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Does An Asteroid Start Off As A Giant Mud Rock

July 21, 2017 by  
Filed under Around The Net

The most common asteroids in the solar system may have started out as giant balls of mud, rather than as rocks, as scientists previously thought, a new study finds.

Such mud balls could still exist today in the heart of the largest asteroids, according to the study.

More than 75 percent of known asteroids are carbonaceous in composition; these grayish asteroids probably consist of clay and stony rocks, and inhabit the main belt’s outer regions

One key reason scientists investigate carbonaceous asteroids is that they were probably the building blocks of the rocky planets of the solar system, said study lead author Philip Bland, a planetary scientist at the Curtin University of Technology in Australia. Analyzing these giant rocks could shed light on the origins of Earth, Mars and the other terrestrial planets.

However, the way carbonaceous asteroids formed in the early days of the solar system is still mysterious. “There have probably been about a dozen different models to explain the origins of these primitive objects over the years, and they’ve all been limited in one way or another,” Bland told Space.com.

Researchers have observed carbonaceous asteroids and analyzed meteorites thought to come from them to glean details about their composition. However, scientists had trouble devising a model that could explain all of these features of the asteroids, Bland said.

“For instance, one model might find there is a lot of water getting circulated around inside the asteroids, so they could lose heat — which would explain why meteorites from these asteroids appear to have experienced alterations at relatively low temperatures,” Bland said. “However, if you have a lot of water circulating inside asteroids, it would strip elements from the rock, and you would get a very different chemical composition than what we see in the meteorites.”

“If there wasn’t water inside the asteroids, you wouldn’t mess up the chemistry we see, but the asteroids would not lose heat as easily,” Bland added. “One way around that is to have the asteroids be smaller so they would cool down more easily, but we don’t see that today.”

All of these previous models assumed the asteroids had lithified — that is, had become rock. “Most people look at meteorites, and they’re rocks. So the natural thing to assume would be that the asteroids they came from were rocks, too,” Bland said. “We were interested in seeing what happened if we deleted that assumption.”

Prior work suggested that carbonaceous asteroids formed from round, porous mineral pellets known as chondrules, as well as fine-grained dust, and ice. When pockets of these materials got pulled together by their own gravity, they would not have become rock, the researchers suggested. Instead, when radioactive materials inside the dust and chondrules melted the ice, the result would have been a sludgy mud, they said.

“When you stop to think about it, there’s no reason that asteroids would be rocks right at the beginning,” Bland said.

The scientists devised computer models that simulated how pockets of dust, chondrules and ice might act with different concentrations of these various ingredients and the density at which these materials were packed together. They found that not only could asteroids emerge from these building blocks without lithification, but the way in which mud churned in these mud balls could help explain the chemical and thermal details seen from carbonaceous asteroids.

“I feel like this helps plug a gap in knowledge when it comes to the question of what happened inside what are amongst the most important objects in the history of our solar system,” Bland said.

After the mud balls formed, they could have lithified in various ways. For instance, if these mud balls hit each other, the force of the impacts would have generated heat that could have welded the components of these mud balls together into rock, Bland said.

As for whether the mud balls might still exist in the solar system, when the researchers modeled Ceres, the largest asteroid, they “found there was a reasonable chance of temperatures above freezing in its interior, so there could still be quite a bit of a mud ball inside Ceres,” Bland said.

Future research could explore how the other kinds of asteroids in the solar system were born, and how asteroids in other star systems might arise and, in turn, influence the formation of alien planets, Bland said.

Bland and his colleague Bryan Travis at the Planetary Science Institute in Tucson, Arizona, detailed their findings online July 14 in the journal Science Advances.

Courtesy-Space

Did Astronomers Find More Evidence That Planet 9 Exist

July 19, 2017 by  
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A new salvo has been fired in the back-and-forth debate about the existence of Planet Nine.

In 2014, astronomers Scott Sheppard and Chadwick Trujillo suggested that a giant unseen “perturber” may lurk in the far outer solar system. The duo based this hypothesis on peculiarities in the orbits of the dwarf planet Sedna, the newfound object 2012 VP113 and several other bodies beyond the orbit of Neptune (trans-Neptunian objects, or TNOs).

The case grew in January 2016, when astronomers Konstantin Batygin and Mike Brown found evidence that the orbits of additional TNOs had been sculpted. Batygin and Brown dubbed the hypothetical perturber “Planet Nine” and calculated that, if the world exists, it’s likely about 10 times more massive than Earth and lies perhaps 600 astronomical units (AU) from the sun. (One AU is the average Earth-sun distance — about 93 million miles, or 150 million kilometers.

Then, last summer, Sheppard and Trujillo found two new TNOs that Planet Nine may have tugged on, increasing the number of possibly affected bodies yet again.

But a team of researchers with the Outer Solar System Origins Survey (OSSOS) project recently cast doubt on the strength of all this evidence. The apparent “clustering” seen in the TNO orbits could simply result from observational biases, the OSSOS team reported in a paper that has been accepted for publication in The Astronomical Journal.

And that’s where the most recent salvo comes in. (But keep in mind that the above paragraphs provide an incomplete recounting; there have been many Planet Nine studies published over the past 18 months.) Two astronomers from the Complutense University of Madrid in Spain studied 22 “extreme” TNOs (ETNOs), which orbit the sun at an average distance of at least 150 AU and never get closer than Neptune. (Neptune lies about 30 AU from the sun and orbits on a roughly circular path.)

Specifically, the duo analyzed the ETNOs’ “nodes,” the two points at which the objects cross the plane of the solar system. (Distant bodies such as ETNOs tend not to lie in the same plane as the sun and the solar system’s eight officially recognized planets.)

The researchers found that the objects’ nodes generally aggregate at certain distances from the sun (as do those of 24 “extreme Centaurs,” very distant objects with some characteristics of asteroids and others of comets). In addition, they discovered a correlation between the nodes’ positions and an orbital parameter known as inclination.

“Assuming that the ETNOs are dynamically similar to the comets that interact with Jupiter, we interpret these results as signs of the presence of a planet that is actively interacting with them in a range of distances from 300 to 400 AU,” he told Spain’s Information and Scientific News Service, which is known by its Spanish acronym, SINC. “We believe that what we are seeing here cannot be attributed to the presence of observational bias.”

A number of research teams are scouring the outer solar system, looking for the putative Planet Nine and/or more objects that have fallen under its gravitational sway. So the new study, which was published late last month in the journal Monthly Notices of the Royal Astronomical Society: Letters, is far from the last word. Stay tuned.

