NASA DAWN: Mysterious Bright Spot on Dwarf Planet Ceres

A mysterious white spot can be seen in the newest images from NASA's Dawn spacecraft, which is rapidly approaching the dwarf planet. 

Credit: NASA /JPL-Caltech /UCLA /MPS /DLR /IDA /PSI

A strange, flickering white blotch found on the dwarf planet Ceres by NASA's Dawn spacecraft has scientists scratching their heads.

The white spot on Ceres in a series of new photos taken on Jan. 13 by NASA's Dawn spacecraft, which is rapidly approaching the round dwarf planet in the asteroid belt between the orbits of Mars and Jupiter, but when the initial photo release on Monday (Jan. 19), the Dawn scientists gave no indication of what the white dot might be.

"Yes, we can confirm that it is something on Ceres that reflects more sunlight, but what that is remains a mystery," Marc Rayman, mission director and chief engineer for the Dawn mission, told Space.com in an email.




The new images show areas of light and dark on the face of Ceres, which indicate surface features like craters, but at the moment, none of the specific features can be resolved, including the white spot.

"We do not know what the white spot is, but it's certainly intriguing," Rayman said. "In fact, it makes you want to send a spacecraft there to find out, and of course that is exactly what we are doing! So as Dawn brings Ceres into sharper focus, we will be able to see with exquisite detail what [the white spot] is."

Ceres is a unique object in our solar system. It is the largest object in the asteroid belt and is classified as an asteroid. It is simultaneously classified as a dwarf planet, and at 590 miles across (950 kilometers, or about the size of Texas), Ceres is the smallest known dwarf planet in the solar system.

The $466 million Dawn spacecraft is set to enter into orbit around Ceres on March 6. Dawn left Earth in 2007 and in the summer of 2011, it made a year-long pit stop at the asteroid Vesta, the second largest object in the asteroid belt.

Mysterious rare five-hour space explosion explained

The X-ray image from the Swift X-ray Telescope of the gamma-ray burst GRB 130925. 

The white object in the center is the gamma-ray burst. 

The large diffuse region to the right is a cluster of galaxies. 

The other objects are X-ray-emitting celestial objects, most likely supermassive black holes at the centers of distant galaxies. 

The full image is approximately the size of the full moon. 

Credit: Phil Evans/ University of Leicester

Next week in St. Petersburg, Russia, scientists on an international team that includes Penn State University astronomers will present a paper that provides a simple explanation for mysterious ultra-long gamma-ray bursts, a very rare form of the most powerful explosions in the universe.

"The recent discovery of ultra-long gamma-ray bursts raised questions about whether some new physics is required to explain them, but our work suggests a much simpler explanation," said David Burrows, a Penn State professor of astronomy and astrophysics.

"Our analysis reveals that these rare gamma-ray bursts, which can last for hours, can be explained as standard explosions occurring in a region with a low density of matter that is located behind a cloud of dust when viewed from Earth."

Dick Willingale, an astronomer at the University of Leicester and a co-author of the study, said, "Not only is this result significant scientifically, but it shows the importance of international collaborations to build observatories, and of sharing information between those observatories."

Burrows is the lead scientist for the X-Ray Telescope on board the Swift satellite, one of two space observatories that the scientists used to collect data from the gamma-ray burst named GRB 130925A, which they observed last year while the energy from its explosion streamed toward Earth for more than five hours.

Swift is a NASA-led collaboration with Penn State in the United States, the University of Leicester and University College-London in the United Kingdom, and the Italian space agency and Brera Observatory in Italy.

The scientists also observed the ultra-long gamma-ray burst with the US/Russian satellite Konus-Wind.

"We could not have reached our conclusions without the Swift and Konus teams working together," Willingale said.

Burrows said it is not surprising that some gamma-ray bursts occur in a low-density region, nor is it surprising when one occurs behind a dust cloud.

"Our analysis of the observations from the two observatories shows that these two conditions existing simultaneously can explain our observations of the ultra-long gamma-ray burst GRB 130925A," Burrows said.

"One reason that these results are satisfying is that scientists generally prefer to find the simplest explanations for mysterious phenomena," he said.

Giant Geysers Mysteriously Disappear on Jupiter's ice-covered moon Europa

This artist's concept image depicts a water vapour geyser erupting from the surface of Jupiter's icy moon Europa.

Credit: NASA/ESA/K. Retherford/SWRI

The huge plumes of water vapour erupting from Jupiter's ice-covered moon Europa seem to have vanished, and scientists aren't sure why.

In December 2013, researchers using NASA's Hubble Space Telescope announced that they had spotted evidence of geysers blasting into space from Europa's south polar region.

The discovery sparked a great deal of excitement among space scientists, as it suggested that a robotic flyby probe might be able to sample Europa's subsurface ocean of liquid water without even touching down.

However, follow-up Hubble observations in January and February of this year showed no signs of the plumes, which were estimated to reach about 125 miles (200 kilometers) into space.



There are several possible explanations, researchers said. For example, Europa's geysers may be sporadic, more like volcanoes here on Earth than the plumes blasting pretty much constantly from the south pole of Saturn's icy moon Enceladus, which harbours a subsurface ocean like Europa.

It's also possible that Europa's plumes are only visible to Hubble's instruments at certain times.

"It could be just the way that we use the auroral emissions coming from those plumes at the UV [ultraviolet] wavelengths of light that we use with Hubble," discovery team member Kurt Retherford, of the Southwest Research Institute in San Antonio, told reporters.

