NASA Finds Mysterious Bright Spot on Dwarf Planet Ceres: What Is It?

A strange, flickering white blotch found on the dwarf planet Ceres by a NASA 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.

While Vesta shared many properties with our solar system's inner planets, scientists with the Dawn mission suspect that Ceres has more in common with the outer most planets. 25 percent of Ceres' mass is thought to be composed of water, which would mean the space rock contains even more fresh water than Earth. Scientists have observed water vapor plumes erupting off the surface of Ceres, which may erupt from volcano-like ice geysers.

The mysterious white spot captured by the Dawn probe is one more curious feature of this already intriguing object.

Rosetta Comet 'Pouring' More Water into Space

There has been a significant increase in the amount of water "pouring" out of comet 67P/Churyumov-Gerasimenko, the comet on which the Rosetta mission's Philae lander touched down in November 2014.

The 2.5-mile-wide (4-kilometer) comet was releasing the earthly equivalent of 40 ounces (1.2 liters) of water into space every second at the end of August 2014. The observations were made by NASA's Microwave Instrument for Rosetta Orbiter (MIRO), aboard the European Space Agency's Rosetta spacecraft. Science results from the MIRO team were released today as part of a special Rosetta-related issue of the journal Science.

"In observations over a period of three months [June through August, 2014], the amount of water in vapor form that the comet was dumping into space grew about tenfold," said Sam Gulkis, principal investigator of the MIRO instrument at NASA's Jet Propulsion Laboratory in Pasadena, California, and lead author of a paper appearing in the special issue. "To be up close and personal with a comet for an extended period of time has provided us with an unprecedented opportunity to see how comets transform from cold, icy bodies to active objects spewing out gas and dust as they get closer to the sun."

The MIRO instrument is a small and lightweight spectrometer that can map the abundance, temperature and velocity of cometary water vapor and other molecules that the nucleus releases. It can also measure the temperature up to about one inch (two centimeters) below the surface of the comet's nucleus. One reason the subsurface temperature is important is that the observed gases likely come from sublimating ices beneath the surface. By combining information on both the gas and the subsurface, MIRO will be able to study this process in detail.

Also in the paper released today, the MIRO team reports that 67P spews out more gas from certain locations and at certain times during its "day." The nucleus of 67P consists of two lobes of different sizes (often referred to as the "body" and "head" because of its duck-like shape), connected by a neck region. A substantial portion of the measured outgassing from June through September 2014 occurred from the neck region during the afternoon.

"That situation may be changing now that the comet is getting warmer," said Gulkis. "MIRO observations would need to be carefully analyzed to deter
mine which factors in addition to the sun's warmth are responsible for the cometary outgassing."
Observations are continuing to search for variability in the production rate and changes in the parts of the nucleus that release gas as the comet's distance from the sun changes. This information will help scientists understand how comets evolve as they orbit and move toward and then away from the sun. The gas production rate is also important to the Rosetta navigation team controlling the spacecraft, as this flowing gas can alter the trajectory of the spacecraft.

In another 67P paper released today, it was revealed that the comet's atmosphere, or coma, is much less homogenous than expected and that comet outgassing varies significantly over time.
"If we would have just seen a steady increase of gases as we closed in on the comet, there would be no question about the heterogeneity of the nucleus," said Myrtha Hässig, a NASA-sponsored scientist from the Southwest Research Institute in San Antonio. "Instead we saw spikes in water readings, and a few hours later, a spike in carbon dioxide readings. This variation could be a temperature effect or a seasonal effect, or it could point to the possibility of comet migrations in the early solar system."
The measurements on the coma were made by the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis Double Focusing Mass Spectrometer (ROSINA DFMS) instrument. Measuring the in situ coma composition at the position of the spacecraft, ROSINA data indicate that the water vapor signal is strongest overall. However, there are periods when the carbon monoxide and carbon dioxide abundances rival that of water.

"Taken together, the MIRO outgassing results and results about heterogeneous fountains from ROSINA suggest fascinating new details to be learned about how comets work,"said Claudia Alexander, NASA project scientist for the U.S. Rosetta team, from JPL. "These results are helping us move the field forward on how comets operate on a fundamental level."

Rosetta is currently about 107 million miles (171 million kilometers) from Earth and about 92 million miles (148 million kilometers) from the sun. Comets are time capsules containing primitive material left over from the epoch when the sun and its planets formed. By studying the gas, dust and structure of the nucleus and organic materials associated with the comet, via both remote and in situ observations, the Rosetta mission should become a key to unlocking the history and evolution of our solar system, as well as answering questions regarding the origin of Earth's water and perhaps even life. Rosetta is the first mission in history to rendezvous with a comet, escort it as it orbits the sun, and deploy a lander to its surface.