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Astronomers Shed Light On Star Explosions

July 18, 2017 by  
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New looks at the heart of a supernova remnant are revealing clues about the deaths of massive stars and how these dramatic events affect their host galaxies, two recent studies report.

Observations made by the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile allowed one research team to construct a detailed 3D map of SN 1987A — the remains of a huge star that exploded three decades ago — and another group to spot several molecules previously undetected in the supernova remnant.

“When this supernova exploded, now more than 30 years ago, astronomers knew much less about the way these events reshape interstellar space and how the hot, glowing debris from an exploded star eventually cools and produces new molecules,” Rémy Indebetouw, an astronomer at the University of Virginia and the National Radio Astronomy Observatory in Charlottesville, said in a statement.

“Thanks to ALMA, we can finally see cold ‘star dust’ as it forms, revealing important insights into the original star itself and the way supernovas create the basic building blocks of planets,” added Indebetouw, who is a co-author on both recent studies.

SN 1987A formed in the aftermath of a Type II supernova, which results when a star at least 10 times more massive than the sun runs out of fuel and ceases pushing outward against the inward pull of its own gravity. The big star’s outer parts then come crashing back on the core, sparking a mammoth explosion that can be seen from great distances.

Indeed, SN 1987A lies 163,000 light-years away, in the Large Magellanic Cloud galaxy, and has been studied intensively by a variety of instruments since its light first reached Earth in February 1987. (The explosion actually occurred about 163,000 years ago, of course, but astronomers such as Indebetouw often refer to it happening in 1987 for simplicity’s sake.)

The supernova sent huge amounts of dust streaming into space, creating a veil that many telescopes have had trouble penetrating. And that’s where the newly reported ALMA observations come in: The radio dishes in the array can peer through the dust, revealing the structure deep within the remnant.

In one of the recent studies, scientists mapped out in 3D the abundances of many molecules that formed in the aftermath of the massive explosion (after SN 1987A had cooled sufficiently to allow this to happen). For example, the ALMA data revealed large amounts of silicon monoxide (SiO) and carbon monoxide (CO) clumping in the remnant’s heart, researchers said.

The other study team performed a molecular inventory of SN 1987A. They found a number of species, including the new detections formyl cation (HCO+) and sulfur monoxide (SO).

“These molecules had never been detected in a young supernova remnant before,” Indebetouw said. “HCO+ is especially interesting, because its formation requires particularly vigorous mixing during the explosion.”

Overall, the combined results reveal new insights about SN 1987A’s composition and how conditions within the supernova remnant have changed over time, researchers said. This information, in turn, could help astronomers better understand galactic evolution.

“The reason some galaxies have the appearance that they do today is in large part because of the supernovas that have occurred in them,” Indebetouw said. “Though less than 10 percent of stars become supernovas, they nonetheless are key to the evolution of galaxies.”

The 3D-mapping study was published last month in The Astrophysical Journal Letters, and the molecular-inventory paper was published in April in the Monthly Notices of the Royal Astronomical Society.

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Did Kepler Help Prove Rocky Planets Are Prevalent

July 11, 2017 by  
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Rocky planets are probably a whole lot more common in our galaxy than astronomers previously believed — according to the latest release of Kepler Space Telescope data last week — a scenario that enhances the prospects for extraterrestrial life in nearby solar systems. 

Kepler’s final tally of exoplanets in the Cygnus constellation — the most comprehensive and detailed catalogue of exoplanets to date — indicates 4,034 possible planets, of which 50 are Earth-sized and reside in the habitable zone of their stars. The set includes KOI 7711 (short for Kepler ‘object of interest’), which is just 30 percent larger than Earth and roughly the same distance from its star as the Earth is to the sun, meaning it receives a similar amount of energy. 

“Kepler has really and truly opened our eyes to these small terrestrial-sized worlds,” said Susan Thompson, Kepler research scientist at the SETI Institute, at the announcement of the new catalogue of planet candidates at NASA Ames Research Center in Mountain View, California. [7 Ways to Discover Alien Planets]

Scientists gathered at NASA Ames June 19-23 for the Kepler Science Conference to present their findings from the original mission as well as update their progress on K2, an extended, “second life” mission that will continue until the spacecraft runs out of fuel or something else goes wrong. 

Prior to Kepler’s launch in 2009, astronomers mainly knew about Jupiter and Neptune-sized planets orbiting at various periods around their stars. It took the continuous gaze of Kepler’s image sensor array at a patch of sky loaded with 200,000 stars to discover this sizable population of rocky-sized worlds, most of them three times the size of Earth or smaller. Many hover close to their stars, but some appear with long orbital periods putting their distance outside a habitable zone. About a half-dozen confirmed exoplanets, though, are circling within the habitable zone of G-dwarf stars — the same type of star as the sun.

“Are we alone?” said Mario Perez, Kepler program scientist in the Astrophysics Division of NASA’s Science Mission Directorate. “Kepler says we are probably not alone.”

Yet, the prospects for life on any single one of these planets remains vastly uncertain. We know virtually nothing about the size and composition of their atmospheres, or whether water is present. For example, at 1,700 light years away, KOI 7711, dubbed ‘Earth’s Twin,’ seems one of the most promising exoplanets for life that we know of to date, given its similar orbital period (it circles its star in 303 days) and size. But Thompson urged caution in drawing hasty conclusions. “There’s a lot we don’t know,” she said. ” I like to remind people that it looks like there are three planets in our habitable zone — Venus, Earth and Mars — and I only want to live on one of them.” 

The recently discovered TRAPPIST-1 star system, a mere 40 light years away from us, has a record-breaking seven rocky planets, raising all kinds of excitement at the possibility of panspermia, the seeding of life from one planet to a neighboring one. But given that they huddle close to their ultra-cool dwarf star, these planets are likely to be tidally locked, like Mercury. One side would be scorching and the other side frigid. Stellar flares could blast away the atmospheres of these planets or subject them to surges of UV radiation, a known detriment to earthly existence. 

But Courtney Dressing, a CalTech astronomer, offered some signs of hope, even for planets that look doomed. She pointed out that new research using sophisticated 3-D models is showing that if tidally-locked planets manage to hang onto their atmospheres, strong air currents could be evening out temperatures. “There’s a chance you could have a bunch of civilizations where maybe all the astronomers live on one side of the planet and everyone else enjoys the sunny, beach-y side close to the star,” she said. 

And UV radiation, which may have sparked life the formation of RNA on early Earth, may not be the end-all even in the form of sudden surges. For example, one study found that haloarchaea, an extremophile microorganism found in highly saline water, could withstand heavy blasts of UV radiation. “Even if the surface is a dangerous place, life could be thriving underground or underwater,” Dressing said. 

