Saturn's moon Enceladus, both considered to be potential sources for harboring life. In March of 2015, NASA's Dawn mission will arrive at the dwarf planet Ceres, the first of the smaller class of planets to be discovered and the closest to Earth.

When Ceres was discovered in 1801, astronomers first classified it as a planet. The massive body traveled between Mars and Jupiter, where scientists had mathematically predicted a planet should lie. Further observations revealed that a number of small bodies littered the region, and Ceres was downgraded to just another asteroid within the asteroid belt. It wasn't until Pluto was classified as a dwarf planet in 2006 that Ceres was upgraded to the same level.

Ceres is the most massive body in the asteroid belt, and larger than some of the icy moons scientists consider ideal for hosting life. It is twice the size of Enceladus, Saturn's geyser-spouting moon that may hide liquid water beneath its surface.

Unlike other asteroids, the Texas-sized Ceres has a perfectly rounded shape that hints toward its origins. As NASA's Dawn mission draws closer to its encounter with the dwarf planet Ceres in early 2015, excitement continues to mount for scientists looking forward to what the satellite might observe. In August and October of 2013, NASA team members hosted a Google+ Hangout to discuss the upcoming visit to the nearest dwarf planet in the solar system. Parts 1 and 11 of this fascinating discussion follow.

"The fact that Ceres is so round tells us that it almost certainly had to form in the early solar system," Schmidt said. She explained that a later formation would have created a less rounded shape. The shape of the dwarf planet, combined with its size and total mass, reveal a body of incredibly low density.

"Underneath this dusty, dirty, clay-type surface, we think that Ceres might be icy," Schmidt said. "It could potentially have had an ocean at one point in its history."

"The difference between Ceres and other icy bodies [in the Solar System] is that it's the closest to the Sun," Castillo-Rogez said.

Less than three times as far as Earth from the Sun, Ceres is close enough to feel the warmth of the star, allowing ice to melt and reform. Investigating the interior of the dwarf planet could provide insight into the early solar system, especially locations where water and other volatiles might have existed.

As large as Ceres is, its distance has made it a challenge to study from Earth. Images taken by the space-based Hubble Space Telescope provided some insight to its surface, but to be sighted, features could be no larger than 25 kilometers in diameter. Several round circular spots mar the terrain, features which Schmidt said could be any one of a number of geologic terrains, including potentially impact basins or chaos terrains similar to those found on Europa. The largest of these, named Piazzi in honor of the dwarf planet's discoverer, has a diameter of about 250 kilometers. If this feature is an impact basin, it would have been formed by an object approximately 25 km in size.

But for Schmidt, this is another possible indication about the dwarf planet's surface: "It doesn't mean that Ceres hasn't been hit by something bigger than 25 kilometers," she said."It just means that whatever is going on on Ceres has totally erased [the topographic signature of that event]."

Ceres may have suffered major impacts, especially during periods of heavy bombardment early in the Solar System's history. If the surface contained ice, however, those features may have been erased.

"The spectrum is telling you that water has been involved in the creation of materials on the surface," Schmidt said.

The spectrum indicates that water is bound up in the material on the surface of Ceres, forming a clay. Schmidt compared it to the recent talk of minerals found by NASA's Curiosity on the surface of Mars. "[Water is] literally bathing the surface of Ceres," she said.

In addition, astronomers have found evidence of carbonates, minerals that form in a process involving water and heat. Carbonates are often produced by living processes.

The original material formed with Ceres has mixed with impacting material over the last 4.5 billion years, creating what Schmidt calls "this mixture of water-rich materials that we find on habitable planets like the Earth and potentially habitable planets like Mars."

Water is considered a necessary ingredient for the evolution of life as we know it. Planets that may have once contained water, such as Mars, as well as moons that could contain it today, like Enceladus and Europa, are all thought to be ideal for hosting or having once hosted life.

Because of its size and closeness, Schmidt calls Ceres "arguably more interesting than some of these icy satellites. If it's icy, it had to have an ocean at some point in time," she said.

Castillo-Rogez compared Earth, Europa, and Ceres, and found that the dwarf planet bore many similarities to Earth, perhaps more than Jupiter's icy moon. Both Earth and Ceres use the Sun as a key heat source, while Europa takes its heat from its tidal interaction with Jupiter. In addition, the surface temperature of the dwarf planet averages 130 to 200 degrees Kelvin, compared to Earth's 300 K, while Europa is a frosty 50 to 110 K.

"At least at the equator where the surface is warmer, Ceres could have preserved a liquid of sorts," Castillo-Rogez said.

Liquid water could exist at other points on the dwarf planet known as cold traps, shadowed areas where frozen water could remain on the surface. Such icy puddles have been found on Earth's moon.

"The chemistry, thermal activity, the heat source, and the prospect for convection within the ice shell are the key ones that make us think that Ceres could have been habitable at least at some point in its history," Castillo-Rogez said.

As scientists develop more information about Europa and Enceladus, there has been a greater call to investigate the two prime sites for life. But Schmidt and Castillo-Rogez think that Ceres could also be a great boon for astrobiology and space exploration.

"It's not a difficult environment to investigate," she said."As we think about the future of landed missions for people and rovers, why not go to Ceres?"

Though it would be more challenging to drill into than Europa, which boasts an icy surface layer, the dwarf planet would make a great site to rove around on. Schmidt also noted that it could make a great launching point when it comes to reaching the outer solar system. Its smaller mass would make it easier to land on--and leave--than Mars, which could make it a good site for manned missions.

"We have such a big planet bias, we have such a bias for things that look exactly like us," Schmidt said. "In this kind of special place in the Solar System, we have a very unique object that might be telling us a lot about what we don't know about building a habitable planet."

"I think when we get to Ceres, it's just going to be an absolute game changer, a new window into the Solar System that we wouldn't have without going there," Schmidt said

As NASA's Dawn mission draws closer to its encounter with the dwarf planet Ceres in early 2015, excitement continues to mount for scientists looking forward to what the satellite might observe. Britney Schmidt, of the George Institute of Technology, and Nicole Gugliucci of CosmoQuest, recently hosted a Google+ Hangout titled 'Ceres: Great Expectations' to discuss the upcoming visit to the nearest dwarf planet in the solar system.

Orbiting in the asteroid belt, a little more than three times as far from the Sun as Earth, Ceres is thought to contain an icy mantle that makes up approximately a third of its mass. "Ceres is very different and very exciting in a lot of ways, totally different from any place that we've been," Schmidt said in the broadcast. "It may be the only primarily icy planet that's out there, at least within reach."

Seen through a telescope, Ceres may not appear very exciting. Scientists can use the light reflected off of a body to find out information about its composition. "Ceres, to the eye, would appear basically pretty black because it's reflecting most colors more or less the same, and reflecting very little light at all," said Andy Rivkin of the Johns Hopkins University Applied Physics Lab.

Even the infrared spectrum, which tends to reveal more information about asteroids such as Vesta — Dawn's first stop — provided very little information about its composition. By utilizing instruments such as the SpeX instrument on the NASA Infrared Telescope Facility (IRTF) on Mauna Kea in Hawaii, scientists were able to catch hints about the dwarf planet's surface.

These observations revealed suggestions of brucite, hydroxyls, and two other features Rivkin says are thought to be due to carbonate minerals. "[This] makes Ceres one of only a few places where we've found carbonates," Rivkin said. "I think other than Earth and Mars, it's Ceres."

He went on to explain that scientists think water interacting with the minerals formed the brucite and the carbonates.

