‘Bathtub Rings’ Around Titan’s Lakes Might Be Made Of Alien Crystals

The frigid lakeshores of Saturn’s moon Titan might be encrusted with strange, unearthly minerals, according to new research being presented here.

Scientists re-creating Titan-esque conditions in their laboratory have discovered new compounds and minerals not found on Earth, including a co-crystal made of solid acetylene and butane.

Acetylene and butane exist on Earth as gases and are commonly used for welding and camp stove fuel. On Titan, with its extremely cold temperatures, acetylene and butane are solid and combine to form crystals, the new research found.

The new mineral might be responsible for the bathtub rings that are suspected to exist around Titan’s hydrocarbon lakes, according to Morgan Cable of NASA’s Jet Propulsion Laboratory at the California Institute of Technology, who will present the new research Monday at the 2019 Astrobiology Science Conference.

Titan’s lakes are filled with liquid hydrocarbons. Previous research using images and data gathered during the Cassini mission has shown that lakes in the moon’s dry regions near the equator contain signs of evaporated material left behind, like rings on a bathtub.

To create Titan-like conditions in the laboratory, the researchers started with a custom-built cryostat, an apparatus to keep things cold. They filled the cryostat with liquid nitrogen to bring the temperature down. They then warmed the chamber slightly, so the nitrogen turned to gas, which is mostly what Titan’s atmosphere contains. Next, they threw in what abounds on Titan, methane and ethane, as well as other carbon-containing molecules, and looked for what formed.

The first things to drop out of their Titan hydrocarbon soup were benzene crystals. Benzene is perhaps best known as a component of gasoline and is a snowflake-shaped molecule made out of a hexagonal ring of carbon atoms. But Titan benzene held a surprise: The molecules rearranged themselves and allowed ethane molecules inside, creating a co-crystal.

The researchers then discovered the acetylene and butane co-crystal, which is probably a lot more common on Titan than benzene crystals, based on what’s known about the moon’s composition, Cable said.

In the moon’s cold climate, the acetylene-butane co-crystals might form rings around the moon’s lakes as the liquid hydrocarbons evaporate and the minerals drop out — in the same way that salts can form crusts on the shores of Earth’s lakes and seas, according to Cable.

To confirm whether Titan has bathtub rings of co-crystals and other, undiscovered, hydrocarbon crystals, scientists will have to wait until a spacecraft can visit the shorelines of this moon, Cable said.

“We don’t know yet if we have these bathtub rings,” Cable said. “It’s hard to see through Titan’s hazy atmosphere.”

Moving Closer to Understanding of Universe’s Most Powerful Explosions

Good fortune and cutting-edge scientific equipment have allowed scientists to observe a Gamma Ray Burst jet with a radio telescope and detect the polarization of radio waves within it for the first time – moving us closer to an understanding of what causes the universe’s most powerful explosions.

Gamma Ray Bursts (GRBs) are the most energetic explosions in the universe, beaming out mighty jets which travel through space at over 99.9% the speed of light, as a star much more massive than our Sun collapses at the end of its life to produce a black hole. The study was published in Astrophysical Journal Letters.

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Studying the light from Gamma Ray Burst jets as we detect it travelling across space is our best hope of understanding how these powerful jets are formed, but scientists need to be quick to get their telescopes into position and get the best data. The detection of polarized radio waves from a burst’s jet, made possible by a new generation of advanced radio telescopes, offers new clues to this mystery.

The light from this particular event, known as GRB 190114C, which exploded with the force of millions of Suns’ worth of TNT about 4.5 billion years ago, reached NASA’s Neil Gehrels Swift Observatory on Jan 14, 2019.

A rapid alert from Swift allowed the research team to direct the Atacama Large Millimeter/Sub-millimeter Array (ALMA) telescope in Chile to observe the burst just two hours after Swift discovered it. Two hours later the team was able to observe the GRB from the Karl G. Jansky Very Large Array (VLA) telescope when it became visible in New Mexico, USA.