Stellar flaring and its impact on life is an area of active research in astrobiology, given that M dwarf stars, many of which are prone to flaring, are numerous in our galaxy and host rocky planets that are astronomers’ most accessible prospects for near-term bio-signature research.
“Regardless of whether any of these newly detected planet candidates are inhabited, the fact that Kepler has discovered 50 potentially habitable planets and planet candidates implies that such worlds are frequent,” wrote Dressing in an email.

Future instruments are what’s needed to move the science forward. Late next year, NASA (alongside the European Space Agency and Canadian Space Agency) is scheduled to launch the James Webb Space Telescope, a next generation space observatory that will be the best observation tool we have to measure the atmospheres of exoplanets close to us — a key to understanding other aspects of habitability. And also in development is the Wide Field Infrared Survey Telescope (WFIRST), which will expand the range of exoplanet exploration and build on Kepler’s foundation. 

“It feels a bit like the end of an era,” said Thompson, “but actually it feels like a new beginning.”

Courtesy-Space

Did Comets Bring The Building Blocks Of Life To Earth

June 20, 2017 by  
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Life on Earth may not have been possible without comet strikes.

A new study suggests that about 20 percent of the noble gas xenon in Earth’s atmosphere was delivered by comets long ago. And these icy wanderers likely brought lots of other stuff to our planet as well, researchers said. 

The “cometary contribution could have been significant for organic matter, especially prebiotic material, and could have contributed to shape the cradle of life on Earth,” said study lead author Bernard Marty, a geochemist at the University of Lorraine and the Centre de Recherches Pétrographiques et Géochimiques in France.  

Marty and his colleagues studied measurements made by the European Space Agency’s (ESA) Rosetta spacecraft, which orbited the 2.5-mile-wide (4 kilometers) Comet 67P/Churyumov-Gerasimenko from August 2014 through September of last year.

Specifically, they analyzed xenon-isotope data that Rosetta gathered during a series of low-altitude orbits of Comet 67P between May 14 and May 31, 2016. (Isotopes are versions of an element that contain different numbers of neutrons in their nuclei. “Heavy” isotopes have more neutrons compared to “lighter” ones.)

Rosetta’s observations revealed that 67P is deficient in heavy xenon. Furthermore, the team determined that the comet’s xenon isotope composition matches a signature of Earth xenon whose origin had been a mystery.

Scientists think asteroids delivered the vast majority of the water in Earth’s oceans, and these space rocks have been regarded as the chief suppliers of the planet’s other “volatiles” — substances with low boiling points, such as nitrogen, carbon dioxide and noble gases — as well. (Models suggest that Earth was extremely hot shortly after its formation about 4.5 billion years ago, so it probably lost its primordial volatiles early on.) 

This inference is drawn partly from the isotopic similarity of hydrogen, nitrogen and other materials on Earth to that of certain asteroids known as carbonaceous chondrites, as measured in meteorite samples, Marty said.

“There was also a dynamical argument: Jupiter and the other giant planets formed early, and the outer solar system (from which comets originate) was isolated early from the inner solar system by the giant planets’ gravitational fields,” he said. “Now our finding calls for a revision of such models.”

Comets are especially enriched in noble gases, explaining how their contribution of xenon (and perhaps other materials) to the early Earth can be outsized compared to the proportion of water these icy wanderers delivered, Marty added.

The newly analyzed Rosetta data also indicate that 67P’s xenon predates the solar system — that is, the comet contains samples of interstellar matter. That’s an exciting result that argues for further, more detailed study of pristine cometary material, Marty said. 

“Returning a cometary sample on Earth should be the highest priority, because it will permit analyses with unprecedented precision of such exotic material and could respond to questions such as: How long interstellar material can survive, which stars contributed to shape the cradle of the solar system, what is the origin(s) of the large isotopic variations of some of the elements (e.g., N, H, O), what was the role of irradiation of early solar system material, etc.,” he said. (N, H and O are nitrogen, hydrogen and oxygen, respectively.)

Rosetta launched in March 2004. A decade later, it became the first mission ever to orbit a comet and the first to touch down softly on one of these bodies. (The Rosetta orbiter dropped a lander called Philae onto 67P in November 2014.)

The mission ended when Rosetta intentionally crash-landed on 67P’s surface on Sept. 30, 2016.

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Amateur Astronomers Discover Prehistoric Supernova

June 7, 2017 by  
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More than 700 volunteer citizen scientists have helped identify more than 30,000 celestial objects, including a star explosion that occurred 970 million years ago, hundreds of millions of years before dinosaurs emerged on Earth. 

When a massive star reaches the end of its life, it creates a bright stellar explosion, also known as a supernova. The Australian National University (ANU) has invitied citizen scientists to join the hunt for supernovas. 

Using images taken by the SkyMapper telescope at the ANU Siding Spring Observatory, volunteer supernova hunters helped discover a star’s dying burst located roughly 970 million light-years from Earth, according to a statement from ANU. That means the star exploded millions of years before dinosaurs roamed the planet.  

“This is the exact type of supernova we’re looking for — Type Ia supernova — to measure properties of and distances across the universe,” Brad Tucker, co-lead researcher from the ANU Research School of Astronomy and Astrophysics, said in the statement. 

The exploding star, called SN2017dxh, is one of seven potential new supernovas reported to the Transient Name Server; the team is tracking another 18 potential supernovas as well, according to the statement.

Supernovas, “which are explosions as bright as 100 million billion billion billion lightning bolts,” researchers said in the statement, can be used to track how the universe is growing and to better understand mysterious dark energy. Based on the brightness and fading of light emitted by a supernova, astronomers can measure how far away a supernova is from Earth, the researchers said. 

The ANU project was set up on the Zooniverse platform and allows volunteers to look through images taken by the SkyMapper telescope for differences that may hint at the presence of a supernova. The volunteers note the differences they observe so that the researchers can follow up on them and determine what they mean. 

“In the first 24 hours, we had over 30,000 classifications” of new celestial objects, Anais Möller, another co-lead researcher from ANU, said in the statement. “We’ve almost reached 40,000 classifications, with more than 1,300 images classified, since the launch of our project.”

When the discovery is reported to the International Astronomical Union, the first three people to find a previously unknown supernova will be mentioned. You can participate in the ANU citizen science project online.

Courtesy-Space

Can Colliding White Dwarfs Solve The Antimatter Mystery?

June 2, 2017 by  
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The majority of antimatter that pervades the Milky Way may come from clashing remnants of dead stars, a new study finds.

