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Can Companies Mine The Moon AT A Profit

May 25, 2017 by  
Filed under Around The Net

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  
Filed under Around The Net

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  
Filed under Around The Net

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  
Filed under Around The Net

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  
Filed under Around The Net

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  
Filed under Around The Net

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.

Courtesy-Space

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

Astronomers Find The Building Blocks Of Life On Ceres

February 23, 2017 by  
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The dwarf planet Ceres keeps looking better and better as a possible home for alien life.

NASA’s Dawn spacecraft has spotted organic molecules — the carbon-containing building blocks of life as we know it — on Ceres for the first time, a study published today (Feb. 16) in the journal Science reports.

And these organics appear to be native, likely forming on Ceres rather than arriving via asteroid or comet strikes, study team members said.

“Because Ceres is a dwarf planet that may still preserve internal heat from its formation period and may even contain a subsurface ocean, this opens the possibility that primitive life could have developed on Ceres itself,” Michael Küppers, a planetary scientist based at the European Space Astronomy Centre just outside Madrid, said in an accompanying “News and Views” article in the same issue of Science.

“It joins Mars and several satellites of the giant planets in the list of locations in the solar system that may harbor life,” added Küppers, who was not involved in the organics discovery.

The $467 million Dawn mission launched in September 2007 to study Vesta and Ceres, the two largest objects in the main asteroid belt between Mars and Jupiter. 

Dawn circled the 330-mile-wide (530 kilometers) Vesta from July 2011 through September 2012, when it departed for Ceres, which is 590 miles (950 km) across. Dawn arrived at the dwarf planet in March 2015, becoming the first spacecraft ever to orbit two different bodies beyond the Earth-moon system.

During its time at Ceres, Dawn has found bizarre bright spots on crater floors, discovered a likely ice volcano 2.5 miles (4 km) tall and helped scientists determine that water ice is common just beneath the surface, especially near the dwarf planet’s poles.

The newly announced organics discovery adds to this list of achievements. The carbon-containing molecules — which Dawn spotted using its visible and infrared mapping spectrometer instrument — are concentrated in a 385-square-mile (1,000 square km) area near Ceres’ 33-mile-wide (53 km) Ernutet crater, though there’s also a much smaller patch about 250 miles (400 km) away, in a crater called Inamahari. 

And there could be more such areas; the team surveyed only Ceres’ middle latitudes, between 60 degrees north and 60 degrees south. 

“We cannot exclude that there are other locations rich in organics not sampled by the survey, or below the detection limit,” study lead author Maria Cristina De Sanctis, of the Institute for Space Astrophysics and Space Planetology in Rome, told Space.com via email.

Dawn’s measurements aren’t precise enough to nail down exactly what the newfound organics are, but their signatures are consistent with tar-like substances such as kerite and asphaltite, study team members said.

“The organic-rich areas include carbonate and ammoniated species, which are clearly Ceres’ endogenous material, making it unlikely that the organics arrived via an external impactor,” co-author Simone Marchi, a senior research scientist at the Southwest Research Institute in Boulder, Colorado, said in a statement. 

In addition, the intense heat generated by an asteroid or comet strike likely would have destroyed the organics, further suggesting that the molecules are native to Ceres, study team members said.

The organics might have formed via reactions involving hot water, De Sanctis and her colleagues said. Indeed, “Ceres shows clear signatures of pervasive hydrothermal activity and aqueous alteration,” they wrote in the new study.

Such activity likely would have taken place underground. Dawn mission scientists aren’t sure yet how organics generated in the interior could make it up to the surface and leave the signatures observed by the spacecraft.

“The geological and morphological settings of Ernutet are still under investigation with the high-resolution data acquired in the last months, and we do not have a definitive answer for why Ernutet is so special,” De Sanctis said.

It’s already clear, however, that Ceres is a complex and intriguing world — one that astrobiologists are getting more and more excited about.

“In some ways, it is very similar to Europa and Enceladus,” De Sanctis said, referring to ocean-harboring moons of Jupiter and Saturn, respectively. 

“We see compounds on the surface of Ceres like the ones detected in the plume of Enceladus,” she added. “Ceres’ surface can be considered warmer with respect to the Saturnian and Jovian satellites, due to [its] distance from the sun. However, we do not have evidence of a subsurface ocean now on Ceres, but there are hints of subsurface recent fluids.” 

