SpaceTime with Stuart Gary

Video

Wed, 24 Jan 2018 18:56:39 +1100

SpaceTime 20180124 Series 21 Episode 06 is now out SpaceTime...

Wed, 24 Jan 2018 18:53:51 +1100

SpaceTime 20180124 Series 21 Episode 06 is now out

SpaceTime covers the latest news in astronomy & space sciences.

The show is available as a free twice weekly podcast through Apple Podcasts (itunes), Stitcher, Pocketcasts, SoundCloud, Bitez.com, YouTube, Audio Boom, your favourite podcast download provider, and from www.spacetimewithstuartgary.com

SpaceTime is also broadcast coast to coast across the United States on Science360 Radio by the National Science Foundation in Washington D.C. around the world on Tune-In Radio and as inflight entertainment aboard Virgin Australia

SpaceTime daily news blog: http://spacetimewithstuartgary.tumblr.com/
SpaceTime facebook: www.facebook.com/spacetimewithstuartgary
SpaceTime Instagram @spacetimewithstuartgary
SpaceTime twitter feed @stuartgary

Today’s stories…

Setting a size limit on neutron stars
A new study claims super dense stellar corpses known as neutron stars couldn’t get much bigger than twice the mass of the Sun. The findings solve a forty year old mystery that’s baffled scientists ever since neutron stars were first discovered.

New clues about the recipe for making stars
Astronomers have shed fresh light on the importance of hydrogen atoms in the birth of new stars. Only hydrogen molecules are thought to directly fuel star formation. But new research shows there are more hydrogen atoms than molecules even in young galaxies that are making a lot of new stars.

Midwest Meteor
The citizenry of the American mid-west have been treated to an unexpected celestial spectacular with the evening skies lit up by a bright meteor and sonic boom. People in the states of Ohio and Michigan and across the border in Ontario Canada witnessed the event around 8’0 clock local time.

No link between earthquakes and the full Moon
A new study has provided more evidence to dispel an enduring myth that large earthquakes tend to happen during certain phases of the Moon or at certain times during the year. The findings confirm that this bit of earthquake lore is incorrect.

Titan has a sea level just like Earth
A new study has confirmed that just like Earth – Saturn’s moon Titan has a sea level. The discovery adds to a growing list of similarities between Earth has this hostile alien world.

The Science Report
2017 confirmed as one of the three warmest years on record.
Atmospheric CO2 levels pass a record 410 parts per million
New blood test capable of detecting eight of the most common cancers.
The war in Syria has entered new phase with Russian troops coming under attack from armed drones.
Finding what crops grow best in the soils of Mars.
Sneezing hard enough to punch a hole in your throat.
Alex on tech wraps up CES

SpaceTime Background
SpaceTime is Australia’s most respected astronomy and space science news program. The show reports on the latest stories and discoveries making news in astronomy, astrophysics, cosmology, planetary science, galactic and stellar evolution, physics, spaceflight, and general science. SpaceTime features interviews with leading Australian scientists about their latest research. The show is broadcast coast to coast across the United States by the National Science Foundation on Science360 Radio, and is available in Australia as a twice weekly podcast which averages around three million downloads annually. It’s hosted through Bitez.com on all major podcast platforms. SpaceTime is also available as inflight entertainment on Virgin Australia Airlines and on Tune in Radio. The SpaceTime program began life in 1995 as ‘StarStuff’ on ABC NewsRadio. Stuart Gary created the show while he was NewsRadio’s Science Editor and evening News anchor. Gary wrote, produced and hosted the program, consistently achieving almost 9 percent of the Australian national radio audience share - according to the Neilsen ratings survey figures for the five major Australian metro markets (Sydney, Melbourne, Brisbane, Adelaide, & Perth). The StarStuff podcast was hosted by ABC Science on line achieving over 1.3 million downloads annually. The program was axed in 2015 following ABC budget cuts. Gary resigned from the ABC, taking the show and audience with him and rebranding it as SpaceTime. The first SpaceTime episode was broadcast on February 8th 2016 and the show has been in production twice weekly ever since.

spacetimewithstuartgary: SpaceTime with Stuart Gary now has its...