Combining the measurements from these observatories allowed the research team to determine the structure of magnetic fields within the jet itself, which affects how the radio light is polarized. Theories predict different arrangements of magnetic fields within the jet depending on the fields’ origin, so capturing radio data enabled the researchers to test these theories with observations from telescopes for the first time.

The research team, from the University of Bath, Northwestern University, the Open University of Israel, Harvard University, California State University in Sacramento, the Max Planck Institute in Garching, and Liverpool John Moores University discovered that only 0.8% of the jet light was polarized, meaning that jet’s magnetic field was only ordered over relatively small patches – each less than about 1% of the diameter of the jet. Larger patches would have produced more polarized light.

These measurements suggest that magnetic fields may play a less significant structural role in GRB jets than previously thought. This helps us narrow down the possible explanations for what causes and powers these extraordinary explosions.

First author Dr. Tanmoy Laskar, from the University of Bath’s Astrophysics group, said: “We want to understand why some stars produce these extraordinary jets when they die, and the mechanism by which these jets are fuelled – the fastest known outflows in the universe, moving at speeds close to that of light and shining with the incredible luminosity of over a billion Suns combined.

“I was in a cab on my way to O’Hare airport in Chicago, following a visit with collaborators when the burst went off. The extreme brightness of this event and the fact that it was visible in Chile right away made it a prime target for our study, and so I immediately contacted ALMA to say we were going to observe this one, in the hope of detecting the first radio polarization signal.

“It was fortuitous that the target was well placed in the sky for observations with both ALMA in Chile and the VLA in New Mexico. Both facilities responded quickly and the weather was excellent. We then spent two months in a painstaking process to make sure our measurement was genuine and free from instrumental effects. Everything checked out, and that was exciting.

Dr. Kate Alexander, who led the VLA observations, said: “The lower frequency data from the VLA helped confirm that we were seeing the light from the jet itself, rather than from the interaction of the jet with its environment.”

Dr. Laskar added: “This measurement opens a new window into GRB science and the studies of energetic astrophysical jets. We would like to understand whether the low level of polarization measured in this event is characteristic of all GRBs, and if so, what this could tell us about the magnetic structures in GRB jets and the role of magnetic fields in powering jets throughout the universe.”

Professor Carole Mundell, Head of Astrophysics at the University of Bath, added: “The exquisite sensitivity of ALMA and rapid response of the telescopes has, for the first time, allowed us to swiftly and accurately measure the degree of polarization of microwaves from a GRB afterglow just two hours after the blast and probe the magnetic fields that are thought to drive these powerful, ultra-fast outflows.”

The research team plans to hunt for more GRBs to continue to unravel the mysteries of the biggest explosions in the universe.

Scientists Use X-Rays from Faraway Galaxy Cluster to Reveal Secrets of Plasma

Most visible matter in the universe doesn’t look like our textbook picture of a nucleus surrounded by tethered electrons. Out beyond our borders, inside massive clusters, galaxies swim in a sea of plasma – a form of matter in which electrons and nuclei wander unmoored.

Though it makes up the majority of the visible matter in the universe, this plasma remains poorly understood; scientists do not have a theory that fully describes its behavior, especially at small scales.

However, a University of Chicago astrophysicist led a study that provides a brand-new glimpse of the small-scale physics of such plasma. Using NASA’s Chandra X-ray Observatory, scientists took a detailed look at the plasma in a distant galaxy cluster and discovered the flow of plasma is much less viscous than expected and, therefore, turbulence occurs on relatively small scales – an important finding for our numerical models of the largest objects in the universe.

“High-resolution X-ray observations allowed us to learn some surprising truths about the viscosity of these plasmas,” said Irina Zhuravleva, an assistant professor of astrophysics and first author of the study, published June 17 in Nature Astronomy. “One might expect that variations in density that arise in the plasma are quickly erased by viscosity; however, we saw the opposite – the plasma finds ways to maintain them.”