Courtesy-Fud

Astronomer Discover Clue To Star Explosions From Young Supernova

February 21, 2017 by  
Filed under Computing

Baby pictures of a newborn supernova have captured this stellar explosion after the first half-dozen hours of its life, shedding light on how these giant explosions happen, a new study finds.

This newly discovered cosmic baby is the type of supernova that occurs when a giant star runs out of fuel and explodes. Supernovas are so bright that they can briefly outshine all of the other stars in their home galaxy.

Astronomers have previously seen glimpses of supernovas within the first minutes after they explode. However, until now, researchers had not captured light from a newborn supernova across the so many wavelengths — including radio waves, visible light and X-rays. The new images add to evidence that suggests that these dying stars may signal their upcoming demise by spewing a disk of material in the months before their deaths, according to a paper describing the finding.  

Much remains unknown about how and why dying stars can detonate with such violence. Studying the final years of a star that is destined to die as a supernova could reveal key details about the way in which these explosions happen, but stars in these brief, final stages are rare — statistically, it is very likely that none of the 100 billion to 400 billion stars in the Milky Way galaxy are within one year of dying as a supernova, according to the new paper. 

Now scientists report the discovery of a supernova just 3 hours after it exploded, helping them capture “the earliest spectra ever taken of a supernova explosion,” said study lead author Ofer Yaron, an astrophysicist at the Weizmann Institute of Science in Rehovot, Israel. A light spectrum is essentially detailed look at the wavelengths of light emitted by an object. Because chemical elements can absorb certain wavelengths, stellar spectra can be used to reveal the composition of a star. 

“Until several years ago, catching a supernova a week after explosion was regarded as early,” Yaron told Space.com. “This is not the case anymore.”

The astronomers detected the supernova known as SN 2013fs on Oct. 6, 2013, using the data from the Intermediate Palomar Transient Factory (iPTF) based at the Palomar Observatory in California. Its star was likely a red supergiant about 10 to 17 times heavier than the sun and several hundred times wider than the sun, Yaron said.

The supernova detonated about 160 million light-years away in a spiral galaxy called NGC 7610. This galaxy is relatively close to the Milky Way, making it easier for scientists to aim more telescopes at it and detect signals from it that span almost the entire the spectrum of light, from radio waves to X-rays. Observations of the supernova were made with telescopes at the Keck Observatory in Hawaii and NASA’s Swift satellite starting about 6 hours after the explosion, Yaron explained.

SN 2013fs was the most common variety of supernova: a Type II. This kind of supernova happens when the core of a massive star runs out of fuel, collapses to an extraordinarily dense nugget in a fraction of a second and then bounces and blasts its material outward.

The astronomers captured pictures of the newborn supernova early enough to spot a disk of matter the star expelled just before its demise. Normally supernovas are seen after the shockwave from the explosions have swept away such material and any secrets that the disk might have contained.

The researchers found that a year or so before this star died, it rapidly spewed out vast amounts of material, equal to about one-thousandth of the sun’s mass, at speeds of nearly 224,000 mph (360,000 km/h). Previous research had seen cases where such early eruptions occurred among unusual subgroups of Type II supernovas, but these new findings suggest that such outpourings also precede more common kinds of Type II supernovas.

“It’s as if the star ‘knows’ its life is ending soon, and puffing material at an enhanced rate during its final breaths,” Yaron told Space.com. “Think of a volcano or geyser bubbling before an eruption.”

These findings suggest that a star may be unstable months before its turns into a Type II supernova. As such, “the structure of the star when it explodes may be different than that assumed so far,” Yaron said. For instance, the core of a star may experience upheavals during its final days, causing strong winds to travel from the depths of the star all the way to its surface and beyond.

New, automated surveys of the sky such as the iPTF have begun capturing supernovas a day or less after they explode. 

“With the help of new sky surveys coming up in the very near future, we expect to significantly increase the number of supernova events for which we are able to obtain early observations within hours and maybe minutes from explosion,” Yaron said.

The scientists detailed their findings online Feb. 13 in the journal Nature Physics.

Courtesy-Space

Is A Supernova Challenging The Evolution Theory For Stars?