Wed, 24 Jan 2018 18:43:04 +1100

spacetimewithstuartgary:

SpaceTime with Stuart Gary now has its own online shop at
http://www.cafepress.com/spacetime

Phoning in earthquakes

Wed, 24 Jan 2018 18:38:46 +1100

Phoning in earthquakes:

sciencenewsforstudents:

At 3:20 a.m. on August 24, 2014 — not quite a year ago — a strong earthquake rocked the northern California town of Napa. It sparked fires. Historic buildings crumbled. And more than 200 people were hurt. This region had not experienced ground shaking that powerful in nearly a quarter-century.

Less than one minute later, about 38 kilometers (24 miles) south of the Napa quake’s underground origin, or epicenter, the quake’s waves reached the city of Berkeley. There, the waves swayed the apartment building where Qingkai Kong lay asleep.

Kong studies earthquake detection systems at the University of California, Berkeley. For this graduate student, the Napa quake was real — and a test. Bleary-eyed, Kong stumbled out of bed and glanced at an instrument on his desk. He saw the familiar flurry of jagged lines that signal an earthquake had occurred.

For many years, the only instruments that could provide that kind of information cost thousands of dollars. This instrument was different: It was Kong’s Android smartphone.

Kong’s phone was running MyShake. This software application — or app — uses the inexpensive sensors in mobile devices to record ground movements. The squiggly waveforms of the Napa quake captured on his phone looked quite similar to those recorded by a nearby scientific sensor, Kong told Science News for Students.

As technological advances make smartphones ever smarter, researchers are enlisting the owners of these popular devices to help study earthquakes. Similar projects are placing portable sensors in homes, schools and offices.

exploremars: A seven-member crew, made up of current and former...

Wed, 24 Jan 2018 18:37:16 +1100

exploremars:

A seven-member crew, made up of current and former @lifeatpurdue students, was selected by Purdue’s chapter of @themarssociety in February to undertake a mission at the @marsdesertresearchstation located near Hanksville, Utah. The crew, known as Boilers2Mars, began its mission on Jan. 1 and concluded its research on Jan. 13. Built in 2001, the #MDRS campus includes a close-quartered living habitat, two observatories, a repair module and a greenhouse. It serves as a resource for #research on how space exploration organizations might establish a sustained presence on the planet after arrival.

The crew was sponsored by a variety of groups here at Purdue, including the School of Aeronautics and Astronautics, the Purdue Engineering Student Council and the department of Earth, Atmospheric and Planetary Sciences.

Source: @purdueexponent

https://www.purdueexponent.org/campus/article_9714dd94-0070-11e8-b198-ab30951dcf24.html

#SimulateMars #HumansToMars #JourneyToMars

4gifs: Dude get up it’s playtime! Oh shi- [video]

Wed, 24 Jan 2018 18:36:41 +1100

4gifs:

Dude get up it’s playtime! Oh shi- [video]

mapsontheweb:Indigenous Australians as percentage of the...

Wed, 24 Jan 2018 18:35:54 +1100

mapsontheweb:

Indigenous Australians as percentage of the population, 2011.

Researchers discover that female cats are more likely to be...

Wed, 24 Jan 2018 18:27:02 +1100

Researchers discover that female cats are more likely to be right-handed

Researchers at Queen’s University Belfast have found that female cats are much more likely to use their right paw than males.

Dr Louise McDowell, Dr Deborah Wells and Professor Peter Hepper from the School of Psychology at Queen’s, recruited 44 cats for the study and found that while there was no overall population preference like the human preference for right handedness, there was a gender preference. The findings have been published in Animal Behaviour.

Until now, studies on limb preference of animals have focused solely on forced experimental challenges. However, in the Queen’s study, the cats - 24 male and 20 female and all neutered - were studied in their own homes so that information could be gathered as they went about their everyday tasks.

The cat owners collected “spontaneous” data on whether the cats used their left or right paws when they stepped down the stairs or over objects and whether they slept on the left or right side of their body. A “forced” test was also carried out where the cats had to reach for food inside a three-tier feeding tower.