"These things depend on Jupiter's plasma environment," Retherford added.

"Maybe there were just a lot of particles, atoms, getting excited by electrons and ions in Europa's atmosphere, more so than at other times, and [they] just lit up the plumes more than they usually do."

Further, the plumes may sometimes simply be too small to see, Retherford said. (Enceladus' geysers have been observed relatively close-up by NASA's Saturn-orbiting Cassini spacecraft, but scientists are relying on the Earth-orbiting Hubble to study the features on Europa.)

This NASA image shows the location of water plumes on Jupiter's icy moon Europa as seen by NASA's Hubble Space Telescope in December 2012. 

The discovery marked the first time strong evidence of water geysers on Europa.

Credit: NASA/ESA/L. Roth/SWRI/University of Cologne

Another possibility is that the geysers don't exist, that the detection by Hubble, which was based primarily on observations the telescope made in December 2012, was an artifact or misinterpretation of some sort but Retherford stressed that this is unlikely.

"The best explanation still is plumes for that dataset, no doubt about it," he said.

Retherford and his colleagues are going to look for the plumes again soon. They'll train Hubble on Europa from November through April, in a more comprehensive attempt to confirm the existence of the water-vapour geysers and to characterise their behaviour.

"The question is the variability aspect of the plumes. Why do we see them in some observation sets and not others?" Retherford said.



Learning more about the plumes is a key priority for astrobiologists and for NASA, which is eyeing a mission to Europa in the mid-2020s.

The leading candidate for that mission at the moment is probably a probe called the Europa Clipper, which would make multiple flybys of the icy satellite.

"This is the kind of thing that could have a profound impact on how we explore Europa," Curt Niebur, outer planets program scientist at NASA headquarters, said during a NASA planetary sciences subcommittee meeting Wednesday (Sept. 3).

"With an ocean that is tens of kilometers below the ice, most likely, if you can have a plume that's possibly bringing material from that ocean up to orbit, well, that's going to affect how you explore," Niebur added.

Silicon-capped hydrocarbons: Mysterious molecules in space

This graph shows absorption wavelength as a function of the number of carbon atoms in the silicon-terminated carbon chains SiC_(2n+1)H, for the extremely strong pi-pi electronic transitions. 

When the chain contains 13 or more carbon atoms, not significantly longer than carbon chains already known to exist in space, these strong transitions overlap with the spectral region occupied by the elusive diffuse interstellar bands. 

Credit: D. Kokkin, ASU

Over the vast, empty reaches of interstellar space, countless small molecules tumble quietly though the cold vacuum.

Forged in the fusion furnaces of ancient stars and ejected into space when those stars exploded, these lonely molecules account for a significant amount of all the carbon, hydrogen, silicon and other atoms in the universe.

In fact, some 20 percent of all the carbon in the universe is thought to exist as some form of interstellar molecule.

Many astronomers hypothesize that these interstellar molecules are also responsible for an observed phenomenon on Earth known as the "diffuse interstellar bands," spectrographic proof that something out there in the universe is absorbing certain distinct colours of light from stars before it reaches the Earth.

But since we don't know the exact chemical composition and atomic arrangements of these mysterious molecules, it remains unproven whether they are, in fact, responsible for the diffuse interstellar bands.

Now in a paper appearing this week in The Journal of Chemical Physics, from AIP Publishing, a group of scientists led by researchers at the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass. has offered a tantalising new possibility: these mysterious molecules may be silicon-capped hydrocarbons like SiC3H, SiC4H and SiC5H, and they present data and theoretical arguments to back that hypothesis.

At the same time, the group cautions that history has shown that while many possibilities have been proposed as the source of diffuse interstellar bands, none has been proven definitively.

"There have been a number of explanations over the years, and they cover the gamut," said Michael McCarthy a senior physicist at the Harvard-Smithsonian Center for Astrophysics (CfA) who led the study.

Molecules in Space and How We Know They're There
Astronomers have long known that interstellar molecules containing carbon atoms exist and that by their nature they will absorb light shining on them from stars and other luminous bodies.

Because of this, a number of scientists have previously proposed that some type of interstellar molecules are the source of diffuse interstellar bands, the hundreds of dark absorption lines seen in color spectrograms taken from Earth.

In showing nothing, these dark bands reveal everything. The missing colours correspond to photons of given wavelengths that were absorbed as they travelled through the vast reaches of space before reaching us.

More than that, if these photons were filtered by falling on space-based molecules, the wavelengths reveal the exact energies it took to excite the electronic structures of those absorbing molecules in a defined way.

Armed with that information, scientists here on Earth should be able to use spectroscopy to identify those interstellar molecules, by demonstrating which molecules in the laboratory have the same absorptive "fingerprints."

But despite decades of effort, the identity of the molecules that account for the diffuse interstellar bands remains a mystery.

Nobody has been able to reproduce the exact same absorption spectra in laboratories here on Earth.

"Not a single one has been definitively assigned to a specific molecule," said Neil Reilly, a former postdoctoral fellow at Harvard-Smithsonian Center for Astrophysics (CfA) and a co-author of the new paper.

Now Reilly, McCarthy and their colleagues are pointing to an unusual set of molecules, silicon-terminated carbon chain radicals, as a possible source of these mysterious bands.

As they report in their new paper, the team first created silicon-containing carbon chains SiC3H, SiC4H and SiC5H in the laboratory using a jet-cooled silane-acetylene discharge.