February 6, 2017 by  
Filed under Around The Net

A perplexing “chameleon supernova” is challenging the way astronomers study massive star explosions. 

When some stars reach the end of their lives, they explode in a bright stellar event called a supernova, releasing material created in the heart of the star out into the universe. There are different types of supernova explosions, and astronomers generally classify these powerful outbursts based on the presence of hydrogen.  

“While stars begin their lives with hydrogen fusing into helium, large stars nearing a supernova death have run out of hydrogen as fuel,” NASA officials said in a statement. “Supernovae in which very little hydrogen is present are called ‘Type I.’ Those that do have an abundance of hydrogen, which are rarer, are called ‘Type II.'”

But in a recent study published in The Astrophysical Journal, astronomers examine a supernova called SN 2014C that released a lot of material (including mostly hydrogen and heavier elements) unusually late in its life but before it exploded. The so-called chameleon supernova — perhaps named because its appearance makes it look like something other than itself — resides in a spiral galaxy about 36 million to 46 million light-years from Earth.

“This ‘chameleon supernova’ may represent a new mechanism of how massive stars deliver elements created in their cores to the rest of the universe,” Raffaella Margutti, lead author of the study and an assistant professor of physics and astronomy at Northwestern University, said in the statement. “Expelling this material late in life is likely a way that stars give elements, which they produce during their lifetimes, back to their environment.”

The material released into the universe following massive star explosions serves as the building blocks of Earth and other planets in our solar system. However, astronomers question why SN 2014C would throw off so much hydrogen before exploding. 

Using NASA’s NuSTAR (Nuclear Spectroscopic Telescope Array) satellite, astronomers found that “SN 2014C had transformed itself from a Type I to a Type II supernova after its core collapsed,” NASA officials said in the statement. Although hydrogen was not detected in initial observations, shock waves coming from the star explosion hit an outer shell of mostly hydrogen material, suggesting the star released the material decades to centuries before it exploded. 

What’s more, astronomers also found that the “supernova brightened in X-rays after the initial explosion, demonstrating that there must be a shell of material, previously ejected by the star, that the shock waves had hit,” according to observations from NASA’s Chandra and Swift observatories

One hypothesis for SN 2014C’s unusual behavior is that the star was part of a binary system and did not die alone — its possible the gravitational pull of a nearby star influenced SN 2014C’s evolution, according to the statement. Roughly seventy percent of massive stars have companions, NASA officials said. 

“The notion that a star could expel such a huge amount of matter in a short interval is completely new,” Fiona Harrison, NuSTAR principal investigator and professor of physics and astronomy at Caltech, said in the NASA statement. “It is challenging our fundamental ideas about how massive stars evolve, and eventually explode, distributing the chemical elements necessary for life.”

Courtesy-Space

Will The U.S. And Russia Team Up For A Venus Mission?

January 19, 2017 by  
Filed under Around The Net

Russia’s space program and NASA are working together on a mission to Venus that would investigate some of the scorching-hot planet’s biggest mysteries, including, perhaps, whether it harbors life.

An international team of scientists tasked with fleshing out the main goals of the mission, which is known as Venera-D, is wrapping up its work and will deliver its final report to NASA and the Russian Academy of Sciences’ Space Research Institute by the end of the month, said David Senske, of NASA’s Jet Propulsion Laboratory in Pasadena, California.

“Is this the mission that’s going to fly? No, but we’re getting there,” Senske, the U.S. co-chair of this “joint science-definition team,” told Space.com last month at the annual fall meeting of the American Geophysical Union, in San Francisco.

Venera-D is led by Russia, which has been developing the project for more than a decade. The mission would mark a return to once-familiar territory for the nation; Russia’s forerunner state, the Soviet Union, launched a number of probes to Venus from the early 1960s through the mid-1980s, as part of its Venera and Vega programs. (“Venera” is the Russian name for Venus.)

“Russia has always been interested in going back to Venus,” Senske said.

NASA got involved about three years ago, when Russia asked if the U.S. space agency would be interested in collaborating on the mission, Senske added.

The joint science-definition team arose out of those initial discussions. The team stood down shortly thereafter; Russia’s March 2014 annexation of Crimea prompted NASA to suspend most cooperation with Roscosmos, Russia’s federal space agency (with activities involving the International Space Station being the most prominent exception).