The majority of cats showed a paw preference when reaching for food (73%), stepping down (70%) and stepping over (66%) and their preference for right and left was consistent for the majority of the tasks, both spontaneous and forced. In all cases, male cats showed a significant preference for using their left paw, while females were more inclined to use their right paw. However, when sleeping the cats did not appear to have a side preference.

Dr Deborah Wells says that while there is further research needed to investigate why there is a gender preference, it could be down to hormones. She comments: “The findings point more and more strongly to underlying differences in the neural architecture of male and female animals.”

The Queen’s University researcher also explains that the findings could help cat owners to understand how their pet deals with stress. “Beyond mere curiosity, there may be value to knowing the motor preference of one’s pet. There is some suggestion that limb preference might be a useful indicator of vulnerability to stress. Ambilateral animals with no preference for one side or the other, and those that are more inclined to left-limb dominance, for example, seem more flighty and susceptible to poor welfare than those who lean more heavily towards right limb use,” says Dr Wells.

She adds: “We have just discovered that left-limbed dogs, for example, are more pessimistic in their outlook than right-limbed dogs. From a pet owner’s perspective, it might be useful to know if an animal is left or right limb dominant, as it may help them gauge how vulnerable that individual is to stressful situations.”

IMAGE….Researchers at Queen’s University Belfast have found that female cats are much more likely to use their right paw than males.
Credit Queen’s University Belfast

First hot firing of Ariane 6’s Vulcain engine The first hot...

Wed, 24 Jan 2018 17:54:13 +1100

First hot firing of Ariane 6’s Vulcain engine

The first hot firing of Ariane 6’s Vulcain 2.1 main engine has been performed at the DLR German Aerospace Center test facility in Lampoldshausen, Germany.

Further tests will examine the ignition conditions, and the behaviour and performance of the engine and its different subsystems.

The engine, developed by ArianeGroup, has a simplified and more robust nozzle, a gas generator made through additive manufacturing, and an oxygen heater for oxygen tank pressurisation. These features lower the cost of the engine and simplify manufacturing.

During this year, three Vulcain test campaigns in Germany and France will help engineers to decide whether adjustments are needed to optimise the functional, thermal and mechanical behaviour, before the start of combined tests.

In parallel, more than 130 test firings on the Vinci engine powering Ariane 6’s upper stage have been carried out. These tests, in particular, have verified Vinci’s multiple ignition capabilities. Tests have used the P41 stand at DLR in Lampoldshausen and the PF52 stand at the ArianeGroup site in Vernon, France.

CubeSats for hunting secrets in lunar darkness Imagine sending...

Wed, 24 Jan 2018 17:52:22 +1100

CubeSats for hunting secrets in lunar darkness

Imagine sending a spacecraft the size of an airline cabin bag to the Moon – what would you have it do? ESA issued that challenge to European teams last year, and two winners have now been chosen.

The Lunar Meteoroid Impact Orbiter, or Lumio for short, would circle over the far side of the Moon to detect bright impact flashes during the lunar night, mapping meteoroid bombardments as they occur.

The other, the Lunar Volatile and Mineralogy Mapping Orbiter, or VMMO, would focus on a permanently shadowed crater near the lunar south pole, searching out deposits of water ice and other volatiles of interest to future colonists, while also measuring lunar radiation.

“It was a difficult process to select these final winners, because the high quality of all the concept studies we received – and especially our four semi-finalists,” explains Roger Walker, ESA’s technology CubeSat manager.

European companies, universities and research centres teamed up to design lunar missions to fit within the low-cost CubeSat standard – built up from 10 cm- cubes.

Roger adds: “The idea behind our lunar CubeSat competition was challenging – up until now CubeSats have operated solely within Earth orbit. However, opportunities should open up to piggyback to the Moon in the coming decade, with circumlunar flights of the NASA–ESA Orion spacecraft and planned commercial flights.”

The two winners were chosen after final presentations within ESA’s advanced multimedia centre used to design all Agency missions. They now have the chance to work with ESA specialists on mission development during February and March.