Hilltop Panorama Marks Mars Rover's 11th Anniversary

This panorama is the view NASA's Mars Exploration Rover Opportunity gained from the top of the "Cape Tribulation" segment of the rim of Endeavour Crater. The rover reached this point three weeks before the 11th anniversary of its January 2004 landing on Mars.

The component images were taken with Opportunity's panoramic camera (Pancam) during the week after the rover's arrival at the summit on Jan. 6, 2015, the 3,894th Martian day, or sol, of the rover's work on Mars.

This location is the highest elevation Opportunity has reached since departing the Victoria Crater area in 2008 on a three-year, down-slope journey to Endeavour Crater. Endeavour spans about 14 miles (22 kilometers) in diameter, with its interior and rim laid out in this 245-degree panorama centered toward east-northeast. Rover tracks imprinted during the rover's approach to the site appear on the left. The far horizon in the right half of the scene includes portions of the rim of a crater farther south, Iazu Crater. An orbital image showing the regional context is at http://photojournal.jpl.nasa.gov/catalog/PIA13082.

The rover climbed about 440 feet (about 135 meters) in elevation from a lower section of the Endeavour rim that it crossed in mid-2013, "Botany Bay," in its drive to the Tribulation summit. It departed the summit on Jan. 17, 2015 (Sol 3902), continuing toward a science destination at "Marathon Valley."

At the summit, Opportunity held its robotic arm so that the U.S. flag would be visible in the scene. The flag is printed on the aluminum cable guard of the rover's rock abrasion tool, which is used for grinding away weathered rock surfaces to expose fresh interior material for examination. The flag is intended as a memorial to victims of the Sept. 11, 2001, attacks on the World Trade Center in New York. The aluminum used for the cable guard was recovered from the site of the twin towers in the weeks following the attacks. Workers at Honeybee Robotics in lower Manhattan, less than a mile from the World Trade Center, were making the rock abrasion tool for Opportunity and NASA's twin Mars Exploration Rover, Spirit, in September 2001.

This version of the image is presented in approximate true color by combing exposures taken through three of the Pancam's color filters, centered on wavelengths of 753 nanometers (near-infrared), 535 nanometers (green) and 432 nanometers (violet). The left edge is toward west-northwest and the right edge is southward.

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Mysterious Signal Points to Monster Black Hole Merger

A mysterious light signal from a faraway galaxy could point to two supermassive black holes finishing up a merger in the galaxy's core, new research reveals.

Scientists saw repeating pulses from a quasar — a bright galactic core powered by at least one huge black hole — and say the light is likely being generated during the latter stages of a monster black hole collision.

If this interpretation is correct, researchers could learn a great deal more about the final phases of such mergers, where simulations tend to break down — a situation dubbed "the final parsec problem."
The light signal from 3.5 billion light-years away was spotted by the Catalina Real-Time Transient Survey (CRTS), a set of three telescopes in Australia and the United States that look at 500 million light sources across 80 percent of the sky observable from Earth.

"There has never been a data set on quasar variability that approaches this scope before," lead study author George Djorgovski, director of the Center for Data-Driven Discovery at the California Institute of Technology, said in a statement.

"In the past, scientists who study the variability of quasars might only be able to follow some tens — or, at most, hundreds — of objects with a limited number of measurements," Djorgovski said in the statement. "In this case, we looked at a quarter-million quasars, and were able to gather a few hundred data points for each one."

The discovery came as a surprise, as the researchers were originally trying to learn more about how quasar brightness varies. While scrutinizing the data, however, they found 20 quasars that varied predictably — unlike the chaotic signals that researchers are used to.

Further analysis showed that one quasar, called PG 1302-102, likely has two black holes separated by just a few hundredths of a light-year. Other mergers observed previously placed such colliding black holes much further apart — anywhere between tens and thousands of light-years.

To verify the signal, which appears to repeat every five years, researchers brought in historical information covering most of the last two decades. Also, the light spectrum revealed something interesting happening in the gases surrounding the disc, which are spinning so quickly that they get superheated.

"When you look at the emission lines in a spectrum from an object, what you're really seeing is information about speed — whether something is moving toward you or away from you and how fast. It's the Doppler effect," said co-author Eilat Glikman, an assistant professor of physics at Middlebury College in Vermont.

"With quasars, you typically have one emission line, and that line is a symmetric curve," Glikman added. "But with this quasar, it was necessary to add a second emission line with a slightly different speed than the first one in order to fit the data. That suggests something else, such as a second black hole, is perturbing this system."

Researchers aren't sure what is causing the repeating light signal, but possibilities could include jets of material rotating around the center, similar to a lighthouse, or a distorted disc of material around the black holes that is either throwing material on the black holes or "blocking light from the quasar at regular intervals," Glikman said.

The results of the research were reported Jan. 7 in the journal Nature.