But the collaboration was up and running again by August 2015, Senske said, and the team met in Moscow that October. More meetings are planned, including a workshop this May that will inform decisions about the mission’s scientific instruments, he added.

Venera-D is a large-scale mission, comparable in scope to NASA “flagship” efforts such as the $2.5 billion Curiosity Mars rover, Senske said. The baseline concept calls for an orbiter that will study Venus from above for at least three years, plus a lander that will operate for a few hours on the planet’s surface.

Mission planners said they had originally hoped the lander could survive for 30 days; the “D” in Venera-D stands for “dolgozhivushaya,” which means “long lasting” in Russian. But this goal was ultimately deemed too difficult and costly, given the blistering temperatures on Venus’ surface, according to RussianSpaceWeb.com (which outlines the mission’s tortuous history in rich detail).

Data gathered by the orbiter should help scientists better understand the composition, structure and dynamics of Venus’ atmosphere, including why the planet’s air rotates so much faster than the surface does, a mysterious phenomenon known as super-rotation, Senske said.

The lander will collect further atmospheric information while descending, then study the composition and morphology of the Venusian surface after touching down.

Venera-D could incorporate additional components as well. Some ideas on the drawing board include a handful of small, relatively simple ground stations that would gather surface data for a month or so (putting the “D” back in Venera-D) and a solar-powered, uncrewed aerial vehicle that would ply the Venusian skies.

The surface of Venus is far too hot to support life as we know it, but temperatures are much more hospitable at an altitude of 31 miles (50 kilometers) or so. Furthermore, the planet’s atmosphere sports mysterious dark streaks that some astronomers have speculated might be signs of microbial life. The UAV could hypothetically investigate this possibility, sampling the air while cruising along.

Engineers have already been thinking about how to build such an aircraft. For example, the U.S. aerospace company Northrop Grumman and partner L’Garde Inc. have been researching a concept vehicle called the Venus Atmospheric Maneuverable Platform (VAMP) for several years now.

It’s still too early to know exactly what Venera-D will look like, what it will do or when the mission will launch. A liftoff in 2025 or 2026 is possible under an “aggressive” time line, Senske said. “It depends when the Russians can get this into their federal space budget,” he said.

Some things are known, however. For instance, Russia will build the orbiter and the lander, and Venera-D will launch atop Russia’s in-development Angara A5 rocket, Senske said. If NASA remains involved in the mission — which is far from a given at this point — the U.S. space agency will likely contribute smaller items, such as individual scientific instruments.

“Russia is definitely in the driver’s seat,” Senske said. “NASA is the junior partner.”

Courtesy-Space

Can Charon Help Pluto Fight The Solar Winds?

January 18, 2017 by  
Filed under Around The Net

Space weather can be a nightmare for planetary atmospheres, particularly for ones that don’t have a magnetic field to protect them — unlike Earth’s, which has a powerful magnetosphere acting as a shield. It might therefore be strange to hear that dwarf planet Pluto, which isn’t known for its powerful global magnetic field, is able to possess an atmosphere at all. But like other planets in the solar system, the sun erodes Pluto’s atmosphere — albeit at a slower rate than expected.

Although astronomical measurements detected the presence of an atmosphere at Pluto long before the NASA New Horizons flyby in July 2015, very little was known about how much was being eroded into space by the continuous stream of solar wind particles. New Horizons measurements, however, proved that the rate of atmospheric loss was 100 times less than expected and, in new research published this week in the journal Icarus, researchers think they know what might be protecting Pluto’s tenuous atmospheric gases.

Researchers from Georgia Institute of Technology have shown that when Charon orbits between Pluto and the sun, its presence can modify the dwarf planet’s bow shock — a standing shock wave that appears “upstream” of Pluto as the solar wind particles encounter Pluto’s thin atmosphere, like the wave that roils in front of a boat’s bow when it powers through water — thereby shielding Pluto’s atmosphere for a short time. Charon maximizes this protection should it also have an atmosphere, but its protective impact is minimal when it either doesn’t have an atmosphere or when it is positioned “downstream” of Pluto.