The impact-tracking Lumio is a single 12-unit CubeSat, conceived by a consortium including Politecnico di Milano; TU Delft, EPFL, S[&]T Norway, Leonardo-Finnmeccanica and the University of Arizona.

Orbiting a special point in space, Lumio’s sophisticated optical camera would detect impacts on the Moon’s far side. Such near-side flashes are mapped by telescopes on Earth during the night, but the Moon’s other face is a blind spot.

Away from the stray light of the terrestrial environment, very faint flashes should be detectable, improving our understanding of past and present meteoroid patterns across the Solar System. Such an observation system could also develop into a system offering early warning to future settlers.

VMMO, developed by MPB Communications Inc, Surrey Space Centre, University of Winnipeg and Lens R&D, also adopts a 12-unit CubeSat design. Its miniaturised laser would probe its primary target of Shackleton Crater, adjacent to the South Pole, for measuring the abundance of water ice. The region inside the crater is in permanent darkness, allowing water molecules to condense and freeze there in the very cold conditions.

Scanning a 10 m-wide path, VMMO would take around 260 days to build a high-resolution map of water ice inside the 20 km-diameter crater. Its laser would also beam high-bandwidth data back to Earth through an optical communications experiment.

VMMO would also map lunar resources such as minerals as it overflew sunlit regions, as well as monitoring the distribution of ice and other volatiles across darkened areas to gain understanding of how condensates migrate across the surface during the two-week lunar night.

A secondary radiation-detecting payload would build up a detailed model of the radiation environment for the benefit of follow-on mission hardware – as well as human explorers.

“This competition – run through ESA’s SysNova Challenge scheme – has helped to bring together lunar and CubeSat specialists,” adds ESA’s Ian Carnelli. “This means Europe’s space sector should be more able to take advantages of such flight opportunities as they arise in future.”

The runner-up missions were the radiation-analysing MoonCARE and the far-side radio astronomy CLE.

TOP IMAGE….The Lunar Meteoroid Impact Orbiter, or Lumio for short, would circle over the far side of the Moon to detect bright impact flashes during the lunar night, mapping meteoroid bombardments as they occur.

CENTRE IMAGE….Lunar south pole

LOWER IMAGE….Hunting for ice The Volatile and Mineralogy Mapping Orbiter, VMMO, developed by MPB Communications Inc, Surrey Space Centre, University of Winnipeg and Lens R&D would comprise a single 12-unit CubeSat to map lunar surface minerals and frozen volatiles including water ice to 10 m resolution using a ‘laser radar’ lidar able to peer into shadowed regions at the poles. VMMO was one of the two winners of an ESA General Studies Programme SysNova contest to design CubeSat missions to the Moon. Copyright ESA

Columbus to scale The focus of this image is the suspended...

Wed, 24 Jan 2018 17:47:11 +1100

Columbus to scale

The focus of this image is the suspended European Columbus module being moved onto a work stand in a cleanroom at the Kennedy Space Center in Florida, USA.

Of course, a cylindrical module of more than 10 t (without payloads) for housing laboratory equipment, storage units and three working astronauts is big, but the contrast between Columbus and the people in the image is startling. Even more so when we remember that Columbus is one of 16 similarly sized modules orbiting 400 km over our heads.

Countless teams across Europe were involved in the planning, building and assembly of the parts that make up this orbital lab. Teams of people were involved in shipping Columbus across the Atlantic, where it was carefully received by even more partners in the greatest human endeavour.

This image of Columbus was taken in the summer of 2006, shortly after the module arrived at the launch site. Teams at NASA put Columbus through its final paces to ensure it was airtight and ready for flight.

It would be another year and half before Columbus made its way to the International Space Station, in 2008. Ten remarkable years later, there is much to celebrate about this long-planned and hard-earned European contribution to the international space community.

SYMMETRY MAGAZINE Neural networks for neutrinos...

Wed, 24 Jan 2018 17:45:27 +1100

SYMMETRY MAGAZINE

Neural networks for neutrinos

01/23/18

|By Diana Kwon

Scientists are using cutting-edge machine-learning techniques to analyze physics data.