The work may solve a 40-year-old astrophysics mystery, the study’s researchers said.

For every particle of normal matter, there is an antimatter counterpart with the opposite electrical charge but the same mass. The antiparticle of the negatively charged electron, for instance, is the positively charged positron.

When a particle meets its antiparticle, they annihilate each other, giving off a burst of energy. A gram of antimatter annihilating a gram of matter would release about twice the amount of energy as the nuclear bomb dropped on Hiroshima, Japan.

More than 40 years ago, scientists first detected that the kind of gamma-rays that are given off when positrons are annihilated were being emitted from all around the galaxy. Their findings suggested that 10^43 positrons — that’s a 1 with 43 zeroes behind it — were being annihilated in the Milky Way every second. Oddly, most of these positrons were detected in the galaxy’s central bulge rather than its outer disk, even though the bulge hosts less than half of the Milky Way’s mass.

These positrons could have been emitted from radioactive material synthesized by stars. However, for decades, researchers have been unable to pinpoint a type of star that could generate such vast amounts of antimatter. This led to suggestions that many positrons could originate from exotic sources, such as the supermassive black hole thought to exist at the center of the galaxy, or from dark matter particles annihilating one another.

“The origin of these positrons is a 40-year-old mystery in astrophysics,” said Roland Crocker, lead author of the new work and a particle astrophysicist at the Australian National University in Canberra.The new study suggests that a kind of supernova — a catastrophic explosion from a star — could generate the vast amounts of positrons that previous research saw and explain the locations in the galaxy from which they are detected.

“You don’t need anything exotic like dark matter to explain the positrons,” Crocker told Space.com.

The scientists focused on a type of supernova known as SN 1991bg-like, which has been detected in other galaxies. Unlike most supernovas, which can briefly outshine all of the other stars in their galaxies, this kind of supernova does not generate much visible light and is fairly rare, which is why it has avoided detection in the Milky Way, Crocker said.

Previous research suggested that these dim supernovas occur when two white dwarfs merge. White dwarfs are superdense, Earth-size cores of dead stars that are left behind when stars have exhausted their fuel and lose their outer layers. Most stars, including the sun, will become white dwarfs one day.

Specifically, these faint supernovas are thought to occur when two low-mass white dwarfs — one rich in carbon and oxygen, and the other rich in helium — slam together. Although such supernovas are rarer than standard supernovas, they generate much larger amounts of a radioactive isotope known as titanium-44, which gives off the kinds of positrons that astronomers have detected zipping across the Milky Way.

The new work suggests that those supernovas could be sufficient to create all of the unexplained positrons, thus solving the galaxy-wide mystery.

Whereas most supernovas occur when young, massive stars die, SN 1991bg-like supernovas are found in neighborhoods richer in older stars that are 3 billion to 6 billion years old. This age difference could explain why the previously detected positrons were seen mostly in the Milky Way’s central bulge, which has a greater proportion of older stars than the galaxy’s outer disk.

Other sources may contribute some of the positrons that prior work detected, Crocker said. Still, “they are not necessary, given the SN1991bg-like supernovae can basically explain the entire positron phenomenology,” he said.”The most recent data show that there’s a positron source connected to the very center of the galaxy,” Crocker added. “In our model, this is explained as due to the old stars distributed on roughly 200-parsec [650 light years] scales around the galaxy’s supermassive black hole, but the black hole itself is an interesting alternative source.”

The scientists detailed their findings online May 22 in the journal Nature Astronomy.

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Can Companies Mine The Moon AT A Profit

May 25, 2017 by  
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The first-ever private mining operation on the moon is scheduled to kick off in 2020, when a landing craft sent by Florida-based Moon Express will ferry a single scoop of lunar dirt and rocks back to Earth.

Unlike the three governments that have led lunar missions — the United States, the Soviet Union, and China — the owners of this private firm have something history-making in mind for that little ball of extraterrestrial soil: They plan to sell it.

“It will instantly become the most valuable and scarcest material on Earth,” says Bob Richards, the CEO of Moon Express. “We’ll make some of it available to scientific research. But we also plan to commoditize it ourselves.”

Moon Express is gearing up to become the first company to ever transport a commercial asset from space back to Earth. But it’s not alone.

Several ambitious startups are busily developing plans to launch mining operations on both the moon and asteroids, with initial proof-of-concept missions set to kick off over the next few years and more robust operations within a decade. China is a key player, too, along with a tiny, unlikely European upstart: the Grand Duchy of Luxembourg.

Those seeking to conquer celestial commodity markets are beckoned by the glittering wealth that could await them in space.

“We believe that the first trillionaires will be made from space resources,” says Richards.

Exactly which minerals will drive those fortunes remains to be seen.

The moon holds significant amounts of a special type of a futuristic fuel source called helium-3 — enough, some say, to meet all of Earth’s power demand for thousands of years providing scientists can master the fusion power technology to utilize it.

A fortune could be made by anyone able to capture and exploit one of the mountain-sized asteroids made of platinum or other precious metals thought to be orbiting the sun, or deposits of rare earth elements on the moon.

Others point to the potential for zero-gravity construction of super-massive colonizing spacecraft and mammoth floating structures using raw materials sourced from asteroids.

Most, however, are focused on a resource that’s commonplace on Earth: water.

Water, space entrepreneurs say, will be the key space commodity for an economy expanding into the solar system — both because it can sustain life as drinking water and breathable air, and because it can be broken down into hydrogen and oxygen to make rocket fuel.

Sourcing water from space could, for example, turn the moon into a depot for more ambitious missions.

“Water is like the oil of the solar system,” said Richards. “The moon could become a gas station in the sky.”

In the near term, Moon Express is focused on providing relatively low-cost transport to the surface of the moon for commercial, private, academic, and government customers.

One client that’s already signed up is the moon-burial company Celestis, which offers to send cremated human remains to the surface of the moon for a starting price of $12,500.

In 2016 Moon Express became the first private company in history to receive permission from the US Federal Aviation Administration to travel beyond Earth’s orbit and land a craft on the moon.

The company is planning three lunar missions by the time it brings back the small scoop of lunar soil, between the size of a baseball and basketball, in 2020.

Selling part of that scoop to private interests — for example, as moon gems for jewelry for the ultra-rich — will set an important precedent. The international Outer Space Treaty of 1967 says no country can claim sovereignty over extraterrestrial territory. But in 2015 President Barack Obama signed a law granting private citizens the rights to resources recovered from space.

The company’s first mission, slated for this year, will be in part an attempt to win the Google Lunar XPrize. The competition offers $20 million to the first private company able to land a rover on the moon’s surface, travel 500 meters, and then broadcast hi-definition images back to Earth.