They then analysed their spectra and carried out theoretical calculations to predict that longer chains in this family might account for some portion of the diffuse interstellar bands.

However, McCarthy cautioned that the work has not yet revealed the smoking gun source of the diffuse interstellar bands.

To prove that these larger silicon capped hydrocarbon molecules are such a source, more work needs to be done in the laboratory to define the exact types of transitions these molecules undergo, and these would have to be directly related to astronomical observations.

But the study provides a tantalising possibility for finding the elusive source of some of the mystery absorption bands, and it reveals more of the rich molecular diversity of space.

"The interstellar medium is a fascinating environment," McCarthy said. "Many of the things that are quite abundant there are really unknown on Earth."

More information: The Journal of Chemical Physics, July 29, 2014. DOI: 10.1063/1.4883521

Fermi finds a mysterious 'transformer' pulsar

These artist's renderings show one model of pulsar J1023 before (top) and after (bottom) its radio beacon (green) vanished. 

Normally, the pulsar's wind staves off the companion's gas stream. 

When the stream surges, an accretion disk forms and gamma-ray particle jets (magenta) obscure the radio beam. 

Credit: NASA's Goddard Space Flight Center

In late June 2013, an exceptional binary containing a rapidly spinning neutron star underwent a dramatic change in behavior never before observed.

The pulsar's radio beacon vanished, while at the same time the system brightened fivefold in gamma rays, the most powerful form of light, according to measurements by NASA's Fermi Gamma-ray Space Telescope.

"It's almost as if someone flipped a switch, morphing the system from a lower-energy state to a higher-energy one," said Benjamin Stappers, an astrophysicist at the University of Manchester, England, who led an international effort to understand this striking transformation.

"The change appears to reflect an erratic interaction between the pulsar and its companion, one that allows us an opportunity to explore a rare transitional phase in the life of this binary."

A binary consists of two stars orbiting around their common center of mass. This system, known as AY Sextantis, is located about 4,400 light-years away in the constellation Sextans.

It pairs a 1.7-millisecond pulsar named PSR J1023+0038 (J1023) with a star containing about one-fifth the mass of the sun.

The stars complete an orbit in only 4.8 hours, which places them so close together that the pulsar will gradually evaporate its companion.

When a massive star collapses and explodes as a supernova, its crushed core may survive as a compact remnant called a neutron star or pulsar, an object squeezing more mass than the sun's into a sphere no larger than Washington, D.C.

Young isolated neutron stars rotate tens of times each second and generate beams of radio, visible light, X-rays and gamma rays that astronomers observe as pulses whenever the beams sweep past Earth.

Pulsars also generate powerful outflows, or "winds," of high-energy particles moving near the speed of light.

The power for all this comes from the pulsar's rapidly spinning magnetic field, and over time, as the pulsars wind down, these emissions fade.

More than 30 years ago, astronomers discovered another type of pulsar revolving in 10 milliseconds or less, reaching rotational speeds up to 43,000 rpm.

While young pulsars usually appear in isolation, more than half of millisecond pulsars occur in binary systems, which suggested an explanation for their rapid spin.

"Astronomers have long suspected millisecond pulsars were spun up through the transfer and accumulation of matter from their companion stars, so we often refer to them as recycled pulsars," explained Anne Archibald, a postdoctoral researcher at the Netherlands Institute for Radio Astronomy (ASTRON) in Dwingeloo who discovered J1023 in 2007.


Zoom into an artist's concept of AY Sextantis, a binary star system whose pulsar switched from radio emissions to high-energy gamma rays in 2013. 

This transition likely means the pulsar's spin-up process is nearing its end. 

Credit: NASA FERMI

During the initial mass-transfer stage, the system would qualify as a low-mass X-ray binary, with a slower-spinning neutron star emitting X-ray pulses as hot gas raced toward its surface.

A billion years later, when the flow of matter comes to a halt, the system would be classified as a spun-up millisecond pulsar with radio emissions powered by a rapidly rotating magnetic field.

To better understand J1023's spin and orbital evolution, the system was regularly monitored in radio using the Lovell Telescope in the United Kingdom and the Westerbork Synthesis Radio Telescope in the Netherlands.

These observations revealed that the pulsar's radio signal had turned off and prompted the search for an associated change in its gamma-ray properties.

A few months before this, astronomers found a much more distant system that flipped between radio and X-ray states in a matter of weeks.

Located in M28, a globular star cluster about 19,000 light-years away, a pulsar known as PSR J1824-2452I underwent an X-ray outburst in March and April 2013. As the X-ray emission dimmed in early May, the pulsar's radio beam emerged.

While J1023 reached much higher energies and is considerably closer, both binaries are otherwise quite similar. What's happening, astronomers say, are the last sputtering throes of the spin-up process for these pulsars.

In J1023, the stars are close enough that a stream of gas flows from the sun-like star toward the pulsar. The pulsar's rapid rotation and intense magnetic field are responsible for both the radio beam and its powerful pulsar wind.

When the radio beam is detectable, the pulsar wind holds back the companion's gas stream, preventing it from approaching too closely but now and then the stream surges, pushing its way closer to the pulsar and establishing an accretion disk.

Gas in the disk becomes compressed and heated, reaching temperatures hot enough to emit X-rays. Next, material along the inner edge of the disk quickly loses orbital energy and descends toward the pulsar.

When it falls to an altitude of about 50 miles (80 km), processes involved in creating the radio beam are either shut down or, more likely, obscured.