The image below shows the the layers of Ceres. Scientists think that the dwarf planet contains a rocky inner core surrounded by a thick mantle of water-ice. A thin outer crust covers the surface, with carbonates and other signs that water lay on the planet's skin at some point. Credit: NASA, ESA, and A. Feild (STScI).


"For Ceres, we think it is much more consistent with a body that had a lot of water available to interact with." But water, considered a potential habitat for life to start, can't exist on the surface of the dwarf planet in either solid or liquid form. "We see no real evidence for ice at the surface of Ceres," Rivkin said, noting that the dwarf planet is too warm. "However, conditions beneath Ceres’ surface should allow buried ice to remain there."

At the same time, observations from the Hubble Space Telescope, as well as theoretical data such as the planet's density, suggest that a large amount of ice exists. "That creates this interesting paradox. We think there's a lot of ice there, (but) we don't see any at the surface," Rivkin said. "How that's going to translate into what we find when we show up there is still very much an open question."


NASA’s Dawn spacecraft has just returned the sharpest images ever seen of the dwarf planet Ceres shown above. The images were taken 147,000 miles (237,000 kilometers) from Ceres on Jan. 25, and represent a new milestone for a spacecraft that soon will become the first human-made probe to visit a dwarf planet.

"We know so little about our vast solar system, but thanks to economical missions like Dawn, those mysteries are being solved," said Jim Green, Planetary Science Division Director at NASA Headquarters in Washington.

At 43 pixels wide, the new images are more than 30 percent higher in resolution than those taken by NASA's Hubble Space Telescope in 2003 and 2004 at a distance of over 150 million miles. The resolution is higher because Dawn is traveling through the solar system to Ceres, while Hubble remains fixed in Earth orbit. The new Dawn images come on the heels of initial navigation images taken Jan. 13 that reveal a white spot on the dwarf planet and the suggestion of craters. Hubble images also had glimpsed a white spot on the dwarf planet, but its nature is still unknown.

Zoomed out -- PIA19173 Ceres appears sharper than ever at 43 pixels across, a higher resolution than images of Ceres taken by the NASA's Hubble Space Telescope in 2003 and 2004.

As the spacecraft gets closer to Ceres, its camera will return even better images. On March 6, Dawn will enter into orbit around Ceres to capture detailed images and measure variations in light reflected from Ceres, which should reveal the planet’s surface composition.

"We are already seeing areas and details on Ceres popping out that had not been seen before. For instance, there are several dark features in the southern hemisphere that might be craters within a region that is darker overall," said Carol Raymond, deputy principal investigator of the Dawn mission at JPL. "Data from this mission will revolutionize our understanding of this unique body. Ceres is showing us tantalizing features that are whetting our appetite for the detailed exploration to come."

Originally described as a planet, Ceres was later categorized as an asteroid, and then reclassified as a dwarf planet in 2006. The mysterious world was discovered in 1801 by astronomer Giuseppe Piazzi, who named the object for the Roman goddess of agriculture, grain crops, fertility and motherly relationships.

“You may not realize that the word ‘cereal’ comes from the name Ceres. Perhaps you already connected with the dwarf planet at breakfast today," said JPL's Marc Rayman, Mission Director and Chief Engineer of the Dawn mission.

Powered by a uniquely capable ion propulsion system, Dawn also orbited and explored Vesta, the second most massive body in the asteroid belt. From 2011 to 2012, Dawn returned more than 30,000 images, 18 million light measurements and other scientific data about the impressive large asteroid. Vesta has a diameter of about 326 miles (525 kilometers).

"With the help of Dawn and other missions, we are continually adding to our understanding of how the solar system began and how the planets were formed,” said Chris Russell, principal investigator for the Dawn mission, based at the University of California, Los Angeles.

Read More

Tuesday, 27 January 2015

Enormous ExoPlanet Ring System 200 Xs Size of Saturn's Found


Astronomers at the Leiden Observatory, The Netherlands, and the University of Rochester, USA, have discovered that the ring system that they see eclipse the very young Sun-like star J1407 is of enormous proportions, much larger and heavier than the ring system of Saturn. The ring system – the first of its kind to be found outside our solar system – was discovered in 2012 by a team led by Rochester’s Eric Mamajek.

A new analysis of the data, led by Leiden’s Matthew Kenworthy, shows that the ring system consists of over 30 rings, each of them tens of millions of kilometers in diameter. Furthermore, they found gaps in the rings, which indicate that satellites (“exomoons”) may have formed. The result has been accepted for publication in the Astrophysical Journal.

“The details that we see in the light curve are incredible. The eclipse lasted for several weeks, but you see rapid changes on time scales of tens of minutes as a result of fine structures in the rings,” says Kenworthy. “The star is much too far away to observe the rings directly, but we could make a detailed model based on the rapid brightness variations in the star light passing through the ring system. If we could replace Saturn’s rings with the rings around J1407b, they would be easily visible at night and be many times larger than the full moon.”

“This planet is much larger than Jupiter or Saturn, and its ring system is roughly 200 times larger than Saturn’s rings are today,” said co-author Mamajek, professor of physics and astronomy at the University of Rochester. “You could think of it as kind of a super Saturn.”

The astronomers analyzed data from the SuperWASP project – a survey that is designed to detect gas giants that move in front of their parent star. In 2012, Mamajek and colleagues at the University of Rochester reported the discovery of the young star J1407 and the unusual eclipses, and proposed that they were caused by a moon-forming disk around a young giant planet or brown dwarf.

In a third, more recent study also led by Kenworthy, adaptive optics and Doppler spectroscopy were used to estimate the mass of the ringed object. Their conclusions based on these and previous papers on the intriguing system J1407 is that the companion is likely to be a giant planet – not yet seen – with a gigantic ring system responsible for the repeated dimming of J1407’s light.

The light curve tells astronomers that the diameter of the ring system is nearly 120 million kilometers, more than two hundred times as large as the rings of Saturn. The ring system likely contains roughly an Earth’s worth of mass in light-obscuring dust particles.

“If you were to grind up the four large Galilean moons of Jupiter into dust and ice and spread out the material over their orbits in a ring around Jupiter, the ring would be so opaque to light that a distant observer that saw the ring pass in front of the sun would see a very deep, multi-day eclipse,” Mamajek says. “In the case of J1407, we see the rings blocking as much as 95 percent of the light of this young Sun-like star for days, so there is a lot of material there that could then form satellites.”

In the data the astronomers found at least one clean gap in the ring structure, which is more clearly defined in the new model. “One obvious explanation is that a satellite formed and carved out this gap,” says Kenworthy. “The mass of the satellite could be between that of Earth and Mars. The satellite would have an orbital period of approximately two years around J1407b.”

Exoring model for J1407b from Matthew Kenworthy on Vimeo.

Astronomers expect that the rings will become thinner in the next several million years and eventually disappear as satellites form from the material in the disks.

“The planetary science community has theorized for decades that planets like Jupiter and Saturn would have had, at an early stage, disks around them that then led to the formation of satellites,” Mamajek explains. “However, until we discovered this object in 2012, no-one had seen such a ring system. This is the first snapshot of satellite formation on million-kilometer scales around a substellar object.”

Astronomers estimate that the ringed companion J1407b has an orbital period roughly a decade in length. The mass of J1407b has been difficult to constrain, but it is most likely in the range of about 10 to 40 Jupiter masses.

The researchers encourage amateur astronomers to help monitor J1407, which would help detect the next eclipse of the rings, and constrain the period and mass of the ringed companion. Observations of J1407 can be reported to the American Association of Variable Star Observers (AAVSO). In the meantime the astronomers are searching other photometric surveys looking for eclipses by yet undiscovered ring systems.