Another company fielding a team for the XPrize, which also plans to eventually tap moon water, is Japan’s ispace Inc.

In December, ispace signed a memorandum of understanding with Japan’s national space agency, JAXA, for the “mining, transport, and use of resources on the moon,” according to a company statement.

During an initial phase of operations, from 2018 through 2023, ispace will go prospecting on the moonscape, sending exploratory robots into lunar craters and caves to check for water. Production is planned to begin in 2024.

China is also eyeing moon resources — especially helium-3.

As an energy source, helium-3 is as alluring as it is elusive: a non-radioactive agent that wouldn’t produce dangerous waste. The isotope is released by the sun and carried through the cosmos on solar winds that are blocked by Earth’s atmosphere, but collect on the surface of the moon.

As a result, the moon is “so rich” in helium-3, it could “solve human beings’ energy demand for around 10,000 years at least,” a top Chinese scientific advisor to the country’s moon exploration program, Professor Ouyang Ziyuan, told the BBC.

 

One of the top proponents of lunar helium-3 is Harrison Schmitt, a geologist who walked on the moon during NASA’s Apollo 17 mission and wrote a 2006 book advocating lunar helium-3 mining called Return to the Moon.

Others, however, are deeply skeptical — even if the necessary fusion technology, which has long eluded researchers, is mastered.

“I do not see this as being an economic solution to Earth’s energy needs,” Ian Crawford of the Department of Earth and Planetary Sciences at Birkbeck College, University of London, said in an email. “The problem is that the abundance is very low, of the order 10 parts per billion by mass in even the most abundant regions.”

Another potentially attractive lunar resource is the platinum group of metals, including iridium, palladium and platinum, which have special qualities that make them highly useful in electronic devices. Such elements, rare on earth, are thought to be bountiful on the moon.

Richards of Moon Express said it’s too soon to specify the most valuable resource on the moon.

“It would be speculative and predictive to say which specific element is going to be the game-changer,” he said. “Pick your favorite spice.”

For now, he says, the key target is water — which, to be sure, can be found on frozen asteroids circling the sun as well.

Two US companies, Planetary Resources and Deep Space Industries, are leading the charge into asteroid mining, largely with the aim of providing resources that other types of space missions will need.

Rick Tumlinson, chairman of Deep Space Industries, said his company plans to land its first prospector on an asteroid by 2020.

The company will use tiny scouts to explore and study prospective targets. When a prime asteroid has been located, a larger robot will land on it, bite out a chunk, and then use solar power to evaporate and capture water from the sample.

“Water, we believe, is relatively easy to harvest from asteroid materials,” said Tumlinson.

If all goes according to plan, “by the middle-20s, we’d be producing serious quantities of resources,” he said.

Planetary Resources is also focused on water.

“You can concentrate that solar energy and heat up the surface of the asteroid and literally bake off the water in the same way you’d bake a clay pot,” says CEO Chris Lewicki.

 

Both Lewicki and Tumlinson also point to the potential for supplying building materials in space, which could allow for the construction of super-massive floating structures that would be ungainly to launch from Earth.

In space, “you can build these huge structures we see in movies and science fiction,” said Lewicki. “The resource that will allow us to do that is the metal that’s on asteroids. We can use technology like 3D printing. We can print up a structure in space that never has to hold itself up on Earth, never has to take a violent rocket ride.”

As billionaires Elon Musk and Jeff Bezos explore ideas for colonizing space and Mars, someone, advocates of space mining say, will need to provide the raw materials, water and fuel the colonizers will need.

And while space mining might sound like science fiction, serious backers with deep pockets are taking notice.

A total of $1.8 billion was invested in space ventures in 2015 — more than in the prior 15 years combined, according to the Tauri Group consultancy. More than 50 venture capital firms invested in space deals in 2015, the most of any year, the group found.

The tiny European nation of Luxembourg has invested 25 million euros in Planetary Resources, and collaborated on the development of Prospector-X, the first spacecraft from Deep Space Industries.

The moon, said Richards, is like Earth’s 8th continent, and it’s largely unexplored.

“We’re like early pioneers,” he said, “looking at a whole new world.”

 

Courtesy-Fud

 

 

Are ‘Excessive’ Gamma-Rays A Sign Of Dark Matter

May 12, 2017 by  
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A promising lead about the nature of elusive dark matter may have just dried up.

A mysterious abundance of gamma-rays — the highest-energy light in the universe — at the Milky Way’s center is likely being produced by fast-spinning stellar corpses called pulsars, rather than bits of dark matter slamming into each other, a new study suggests.

“Our study shows that we don’t need dark matter to understand the gamma-ray emissions of our galaxy,” co-author Mattia Di Mauro, from the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) in California, said in a statement.

Though dark matter apparently neither emits nor absorbs light (hence the name), astronomers know the stuff exists; they have observed its gravity affecting the “normal” matter we can see and touch. Indeed, such work suggests that dark matter makes up about 85 percent of the material universe.

However, scientists still don’t know what the mysterious stuff is. One leading hypothesis holds that dark matter is composed mostly of Weakly Interacting Massive Particles (WIMPs). Theoretical physicists think  that WIMPs generate gamma-rays when they interact with each other, either via direct annihilation or the production of a fast-decaying secondary particle.

So it was exciting when, several years ago, Fermi spotted an “excess” of gamma-rays near the Milky Way’s core that astronomers said could not be explained by traditional sources such as pulsars. Process of elimination seemed to indicate that dark matter — in the form of WIMPs — was responsible.

The researchers behind such studies stressed at the time that this interpretation was tentative and in need of backing by other observations.  

“Two recent studies by teams in the U.S. and the Netherlands have shown that the gamma-ray excess at the galactic center is speckled, not smooth as we would expect for a dark matter signal,” KIPAC’s Eric Charles, who contributed to the new analysis, said in the same statement.

“Those results suggest the speckles may be due to point sources that we can’t see as individual sources with the LAT because the density of gamma-ray sources is very high and the diffuse glow is brightest at the galactic center,” Charles added.

The new study further supports this idea, linking the speckled signal to pulsars.

“Considering that about 70 percent of all [gamma-ray] point sources in the Milky Way are pulsars, they were the most likely candidates,” Di Mauro said. “But we used one of their physical properties to come to our conclusion. Pulsars have very distinct spectra — that is, their emissions vary in a specific way with the energy of the gamma-rays they emit. Using the shape of these spectra, we were able to model the glow of the galactic center correctly with a population of about 1,000 pulsars and without introducing processes that involve dark matter particles.”