As Pluto and Charon orbit so close to one another, the pair are believed to share atmospheric gases and when Charon passes behind Pluto particles originating from Pluto are deposited at the moon’s poles, appearing as a dark brown deposit in New Horizons observations.

As Pluto is located so far away from the sun in the Kuiper Belt, the impact of the solar wind is much lower than its impact on planets closer to the sun. The space weather impact has been reduced even further with the help of Charon.

As a result inner Planets by solar wind,” said Georgia Tech student John Hale. “Even at its great distance from the sun, Pluto is slowly losing its atmosphere. Knowing the rate at which Pluto’s atmosphere is being lost can tell us how much atmosphere it had to begin with, and therefore what it looked like originally. From there, we can get an idea of what the solar system was made of during its formation.”

As Pluto and Charon orbit so close and Charon is roughly half the size of its dwarf planet buddy, the pair orbits a common point in space known as the “barycenter.” This orbital oddity added fuel to the debate as to whether Pluto should be called a dwarf planet, or whether Pluto and Charon should be designated a “binary planet.” Now, with more findings about the pair’s atmospheric interactions, it could be argued that the case for calling Pluto a binary planet is as valid as ever.

Courtesy-Fud

Did Betelgeuse Cannibalize Other Stars?

December 26, 2016 by  
Filed under Around The Net

betelThe huge, red star Betelgeuse, which marks the hunter’s shoulder in the constellation Orion, may have swallowed up a companion star not long ago, a new study suggests.

Betelgeuse is a “red supergiant” that will soon die in a supernova explosion. As the name of its stellar class indicates, Betelgeuse has bloated immensely as the end of its life has neared. Although Betelgeuse’s mass is just 15 to 25 times that of the sun, the star is currently about 860 million miles (1.4 billion kilometers) across, or 1,000 times wider than Earth’s star. (If you put Betelgeuse in the sun’s location, the red star’s surface would extend past the orbit of Mars and into the asteroid belt.)

Such an enormous star should be spinning slowly, since rotation rate decreases as size increases. (Think about how ice-skaters control their spin speed by bringing their arms in close to their body or extending them.) But that’s not the case with Betelgeuse, which is rotating at a blazing 33,500 mph (53,900 km/h), astronomers said. 

“We cannot account for the rotation of Betelgeuse,” study lead author J. Craig Wheeler, an astronomer at the University of Texas at Austin, said in a statement. “It’s spinning 150 times faster than any plausible single star just rotating and doing its thing.”

But Wheeler and his colleagues may have an answer. Their computer models suggest that Betelgeuse’s puzzling spin could be explained if the giant gobbled up a companion roughly the same mass as the sun 100,000 years or so ago. (The angular momentum of the companion’s orbit would be transferred to Betelgeuse, speeding up the giant’s rotation to its current rate

This act of cannibalism likely would have spurred a cosmic belch of sorts, causing Betelgeuse to blast a cloud of material out into space at about 22,400 mph (36,000 km/h), Wheeler said. Indeed, astronomers have spotted a shell of matter at roughly the distance from Betelgeuse that this scenario predicts, he added.

Although there are other possible explanations for this space cloud, “the fact is, there is evidence that Betelgeuse had some kind of commotion on roughly this timescale,” Wheeler said.

Betelgeuse lies about 640 light-years from the sun. Like other supergiants, it will die young; the star is only about 10 million years old. The sun, by contrast, is nearly 4.6 billion years old and is only about halfway through its life.

The new study was published today (Dec. 19) in the journal Monthly Notices of the Royal Astronomical Society.

Courtesy-Space

Does Pluto Have Oceans Below?

November 22, 2016 by  
Filed under Around The Net

pluto-ocean-viewPluto’s famous heart-shaped feature caused the dwarf planet to roll over the eons, and this reorientation probably wouldn’t have been possible without a subsurface ocean, new research suggests.

The left lobe of Pluto’s “heart” is a 600-mile-wide (1,000 kilometers) plain called Sputnik Planitia (formerly known as Sputnik Planum), which astronomers think is an enormous impact crater. This basin has been filling with nitrogen ice over the years and now contains huge amounts of the stuff. Indeed, observations by NASA’s New Horizons spacecraft, which flew by Pluto last year, suggest that Sputnik Planitia’s ice may be up to 6 miles (10 km) thick.