Particle physics and machine learning have long been intertwined.

One of the earliest examples of this relationship dates back to the 1960s, when physicists were using bubble chambers to search for particles invisible to the naked eye. These vessels were filled with a clear liquid that was heated to just below its boiling point so that even the slightest boost in energy—for example, from a charged particle crashing into it—would cause it to bubble, an event that would trigger a camera to take a photograph.

Female scanners often took on the job of inspecting these photographs for particle tracks. Physicist Paul Hough handed that task over to machines when he developed the Hough transform, a pattern recognition algorithm, to identify them.

The computer science community later developed the Hough transform for use in applications such as computer vision, attempts to train computers to replicate the complex function of a human eye.

“There’s always been a little bit of back and forth” between these two communities, says Mark Messier, a physicist at Indiana University.

Since then, the field of machine learning has rapidly advanced. Deep learning, a form of artificial intelligence modeled after the human brain, has been implemented for a wide range of applications such as identifying faces, playing video games and even synthesizing life-like videos of politicians.

Over the years, algorithms that help scientists pick interesting aberrations out of background data have been used in physics experiments such as BaBar at SLAC National Accelerator Laboratory and experiments at the Large Electron-Positron Collider at CERN and the Tevatron at Fermi National Accelerator Laboratory. More recently, algorithms that learn to recognize patterns in large datasets have been handy for physicists studying hard-to-catch particles called neutrinos.

This includes scientists on the NOvA experiment, who study a beam of neutrinos created at the US Department of Energy’s Fermilab near Chicago. The neutrinos stream straight through Earth to a 14,000-metric-ton detector filled with liquid scintillator sitting near the Canadian border in Minnesota.

When a neutrino strikes the liquid scintillator, it releases a burst of particles. The detector collects information about the pattern and energy of those particles. Scientists use that information to figure out what happened in the original neutrino event.

“Our job is almost like reconstructing a crime scene,” Messier says. “A neutrino interacts and leaves traces in the detector—we come along afterward and use what we can see to try and figure out what we can about the identity of the neutrino.”

Over the last few years, scientists have started to use algorithms called convolutional neural networks (CNNs) to take on this task instead.

CNNs, which are modelled after the mammalian visual cortex, are widely used in the technology industry—for example, to improve computer vision for self-driving cars. These networks are composed of multiple layers that act somewhat like filters: They contain densely interconnected nodes that possess numerical values, or weights, that are adjusted and refined as inputs pass through.

“The ‘deep’ part comes from the fact that there are many layers to it,” explains Adam Aurisano, an assistant professor at the University of Cincinnati. “[With deep learning] you can take nearly raw data, and by pushing it through these stacks of learnable filters, you wind up extracting nearly optimal features.”

For example, these algorithms can extract details associated with particle interactions of varying complexity from the “images” collected by recording different patterns of energy deposits in particle detectors.

“Those stacks of filters have sort of sliced and diced the image and extracted physically meaningful bits of information that we would have tried to reconstruct before,” Aurisano says.

Although they can be used to classify events without recreating them, CNNs can also be used to reconstruct particle interactions using a method called semantic segmentation.

When applied to an image of a table, for example, this method would reconstruct the object by tagging each pixel associated with it, Aurisano explains. In the same way, scientists can label each pixel associated with characteristics of neutrino interactions, then use algorithms to reconstruct the event.

Physicists are using this method to analyze data collected from the MicroBooNE neutrino detector.

“The nice thing about this process is that you might find a cluster that’s made by your network that doesn’t fit in any interpretation in your model,” says Kazuhiro Terao, a scientist at SLAC National Accelerator Laboratory. “That might be new physics. So we could use these tools to find stuff that we might not understand.”

Scientists working on other particle physics experiments, such as those at the Large Hadron Collider at CERN, are also using deep learning for data analysis.

“All these big physics experiments are really very similar at the machine learning level,” says Pierre Baldi, a computer scientist at the University of California, Irvine. “It’s all images associated with these complex, very expensive detectors, and deep learning is the best method for extracting signal against some background noise.”