There are other reasons to doubt that the gamma-ray excess is being generated by dark matter, study team members said.

“If the signal were due to dark matter, we would expect to see it also at the centers of other galaxies,” Seth Digel, head of KIPAC’s Fermi group, said in the same statement. “The signal should be particularly clear in dwarf galaxies orbiting the Milky Way. These galaxies have very few stars, typically don’t have pulsars and are held together because they have a lot of dark matter. However, we don’t see any significant gamma-ray emissions from them.”

The team plans to observe the Milky Way’s center with radio telescopes, in an attempt to determine if the point sources there are emitting their light in pulses, as pulsars seem to do. (This is just an illusion, however. Pulsars emit light beams continuously in opposite directions; the light appears to flicker because pulsars spin, and their beams are therefore not always pointing at Earth.)

The new study has been submitted to The Astrophysical Journal. You can read it for free at the online preprint site arXiv.org.

Courtesy-Space

Does Planet 9 Really Exist?

May 3, 2017 by  
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Ever since enthusiasm started growing over the possibility that there could be a ninth major planet orbiting the sun beyond Neptune, astronomers have been busy hunting it. One group is investigating four new moving objects found by members of the public to see if they are potential new solar system discoveries. As exciting as this is, researchers are also making discoveries that question the entire prospect of a ninth planet.

One such finding is our discovery of a minor planet in the outer solar system: 2013 SY99. This small, icy world has an orbit so distant that it takes 20,000 years for one long, looping passage. We found SY99 with the Canada-France-Hawaii Telescope as part of the Outer Solar System Origins Survey. SY99’s great distance means it travels very slowly across the sky. Our measurements of its motion show that its orbit is a very stretched ellipse, with the closest approach to the sun at 50 times that between the Earth and the sun (a distance of 50 “astronomical units”).

The new minor planet loops even further out than previously discovered dwarf planets such as Sedna and 2013 VP113. The long axis of its orbital ellipse is 730 astronomical units. Our observations with other telescopes show that SY99 is a small, reddish world, some 250 kilometres in diameter, or about the size of Wales in the UK.

SY99 is one of only seven known small icy worlds that orbit beyond Neptune at remarkable distances. How these “extreme trans-Neptunian objects” were placed on their orbits is uncertain: their distant paths are isolated in space. Their closest approach to the sun is so far beyond Neptune that they are thought to be “detached” from the strong gravitational influence of the giant planets in our solar system. But at their furthest points, they are still too close to be nudged around by the slow tides of the galaxy itself.

Planet Nine could explain why the few known extreme trans-Neptunian objects seem to be clustered together in space. The diagram was created using WorldWide Telescope.

 

It’s been suggested that the extreme trans-Neptunian objects could be clustered in space by the gravitational influence of a “Planet Nine” that orbits much further out than Neptune. This planet’s gravity could lift out and detach their orbits – constantly changing their tilt. But this planet is far from proven.

In fact, its existence is based on the orbits of only six objects, which are very faint and hard to discover even with large telescopes. They are therefore prone to odd biases. It’s a bit like looking down into the deep ocean at a school of fish. The fish swimming near the surface are clearly visible. But the ones even only a meter down are fainter and murky, and take quite a lot of peering to be certain. The great bulk of the school, in the depths, is completely invisible. But the fish at the surface and their behaviour betray the existence of a whole school.

The biases mean SY99’s discovery can’t prove or disprove the existence of a Planet Nine. However, computer models do show that a Planet Nine would be an unfriendly neighbour to tiny worlds like SY99: its gravitational influence would starkly change its orbit – throwing it from the solar system entirely, or poking it into an orbit so highly inclined and distant that we wouldn’t be able to see it. SY99 would have to be one of an utterly vast throng of small worlds, continuously being sucked in and cast out by the planet.

 

But it turns out that there are other explanations. Our study based on computer modelling, accepted for publication in the Astronomical Journal, hint at the influence of an idea from everyday physics called diffusion. This is a very common type of behaviour in the natural world. Diffusion typically explains the random movement of a substance from a region of higher concentration to one of lower concentration – such as the way perfume drifts across a room.

We showed that a related form of diffusion can cause the orbits of minor planets to change from an ellipse that is initially only 730 astronomical units on its long axis to one that is as big as 2,000 astronomical units or bigger – and change it back again. In this process, the size of each orbit would vary by a random amount. When SY99 comes to its closest approach every 20,000 years, Neptune will often be in a different part of its orbit on the opposite side of the solar system. But at encounters where both SY99 and Neptune are close, Neptune’s gravity will subtly nudge SY99, minutely changing its velocity. As SY99 travels out away from the sun, the shape of its next orbit will be different.

The long axis of SY99’s ellipse will alter, becoming either larger or smaller, in what physicists call a “random walk.” The orbit change takes place on truly astronomical time scales. It diffuses over the space of tens of millions of years. The long axis of SY99’s ellipse would change by hundreds of astronomical units over the 4.5 billion-year history of the solar system.

Several other extreme trans-Neptunian objects with smaller orbits also show diffusion, on a smaller scale. Where one goes, more can follow. It’s entirely plausible that the gradual effects of diffusion act on the tens of millions of tiny worlds orbiting in the near fringe of the Oort cloud (a shell of icy objects at the edge of the solar system). This gentle influence would slowly lead some of them to randomly shift their orbits closer to us, where we see them as extreme trans-Neptunian objects.

However, diffusion won’t explain the distant orbit of Sedna, which has its closest point too far out from Neptune for it to change its orbit’s shape. Perhaps Sedna gained its orbit from a passing star, aeons ago. But diffusion could certainly be bringing in extreme trans-Neptunian objects from the inner Oort cloud – without the need for a Planet Nine. To find out for sure, we’ll need to make more discoveries in this most distant region using our largest telescopes.

Courtesy-Space

DeeDee Becomes A Dwarf

April 24, 2017 by  
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The solar system’s dwarf-planet population is about to increase by one.

The far-flung object 2014 UZ224 — informally known as DeeDee, for “Distant Dwarf” — is about 395 miles wide (635 kilometers), new observations reveal. That means the frigid object probably harbors enough mass to be shaped into a sphere by its own gravity, entitling it to “dwarf planet” status, researchers said.

Astronomers first spotted DeeDee in 2014 using the optical Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile (though they didn’t announce the discovery until 2016).

The initial Blanco observations allowed the discovery team to nail down DeeDee’s orbit. The object loops around the sun on a highly elliptical path that takes more than 1,100 Earth years to complete; it’s currently about 92 astronomical units (AU) from the sun but comes as close as 38 AU and gets as far away as 180 AU. (One AU is the average Earth-sun distance — about 93 million miles, or 150 million km.)