Kenworthy adds that finding eclipses from more objects like J1407’s companion “is the only feasible way we have of observing the early conditions of satellite formation for the near future. J1407’s eclipses will allow us to study the physical and chemical properties of satellite-spawning circumplanetary disks.”

Read More

Solar System Formed at the Dawn of the Milky Way Discovered with 5 Earthlike Planets


"There are far-reaching implications for this discovery," said Tiago Campante, from the University of Birmingham's School of Physics and Astronomy, who led the research. "We now know that Earth-sized planets have formed throughout most of the Universe's 13.8 billion year history, which could provide scope for the existence of ancient life in the Galaxy. By the time the Earth formed, the planets in this system were already older than our planet is today."

Thanks to the NASA Kepler mission, the scientists announced today (Tuesday 27 January 2015) in The Astrophysical Journal the observation of a Sun-like star (Kepler-444) hosting 5 planets with sizes between Mercury and Venus, that was formed 11.2 billion years ago, when the Universe was less than 20% its current age. This is the oldest known system of terrestrial-sized planets in our Galaxy - 2 and a half times older than the Earth.

The University of Birmingham team carried out the research using asteroseismology - listening to the natural resonances of the host star which are caused by sound trapped within it. These oscillations lead to miniscule changes or pulses in its brightness which allow the researchers to measure its diameter, mass and age. The planets were then detected from the dimming that occurs when the planets transited, or passed across, the stellar disc. This fractional fading in the intensity of the light received from the star enables scientists to accurately measure the size of the planets relative to the size of the star.

"The first discoveries of exoplanets around other Sun-like stars in our Galaxy have fuelled efforts to find other worlds like Earth and other terrestrial planets outside our Solar System," said Bill Chaplin, also from the University of Birmingham who has been leading the team studying solar-type stars using asteroseismology for the Kepler Mission. " We are now getting first glimpses of the variety of Galactic environments conducive to the formation of these small worlds. As a result, the path towards a more complete understanding of early planet formation in the Galaxy is now unfolding before us.'

Read More

Monday, 26 January 2015

The Dark-Matter Mystery Deepens --"Physicists Trying to Decode Hidden Message"

Our Milky Way galaxy is still assembling itself from dark matter and normal matter. Scientists have long known that dark matter is out there, silently orchestrating the universe’s movement and structure. But what exactly is dark matter made of? And what does a dark matter particle look like? That remains a mystery, with experiment after experiment coming up empty handed in the quest to detect these elusive particles


Leslie Rosenberg, a physicist with the University of Washington has published a paper in Proceedings of the National Academy of Sciences, describing the current state of research that involves investigating the possibility that axions are what make up dark matter. He also offers some perspective on the work suggesting that at least one project is likely to lead to either proving or disproving that axions are dark matter.

In the late 20th century, cosmology became a precision science. Now, at the beginning of the next century, the parameters describing how our universe evolved from the Big Bang are generally known to a few percent. One key parameter is the total mass density of the universe. Normal matter constitutes only a small fraction of the total mass density. Observations suggest this additional mass, the dark matter, is cold (that is, moving nonrelativistically in the early universe) and interacts feebly if at all with normal matter and radiation. There’s no known such elementary particle, so the strong presumption is the dark matter consists of particle relics of a new kind left over from the Big Bang.

One of the most important questions in science is the nature of this dark matter. One attractive particle dark-matter candidate is the axion. Physicists calculate that dark matter comprises 27 percent of the universe; normal matter 5 percent. WIMPS, weakly interacting massive particles, or axions, are weakly interacting low-mass particles.

Axion searches use a wide range of technologies, and the experiment sensitivities are now reaching likely dark-matter axion couplings and masses.

“We’re all looking and somewhere, maybe even now, there’s a little bit of data that will cause someone to have an ‘Ah ha!’ moment,” said Harry Nelson, professor of physics at the University of California, Santa Barbara and science lead for the LUX upgrade, called LUX-ZEPLIN. “This idea that there’s something out there that we can’t sense yet is one of those things that sends chills down my spine.”

With some luck, that may be about to change. With ten times the sensitivity of previous detectors, three recently funded dark matter experiments have scientists crossing their fingers that they may finally glimpse these long-sought particles. In recent conversations with The Kavli Foundation, scientists working on these new experiments expressed hope that they would catch dark matter, but also agreed that, in the end, their success or failure is up to nature to decide.

While studying over data collected by the European Space Agency's XMM-Newton spacecraft, a team of researchers last week observed an odd spike in X-ray emissions coming from two different celestial objects — the Andromeda galaxy and the Perseus galaxy cluster that corresponds to no known particle or atom and thus may have been produced by dark matter.

The image at the top of the page shows the central region of the Perseus galaxy cluster, using NASA's Chandra X-ray Observatory and 73 other clusters with ESA's XMM-Newton has revealed a mysterious X-ray signal in the data. The signal is also seen in over 70 other galaxy clusters using XMM-Newton. One intriguing possible explanation of this X-ray emission line is that it is produced by the decay of sterile neutrinos, a type of particle that has been proposed as a candidate for dark matter. While holding exciting potential, these results must be confirmed with additional data to rule out other explanations and determine whether it is plausible that dark matter has been observed.

The Perseus Cluster is one of the most massive objects in the Universe, and contains thousands of galaxies immersed in an enormous cloud of superheated gas. In Chandra's X-ray image, enormous bright loops, ripples, and jet-like streaks throughout the cluster can be seen. The dark blue filaments in the center are likely due to a galaxy that has been torn apart and is falling into NGC 1275 (a.k.a. Perseus A), the giant galaxy that lies at the center of the cluster.

There is uncertainty in these results, in part, because the detection of this emission line is pushing the capabilities of both Chandra and XMM-Newton in terms of sensitivity. Also, there may be explanations other than sterile neutrinos if this X-ray emission line is deemed to be real. For example, there are ways that normal matter in the cluster could have produced the line, although the team's analysis suggested that all of these would involve unlikely changes to our understanding of physical conditions in the galaxy cluster or the details of the atomic physics of extremely hot gases.

"The signal's distribution within the galaxy corresponds exactly to what we were expecting with dark matter — that is, concentrated and intense in the center of objects and weaker and diffuse on the edges," study co-author Oleg Ruchayskiy, of the École Polytechnique Fédérale de Lausanne (EPFL) said.

The first of the new experiments, called the Axion Dark Matter eXperiment, searches for a theoretical type of dark matter particle called the axion. ADMX seeks evidence of this extremely lightweight particle converting into a photon in the experiment’s high magnetic field. By slowly varying the magnetic field, the detector hunts for one axion mass at a time.

“We've demonstrated that we have the tools necessary to see axions,” said Gray Rybka, research assistant professor of physics at the University of Washington who co-leads the ADMX Gen 2 experiment. “With Gen2, we're buying a very, very powerful refrigerator that will arrive very shortly. Once it arrives, we'll be able to scan very, very quickly and we feel we'll have a much better chance of finding axions – if they're out there.”

The two other new experiments look for a different type of theoretical dark matter called the WIMP. Short for Weakly Interacting Massive Particle, the WIMP interacts with our world very weakly and very rarely. The Large Underground Xenon, or LUX, experiment, which began in 2009, is now getting an upgrade to increase its sensitivity to heavier WIMPs. Meanwhile, the Super Cryogenic Dark Matter Search collaboration, which has looked for the signal of a lightweight WIMP barreling through its detector since 2013, is in the process of finalizing the design for a new experiment to be located in Canada.