The inner edge of the disk probably fluctuates considerably at this altitude. Some of it may become accelerated outward at nearly the speed of light, forming dual particle jets firing in opposite directions, a phenomenon more typically associated with accreting black holes.

Shock waves within and along the periphery of these jets are a likely source of the bright gamma-ray emission detected by Fermi.

The findings were published in the July 20 edition of The Astrophysical Journal. The team reports that J1023 is the first example of a transient, compact, low-mass gamma-ray binary ever seen.

The researchers anticipate that the system will serve as a unique laboratory for understanding how millisecond pulsars form and for studying the details of how accretion takes place on neutron stars.

"So far, Fermi has increased the number of known gamma-ray pulsars by about 20 times and doubled the number of millisecond pulsars within in our galaxy," said Julie McEnery, the project scientist for the mission at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

"Fermi continues to be an amazing engine for pulsar discoveries."

More information: Paper: "A State Change In The Missing Link Binary Pulsar System PSR J1023+0038" iopscience.iop.org/0004-637X/790/1/39 - Paper: "A Radio Pulsar/X-ray Binary Link" arxiv.org/abs/0905.3397

Mysterious dance of dwarfs may force a cosmic rethink

This is an artist's impression of the coherent orbit of dwarf galaxies about a large galaxy. 

Credit: Geraint Lewis

The discovery that many small galaxies throughout the universe do not 'swarm' around larger ones like bees do but 'dance' in orderly disc-shaped orbits is a challenge to our understanding of how the universe formed and evolved.

The finding, by an international team of astronomers, including Professor Geraint Lewis from the University of Sydney's School of Physics, is announced today in Nature.

"Early in 2013 we announced our startling discovery that half of the dwarf galaxies surrounding the Andromeda Galaxy are orbiting it in an immense plane" said Professor Lewis.

"This plane is more than a million light years in diameter, but is very thin, with a width of only 300 000 light years."

The universe contains billions of galaxies. Some, such as the Milky Way, are immense, containing hundreds of billions of stars. Most galaxies, however, are dwarfs, much smaller and with only a few billion stars.

For decades astronomers have used computer models to predict how these dwarf galaxies should orbit large galaxies. They had always found that they should be scattered randomly.

"Our Andromeda discovery did not agree with expectations, and we felt compelled to explore if it was true of other galaxies throughout the universe," said Professor Lewis.

Using the Sloan Digital Sky Survey (SDSS), a remarkable resource of colour images and 3-D maps covering more than a third of the sky, the researchers dissected the properties of thousands of nearby galaxies.

"We were surprised to find that a large proportion of pairs of satellite galaxies have oppositely directed velocities if they are situated on opposite sides of their giant galaxy hosts", said lead author Neil Ibata of the Lycée International in Strasbourg, France.

"Everywhere we looked we saw this strangely coherent coordinated motion of dwarf galaxies. From this we can extrapolate that these circular planes of dancing dwarfs are universal, seen in about 50 percent of galaxies," said Professor Geraint Lewis.

"This is a big problem that contradicts our standard cosmological models. It challenges our understanding of how the universe works including the nature of dark matter."

The researchers believe the answer may be hidden in some currently unknown physical process that governs how gas flows in the universe, although, as yet, there is no obvious mechanism that can guide dwarf galaxies into narrow planes.

Some experts, however, have made more radical suggestions, including bending and twisting the laws of gravity and motion.

"Throwing out seemingly established laws of physics is unpalatable," said Professor Lewis, "but if our observations of nature are pointing us in this direction, we have to keep an open mind. That's what science is all about."

More information: "Velocity anti-correlation of diametrically opposed galaxy satellites in the low-redshift Universe." Neil G. Ibata, et al. Nature (2014) DOI: 10.1038/nature13481. 

Cosmic rays Hotspot: Physicists closer to finding the mysterious sources

This map of the northern sky shows cosmic ray concentrations, with a "hotspot" with a disproportionate number of cosmic rays shown as the bright red and yellow spot, upper right. 

An international team of physicists using the University of Utah-operated Telescope Array near Delta, Utah, say their discovery of the hotspot should narrow the search for the mysterious source or sources of ultrahigh-energy cosmic rays, which carry more energy than any other known particle in the universe. 

Credit: Kazumasa Kawata, University of Tokyo Institute for Cosmic Ray Research.

An observatory run by the University of Utah found a "hotspot" beneath the Big Dipper emitting a disproportionate number of the highest-energy cosmic rays.

The discovery moves physics another step toward identifying the mysterious sources of the most energetic particles in the universe.

Gordon Thomson

"This puts us closer to finding out the sources, but no cigar yet," says University of Utah physicist Gordon Thomson, spokesman and co-principal investigator for the $25 million Telescope Array cosmic ray observatory west of Delta, Utah; the Northern Hemisphere's largest cosmic ray detector.

"All we see is a blob in the sky, and inside this blob there is all sorts of stuff – various types of objects, that could be the source" of the powerful cosmic rays, he adds. "Now we know where to look."

A new study identifying a hotspot in the northern sky for ultrahigh-energy cosmic rays has been accepted for publication by Astrophysical Journal Letters.

Thomson says many astrophysicists suspect ultrahigh-energy cosmic rays are generated by active galactic nuclei (AGNs), in which material is sucked into a supermassive black hole at the center of galaxy, while other material is spewed away in a beam-like jet known as a blazar.

Another popular possibility is that the highest-energy cosmic rays come from some supernovas (exploding stars) that emit gamma rays bursts.