Although most of the information is currently flowing from computer scientists to particle physicists, other communities may also gain new tools and insights from these experimental applications as well.

For example, according to Baldi, one question that’s currently being discussed is whether scientists can write software that works across all these physics experiments with a minimal amount of human tuning. If this goal were achieved, it could benefit other fields, such a biomedical imaging, that use deep learning as well. “[The algorithm] would look at the data and calibrate itself,” he says. “That’s an interesting challenge for machine learning methods.”

Another future direction, Terao says, would be to get machines to ask questions—or, more simply, to be able to identify outliers and try to figure out how to explain them.

“If the AI can form a question and come up with a logical sequence to solve it, then that replaces a human,” he says. “To me, the kind of AI you want to see is a physics researcher—one that can do scientific research.”

TRAPPIST-1 SYSTEM PLANETS POTENTIALLY HABITABLE Two exoplanets...

Wed, 24 Jan 2018 17:43:31 +1100

TRAPPIST-1 SYSTEM PLANETS POTENTIALLY HABITABLE

Two exoplanets in the TRAPPIST-1 system have been identified as most likely to be habitable, a paper by PSI Senior Scientist Amy Barr says.

The TRAPPIST-1 system has been of great interest to observers and planetary scientists because it seems to contain seven planets that are all roughly Earth-sized, Barr and co-authors Vera Dobos and Laszlo L. Kiss said in “Interior Structures and Tidal Heating in the TRAPPIST-1 Planets” that appears in Astronomy & Astrophysics.

“Because the TRAPPIST-1 star is very old and dim, the surfaces of the planets have relatively cool temperatures by planetary standards, ranging from 400 degrees Kelvin (260 degrees Fahrenheit), which is cooler than Venus, to 167 degrees Kelvin (-159 degrees Fahrenheit), which is colder than Earth’s poles,” Barr said. “The planets also orbit very close to the star, with orbital periods of a few days. Because their orbits are eccentric – not quite circular – these planets could experience tidal heating just like the moons of Jupiter and Saturn.”

“Assuming the planets are composed of water ice, rock, and iron, we determine how much of each might be present, and how thick the different layers would be. Because the masses and radii of the planets are not very well-constrained, we show the full range of possible interior structures and interior compositions.” Barr said. The team’s results show that improved estimates of the masses of each planet can help determine whether each of the planets has a significant amount of water.

The planets studied are referred to by letter, planets b through h, in order of their distance from the star. Analyses performed by co-author Vera Dobos show that planets d and e are the most likely to be habitable due to their moderate surface temperatures, modest amounts of tidal heating, and because their heat fluxes are low enough to avoid entering a runaway greenhouse state. A global water ocean likely covers planet d.

The team calculated the balance between tidal heating and heat transport by convection in the mantles of each planet. Results show that planets b and c likely have partially molten rock mantles. The paper also shows that planet c likely has a solid rock surface, and could have eruptions of silicate magmas on its surface driven by tidal heating, similar to Jupiter’s moon Io.

Photo

Wed, 24 Jan 2018 17:41:31 +1100

Celebrating 60 Years of America in Space on Jan. 31 America...

Wed, 24 Jan 2018 17:21:16 +1100

Celebrating 60 Years of America in Space on Jan. 31

America became a space-faring nation with the launch of the Explorer 1 satellite on Jan. 31, 1958.

Late in the evening of Jan. 31, 1958, the United States took its first step into space with the launch of the Explorer 1 satellite from Cape Canaveral, Florida. The slender, 30-pound satellite would yield a major scientific discovery – the Van Allen radiation belts circling our planet – and ushered in six decades of groundbreaking U.S. space science and human exploration.

In commemoration of this achievement, NASA is supporting events in Florida, California, and Washington, D.C., to mark the 60th anniversary of the launch. The Florida event provides media with the opportunity to visit the historic Explorer 1 launch complex at Cape Canaveral Air Force Station.