What Makes an Earth-Like Planet? Here's the Recipe

Earth is a unique, life-supporting world, but new research shows that the "recipe" for Earth might also apply to terrestrial exoplanets orbiting distant stars.

The new research suggests that other rocky, Earth-like planets follow the same basic mix of elements and likely formed the same way Earth did. These Earth-like planets include the recently discovered Kepler-93b, which is about 300 light-years from Earth.

"Our solar system is not as unique as we might have thought," Courtney Dressing, lead author of the new study and a researcher at the Harvard-Smithsonian Center for Astrophysics, said in a statement. "It looks like rocky exoplanets use the same basic ingredients."
These potentially Earth-like exoplanets need the right mix of chemicals and must be in a relatively young star's habitable zone— the orbit where liquid water could theoretically exist on a planet's surface. Then, if an asteroid delivers water and the right kind of organic compounds, the planet can potentially host life, according to the new research, which was presented by Dressing during the American Astronomical Society meeting in Seattle earlier this month.

The new findings come from the High-Accuracy Radial Velocity Planet Searcher (HARPS)-North instrument mounted on a telescope called the Telescopio Nazionale Galileo in Spain's Canary Islands. The instrument is specially designed to study exoplanets and differentiate between the terrestrial, Earth-like exoplanets and the more gaseous alien worlds.

The HARPS device can accurately determine a planet's mass by measuring how much light it blocks when it passes in front of its neighboring star. The mass of a planet can be used to calculate its density, and the density reveals what the planet is made of and if it's potentially habitable.

Dressing and a team of researchers focused on Kepler-93b, a planet about 1.5 times the size of Earth. The HARPS-North telescope measured Kepler-93b's mass as about four times that of Earth. This means that the planet is most likely a rocky, Earth-like planet, they said.

The team then measured the mass of the 10 other exoplanets, all with diameters of less than 2.7 times Earth's diameter. The results show that the five smallest planets have a very close relationship between mass and size, and are likely rocky, like Earth, scientists said. The five larger planets had much lower densities, meaning they're likely made of a large portion of low-density materials like water, hydrogen or helium, the research team added.

Astronomers using HARPS-North have focused their efforts on planets less than twice the size of Earth, but the cutoff size for Earth-like planets might be even smaller.

"To find a truly Earth-like world, we should focus on planets less than 1.6 times the size of Earth, because those are the rocky worlds," Dressing said in the same statement.

The new research has been accepted for publication in The Astrophysical Journal.

Cosmic 'Nuclear Pasta' May Be Stranger Than Originally Thought

The crusts of neutron stars — cosmic cousins of black holes — possess a weird form of matter known as "nuclear pasta."

Now, scientists have found that nuclear pasta may be even stranger than previously thought, forming defects that bond pieces together into complex, disorderly shapes. This complex nuclear pasta could ultimately doom the powerful magnetic fields seen from neutron stars, researchers say.

A neutron star, like a black hole, is a remnant of a star that died in a catastrophic explosion known as a supernova. Neutron stars are typically small, with diameters of about 12 miles (19 kilometers) or so, but they are so dense that a neutron star's massmay be about the same as that of the sun. A chunk of a neutron star the size of a sugar cube can weigh as much as 100 million tons, making neutron stars the densest objects in the universe besides black holes.
In the base of the crusts of neutron stars, the nuclei of atoms get crammed together so tightly that protons and neutrons arrange themselves in patterns akin to pasta shapes. Sometimes, nuclear pasta comes in rods like spaghetti, flat sheets like lasagna or spirals like fusilli.

Nuclear pasta had been proposed by theorists years ago. In 2013, researchers experimentally detected evidence that this odd phase of matter actually exists.

Prior research suggested that nuclear pasta would make it more difficult for heat and electricity to conduct through neutron stars. This, in turn, would make the magnetic fields of neutron stars dissipate much faster than expected. With a lower magnetic field, neutron stars would radiate less energy into space, keeping them spinning for longer. Scientists recently found that there's a scarcity of slow-whirling neutron stars. This hinted at the presence of nuclear pasta.

However, past analysis of this new state of matter's properties assumed that nuclear pasta took on perfect, simple pieces. But now, scientists have found that nuclear pasta can form more complex, disorderly shapes.
 "We are trying to determine ever more detailed properties of extremely dense exotic materials in stars," said lead study author Charles Horowitz, a physicist at Indiana University in Bloomington.

Since the scientists have no way of creating neutron-star matter on Earth, they relied on computer simulations of nuclear pasta. These involved nearly 410,000 nucleons — that is, protons and neutrons, the particles that make up atomic nuclei.

"Our nuclear-pasta simulations involve more nucleons than any previous work," Horowitz said.

The investigators found that lasagna-sheet-like pieces of nuclear pasta could form long-lived defects shaped like corkscrews that connect these sheets.