Lower-energy cosmic rays come from the sun, other stars and exploding stars, but the source or sources of the most energetic cosmic rays has been a decades-long mystery.

The study was conducted by 125 researchers in the Telescope Array project, including Thomson and 31 other University of Utah physicists, plus 94 other scientists from the University of Tokyo (ICRR) and 28 other research institutions in Japan, the United States, South Korea, Russia and Belgium.

Read the full article here

More Information: Indications of Intermediate-Scale Anisotropy of Cosmic Rays with Energy Greater Than 57 EeV in the Northern Sky Measured with the Surface Detector of the Telescope Array Experiment - Authors: K. Kawata, et al.

NASA Cassini Titan flyby: Data collected on mysterious hydrocarbon lakes

Credit: NASA/JPL-Caltech /University of Arizona /University of Idaho

NASA's Cassini mission flew past Titan early Wednesday morning, successfully completing a complex maneuver that will help scientists better understand one of the solar system's most intriguing moons.

Beginning around midnight, a team of scientists and engineers guided the spacecraft into an orbit that allowed them to bounce a radio signal off the surface of Titan toward Earth, where it was received by a land-based telescope array 1 billion miles away.

"We are essentially using Titan as a mirror," said Essam Marouf of San Jose State University, who's a member of the Cassini radio science team. "And the nature of the echo can tell us about the nature of Titan's surface, whether it is liquid or solid, and the physical properties of the material."

Saturn's moon Titan is the second-largest moon in the solar system after Jupiter's moon Ganymede, and in some ways it's one of the most Earth-like bodies we have encountered.

Like Earth, it has a thick atmosphere, and it is the only other world we know of that has a system of liquid lakes and seas on its surface.

However, unlike Earth, its surface is far too cold to sustain liquid water.

Scientists have hypothesized that Titan's famous lakes and seas are made of liquid methane or ethane, but Marouf explains that those inferences are mostly based on the fact that methane and ethane would take on a liquid state in the conditions on Titan, rather than direct observation.

"There is no really direct measurement that tells us what they are exactly," he said.

"If the data from this morning is good enough, it will tell us what these liquids really are."

From 11:30 Tuesday evening to 11 Wednesday morning, Marouf gathered with other members of Cassini's radio science team in a control room at the Jet Propulsion Laboratory in La Canada Flintridge near downtown Los Angeles, watching as the new data were received by a radio telescope array in Australia.

He said they could not analyze the data in real time, but they were able to tell that the signal was clear enough to give them something to work with.

Cassini performed a similar experiment on Saturn's surface on May 17 that was also a success. That time, the researchers were able to collect information from two of the largest bodies of liquid on Titan: Ligea Mare and Kraken Mare.

This time, Cassini bounced its radio signal off an area between the two seas where radar images had found smaller liquid regions similar to rivers, lakes and channels on Earth.

"This kind of experiment takes a meticulous kind of preparation to first know where to look, and then design the maneuvers," Marouf said. "There are many pieces that have to work flawlessly to end up with the data."

He said the team hopes to look over the data this week and share its early results at a Cassini science team meeting next week in the Netherlands.

Astronomers witness mysterious and unique disintegration of asteroid

This series of Hubble Space Telescope images reveals the breakup of an asteroid over a period of several months in late 2013. 

The largest fragments are up to 200 yards in radius, each with "tails" caused by dust lifted from their surfaces and pushed back by the pressure of sunlight. 

The 10 pieces of the asteroid drift apart slowly and show a range of breakup times, suggesting that the disintegration cannot be explained by a collision with another asteroid. 

One idea for the breakup is that the asteroid was accelerated by sunlight to spin at a fast enough rate to fly apart by centrifugal force. 

The images were taken in visible light with Hubble's Wide-Field Camera 3. 

Credit: NASA, ESA, D. Jewitt/UCLA

Astronomers have witnessed for the first time the breakup of an asteroid into as many as 10 smaller pieces.

The discovery is published online March 6 in Astrophysical Journal Letters.

Though fragile comet nuclei have been seen falling apart as they near the sun, nothing resembling this type of breakup has been observed before in the asteroid belt. NASA's Hubble Space Telescope photographed the demolition.

"Seeing this rock fall apart before our eyes is pretty amazing," said David Jewitt, a professor in the UCLA Department of Earth, Planetary and Space Sciences and the UCLA Department of Physics and Astronomy, who led the astronomical forensics investigation.

The crumbling asteroid, designated P/2013 R3, was first noticed as an anomalous, fuzzy-looking object on Sept. 15, 2013, by the Catalina and Pan-STARRS sky-survey telescopes.

Pan-STARRS sky-survey telescope

A follow-up observation on Oct. 1 with the W.M. Keck telescope on Hawaii's Mauna Kea revealed three co-moving bodies embedded in a dusty envelope that is nearly the diameter of Earth.

"The Keck telescope showed us that this asteroid was worth looking at with Hubble," Jewitt said.

With its superior resolution, the Hubble telescope revealed that there were really 10 embedded objects, each with comet-like dust tails.

The four largest rocky fragments are up to 200 yards in radius, about twice the length of a football field.

The Hubble data showed that the fragments are drifting away from each other at a leisurely pace of one mile per hour—slower than a strolling human.

The asteroid began coming apart early last year, but new pieces continue to emerge in the most recent images.

This makes it unlikely that the asteroid is disintegrating because of a collision with another asteroid, which would be instantaneous and violent.

Some of the debris from such a high-velocity smash-up would also be expected to travel much faster than observed.