Scattered around the universe are massive clusters of galaxies, some of them millions of light-years across containing thousands of galaxies. They sit in a type of plasma that we cannot recreate on Earth. It is extremely sparse – on the order of a sextillion times less dense than air on Earth – and has very weak magnetic fields, tens of thousands of times weaker than we experience on the Earth’s surface. To study this plasma, therefore, scientists must rely on cosmic laboratories such as clusters of galaxies.

Zhuravleva and the team chose a relatively nearby galaxy cluster called the Coma Cluster, a gigantic, bright cluster made up of more than 1,000 galaxies. They chose a less dense region away from the cluster center, where they hoped to be able to capture the average distance that particles travel between interactions with NASA’s Chandra X-ray Observatory. In order to build a high-quality map of the plasma, they observed the Coma cluster for almost 12 days – much longer than a typical observing run.

One thing that jumped out was how viscous the plasma was – how easily it’s stirred. “One could expect to see the viscosity resisting chaotic motions of plasma as we zoom in to smaller and smaller scales,” Zhuravleva said. But that didn’t happen; the plasma was clearly turbulent even on such small scales.

“It turned out that plasma behavior is more similar to the swirling motions of milk stirred in a coffee mug than the smoother ones that honey makes,” she said.

Such low viscosity means that microscopic processes in plasma cause small irregularities in the magnetic field, causing particles to collide more frequently and making the plasma less viscous. Alternately, Zhuravleva said, viscosity could be different along and perpendicular to magnetic field lines.

Understanding the physics of such plasmas is essential for improving our models of how galaxies and galaxy clusters form and evolve with time.

“It is exciting that we were able to use observations of clusters of galaxies to understand fundamental properties of intergalactic plasmas,” said Zhuravleva. “Our observations confirm that clusters are great laboratories that can sharpen theoretical views on plasmas.”

Other scientists on the study were affiliated with Stanford University, the Max Planck Institute for Astrophysics in Germany, the Space Research Institute in Russia, the University of Oxford, Niels Bohr International Academy, SLAC National Accelerator Laboratory, Harvard-Smithsonian Center for Astrophysics, Masaryk University, Eötvös Loránd University and Hiroshima University.

What Have We Learned from 20 Years of X-rays?

This year marks the 20th anniversary of two landmark missions: the Chandra X-ray Observatory, one of NASA’s Great Observatories, which launched July 23, 1999, and the X-ray Multi-Mirror mission (XMM-Newton), which launched a few months later on December 10th. Together, these satellites revolutionized X-ray astronomy, bringing it on par with astronomy at other wavelengths. We celebrate the history of X-ray astronomy in the August 2019 issue; here, we mark seven discoveries heralded by these two missions.

The Anatomy of a Supernova

To astronomers’ surprise, Chandra’s image of Cassiopeia A, the bloom of gas left over after a massive star went supernova some 340 years ago, revealed a star turned inside out. While massive stars fuse the heaviest elements in their cores and lighter elements in surrounding, onion-like layers, the Cas A explosion had flung clumps of iron to the outermost regions. The find suggests the star’s contents mixed together right before or after its core collapsed (or both).

Stellar Nurseries

XMM-Newton surveyed low-mass stars forming in the Taurus Molecular Cloud while Chandra examined massive stars coming together in the Orion Nebula. Most of the X-rays in these images, including the Chandra Ultra-deep Orion Project pictured above, come from young stars. In some cases interacting stellar winds from massive young stars produce the X-rays. The surveys have given astronomers a wealth of data on the newborn stars’ magnetic fields.

Black Hole Physics

With Chandra and XMM-Newton, astronomers could for the first time estimate black hole spin. By measuring how a black hole’s strong gravity smears the emissions from iron ions, astronomers can see how close the gas comes to the event horizon — the closer it comes, the faster the black hole is spinning. Astronomers have used this and other X-ray-based methods to gauge the spins of dozens of black holes.

Monitoring by Chandra and XMM-Newton has also shed light on the slumbering beast at the center of the Milky Way known as Sgr A*. While Sgr A* doesn’t seem to be devouring gas in the manner of the supermassive black holes that power distant quasars, it’s doing something that sets off roughly daily X-ray flares. Sometimes they’re accompanied by infrared sizzles, but other times the X-rays pop on their own. The flares may originate in snapping magnetic fields, the occasional ingestion of an asteroid, or something else entirely — the jury’s still out.