Sputnik Planitia is aligned nicely with Pluto’s “tidal axis” — the line along which the gravitational pull from the dwarf planet’s largest moon, Charon, is the strongest. And that’s probably no coincidence, according to two new studies, both of which were published online today (Nov. 16) in the journal Nature.  

In the first study, James Keane, a doctoral student at the University of Arizona’s Lunar and Planetary Laboratory, and his colleagues modeled what happened as nitrogen ice accumulated in Sputnik Planitia. The results were dramatic.

“Once enough ice has piled up, maybe a hundred meters thick, it starts to overwhelm the planet’s shape, which dictates the planet’s orientation,” Keane said in a statement. “And if you have an excess of mass in one spot on the planet, it wants to go to the equator. Eventually, over millions of years, it will drag the whole planet over.”

This tumble brought Sputnik Planitia to the southeast, until the plain faced directly away from Charon as it does today. The team’s models predicted this very orientation: In this spot, near the tidal axis, the additional mass causes the least wobble in Pluto’s spin, the researchers said. (Pluto and Charon are tidally locked, meaning the two bodies always show the same face to each other, just as Earth’s moon always shows just one side to Earth.) 

Pluto’s reorientation would have stressed the dwarf planet’s crust, leading to a network of faults and fractures on the surface, Keane and his colleagues report. And New Horizons spotted just such a network, whose characteristics match those predicted by the team’s models, they said.

Those models assume that Pluto harbors a subsurface ocean of liquid water — a notion bolstered by the second study, which was led by Francis Nimmo, a professor of Earth and planetary sciences at the University of California, Santa Cruz.

Nimmo and his team determined that the odds of Sputnik Planitia occurring in its present location, so close to the tidal axis, purely by chance were just 5 percent. So they, too, believe that a substantial reorientation has taken place.

The researchers suggested that the impact that created the basin weakened the crust overlying a buried ocean, causing some of the water to rise close to the surface. This action, along with the deposition of nitrogen ice in Sputnik Planitia, would have created enough of a “positive mass anomaly” to roll the dwarf planet, Nimmo and his colleagues wrote. 

It’s hard to imagine Pluto reorienting in this way if it didn’t have an ocean, Nimmo said. For example, the team’s calculations suggest that Sputnik Planitia’s ice layer would have to be 25 miles (40 km) thick if no ocean existed.

“Our view is that 40 kilometers’ thickness of nitrogen ice is not that likely,” Nimmo told Space.com. “So if you want to have another source of dense material down there, then water seemed like a very natural explanation, because water is a lot denser than ice.”

The team also considered the possibility that rock migrated in to make up the extra mass, but that explanation doesn’t seem likely, either, Nimmo said.

“The rock is so far down there, and it’s also pretty strong,” he said. “So it’s hard to figure out how that rock would get moved around in the way that you would need.”

Other research groups also have suggested that Pluto may harbor a subsurface ocean, using other lines of evidence. One such argument points to the dwarf planet’s surface fractures, which may be the result of this ocean gradually freezing over time — a prospect also raised by Keane and his colleagues in their paper. (Water expands as it freezes, which would lead to stresses in overlying rock or ice.) In addition, Nimmo said, Pluto doesn’t have an equatorial bulge — and bodies with oceans can’t maintain such a bulge.

“All these lines of argument are pointing in the same direction,” Nimmo said.

If Pluto does have an ocean, how has it managed to avoid freezing up entirely over the past 4.5 billion years? Pluto is big enough that it may have retained a substantial amount of internal heat, Nimmo said. And the dwarf planet’s water may contain significant amounts of ammonia or other substances that act as an antifreeze, he added.

Astronomers think subsurface oceans exist on the Saturn moons Enceladus and Titan; the Jovian satellites Europa, Ganymede and Callisto; and a number of other solar system bodies. Indeed, such buried water may be abundant in the Kuiper Belt, the ring of frigid objects beyond Neptune’s orbit, Nimmo said.

“My guess is that, on big Kuiper Belt objects, these kinds of oceans are pretty common,” Nimmo said. “One of the lessons of the last 20 years is that oceans pop up in all kinds of unexpected places.” 

Courtesy-Space

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