Mysterious Fireball Caught On Security Camera

Mysterious Fireball Caught On Security Camera

CCTV Video Footage shows a fiery object streaking across the sky in America's Midwest - but what was the object?

USAF Mysterious X-37B Space Plane Nears One Year In Orbit

This NASA Marshall Space Flight Centre image shows on-orbit functions for the reusable X-37 space plane, now under the wing of the U.S. Air Force. 

Credit: NASA/MSFC

The U.S. Air Force's mysterious X-37B space plane is nearing a major milestone — one year of travel in Earth orbit, performing duties in support of long-term space objectives.

The unmanned X-37B spacecraft — flying a mission known as Orbital Test Vehicle 3 (OTV-3) — launched into space atop an Atlas 5 rocket from Florida’s Cape Canaveral Air Force Station on Dec. 11, 2012.

What payloads the space plane is toting and the overall mission goals on its confidential cruise are classified.

But it is known that the OTV-3 mission signals a milestone for the X-37B program.

This same vehicle was flown on the X-37B program's inaugural flight back in 2010.

That OTV-1 mission lasted nearly 225 days in orbit, gliding back to Earth on autopilot over the Pacific Ocean and touching down at Vandenberg Air Force Base in California.

An OTV-2 mission, which used a different X-37B space plane, was lofted in 2011. That vehicle flew for 469 days, more than doubling its sister ship’s space stay, concluding its mission by also making a Vandenberg landing.



Next-generation technology
According to a Boeing fact sheet, each space plane is built with lightweight composite structures, rather than traditional aluminum.

A new generation of high-temperature leading-edge tiles for the wings is utilized, distinct from the space shuttle’s carbon leading-edge segments.

The X-37B is outfitted with toughened uni-piece fibrous insulation impregnated silica tiles, which are significantly more durable than the first-generation tiles used by the space shuttle.

Advanced conformal reusable insulation blankets are used for the first time on the X-37B.

The Boeing fact sheet also points out that avionics on an X-37B are designed to automate all de-orbit and landing functions.

Additionally, there are no hydraulics onboard the winged vehicle; flight controls and brakes use electromechanical actuation.

Astronomers reveal contents of mysterious black hole jets

This is a model of the black hole system with the jets that have been found to contain atomic matter. 

Credit: J. Miller-Jones (ICRAR) using software created by R. Hynes.

An international team of astronomers has answered a long standing question about the enigmatic jets emitted by black holes, in research published today in prestigious journal Nature.

Jets are narrow beams of matter spat out at high speed from near a central object, like a black hole.

"Although they have been observed for decades, we're still not sure what they are made of, or what powers them," ESO astronomer Dr María Díaz Trigo, lead author of the study, said.

The team studied the radio waves and X-rays emitted by a small black hole a few times the mass of the Sun.

The black hole in question was known to be active, but the team's radio observations did not show any jets, and the X-ray spectrum didn't reveal anything unusual.

However, a few weeks later, the team took another look and this time saw radio emissions corresponding to the sudden appearance of these jets, and even more interestingly, lines had appeared in the X-ray spectrum – the tell-tale signature of ordinary atoms – around the black hole.

During the first observation the X-ray emission can be fully described by emission from a standard accretion disc. 

Credit: Riccardo Lanfranchi

"Intriguingly, we found the lines were not where they should be, but rather were shifted significantly," Dr James Miller Jones from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR), who led the radio observations, said.

The same effect occurs when a siren from a vehicle changes pitch as it moves towards or away from us, as the sound wave is shortened or lengthened by the movement.

During the second observation the appearance of a jet is detected in radio emission and the X-ray spectrum requires an additional component attributed to coronal emission above the disc and three narrow emission lines indicating the presence of baryons. 

Credit: Riccardo Lanfranchi

"It led us to conclude the particles were being accelerated to fast speeds in the jets, one directed towards Earth, and the other one in the opposite direction," team member Dr Simone Migliari from the University of Barcelona said.

Dr Miller-Jones said this is the first strong evidence of such particles in jets from a typical small black hole.

"We've known for a long time that jets contain electrons, but haven't got an overall negative charge, so there must be something positively charged in them too," Dr Miller Jones said.

"Until now it wasn't clear whether the positive charge came from positrons, the antimatter 'opposite' of electrons, or positively charged atoms. Since our results found nickel and iron in these jets, we now know ordinary matter must be providing the positive charge."

Positively charged atoms are much heavier than the positrons astronomers thought might make up the jets, and therefore the jets can carry away far more energy from the black hole than previously confirmed.

What's more, astronomers aren't sure whether the jets are powered by the spin of the rotating black hole itself, or whether they are instead launched directly from the disk of matter that surrounds the black hole.

"Our results suggest it's more likely the disk is responsible for channelling the matter into the jets, and we are planning further observations to try and confirm this," Dr Miller-Jones said.

Using the X-ray data, the team also determined the jets were moving at 66% of the speed of light, or 198,000 km/s, the most accurate determination to date of the jet speed from a run-of-the-mill black hole that's a few times the mass of the Sun.

For their observations, the team used the European Space Agency's XMM-Newton satellite to observe X-ray emission from the black hole, as well as CSIRO's Australia Telescope Compact Array for the radio observations.

More information: Nature paper: dx.doi.org/10.1038/nature12672

Mysterious 13th Century eruption traced to Lombok, Indonesia

The caldera that is today Segara Anak Crater Lake, formed after the eruption

Scientists think they have found the volcano responsible for a huge eruption that occurred in the 13th Century.