Jets of Change

The combination of X-ray and radio observations of galaxy clusters solved a long-term mystery: The hot gas between galaxies in clusters ought to cool over time, raining down on the clusters’ central galaxies and forming stars by the handful. But in many clusters astronomers haven’t found the expected stellar newborns. Turns out radio-emitting jets from the central galaxies’ supermassive black holes blow bubbles into the surrounding X-ray-emitting gas, sending out pressure waves that pump heat back into the surrounding medium, which prevents it from cooling. Astronomers soon realized that this concept of “black hole feedback” might affect everything from galaxy evolution to cosmology.

Extragalactic X-ray Background

From the launch of the Aerobee rocket in 1962, astronomers had known that the X-ray sky wasn’t dark, instead teeming with high-energy photons. The Einstein Observatory showed that supermassive black holes, too far away or faint to be seen individually, could explain this background. But it was Chandra that sharpened the view, resolving almost all of the background into its individual sources. Data from Chandra and XMM-Newton suggest that most of the sources that remain undetected are shrouded in gas and dust.

Hot Jupiters and Habitability

X-ray observations have provided direct evidence of star-planet interactions, such as when XMM-Newton caught flares from the HD 17156 system that appeared whenever the hot Jupiter came closest to its star. X-ray data also temper ideas of habitability: XMM-Newton observations revealed that high-energy radiation irradiates the three Earth-size planets in Trappist-1’s so-called habitable zone and has probably long ago stripped them of their atmospheres. Likewise, observations showed that Proxima Centauri b receives 250 times more X-rays from its star than Earth does from the Sun; its habitability, too, is uncertain.

Dark Matter, Dark Energy

Galaxy clusters have proven key to testing dark matter and understanding dark energy. X-ray observations first revealed the wildly hot gas within clusters — gas that would have drifted away if it weren’t for the cluster’s dark matter, which gravitationally holds it in place. Then, astronomers observed clusters dating back to when the universe was less than half its current age, estimating the growth of these huge structures over cosmic time. The result: solid evidence for the existence of dark energy and a unique way to gauge its density and equation of state.

 

Big Earthquakes Might Make Sea Level Rise Worse

A GEOLOGIC ONE-TWO punch rocked the South Pacific in September 2009, as a magnitude 8.1 earthquake struck off the coast of the island nation of Samoa, followed mere moments later by a similarly intense temblor. A towering tsunami soon crashed onto the shores of islands nearby, leaving more than 180 dead and communities in ruins in Samoa, the neighboring U.S. territory of American Samoa, and surrounding islands.

But a new study, published in the Journal of Geophysical Research: Solid Earth, reveals that the quakes also sparked a slow-burning danger for the more than 55,000 residents of American Samoa: sea level rise that is five times as fast as the global average.

Like other island and coastal regions around the world, Samoa and American Samoa are facing encroaching waters as our warming world sends sea levels soaring at accelerating rates. In the wake of the mega-quakes, though, the researchers discovered that these Pacific islands are also sinking. The situation is particularly concerning for American Samoa, where the team estimates that, over the next 50 to a hundred years, local sea levels could rise by roughly a foot in addition to the anticipated effects of climate change.

While the contributions of big earthquakes won’t be the same everywhere, the discovery emphasizes the sometimes overlooked effects that geology can have on the increasing number of people around the world who call coastlines home. (Also find out how powerful quakes are priming the region around Mount Everest for a huge disaster.)

“Everybody is talking about climate change issues … but they overlooked the impact of the earthquake and associated land subsidence,” says study leader Shin-Chan Han of the University of Newcastle, Australia, referring to documents from regional governments on sea level rise.

“This is a really important thing to point out,” says geophysicist Laura Wallace of the geoscience consultancy firm GNS Science, Te Pū Ao, in New Zealand, who was not involved in the study. “It obviously has a big impact on the relative sea level changes people are going to see in places like [the Samoan islands].”