“In a way it's like looking for gold,” said Figueroa-Feliciano, a member of the SuperCDMS experiment. “Harry has his pan and he's looking for gold in a deep pond, and we're looking in a slightly shallower pond, and Gray's a little upstream, looking in his own spot. We don't know who's going to find gold because we don't know where it is.”

Rybka agreed, but added the more optimistic perspective that it’s also possible that all three experiments will find dark matter. “There's nothing that would require dark matter to be made of just one type of particle except us hoping that it's that simple,” he said. “Dark matter could be one-third axions, one-third heavy WIMPs and one-third light WIMPs. That would be perfectly allowable from everything we've seen.”

Yet the nugget of gold for which all three experiments search is a very valuable one. And even though the search is difficult, all three scientists agreed that it’s worthwhile because glimpsing dark matter would reveal insight into a large portion of the universe.

The physics community has spent three decades searching for and finding no evidence that dark matter is made of tiny exotic particles. Recently, Case Western Reserve University physics professor Glenn Starkman and David Jacobs, who received his PhD in Physics from CWRU in May and is now a fellow at the University of Cape Town, say published observations provide guidance, limiting where to look. The Macros, as Starkman and Jacobs call them, would not only dwarf WIMPS and axions, but differ in an important way. They could potentially be assembled out of particles in the Standard Model of particle physics instead of requiring new physics to explain their existence.

"We've been looking for WIMPs for a long time and haven't seen them," Starkman said. "We expected to make WIMPS in the Large Hadron Collider, and we haven't."

WIMPS and axions remain possible candidates for dark matter, but there's reason to search elsewhere, the theorists argue. "The community had kind of turned away from the idea that dark matter could be made of normal-ish stuff in the late '80s," Starkman added. "We ask, was that completely correct and how do we know dark matter isn't more ordinary stuff— stuff that could be made from quarks and electrons?"

After eliminating most ordinary matter, including failed Jupiters, white dwarfs, neutron stars, stellar black holes, the black holes in centers of galaxies and neutrinos with a lot of mass, as possible candidates, physicists turned their focus on the exotics. Matter that was somewhere in between ordinary and exotic—relatives of neutron stars or large nuclei—was left on the table, Starkman said. "We say relatives because they probably have a considerable admixture of strange quarks, which are made in accelerators and ordinarily have extremely short lives," he said.

Although strange quarks are highly unstable, Starkman points out that neutrons are also highly unstable. But in helium, bound with stable protons, neutrons remain stable. "That opens the possibility that stable strange nuclear matter was made in the early universe and dark matter is nothing more than chunks of strange nuclear matter or other bound states of quarks, or of baryons, which are themselves made of quarks," he said. Such dark matter would fit the Standard Model.

The Macros would have to be assembled from ordinary and strange quarks or baryons before the strange quarks or baryons decay, and at a temperature above 3.5 trillion degrees Celsius, comparable to the temperature in the center of a massive supernova, Starkman and Jacobs calculated. The quarks would have to be assembled with 90 percent efficiency, leaving just 10 percent to form the protons and neutrons found in the universe today.

The limits of the possible dark matter are as follows:

A minimum of 55 grams. If dark matter were smaller, it would have been seen in detectors in Skylab or in tracks found in sheets of mica. A maximum of 1024 (a million billion billion) grams. Above this, the Macros would be so massive they would bend starlight, which has not been seen. The range of 1017 to 1020 grams should also be eliminated from the search, the theorists say. Dark matter in that range would be massive for gravitational lensing to affect individual photons from gamma ray bursts in ways that have not been seen.

If dark matter is within this allowed range, there are reasons it hasn't been seen.

At the mass of 1018 grams, dark matter Macros would hit the Earth about once every billion years. At lower masses, they would strike the Earth more frequently but might not leave a recognizable record or observable mark. In the range of 109 to 1018, dark matter would collide with the Earth once annually, providing nothing to the underground dark matter detectors in place.

Read More

Friday, 23 January 2015

Three Extreme Objects Spotted in Milky Way Dwarf Galaxy


In the latest discovery, a multinational team of astronomers working on the High Energy Stereoscopic System (H.E.S.S.) telescopes found three extremely luminous gamma-ray sources in the Large Magellanic Cloud (LMC), a satellite dwarf galaxy of the Milky Way. These are objects of different types, namely the most powerful pulsar wind nebula (above); the most powerful supernova remnant; and a shell of 270 light years in diameter blown by multiple stars, and supernovae -- a so-called superbubble.

"This is a very important breakthrough for the team," says Professor Sergio Colafrancesco, DST/NRF SKA Research Chair in the Wits School of Physics. "It paves the way to study external galaxies with very high-E telescopes such as H.E.S.S and then later with the planned Cherenkov Telescope Array (CTA) in Namibia. It will lead us to re-examine galaxy evolution and answer questions such as how high-E particles can affect the evolution of cosmic structures in the universe, principally galaxies, and the life cycles of matter in galaxies."

Very high-energy gamma rays are the best tracers of cosmic accelerators such as supernova remnants and pulsar wind nebulae -- end-products of massive stars. There, charged particles are accelerated to extreme velocities. When these particles encounter light or gas in and around the cosmic accelerators, they emit gamma rays. Very high-energy gamma rays can be measured on Earth by observing the Cherenkov light emitted from the particle showers produced by incident gamma rays high up in the atmosphere using large telescopes with fast cameras.

The Large Magellanic Cloud (LMC) is a dwarf satellite galaxy of our Milky Way, located about 170,000 light years away and showing us its face. New, massive stars are formed at a high rate in the LMC, and it harbors numerous massive stellar clusters. The LMC's supernova rate relative to its stellar mass is five times that of our Galaxy. The youngest supernova remnant in the local group of galaxies, SN 1987A, is also a member of the LMC. Therefore, the H.E.S.S. scientists dedicated significant observation to searching for very high-energy gamma rays from this cosmic object.


For a total of 210 hours, H.E.S.S. has observed the largest star-forming region within the LMC called Tarantula Nebula. For the first time in a galaxy outside the Milky Way, individual sources of very high-energy gamma rays could be resolved: three extremely energetic objects of different types.

The so-called superbubble 30 Dor C is the largest known X-ray-emitting shell and appears to have been created by several supernovae and strong stellar winds. Superbubbles are broadly discussed as (complementary or alternative to individual supernova remnants) factories where the galactic cosmic rays are produced. The H.E.S.S. results demonstrate that the bubble is a source of, and filled by, highly energetic particles. The superbubble represents a new class of sources in the very high-energy regime.

Pulsars are highly magnetized, fast rotating neutron stars that emit a wind of ultra-relativistic particles forming a nebula. The most famous one is the Crab Nebula, one of the brightest sources in the high-energy gamma-ray sky. The pulsar PSR J0537?6910 driving the wind nebula N 157B discovered by the H.E.S.S. telescopes in the LMC is in many respects a twin of the very powerful Crab pulsar in our own Galaxy. However, its pulsar wind nebula N 157B outshines the Crab Nebula by an order of magnitude, in very high-energy gamma rays. Reasons are the lower magnetic field in N 157B and the intense starlight from neighboring star-forming regions, which both promote the generation of high-energy gamma rays.

The supernova remnant N 132D, known as a bright object in the radio and infrared bands, appears to be one of the oldest -- and strongest -- supernova remnants still glowing in very high-energy gamma rays. Between 2500 and 6000 years old -- an age where models predict that the supernova explosion front has slowed down and it ought no longer to be efficiently accelerating particles -- it still outshines the strongest supernova remnants in our Galaxy.

The observations confirm suspicions raised by other H.E.S.S. observations, that supernova remnants can be much more luminous than thought before.