The mystery event in 1257 was so large its chemical signature is recorded in the ice of both the Arctic and the Antarctic.

European medieval texts talk of a sudden cooling of the climate, and of failed harvests.

In the PNAS journal, an international team points the finger at the Samalas Volcano on Lombok Island, Indonesia.

Little remains of the original mountain structure - just a huge crater lake.

The team has tied sulphur and dust traces in the polar ice to a swathe of data gathered in the Lombok region itself, including radiocarbon dates, the type and spread of ejected rock and ash, tree-rings, and even local chronicles that recall the fall of the Lombok Kingdom sometime in the 13th Century.

"The evidence is very strong and compelling," Prof Clive Oppenheimer, from Cambridge University, UK, told reporters.

Co-worker Prof Franck Lavigne, from the Pantheon-Sorbonne University, France, added: "We conducted something similar to a criminal investigation.

"We didn't know the culprit at first, but we had the time of the murder and the fingerprints in the form of the geochemistry in the ice cores, and that allowed us to track down the volcano responsible."

The 1257 eruption has been variously linked with volcanoes in Mexico, Ecuador and New Zealand.

But these candidates fail on their dating or geochemistry, the researchers say. Only Samalas can "tick all the boxes".

ESA XMM-Newton: Mysterious magnetar boasts one of strongest magnetic fields in Universe

Artist's impression of a magnetar Credit: ESA /ATG Medialab

A team of astronomers including two researchers from UCL's Mullard Space Science Laboratory has made the first ever measurement of the magnetic field at a specific spot on the surface of a magnetar.

Magnetars are a type of neutron star, the dense and compact core of a giant star which has blasted away its outer layers in a supernova explosion.

Magnetars have among the strongest magnetic fields in the Universe. Until now, only their large scale magnetic field had been measured.

However, using a new technique and observations of a magnetar in X-rays, the astronomers have now revealed a strong, localised surface magnetic field on one.

Magnetars are very puzzling neutron stars. Astronomers discovered them through their unusual behaviour when observed in X-ray wavelengths, including sudden outbursts of radiation and occasional giant flares.

These peculiar features of magnetars are caused by the evolution, dissipation and decay of their super-strong magnetic fields, which are hundreds or thousands of times more intense than those of the more common type of neutron stars, the radio pulsars.

The magnetic field of a magnetar can have a complex structure. The most obvious, and easy-to-measure, component is the large scale external magnetic field, which is shaped (and behaves) much like a regular bar magnet's. This is known as the dipolar field.

The study was carried out on a magnetar called SGR 0418+5729. A few years ago, this star was discovered to have a relatively gentle dipolar magnetic field compared to other magnetars.

However, the star was showing the typical flaring and bursting activities seen in other magnetars, leading scientists to suggest that the star's magnetic activity might be caused by a field hidden beneath its surface.

Sometimes, the surface breaks and the hidden magnetic field leaks out (artist's impression) Credit: ESA/ATG Medialab

This new study, based on observations from ESA's XMM-Newton X-ray space telescope, has finally found evidence that SGR 0418+5729 is indeed concealing a very strong magnetic field in its interior.

"This magnetar has a strong magnetic field inside it, but it is hidden beneath the surface. The only way you can detect that is to find a flaw on the surface, where the concealed magnetic field can leak out," says Silvia Zane (UCL Mullard Space Science Laboratory), one of the co-authors of the study.

More information: "A variable absorption feature in the X-ray spectrum of a magnetar," by A. Tiengo et al is published in Nature, 15 August 2013.

Kilonova: Dead-Star Crashes May Spark Mysterious Cosmic Explosions

These images taken by NASA’s Hubble Space Telescope reveal a new type of stellar explosion produced by the merger of two compact objects: either two neutron stars or a neutron star and a black hole. 

The galaxy in the center of the left image produced the gamma-ray burst, whose lingering effects were visible on June 13 but had faded by July 3. 

Credit: NASA, ESA, N. Tanvir (University of Leicester), and A. Fruchter, Z. Levay (Space Telescope Science Institute), A. Levan (University of Warwick)

Cataclysmic crashes involving black holes and ultradense neutron stars may explain the briefest of the most powerful explosions in the universe, scientists say.

NASA scientists are calling the new type of short, but intense, cosmic collision and conflagration a "kilonova," an explosion so powerful it is 1,000 times stronger than a typical star explosion, called a nova.

Such events have long been predicted by astronomers, but never seen until now, researchers said. The discovery could shed light on the origin of heavy elements such as gold and platinum, they added.

Gamma-ray bursts are the most intense outbursts ever detected, giving off as much energy in an instant as our sun will beam out during its entire 10-billion-year lifetime.

A nearby burst directed at Earth could easily cause a mass extinction, researchers say

ESA NASA Hubble Image: Mysterious Old Spiral

Credit: ESA/Hubble & NASA, Acknowledgement: Judy Schmidt

This striking cosmic whirl is the center of galaxy NGC 524, as seen with the NASA/ESA Hubble Space Telescope.

This galaxy is located in the constellation of Pisces, some 90 million light-years from Earth.

NGC 524 is a lenticular galaxy.

Lenticular galaxies are believed to be an intermediate state in galactic evolution — they are neither elliptical nor spiral.

Spirals are middle-aged galaxies with vast, pin wheeling arms that contain millions of stars.