Geologic geometry

Plate tectonics is constantly reshaping the surface of our planet—a role particularly evident during an earthquake. Generally speaking, these events occur where tectonic plates are colliding or sliding against each other, building up geologic stress. When that pent-up energy is released suddenly, it can send blocks of the planet’s crust careening out of place. (Find out how smaller “hidden” earthquakes are affecting California.)

But not all the change from a big earthquake is immediate. Unlike the rigid crust, the rocks of the mantle below flow like cold molasses and gradually adjust to the sudden surface jolt, Wallace says. This can cause either sinking or uplift of the land that can continue for decades after a temblor strikes.

This prolonged landscape deformation is what intrigues Han. For years, he’s scoured data from the Gravity Recovery and Climate Experiment, or GRACE, satellites to hunt for the rise and fall of land after a quake. This satellite duo orbited Earth in a line from 2002 to 2017 and precisely tracked the gap between the spacecraft. As they passed over zones with slightly more mass, and thus stronger gravity, the leading craft would feel the tug just before the trailing one. This tweaked the space in between and registered as a wobble in the planet’s gravitational field that can reveal changes in the landmass below.

In the case of the 2009 earthquake, such changes were minute on a day-to-day basis. But eventually, the effects were large enough that Han saw something strange happening in the Samoan islands while poring over the GRACE data.

A rare coincidence

The 2009 event was a particularly unusual earthquake that initially baffled scientists, since the pair of powerful temblors ripped through the Earth nearly at the same time. One broke along a so-called normal fault, created due to the flex of the oceanic crust as it plunges under another tectonic plate in what’s known as a subduction zone. Another quake broke within the subduction zone due to the compressive forces of the colliding plates.

The researchers investigated the lingering impacts of these quakes using a combination of GRACE data and local GPS and tide gauge records. They then built a computer model to tease apart the complex interplay between the temblors and what is happening at the surface.

This data showed slow sinking of the landscape, driven primarily by the normal-fault quake. This particular earthquake causes one side of the landscape to fall in relation to the other, which sent the nearby islands sinking downward.

The team found that nearly a decade after the event, the island of Samoa has sunk by roughly 0.4 inches a year. The situation is particularly acute for American Samoa, which has seen more than 0.6 inches of subsidence each year, and it doesn’t look like it’s stopping anytime soon.

The pace outstrips the estimated rate of global sea level rise, which is creeping upward at some 0.13 inches a year. Flooding and seawater intrusion in freshwater aquifers are already grave concerns for residents of American Samoa, Han says, and the latest find only adds to the worry.

Bathtub oceans

This latest study emphasizes the need for greater awareness and continued monitoring to mitigate the potential effects of mega-quakes, Wallace says. However, predicting such sea level effects before an earthquake strikes is not feasible, since earthquake prediction itself remains elusive.

“This might be a problem that suddenly causes you heartburn next week,” Freymueller says, “or it might not cause any problem for the next century.”

This latest study emphasizes the need for greater awareness and continued monitoring to mitigate the potential effects of mega-quakes, Wallace says. However, predicting such sea level effects before an earthquake strikes is not feasible, since earthquake prediction itself remains elusive.

“This might be a problem that suddenly causes you heartburn next week,” Freymueller says, “or it might not cause any problem for the next century.”

Site Of Biggest Ever Meteorite Collision In The UK Discovered

Scientists believe they have discovered the site of the biggest meteorite impact ever to hit the British Isles.

Evidence for the ancient, 1.2 billion years old, meteorite strike, was first discovered in 2008 near Ullapool, NW Scotland by scientists from Oxford and Aberdeen Universities. The thickness and extent of the debris deposit they found suggested the impact crater — made by a meteorite estimated at 1km wide — was close to the coast, but its precise location remained a mystery.

In a paper published today in Journal of the Geological Society, a team led by Dr Ken Amor from the Department of Earth Sciences at Oxford University, show how they have identified the crater location 15-20km west of a remote part of the Scottish coastline. It is buried beneath both water and younger rocks in the Minch Basin.