Observed at the limits of detectability, and partially overlapping with each other, these new sources challenged the H.E.S.S. scientists. The discoveries were only possible due to the development of advanced methods of interpreting the Cherenkov images captured by the telescopes, improving in particular the precision with which gamma-ray directions can be determined.

Indeed, the new H.E.S.S. II 28 m telescope will boost the performance of the H.E.S.S. telescope system, and in the more distant future the planned Cherenkov Telescope Array (CTA) will provide even deeper and higher-resolution gamma-ray images of the LMC -- in the plans for science with CTA, the satellite galaxy is already identified as a "Key Science Project" deserving special attention.

Read More

The Universe is a 'Complexity Machine' --"Intelligent Life and Technology May be Common in the Cosmos"


Recent developments in science are beginning to suggest that the universe naturally produces complexity. The emergence of life in general and perhaps even rational life, with its associated technological culture, may be extremely common, argues Clemson researcher Kelly Smith in a recently published paper in the journal Space Policy. What's more, he suggests, this universal tendency has distinctly religious overtones and may even establish a truly universal basis for morality.

Smith, a Philosopher and Evolutionary Biologist, applies recent theoretical developments in Biology and Complex Systems Theory to attempt new answers to the kind of enduring questions about human purpose and obligation that have long been considered the sole province of the humanities.

He points out that scientists are increasingly beginning to discuss how the basic structure of the universe seems to favor the creation of complexity. The large scale history of the universe strongly suggests a trend of increasing complexity: disordered energy states produce atoms and molecules, which combine to form suns and associated planets, on which life evolves. Life then seems to exhibit its own pattern of increasing complexity, with simple organisms getting more complex over evolutionary time until they eventually develop rationality and complex culture.

And recent theoretical developments in Biology and complex systems theory suggest this trend may be real, arising from the basic structure of the universe in a predictable fashion.

"If this is right," says Smith, "you can look at the universe as a kind of 'complexity machine', which raises all sorts of questions about what this means in a broader sense. For example, does believing the universe is structured to produce complexity in general, and rational creatures in particular, constitute a religious belief? It need not imply that the universe was created by a God, but on the other hand, it does suggest that the kind of rationality we hold dear is not an accident."

And Smith feels another similarity to religion are the potential moral implications of this idea. If evolution tends to favor the development of sociality, reason, and culture as a kind of "package deal", then it's a good bet that any smart extraterrestrials we encounter will have similar evolved attitudes about their basic moral commitments.

In particular, they will likely agree with us that there is something morally special about rational, social creatures. And such universal agreement, argues Smith, could be the foundation for a truly universal system of ethics.

Read More

Wednesday, 21 January 2015

Hidden Magnetic Messages in Meteorites from Early Solar System Uncovered


Geologists from the University of Cambridge uncover hidden magnetic messages from the early solar system in meteorites measured at BESSY II. A team of scientists led by Richard Harrison from the University of Cambridge, has captured information stored inside tiny magnetic regions in meteorite samples that captures the dying moments of the magnetic field during core solidification on a meteorite parent body, providing a sneak preview of the fate of Earth's own magnetic field as its core continues to freeze.

Meteorites were previously thought to have poor magnetic memories, with the magnetic signals they carry having been written and rewritten many times during their long journey to Earth. Harrison, however, identified specific regions filled with nanoparticles that were magnetically extremely stable. These "tiny space magnets" retain a faithful record of the magnetic fields generated by the meteorite's parent body. Harrison and his colleagues could map these tiny magnetic signals using circular polarized X-ray synchrotron radiation at BESSY II. Their results have now been published in Nature.

Meteorites have witnessed a long and violent history; they are fragments of asteroids which formed in the early solar system, 4.5 billion years ago. Shortly after their formation, some asteroids were heated up by radioactive decay, causing them to melt and segregate into a liquid metal core surrounded by a solid rocky mantle. Convection of the liquid metal created magnetic fields, just as the liquid outer core of the Earth generates a magnetic field today. From time to time asteroids crash together and tiny fragments fall to Earth as meteorites, giving scientists the opportunity to study the properties of the magnetic fields that were generated billions of years ago.

"They are like natural hard discs", Harrison believes. The geologist from the Department of Earth Sciences, University of Cambridge, UK, is searching for methods to decipher the information stored deep inside the space rocks. Now his new approach has yielded its first results.

Until now it was not clear whether ancient magnetic signals could be retained by stony-iron meteorites at all. Large and highly mobile magnetic domains are found within the iron metal: these domains create huge magnetic signals but are easily overwritten by new events. The probability that these regions might contain useful information about early magnetic fields in the solar system is extremely low.

But Harrison took a much closer look. At the PEEM-Beamline of BESSY II, Harrison and PhD student James Bryson found dramatic variation in magnetic properties as they went through the meteorite. They saw not only regions containing large, mobile magnetic domains, but also identified an unusual region called the cloudy zone containing thousands of tiny particles of tetrataenite, a super hard magnetic material. "These tiny particles, just 50 to 100 nanometers in diameter, hold on to their magnetic signal and don't change. So it is only these very small regions of chaotic looking magnetization that contain the information we want", Bryson concludes.

The PEEM-Beamline offers X-rays with the specific energy and polarization needed to make sense of these magnetic signals. Since the absorption of the X-rays depends on the magnetization, the scientists could map the magnetic signals on the sample surface in ultrahigh resolution without changing them by the procedure. "The new technique we have developed is a way of analyzing these images to extract real information. So we can do for the first time paleomagnetic measurements of very small regions of these rocks, regions which are less than one micrometer in size. These are the highest resolution paleomagnetic measurements ever made", Harrison points out.

By spatially resolving the variations in magnetic signal across the cloudy zone, the team were able to reconstruct the history of magnetic activity on the meteorite parent body, and were even able to capture the moment when the core finished solidifying and the magnetic field shut down. These new measurements answer many open questions regarding the longevity and stability of magnetic activity on small bodies. Their observations, supported by computer simulations, demonstrate that the magnetic field was created by compositional, rather than thermal, convection - a result that changes our perspective on the way magnetic fields were generated during the early solar system and even provides a sneak preview of the fate of Earth's own magnetic field as its core continues to freeze.

Read More

"Dark Matter May be 'Another Dimension' --Or Even a Major Galactic Transport System"


"If we combine the map of the dark matter in the Milky Way with the most recent Big Bang model to explain the universe and we hypothesise the existence of space-time tunnels, what we get is that our galaxy could really contain one of these tunnels, and that the tunnel could even be the size of the galaxy itself. But there's more", explains Paolo Salucci, astrophysicist of the International School for Advanced Studies (SISSA) of Trieste and a dark matter expert. "We could even travel through this tunnel, since, based on our calculations, it could be navigable. Just like the one we've all seen in the recent film 'Interstellar'".

Although space-time tunnels (or wormholes or Einstein-Penrose bridges) have only recently gained great popularity among the public thanks to Christopher Nolan's sci-fi film, they have been the focus of astrophysicists' attention for many years. "What we tried to do in our study was to solve the very equation that the astrophysicist 'Murph' was working on. Clearly we did it long before the film came out" jokes Salucci. "It is, in fact, an extremely interesting problem for dark matter studies". Click here for a video of the space-time tunnel.

"Obviously we're not claiming that our galaxy is definitely a wormhole, but simply that, according to theoretical models, this hypothesis is a possibility". Can it ever be tested experimentally? "In principle, we could test it by comparing two galaxies - our galaxy and another, very close one like, for example, the Magellanic Cloud, but we are still very far from any actual possibility of making such a comparison".