Along with these stars are large clouds of gas and dust that, when dense enough, are the nurseries where new stars are born. When all the gas is either depleted or lost into space, the arms gradually fade away and the spiral shape begins to weaken.

At the end of this process, what remains is a lenticular galaxy — a bright disc full of old, red stars surrounded by what little gas and dust the galaxy has managed to cling on to.

This image shows the shape of NGC 524 in detail, formed by the remaining gas surrounding the galaxy’s central bulge. Observations of this galaxy have revealed that it maintains some spiral-like motion, explaining its intricate structure.

Billionaire Elon Musk Unveiling Mysterious 'Hyperloop' Transport System

SpaceX CEO Elon Musk stands next to the company's Falcon 9 rocket, which blasted SpaceX's Dragon capsule into orbit in December 2010.

Credit: SpaceX

How would you like to zip from Los Angeles to San Francisco in less than 30 minutes, on the cheap and on your own schedule?

Billionaire entrepreneur Elon Musk says it can be done, and he's going to tell us how next month.

Elon Musk, the visionary behind electric-car firm Tesla and the private spaceflight company SpaceX, has been teasing us for a year about something he calls the "Hyperloop."

This new solar-powered travel technology, Musk says, would go twice as fast as an airplane and be completely crash-proof.

The Hyperloop would also be a cheap way to get around, with tickets costing much less than a seat aboard a plane or train. And there would be no scrambling to make a set departure time — you'd be sent on your way whenever you showed up at the station.

Musk has described the Hyperloop as a "cross between a Concorde and a railgun and an air hockey table," inspiring speculation about passenger-packed pods being blasted pneumatically through vacuum tubes.

A diagram of such a system drawn up by self-described "tinker" John Gardi "is the closest I've seen anyone guess so far," Musk tweeted on July 15.

But Musk has mostly remained mum, keeping details about the Hyperloop to himself.

He has said he will publish a design of the concept by Aug. 12, so we'll all just have to be patient for a few more weeks.

Betelgeuse: Mysterious hot spots observed in a cool red supergiant

Comparison between the red supergiant Antares and the Sun, shown as the tiny dot toward the upper right. 

The black circle is the size of the orbit of Mars. 

Arcturus is also included in the picture for size comparison. 

Credit: Wikipedia.

Astronomers have released a new image of the outer atmosphere of Betelgeuse – one of the nearest red supergiants to Earth – revealing the detailed structure of the matter being thrown off the star.

The new image, taken by the e-MERLIN radio telescope array operated from the Jodrell Bank Observatory in Cheshire, also shows regions of surprisingly hot gas in the star's outer atmosphere and a cooler arc of gas weighing almost as much as the Earth.

Betelgeuse is easily visible to the unaided eye as the bright, red star on the shoulder of Orion the Hunter.

The star itself is huge – 1,000 times larger than our Sun – but at a distance of about 650 light years it still appears as a tiny dot in the sky, so special techniques combining telescopes in arrays are required to see details of the star and the region around it.

The new e-MERLIN image of Betelgeuse – published in the journal Monthly Notices of the Royal Astronomical Society, shows its atmosphere extends out to five times the size of the visual surface of the star.

It reveals two hot spots within the outer atmosphere and a faint arc of cool gas even farther out beyond the radio surface of the star.

The hot spots are separated by roughly half the visual diameter of the star and have a temperature of about 4,000-5,000 Kelvin, much higher than the average temperature of the radio surface of the star (about 1,200 Kelvin) and even higher than the visual surface (3,600 Kelvin).

The arc of cool gas lies almost 7.4 billion kilometres away from the star – about the same distance as the farthest Pluto gets from the Sun. It is estimated to have a mass almost two thirds that of the Earth and a temperature of about 150 Kelvin.

Dr Anita Richards

Lead author Dr Anita Richards, from The University of Manchester, said that it was not yet clear why the hot spots are so hot.

She said: "One possibility is that shock waves, caused either by the star pulsating or by convection in its outer layers, are compressing and heating the gas. Another is that the outer atmosphere is patchy and we are seeing through to hotter regions within. The arc of cool gas is thought to be the result of a period of increased mass loss from the star at some point in the last century but its relationship to structures like the hot spots, which lie much closer in, within the star's outer atmosphere, is unknown."

The mechanism by which supergiant stars like Betelgeuse lose matter into space is not well understood despite its key role in the lifecycle of matter, enriching the interstellar material from which future stars and planets will form.

Detailed high-resolution studies of the regions around massive stars like the ones presented here are essential to improving our understanding.

Dr Richards, who is based in Manchester's School of Physics and Astronomy, added: "Betelgeuse produces a wind equivalent to losing the mass of the Earth every three years, enriched with the chemicals that will go into the next generation of star and planet formation. The full detail of how these cool, evolved stars launch their winds is one of the remaining big questions in stellar astronomy."

"This is the first direct image showing hot spots so far from the centre of the star. We are continuing radio and microwave observations to help decide which mechanisms are most important in driving the stellar wind and producing these hot spots. This won't just tell us how the elements that form the building blocks of life are being returned to space, it will also help determine how long it is before Betelgeuse explodes as a supernova."

Future observations planned with e-MERLIN and other arrays, including ALMA and VLA, will test whether the hotspots vary in concert due to pulsation, or show more complex variability due to convection. If it is possible to measure a rotation speed this will identify in which layer of the star they originate.

More information: 'e-MERLIN resolves Betelgeuse at wavelength 5 cm: hotspots at 5R*,' Monthly Notices of the Royal Astronomical Society, 2013.