Anniversary events spotlight the historical significance of the Explorer 1 mission, the legacy of scientific accomplishments produced by America’s space program, and NASA’s continuing journey of discovery in space.

THREE TYPES OF EXTREME-ENERGY SPACE PARTICLES MAY HAVE UNIFIED...

Wed, 24 Jan 2018 17:17:37 +1100

THREE TYPES OF EXTREME-ENERGY SPACE PARTICLES MAY HAVE UNIFIED ORIGIN

** Synopsis: New model connects the origins of very high-energy neutrinos, ultrahigh-energy cosmic rays, and high-energy gamma rays with black-hole jets embedded in their environments. **

One of the biggest mysteries in astroparticle physics has been the origins of ultrahigh-energy cosmic rays, very high-energy neutrinos, and high-energy gamma rays. Now, a new theoretical model reveals that they all could be shot out into space after cosmic rays are accelerated by powerful jets from supermassive black holes and they travel inside clusters and groups of galaxies.

The model explains the natural origins of all three types of “cosmic messenger” particles simultaneously, and is the first astrophysical model of its kind based on detailed numerical computations. A scientific paper that describes this model, produced by Penn State and University of Maryland scientists, was published as an Advance Online Publication on the website of the journal Nature Physics on January 22, 2018.

“Our model shows a way to understand why these three types of cosmic messenger particles have a surprisingly similar amount of power input into the universe, despite the fact that they are observed by space-based and ground-based detectors over ten orders of magnitude in individual particle energy,” said Kohta Murase, assistant professor of physics and astronomy and astrophysics at Penn State. “The fact that the measured intensities of very high-energy neutrinos, ultrahigh-energy cosmic rays, and high-energy gamma rays are roughly comparable tempted us to wonder if these extremely energetic particles have some physical connections. The new model suggests that very high-energy neutrinos and high-energy gamma rays are naturally produced via particle collisions as daughter particles of cosmic rays, and thus can inherit the comparable energy budget of their parent particles. It demonstrates that the similar energetics of the three cosmic messengers may not be a mere coincidence.”

Ultrahigh-energy cosmic rays are the most energetic particles in the universe – each of them carries an energy that is too high to be produced even by the Large Hadron Collider, the most powerful particle accelerator in the world. Neutrinos are mysterious and ghostly particles that hardly ever interact with matter. Very high-energy neutrinos, with energy more than one million mega-electron-volts, have been detected in the IceCube neutrino observatory in Antarctica. Gamma rays have the highest-known electromagnetic energy – those with energies more than a billion times higher than a photon of visible light have been observed by the Fermi Gamma-ray Space Telescope and other ground-based observatories. “Combining all information on these three types of cosmic messengers is complementary and relevant, and such a multi-messenger approach has become extremely powerful in the recent years,” Murase said.

Murase and the first author of this new paper, Ke Fang, a postdoctoral associate at the University of Maryland, attempt to explain the latest multi-messenger data from very high-energy neutrinos, ultrahigh-energy cosmic rays, and high-energy gamma rays, based on a single but realistic astrophysical setup. They found that the multi-messenger data can be explained well by using numerical simulations to analyze the fate of these particles.

“In our model, cosmic rays accelerated by powerful jets of active galactic nuclei escape through the radio lobes that are often found at the end of the jets,” Fang said. “Then we compute the cosmic-ray propagation and interaction inside galaxy clusters and groups in the presence of their environmental magnetic field. We further simulate the cosmic-ray propagation and interaction in the intergalactic magnetic fields between the source and the Earth. Finally we integrate the contributions from all sources in the universe.”

The leading suspects in the half-century old mystery of the origin of the highest-energy cosmic particles in the universe were in galaxies called “active galactic nuclei,” which have a super-radiating core region around the central supermassive black hole. Some active galactic nuclei are accompanied by powerful relativistic jets. High-energy cosmic particles that are generated by the jets or their environments are shot out into space almost as fast as the speed of light.