To reach their conclusions the astrophysicists combined the equations of general relativity with an extremely detailed map of the distribution of dark matter in the Milky Way: "the map was one we obtained in a study we carried out in 2013", explains Salucci. "Beyond the sci-fi hypothesis, our research is interesting because it proposes a more complex reflection on dark matter".

As Salucci points out, scientists have long tried to explain dark matter by hypothesising the existence of a particular particle, the neutralino, which, however, has never been identified at CERN or observed in the universe. But alternative theories also exist that don't rely on the particle, "and perhaps it's time for scientists to take this issue 'seriously'", concludes Salucci. "Dark matter may be 'another dimension', perhaps even a major galactic transport system. In any case, we really need to start asking ourselves what it is".

Read More

Tuesday, 20 January 2015

Supernova's 25-Million-Year-Old Dust on Ocean Floor --Contradicts Current Theories


Scientists plumbing the depths of the ocean have made a surprise finding that could change the way we understand supernovae, exploding stars way beyond our solar system. They have analysed extraterrestrial dust thought to be from supernovae, that has settled on ocean floors to determine the amount of heavy elements created by the massive explosions.

"Small amounts of debris from these distant explosions fall on the earth as it travels through the galaxy," said lead researcher Anton Wallner, from the Research School of Physics and Engineering at The Australian National University (ANU).

"We've analysed galactic dust from the last 25 million years that has settled on the ocean and found there is much less of the heavy elements such as plutonium and uranium than we expected."

The findings are at odds with current theories of supernovae, in which some of the materials essential for human life, such as iron, potassium and iodine are created and distributed throughout space. Supernovae also create lead, silver and gold, and heavier radioactive elements such as uranium and plutonium.

Wallner's team studied plutonium-244 which serves as a radioactive clock by the nature of its radioactive decay, with a half-life of 81 million years. "Any plutonium-244 that existed when the earth formed from intergalactic gas and dust over four billion years ago has long since decayed," Wallner said. "So any plutonium-244 that we find on earth must have been created in explosive events that have occurred more recently, in the last few hundred million years."

The team analysed a 10 centimetre-thick sample of the earth's crust, representing 25 million years of accretion, as well as deep-sea sediments collected from a very stable area at the bottom of the Pacific Ocean.

"We found 100 times less plutonium-244 than we expected," Wallner said. "It seems that these heaviest elements may not be formed in standard supernovae after all. It may require rarer and more explosive events such as the merging of two neutron stars to make them."

The fact that these heavy elements like plutonium were present, and uranium and thorium are still present on earth suggests that such an explosive event must have happened close to the earth around the time it formed, says Wallner.

"Radioactive elements in our planet such as uranium and thorium provide much of the heat that drives continental movement, perhaps other planets don't have the same heat engine inside them."

Read More

Monday, 19 January 2015

Eco-Alert: "Human Civilization has Crossed Four of Nine Planetary Boundaries"

201305211100552458 (1)

"It might be possible for human civilization to live outside Holocene conditions, but it's never been tried before," says Steve Carpenter, director of the University of Wisconsin-Madison Center for Limnology. "We know civilization can make it in Holocene conditions, so it seems wise to try to maintain them."

An international team of researchers says climate change, the loss of biosphere integrity, land-system change, and altered biogeochemical cycles like phosphorus and nitrogen runoff have all passed beyond levels that put humanity in a "safe operating space."

Civilization has crossed four of nine so-called planetary boundaries as the result of human activity, according to a report published today in Science by the 18-member research team. Among them is Carpenter, the only U.S.-based researcher on the study.

The report, an update to previous studies, is titled "Planetary Boundaries: Guiding human development on a changing planet," and will be discussed next week at the World Economic Forum in Davos, Switzerland.

It should be a wake-up call to policymakers that "we're running up to and beyond the biophysical boundaries that enable human civilization as we know it to exist," says Carpenter.

For the last 11,700 years until roughly 100 years ago, Earth had been in a "remarkably stable state," says Carpenter. During this time, known as the Holocene epoch, "everything important to civilization" has occurred. From the development of agriculture, to the rise and fall of the Roman Empire, to the Industrial Revolution, the Holocene has been a good time for human endeavors.

But over the last century, some of the parameters that made the Holocene so hospitable have changed.

While the study focuses on several of these, including climate change and a troubling loss of biodiversity, Carpenter led the examination of biogeochemical cycle changes. Specifically, Carpenter looked at two elements essential to life as we know it, phosphorus and nitrogen.

Both are widely used to fertilize crops, and the rise of large-scale, industrial agriculture has led to an immense increase in the amount of the chemicals entering our ecosystems.

"We've changed nitrogen and phosphorus cycles vastly more than any other element," Carpenter says. "(The increase) is on the order of 200 to 300 percent. In contrast, carbon has only been increased 10 to 20 percent and look at all the uproar that has caused in the climate."

The increase in phosphorus and nitrogen has been especially detrimental to water quality. Phosphorus loading is the leading cause of both harmful algal blooms and the oxygen-starved "dead zone" in Lake Erie. Likewise, nitrogen flowing down the Mississippi River is the main culprit behind the "dead zone" in the Gulf of Mexico.

While nitrogen and phosphorus levels overall are well beyond the Holocene boundaries, Carpenter says the chemical load isn't spread evenly over the planet.

"There are places that are really, really overloaded with nutrient pollution," he says. "Wisconsin and the entire Great Lakes region are some of those. But there are other places where billions of people live that are undersupplied with nitrogen and phosphorus."

For instance, much of Africa is largely lacking these two essential elements, Carpenter says. "We've got certain parts of the world that are overpolluted with nitrogen and phosphorus, and others where people don't even have enough to grow the food they need."

It's a "distribution problem," Carpenter says, and suggests places like the Midwestern U.S. could vastly reduce its use of fertilizers and still maintain productive crops while nutrient-poor regions of the globe increase their use -- all while keeping the global levels safely within the study's prescribed "planetary boundary."

Read More

Sunday, 18 January 2015

Getting Closer? Newest Kepler-2 Findings "Reveal Earthlike Planets Common in Milky Way Galaxy"


"Most planets we have found to date are scorched. This system is the closest star with lukewarm transiting planets," Petigura said. "There is a very real possibility that the outermost planet is rocky like Earth, which means this planet could have the right temperature to support liquid water oceans."

NASA's Kepler Space Telescope, despite being hobbled by the loss of critical guidance systems, has discovered a star with three planets only slightly larger than Earth. The outermost planet orbits in the "Goldilocks" zone, a region where surface temperatures could be moderate enough for liquid water and perhaps life, to exist.

University of Hawaii astronomer Andrew Howard noted that extrasolar planets are discovered by the hundreds these days, though many astronomers are left wondering if any of the newfound worlds are really like Earth. The newly discovered planetary system will help resolve this question, he said.

"We've learned in the past year that planets the size and temperature of Earth are common in our Milky Way galaxy," Howard said. "We also discovered some Earth-size planets that appear to be made of the same materials as our Earth, mostly rock and iron."

The star, EPIC 201367065, is a cool red M-dwarf about half the size and mass of our own sun. At a distance of 150 light years, the star ranks among the top 10 nearest stars known to have transiting planets. The star's proximity means it's bright enough for astronomers to study the planets' atmospheres to determine whether they are like Earth's atmosphere and possibly conducive to life.

"A thin atmosphere made of nitrogen and oxygen has allowed life to thrive on Earth. But nature is full of surprises. Many exoplanets discovered by the Kepler mission are enveloped by thick, hydrogen-rich atmospheres that are probably incompatible with life as we know it," said Ian Crossfield, the University of Arizona astronomer who led the study.