DeeDee is therefore the second most distant “trans-Neptunian object” with a confirmed orbit at the moment, researchers said. The dwarf planet Eris is more far-flung, though that’s not always the case; Eris is currently about 96.5 AU from the sun, but it never gets more than 98 AU from Earth’s star.

For perspective, Pluto orbits the sun at an average distance of 40 AU, with a maximum orbital distance of 49 AU.

But the Blanco data did not allow the discovery team — which was led by David Gerdes, an astronomer at the University of Michigan — to pinpoint DeeDee’s size. While the researchers suspected that the object is a dwarf planet, they couldn’t definitively determine from the optical observations whether DeeDee is relatively small and bright, or big and dark.

So Gerdes and his colleagues studied DeeDee with the Atacama Large Millimeter/submillimeter Array (ALMA), a system of powerful radio telescopes in Chile. ALMA picked up the faraway object’s heat signature, which is directly proportional to its size.

“We calculated that this object would be incredibly cold, only about 30 degrees Kelvin, just a little above absolute zero,” Gerdes said in a statement.

ALMA also measured DeeDee’s brightness in millimeter-wavelength light, finding that the object reflects just 13 percent of the sunlight that hits it. That means DeeDee is about as dark as the dirt on a baseball infield, astronomers said.

Combining the ALMA data with the earlier Blanco observations allowed the team to figure out how big DeeDee is, a result they just published in the Astrophysical Journal Letters. (Some more perspective: DeeDee is larger than Saturn’s spherical, geyser-spouting moon Enceladus, which has a diameter of 313 miles, or 504 km.)

The discovery and study of DeeDee (which has not yet officially been anointed a dwarf planet) shows that astronomers can probe the deep outer solar system and that similar techniques could potentially spot Planet Nine, the big world hypothesized to lurk out there undetected, researchers said.

“There are still new worlds to discover in our own cosmic backyard,” Gerdes said. “The solar system is a rich and complicated place.”

Courtesy-Space

Did Astronomers Spot Planet 9 Candidates?

April 14, 2017 by  
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Citizen scientists have flagged four objects for follow-up study in the hunt for the hypothetical Planet Nine.

The four unknown objects were spotted in images of the southern sky captured recently by the SkyMapper telescope at Siding Spring Observatory in Australia. More than 60,000 people from around the world scoured these photos, making about 5 million classifications, said researchers with the Australian National University (ANU), which organized the citizen-science project.

Astronomers will now use Siding Spring and other telescopes around the world to investigate the four objects to determine if they’re viable Planet Nine candidates. But even if they’re not, the search has still yielded valuable information, project team members said.  

“We’ve managed to rule out a planet about the size of Neptune being in about 90 percent of the southern sky out to a depth of about 350 times the distance the Earth is from the sun,” research leader Brad Tucker, from the ANU Research School of Astronomy and Astrophysics, said in a statement.

“With the help of tens of thousands of dedicated volunteers sifting through hundreds of thousands of images taken by SkyMapper, we have achieved four years of scientific analysis in under three days,” Tucker added. “One of those volunteers, Toby Roberts, has made 12,000 classifications

The existence of Planet Nine was first seriously proposed in 2014 by astronomers Scott Sheppard and Chadwick Trujillo, who noted that the newfound body 2012 VP113, the dwarf planet Sedna and several other objects far beyond Pluto share distinct orbital characteristics. This coincidence could be explained by a giant, unseen “perturber” lurking in the solar system’s outer reaches and tugging on the objects, Sheppard and Trujillo said.

Astronomers Konstantin Batygin and Mike Brown bolstered this hypothesis in January 2016, finding evidence that this putative perturber (which they dubbed Planet Nine) may be sculpting the orbits of additional distant objects.

Batygin and Brown calculated that Planet Nine — if it exists — is likely about 10 times more massive than Earth and orbits the sun on a highly elliptical path that takes it up to 1,000 astronomical units (AU) from the sun. (One AU is the average Earth-sun distance — about 93 million miles, or 150 million kilometers.)

The hunt for Planet Nine is now on, as shown by the ANU-led effort, which involved the citizen-science site Zooniverse.org. You can learn more about it here (but note that the public-participation aspect of the project has ended).

Courtesy-Space

Astronomers Catch Star Diving Into A Black Hole

April 3, 2017 by  
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A star’s long-ago death dive into a black hole generated cosmic fireworks that are revealing more and more about the dramatic encounter. 

The star got too close to its galaxy’s central black hole about 290 million years ago, and collisions among its torn-apart pieces caused an eruption of optical, ultraviolet and X-ray light that was first spotted by scientists in 2014.

Fresh observations of this radiation by NASA’s Swift telescope have yielded more details about where these different wavelengths were generated in the event, which is called ASASSN-14li, a new study reports.  

We discovered brightness changes in X-rays that occurred about a month after similar changes were observed in visible and UV light,” study lead author Dheeraj Pasham, an astrophysicist at the Massachusetts Institute of Technology, said in a NASA statement. “We think this means the optical and UV emission arose far from the black hole, where elliptical streams of orbiting matter crashed into each other.”

The doomed star harbored about the same mass as Earth’s sun, making it no match for the 3-million-solar-mass black hole that it encountered, NASA officials said. Tidal forces within the black hole overcame the star’s gravity, tearing the star apart into a debris stream. 

Next, the debris from this star formed a spinning accretion disk, with the matter compressing and heating before falling into the black hole. 

The new research suggests that interactions among the debris could generate the optical and UV emission. That’s because the debris falling into the black hole at first overshoots it, zinging back out in an elliptical orbit and colliding with incoming pieces, study team members said.

This helps clarify earlier work, which shows that UV and optical wavelengths appeared to be located far from where the black hole’s tidal influence would destroy the star.

“Returning clumps of debris strike the incoming stream, which results in shock waves that emit visible and ultraviolet light,” said acting Swift principal investigator and study co-author Bradley Cenko, of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “As these clumps fall down to the black hole, they also modulate the X-ray emission there.”

The new study was published last week in The Astrophysical Journal Letters.

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Astronomers Find Supernova Explosion Still Shinning

March 8, 2017 by  
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The strikingly bright shock waves from a massive star explosion first observed in 1987 can still be seen today, three decades later. 

This brilliant star explosion, called Supernova 1987A, occurred only 160,000 light-years from Earth in a satellite galaxy of the Milky Way known as the Large Magellanic Cloud. When it was first discovered on Feb. 23, 1987, the supernova was one of the brightest observed and closest to Earth, providing astronomers with a unique opportunity to study the phases before, during and after the death of a star, officials said in a statement from the European Space Agency (ESA). 