"I have been trying for years to imagine neutron stars as geologic worlds with different kinds of nuclear rocks, faults, mountains," Horowitz said. "Then, one molecular dynamics simulation found a mistake — a defect in the otherwise regularly perfect pasta shapes that persisted for a very long time."

These misshapen pieces of nuclear pasta could make neutron stars even less conductive to heat and electricity than the perfect pieces of nuclear pasta that prior studies had modeled. This could explain the spectrum of light from the system MXB 1659-29, which possesses a neutron star.

"X-ray observations of neutron-star crust cooling can provide information on exotic pasta phases buried a kilometer under the surface," Horowitz said. "These observations can then tell if the pasta is disordered and have low electrical and thermal conductivities."

The existence of complex, disorderly nuclear pasta "may tell us the fate of the huge magnetic fields in neutron stars, which can be a trillion or more times stronger than the Earth's field," Horowitz said. "If the conductivity is low, the great electrical currents supporting the fields may dissipate in about a million years."

The scientists will detail their findings in an upcoming issue of the journal Physical Review Letters.

Telescope To Seek Dust Where Other Earths May Lie

The NASA-funded Large Binocular Telescope Interferometer, or LBTI, has completed its first study of dust in the "habitable zone" around a star, opening a new door to finding planets like Earth. Dust is a natural byproduct of the planet-formation process, but too much of it can block our view of planets.

The findings will help in the design of future space missions that have the goal of taking pictures of planets similar to Earth, called exo-Earths.

"Kepler told us how common Earth-like planets are," said Phil Hinz, the principal investigator of the LBTI project at the University of Arizona, Tucson, referring to NASA's planet-hunting Kepler mission, which has identified more than 4,000 planetary candidates around stars. "Now we want to find out just how dusty and obscured planetary environments are, and how difficult the planets will be to image."

The new instrument, based at the Large Binocular Telescope Observatory at the top of Mount Graham in southeastern Arizona, will obtain the best infrared images yet of dust permeating a star's habitable zone, the region around the star where water -- an essential ingredient for life as we know it -- could pool on a planet. Earth sits comfortably within our sun's habitable zone, hence its glistening surface of oceans.

Scientists want to take pictures of exo-Earths and break up their light into a rainbow of colors. This color information is displayed in plots, called spectra, which reveal chemical clues about whether a planet could sustain life. But dust -- which comes from colliding asteroids and evaporating comets -- can outshine the feeble light of a planet, making this task difficult.

"Imagine trying to view a firefly buzzing around a lighthouse in Canada from Los Angeles," said Denis Defrère of the University of Arizona, lead author of the new study that appears in the Jan. 14 issue of the Astrophysical Journal. "Now imagine that fog is in the way. The fog is like our stardust. We want to eliminate the stars with fog from our list of targets to study in the future."

A previous NASA project, called the Keck Interferometer, had a similar task of seeking out this dust, finding good news for planet hunters: The stars they observed didn't seem to be all that dusty on average. LBTI is taking the research a step further, more precisely quantifying the amount of dust around stars. It will be 10 times more sensitive than the Keck Interferometer, and is specially designed to target a star's inner region -- its sweet spot, the habitable zone.

The new study reports LBTI's first test observations of stardust, in this case around a mature, sun-like star called eta Corvi known to be unusually dusty. According to the science team, this star is 10,000 times dustier than our own solar system, likely due to a recent impact between planetary bodies in its inner regions. The surplus of dust gives the telescope a good place to practice its dust-detecting skills.

The results showed the telescope works as intended, but also yielded a surprise: The dust was observed to be significantly closer to the star than previously thought, lying between the star and its habitable zone. NASA's Spitzer Space Telescope has previously estimated the dust to be farther out, based on models of the size of the dust grains.

"With LBTI, we can really see where the dust is," said Hinz. "This star is a not a good candidate for direct imaging of planets, but it demonstrates what LBTI is good for: We are figuring out the architecture of planetary systems in a way that has not been done before."

LBTI will begin its official science operations this spring, and will operate for at least three years. One of the project's goals is to find stars 10 times less dusty than our solar system -- the good candidates for planet imaging. These survey results will inform designs and strategies for upcoming exo-Earth imaging missions now in early planning stages. The journey to find worlds ripe for life begins in part by following a trail of dust.

LBTI is funded by NASA Headquarters. It is managed by the agency's Jet Propulsion Laboratory, Pasadena, California, for NASA's Exoplanet Exploration Program office, and operated by the University of Arizona. The Large Binocular Telescope Observatory is operated by an international collaboration among institutions in the United States, Italy and Germany. JPL is a division of the California Institute of Technology in Pasadena.

The Astrophysical Journal paper is online at:

http://iopscience.iop.org/0004-637X/799/1/42/article