A paper describing the find by astronomers at the University of Arizona, the University of California, Berkeley, the University of Hawaii, Manoa, and other institutions has been submitted to Astrophysical Journal and is freely available on the arXiv website . NASA and the National Science Foundation funded the research.

Co-authors of the paper include Joshua Schlieder of NASA Ames Research Center and colleagues from Germany, the United Kingdom and the U.S.

The three planets are 2.1, 1.7 and 1.5 times the size of Earth. The smallest and outermost planet, at 1.5 Earth radii, orbits far enough from its host star that it receives levels of light from its star similar to those received by Earth from the sun, said UC Berkeley graduate student Erik Petigura. He discovered the planets Jan. 6 while conducting a computer analysis of the Kepler data NASA has made available to astronomers. In order from farthest to closest to their star, the three planets receive 10.5, 3.2 and 1.4 times the light intensity of Earth, Petigura calculated.

After Petigura found the planets in the Kepler light curves, the team quickly employed telescopes in Chile, Hawaii and California to characterize the star's mass, radius, temperature and age. Two of the telescopes involved, the Automated Planet Finder on Mount Hamilton near San Jose, California, and the Keck Telescope on Mauna Kea, Hawaii, are University of California facilities.

The next step will be observations with other telescopes, including the Hubble Space Telescope, to take the spectroscopic fingerprint of the molecules in the planetary atmospheres. If these warm, nearly Earth-size planets have puffy, hydrogen-rich atmospheres, Hubble will see the telltale signal, Petigura said.

The discovery is all the more remarkable, he said, because the Kepler telescope lost two reaction wheels that kept it pointing at a fixed spot in space.

Kepler was reborn in 2014 as 'K2' with a clever strategy of pointing the telescope in the plane of Earth's orbit, the ecliptic, to stabilize the spacecraft. Kepler is now back to mining the cosmos for planets by searching for eclipses or "transits," as planets pass in front of their host stars and periodically block some of the starlight.

"This discovery proves that K2, despite being somewhat compromised, can still find exciting and scientifically compelling planets," Petigura said. "This ingenious new use of Kepler is a testament to the ingenuity of the scientists and engineers at NASA. This discovery shows that Kepler can still do great science."

Kepler sees only a small fraction of the planetary systems in its gaze: only those with orbital planes aligned edge-on to our view from Earth. Planets with large orbital tilts are missed by Kepler. A census of Kepler planets the team conducted in 2013 corrected statistically for these random orbital orientations and concluded that one in five sun-like stars in the Milky Way Galaxy have Earth-size planets in the habitable zone. Accounting for other types of stars as well, there may be 40 billion such planets galaxy wide.

The original Kepler mission found thousands of small planets, but most of them were too faint and far away to assess their density and composition and thus determine whether they were high-density, rocky planets like Earth or puffy, low-density planets like Uranus and Neptune. Because the star EPIC-201 is nearby, these mass measurements are possible. The host star, an M-dwarf, is less intrinsically bright than the sun, which means that its planets can reside close to the host-star and still enjoy lukewarm temperatures.

According to Howard, the system most like that of EPIC-201 is Kepler-138, an M-dwarf star with three planets of similar size, though none are in the habitable zone.

Read More

Saturday, 17 January 2015

The Spiral Galaxy Enigma --"Grand-Design Galaxies Simply Didn't Exist at Such an Early time in the History of the Universe" (Weekend Feature)


In July of 2012, astronomers observed a spiral galaxy in the early universe, billions of years before many other spiral galaxies formed while using the Hubble Space Telescope. "The fact that this galaxy exists is astounding," said David Law, lead author of the study and Dunlap Institute postdoctoral fellow at the University of Toronto's Dunlap Institute for Astronomy & Astrophysics. "Current wisdom holds that such 'grand-design' spiral galaxies simply didn't exist at such an early time in the history of the universe." A 'grand design' galaxy has prominent, well-formed spiral arms. The galaxy, which goes by the not very glamorous name of BX442, is quite large compared with other galaxies from this early time in the universe.

"BX442 looks like a nearby galaxy, but in the early universe, galaxies were colliding together much more frequently," says Alice Shapley, a UCLA associate professor of physics and astronomy. "Gas was raining in from the intergalactic medium and feeding stars that were being formed at a much more rapid rate than they are today; black holes grew at a much more rapid rate as well. The universe today is boring compared to this early time. As you go back in time to the early universe, galaxies look really strange, clumpy and irregular, not symmetric. The vast majority of old galaxies look like train wrecks. Our first thought was, why is this one so different, and so beautiful?"

The astronomers were taking pictures of about 300 very distant galaxies in the early universe to study their properties. This distant spiral galaxy they discovered existed roughly three billion years after the Big Bang, and light from this part of the universe has been traveling to Earth for about 10.7 billion years.

Galaxies in today's universe divide into various types, including spiral galaxies like our own Milky Way, which are rotating disks of stars and gas in which new stars form, and elliptical galaxies, which include older, redder stars moving in random directions. The mix of galaxy structures in the early universe is quite different, with a much greater diversity and larger fraction of irregular galaxies, Shapley said.

To gain deeper insight into their unique image of BX442, Law and Shapley went to the W.M. Keck Observatory atop Hawaii's dormant Mauna Kea volcano and used a unique state-of-the-science instrument called the OSIRIS spectrograph, which was built by James Larkin, a UCLA professor of physics and astronomy. They studied spectra from some 3,600 locations in and around BX442, which provided valuable information that enabled them to determine that it actually is a rotating spiral galaxy — and not, for example, two galaxies that happened to line up in the image.

"We first thought this could just be an illusion, and that perhaps we were being led astray by the picture," Shapley said. "What we found when we took the spectral image of this galaxy is that the spiral arms do belong to this galaxy. It wasn't an illusion. We were blown away." Law and Shapley also see some evidence of an enormous black hole at the center of the galaxy, which may play a role in the evolution of BX442.

Why does BX442 look like galaxies that are so common today but were so rare back then?

Law and Shapley say the answer may have to do with a companion dwarf galaxy, which the OSIRIS spectrograph reveals as a blob in the upper left portion of the image, and the gravitational interaction between them. Support for this idea is provided by a numerical simulation conducted by Charlotte Christensen, a postdoctoral scholar at the University of Arizona and a co-author of the research in Nature. Eventually the small galaxy is likely to merge into BX442, Shapley said.

Law, a former Hubble postdoctoral fellow at UCLA, and Shapley will continue to study BX442.

"We want to take pictures of this galaxy at other wavelengths," Shapley said. "That will tell us what type of stars are in every location in the galaxy. We want to map the mixture of stars and gas in BX442."

Shapley said that BX442 represents a link between early galaxies that are much more turbulent and the rotating spiral galaxies that we see around us. "Indeed, this galaxy may highlight the importance of merger interactions at any cosmic epoch in creating grand design spiral structure," she said.

Studying BX442 is likely to help astronomers understand how spiral galaxies like the Milky Way form, Shapley concluded.

The image at the top of the page is an artist's conception of the farthest spiral galaxy ever seen; in a Hubble/Keck image (inset), the blob at upper left is a companion galaxy whose gravity may have sparked the spiral structure. Credit: (left) David Law; (right) Joe Bergeron, Dunlap Institute for Astronomy and Astrophysics

Read More

Friday, 16 January 2015

"The Unexplored Planet" --NASA Spacecraft Begins 1st stage of Epic Pluto Probe


“NASA first mission to distant Pluto will also be humankind’s first close up view of this cold, unexplored world in our solar system,” said Jim Green, director of NASA’s Planetary Science Division at the agency’s Headquarters in Washington. “The New Horizons team worked very hard to prepare for this first phase, and they did it flawlessly.”