Dr Ken Amor said: ‘The material excavated during a giant meteorite impact is rarely preserved on Earth, because it is rapidly eroded, so this is a really exciting discovery. It was purely by chance this one landed in an ancient rift valley where fresh sediment quickly covered the debris to preserve it.

‘The next step will be a detailed geophysical survey in our target area of the Minch Basin.’

Using a combination of field observations, the distribution of broken rock fragments known as basement clasts and the alignment of magnetic particles, the team was able to gauge the direction the meteorite material took at several locations, and plotted the likely source of the crater.

Dr Ken Amor said: ‘It would have been quite a spectacle when this large meteorite struck a barren landscape, spreading dust and rock debris over a wide area.’

1.2 billion years ago most of life on Earth was still in the oceans and there were no plants on the land. At that time Scotland would have been quite close to the equator and in a semi-arid environment. The landscape would have looked a bit like Mars when it had water at the surface.

Earth and other planets may have suffered a higher rate of meteorite impacts in the distant past, as they collided with debris left over from the formation of the early solar system.

However, there is a possibility that a similar event will happen in the future given the number of asteroid and comet fragments floating around in the solar system. Much smaller impacts, where the meteorite is only a few meters across are thought to be relatively common perhaps occurring about once every 25 years on average.

It is thought that collisions with an object about 1 km (as in this instance) across occur between once every 100,000 years to once every one million years — but estimates vary.

One of the reasons for this is that our terrestrial record of large impacts is poorly known because craters are obliterated by erosion, burial and plate tectonics.

Part VII – Coming Back Around to Earth’s Magnetic Reversal

New findings suggest a series of current events are weakening the Earth’s magnetic field. Above the liquid outer core is the mantle – made up of viscous rock composition which can be molded or shaped due to intense heat and high pressure, this is called convection. At the boundary between Earth’s core and mantle there is an intense heat exchange – this is called convection.

What creates Earth’s magnetic field is the process through which a rotating, convecting, and electrically conducting fluid which makes up the geodynamo mechanism. Recent studies indicate a slow flowing solid mantle and its reciprocal connection with a hot fast flowing outer core – is the central focus of Earth’s magnetic field weakening. The outcome of this convection between Earth’s outer core and mantle is the production of mantle plumes and the formation of fluid ‘crystallization’. Mantle plumes are a reaction to the Earth’s dipole magnetic core acting as a thermostat.

As a result of a weakened magnetic field coupled with a deep solar minimum, is allowing an alarming amount of galactic cosmic rays to enter our planets environment. In a paper published in the journal American Geophysical Union (AGU) Space Weather, associate professor Nathan Schwadron of the UNH Institute for the Study of Earth, Oceans, and Space (EOS) and the department of physics; says that due to this solar cycles vast drop in solar activity, a stream of cosmic ray particles are flooding Earth’s atmosphere – and further driving in and through Earth’s core.

Additionally, a major consequence of a weakened magnetic field, in conjunction with an inundation of space radiation, allows for the redistribution of gas and fluids which could contribute to Earth’s tilt and wobble. It is this action/reaction which could affect the convection process allowing for the north/south magnetic field lines to bounce around northern latitudes. This is known as geomagnetic excursion.

My research suggests radiation produced by GCRs has a significant influence on Earth’s core by increasing temperatures. In viewing Earth as a living entity, a natural reaction to overheating would be to find a way to cool down. And that’s exactly what Earth does. When our planet becomes overheated…it sweats. Yes, just like us humans when we get overheated, we sweat through our pores. When Earth becomes overheated it sweats through its pores called ‘mantle plumes’. Earth, just like humans is always seeking to maintain its ambient temperature.

In relation to this current moderate-term cycle i.e. 20,000-40,000 years – in conjunction with this long-term cycle i.e. 22myr -60myr (million years) my study’s identify a pattern of a weakening magnetic field, and influx of highly charged particles sets up the perfect conditions to produce a magnetic excursion followed by a magnetic reversal.

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Part – VIII How Far Along Are We In This Cycle?