To celebrate the 30th anniversary of SN 1987A, researchers have released new images, time-lapse videos and animation of the supernova’s evolution.  

“Because of its early detection and relative proximity to Earth, SN 1987A has become the best studied supernova ever,” ESA officials said in the statement. “Prior to SN 1987A, our knowledge of supernovae was simplistic and idealized. But by studying the evolution of SN 1987A from supernova to supernova remnant in superb detail, using telescopes in space and on the ground, astronomers have gained revolutionary insights into the deaths of massive stars.” 

The Hubble Space Telescope has also studied the supernova in great detail since it launched into space in 1990. At the time, “Hubble was the first to see the event in high resolution” and clearly image the structure of the supernova, which consists of a main ring surrounding the exploded star and two fainter outer rings, ESA officials said. 

The Chandra X-ray telescope, which launched in 1999, has also been keeping a close eye on the expanding cloud of gas and remnant star material over the years. 

Based on the latest observations of SN 1987A, astronomers have found that the gas and star material was ejected 20,000 years before the supernova explosion actually occurred. Slow-moving stellar winds initially carried some of this material away from the dying star. 

However, as the doomed star neared the end of its life, it evolved into a hot body and generated faster stellar winds that caused the slower material to pile up and form the concentric ring-like structures observed around the exploded star, ESA officials said. 

“The initial burst of light from the supernova illuminated the rings. They slowly faded over the first decade after the explosion, until the shock wave of the supernova slammed into the inner ring in 2001, heating the gas to searing temperatures and generating strong X-ray emission,” ESA officials said in the statement. “Hubble’s observations of this process shed light on how supernovae can affect the dynamics and chemistry of their surrounding environment, and thus shape galactic evolution.”

Courtesy-Space

Does Pluto Have The Right Ingredients For E.T.?

March 7, 2017 by  
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Pluto has long been viewed as a distant, cold and mostly dead world, but the first spacecraft to pass by it last year revealed many surprises about this distant dwarf planet.

Data from the New Horizons flyby finished downloading to Earth in October, and while it will take many years for scientists to complete their inventory and model the results, early studies offer intriguing hints of its complex chemistry, perhaps even some form of pre-biological processes below Pluto’s surface. Complex layers of organic haze; water ice mountains from some unknown geologic process; possible organics on the surface; and a liquid water ocean underneath — all of these features point to a world with much more vibrancy than scientists have long presumed.

“The connection with astrobiology is immediate — it’s right there in front of your face. You see organic materials, water and energy,” said Michael Summers, a planetary scientist on the New Horizons team who specializes in the structure and evolution of planetary atmospheres.

Summers has co-authored two research papers on the topic, with the first, “The Photochemistry of Pluto’s Atmosphere as Illuminated by New Horizons,” published in the journal Icarus in September. The second paper, “Constraints on the Microphysics of Pluto’s Photochemical Haze from New Horizons Observations” is in press at the same journal.

In first looking at the images of Pluto, Summers was reminded of a world he has studied for decades while working at George Mason University. Titan, an icy orange colored moon of Saturn, is the only moon in the Solar System with a substantial atmosphere and a liquid (methane) hydrological cycle. It has hydrocarbon chemistry, including ethane and methane lakes that have compounds that may be precursors to the chemistry required for life.

Unlike Titan, Pluto’s atmosphere is thin and sparse, with haze reaching out at least 200 kilometers (125 miles) above the surface, at least ten times higher than scientists expected. But above 30 km (19 miles) Pluto displays a similar paradox to Titan with condensation happening in a region that’s too warm in temperature for haze particles to occur.

NASA’s Cassini spacecraft saw the same oddity in the highest reaches of Titan’s atmosphere (the ionosphere) at about 500 to 600 kilometers above the surface (roughly 310 or 370 miles). Through modeling, scientists determined that the condensation is partially the result of Titan’s photochemistry, whereby ultraviolet sunlight breaks down methane, triggering the formation of hydrocarbons.

“This haze formation is initiated in the ionosphere, where there are electrically charged particles (electrons and ions),” Summers said. “The electrons attach to the hydrocarbons and make them stick together. They become very stable, and as they fall through the atmosphere they grow by other particles sticking to them. The bigger they are, the faster they fall. On Titan, as you go down in the atmosphere the haze particles get more numerous and much larger than on Pluto.”

In retrospect, Summers said it shouldn’t have been too much of a surprise that Pluto likely has the same process. Like Titan, it has a nitrogen atmosphere with methane as a minor component. The main difference, however, is Pluto’s atmosphere is just 10 millibars at the surface, compared to Titan’s 1.5 bar. (A bar is a metric unit of pressure, with 1 bar equal to 10,000 pascal units, or slightly less than the average atmospheric pressure on Earth at sea level.) The atmospheric pressure difference of the two bodies also affects the shape of the haze particles as Titan’s particles taking much longer to fall to the surface and ultimately become spherical, while Pluto’s haze particles fall more rapidly and grow into fractals.

With the possible production of hydrocarbons and nitriles (another organic molecule) on Pluto, even more interesting pre- chemistry for life could take place, Summers said. “You can start building complex pre-biotic molecules,” he said. An example is hydrogen cyanide, possibly a key molecule leading to prebiotic chemistry.

What’s also abundant on Titan are tholins, complex organic compounds created when the Sun’s ultraviolet light strikes the haze particles. It’s rare on Earth, but common on Titan and may have contributed to its orange color. There is also a reddish hue on parts of Pluto’s surface, which could be from a layer of tholins, Summers said.

His quick calculation estimates these tholins could be 10 to 30 meters thick, providing more organic material per square meter than a forest on Earth. This material may also change its chemical composition as cosmic rays (high-energy radiation particles) strike the surface.

Intriguingly, reddish material was also spotted near Pluto’s ice volcanoes, or calderas. It’s possible that the dwarf planet could have a subsurface ocean similar to that suspected on Titan, Saturn’s Enceladus and Jupiter’s Europa. These moons, however, have a tidal source of energy within, created by orbiting their huge central planets and interacting gravitationally with other moons. Pluto is bereft of such heating, but it’s possible that radioactivity in its interior could be keeping the inside liquid, Summers said.

“These are the things you need for life: organics, raw material and energy,” Summers said.

While it’s a stretch right now to say Pluto is hospitable for life, Summers said he is looking forward to doing more modeling. “I’ve been studying Pluto all my life, and never expected to talk about these things being there.”

Courtesy-Space

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