NASA's New Horizons spacecraft recently began its long-awaited, historic encounter with Pluto. The spacecraft is entering the first of several approach phases that culminate July 14 with the first close-up flyby of the dwarf planet, 4.67 billion miles (7.5 billion kilometers) from Earth.

The fastest spacecraft when it was launched, New Horizons lifted off in January 2006. It awoke from its final hibernation period last month after a voyage of more than 3 billion miles, and will soon pass close to Pluto, inside the orbits of its five known moons. In preparation for the close encounter, the mission’s science, engineering and spacecraft operations teams configured the piano-sized probe for distant observations of the Pluto system that start Sunday, Jan. 25 with a long-range photo shoot.

The images captured by New Horizons’ telescopic Long-Range Reconnaissance Imager (LORRI) will give mission scientists a continually improving look at the dynamics of Pluto’s moons. The images also will play a critical role in navigating the spacecraft as it covers the remaining 135 million miles (220 million kilometers) to Pluto.

“We’ve completed the longest journey any spacecraft has flown from Earth to reach its primary target, and we are ready to begin exploring,” said Alan Stern, New Horizons principal investigator from Southwest Research Institute in Boulder, Colorado.

LORRI will take hundreds of pictures of Pluto over the next few months to refine current estimates of the distance between the spacecraft and the dwarf planet. Though the Pluto system will resemble little more than bright dots in the camera’s view until May, mission navigators will use the data to design course-correction maneuvers to aim the spacecraft toward its target point this summer. The first such maneuver could occur as early as March.

“We need to refine our knowledge of where Pluto will be when New Horizons flies past it,” said Mark Holdridge, New Horizons encounter mission manager at Johns Hopkins University’s Applied Physics Laboratory (APL) in Laurel, Maryland. “The flyby timing also has to be exact, because the computer commands that will orient the spacecraft and point the science instruments are based on precisely knowing the time we pass Pluto – which these images will help us determine.”

The “optical navigation” campaign that begins this month marks the first time pictures from New Horizons will be used to help pinpoint Pluto’s location.

Throughout the first approach phase, which runs until spring, New Horizons will conduct a significant amount of additional science. Spacecraft instruments will gather continuous data on the interplanetary environment where the planetary system orbits, including measurements of the high-energy particles streaming from the sun and dust-particle concentrations in the inner reaches of the Kuiper Belt. In addition to Pluto, this area, the unexplored outer region of the solar system, potentially includes thousands of similar icy, rocky small planets.

More intensive studies of Pluto begin in the spring, when the cameras and spectrometers aboard New Horizons will be able to provide image resolutions higher than the most powerful telescopes on Earth. Eventually, the spacecraft will obtain images good enough to map Pluto and its moons more accurately than achieved by previous planetary reconnaissance missions.

Read More

Long-Lost Mars Express Lander Found


The UK-led Beagle 2 Mars Lander, thought lost on Mars since 2003, has been found partially deployed on the surface of the planet, ending the mystery of what happened to the mission more than a decade ago. Images taken by the HiRISE camera on NASA's Mars Reconnaissance Orbiter, or MRO, and initially searched by Michael Croon of Trier, Germany, a former member of the European Space Agency's Mars Express operations team at the European Space Operations Centre, have identified clear evidence for the lander and convincing evidence for key entry and descent components on the surface of Mars within the expected landing area of Isidis Planitia, an impact basin close to the equator.

This finding shows that the Entry, Descent and Landing, or EDL, sequence for Beagle 2 worked and the lander did successfully touchdown on Mars on Christmas Day 2003.

"We've been looking for all the past landers with HiRISE, this is the first time we found one that didn't send a signal after it landed," said Alfred McEwen, principal investigator of the HiRISE mission and professor in the UA's Lunar and Planetary Lab. "If the landing sequence works correctly, the probe sends a radio signal, and you can use that to pinpoint where it is coming from, even if it broadcasts only very briefly. But in the case of Beagle 2, we didn't get anything. All we had to go by was the target landing area."

Since the loss of Beagle 2 following its landing timed for Dec. 25, 2003, a search for it has been underway using images taken by the HiRISE camera on the MRO. HiRISE has been taking occasional pictures of the landing site in addition to pursuing its scientific studies of the surface of Mars. The planned landing area for Beagle 2 at the time of launch was approximately 170 x 100 kilometers (105 x 62 miles) within Isidis Planitia. With a fully deployed Beagle 2 being less than a few meters across and a camera image scale of about 0.3 m (10 inches), detection is a very difficult and a painstaking task. The initial detection came from HiRISE images taken on Feb. 28, 2013, and June 29, 2014 (Images ESP_037145_1915 and ESP_030908_1915). Croon had submitted a request through the HiWISH program, which allows anyone to submit suggestions for HiRISE imaging targets.

"He found something that would be a good candidate at the edge of the frame," McEwen said. "But contrast was low in the first image, and it was difficult to convince yourself something special was there."

The team acquired several more images, which showed a bright spot that seemed to move around.

"That was consistent with Beagle 2," McEwen said. "Because its solar panels were arranged in petals, each one would reflect light differently depending on the angles of the sun and MRO, especially if the lander was resting on sloping ground."

The imaging data may be consistent with only a partial deployment of Beagle 2 following landing, which would explain why no signal or data was received from the lander, as full deployment of all solar panels was needed to expose the RF antenna, which would transmit data and receive commands from Earth via orbiting Mars spacecraft.

The HiRISE images reveal only two or three of the motorized solar panels, but that may be due to their favorable tilts for sun glints. According to the UK Space Agency, if some panels failed to deploy, reasons could include obstruction from an airbag remaining in the proximity of the lander due to gas leakage, or a damaged mechanism or structure or broken electrical connection, perhaps due to unexpected shock loads during landing. The scenario of local terrain topology, including rocks blocking the deployment, is considered unlikely given images of the landing area, which show few rocks, but this cannot be ruled out. Further imaging and analysis is planned to narrow the options for what happened. Slope and height derived from the HiRISE images show that Beagle 2 landed on comparable flat terrain with no major hazards.

The discovery benefited from an additional image clean-up step that the HiRISE team has been testing, which removes very subtle electronic noise patterns that have to do with the way the instruments work on the MRO. Sarah Sutton, a HiRISE image processing scientist at LPL who was involved in processing the images that revealed the marooned lander, pointed out that this process is an additional step to make the images "just a little bit clearer."

"We have to be really careful not to modify the science data," said Sutton, who received her bachelor's degree in mathematics from the UA. "We do not make any enhancements or modify the images. All we do is eliminate subtle artifacts from high-frequency electronic noise. The untrained eye would not see it, but I see it.

"When we look at objects that are at the limit of the resolution of HiRISE, like Beagle 2, every bit of image clean-up helps."

Beagle 2 was part of the ESA Mars Express Mission launched in June 2003. Mars Express is still orbiting Mars and returning scientific data on the planet. Beagle 2 was successfully ejected from ESA's Mars Express spacecraft on the Dec. 19, 2003 -- 5.75 days away from Mars and Mars Express' engine firing and orbital injection.

Beagle 2 inspired many in the general public and led indirectly to the UK becoming a leading member of ESA's Aurora program and the UK-led ESA ExoMars mission. This rover will explore Mars in 2019, drilling up to 2 meters (6 feet) beneath the soil to explore the geochemistry and mineralogy of Mars and search for potential evidence of past life.

Read More

About Me

Designed ByBlogger Templates