“Our work demonstrates that the ultrahigh-energy cosmic rays escaping from active galactic nuclei and their environments such as galaxy clusters and groups can explain the ultrahigh-energy cosmic-ray spectrum and composition. It also can account for some of the unexplained phenomena discovered by ground-based experiments,” Fang said. “Simultaneously, the very high-energy neutrino spectrum above one hundred million mega-electron-volts can be explained by particle collisions between cosmic rays and the gas in galaxy clusters and groups. Also, the associated gamma-ray emission coming from the galaxy clusters and intergalactic space matches the unexplained part of the diffuse high-energy gamma-ray background that is not associated with one particular type of active galactic nucleus.”

“This model paves a way to further attempts to establish a grand-unified model of how all three of these cosmic messengers are physically connected to each other by the same class of astrophysical sources and the common mechanisms of high-energy neutrino and gamma-ray production,” Murase said. “However, there also are other possibilities, and several new mysteries need to be explained, including the neutrino data in the ten-million mega-electron-volt range recorded by the IceCube neutrino observatory in Antarctica. Therefore, further investigations based on multi-messenger approaches – combining theory with all three messenger data – are crucial to test our model.”

The new model is expected to motivate studies of galaxy clusters and groups, as well as the development of other unified models of high-energy cosmic particles. It is expected to be tested rigorously when observations begin to be made with next-generation neutrino detectors such as IceCube-Gen2 and KM3Net, and the next-generation gamma-ray telescope, Cherenkov Telescope Array.

“The golden era of multi-messenger particle astrophysics started very recently,” Murase said. “Now, all information we can learn from all different types of cosmic messengers is important for revealing new knowledge about the physics of extreme-energy cosmic particles and a deeper understanding about our universe.”

IMAGE….This image illustrates the “multi-messenger’’ emission from a gigantic reservoir of cosmic rays that are accelerated by powerful jets from a supermassive black hole. The high-energy cosmic rays escaping from the black hole’s active galactic nucleus are trapped in the magnetized environment that serves as a reservoir of cosmic rays. The high-energy neutrinos and gamma rays are produced in the magnetized environment during their confinement and in the intergalactic space during their propagation. The ultrahigh-energy cosmic rays, high-energy neutrinos, and gamma rays eventually reach the Earth, where they can give us a unified picture of all three cumulative fluxes of the cosmic particles. Credit: Kanoko Horio

Explorer 1: The Beginning of American Space Science Sixty years...

Wed, 24 Jan 2018 16:58:53 +1100

Explorer 1: The Beginning of American Space Science

Sixty years ago next week, the hopes of Cold War America soared into the night sky as a rocket lofted skyward above Cape Canaveral, a soon-to-be-famous barrier island off the Florida coast.

The date was Jan. 31, 1958. NASA had yet to be formed, and the honor of this first flight belonged to the U.S. Army. The rocket’s sole payload was a javelin-shaped satellite built by the Jet Propulsion Laboratory in Pasadena, California. Explorer 1, as it would soon come to be called, was America’s first satellite.

Against the backdrop of the 1950s Cold War, after the Soviet Union successfully launched Sputnik, Americans were determined to launch their own Earth-orbiting satellite. Flash back to events leading up to the successful launch of America’s Explorer 1, and the beginnings of America’s Space Age, as told through newsreel and documentary clips of the time.

“The launch of Explorer 1 marked the beginning of U.S. spaceflight, as well as the scientific exploration of space, which led to a series of bold missions that have opened humanity’s eyes to new wonders of the solar system,” said Michael Watkins, current director of JPL. “It was a watershed moment for the nation that also defined who we are at JPL.”

In the mid-1950s, both the United States and the Soviet Union were proceeding toward the capability to put a spacecraft in orbit. Yet great uncertainty hung over the pursuit. As the Cold War between the two countries deepened, it had not yet been determined whether the sovereignty of a nation’s borders extended upward into space. Accordingly, then-President Eisenhower sought to ensure that the first American satellites were not perceived to be military or national security assets.

In 1954, an international council of scientists called for artificial satellites to be orbited as part of a worldwide science program called the International Geophysical Year (IGY), set to take place from July 1957 to December 1958. Both the American and Soviet governments seized on the idea, announcing they would launch spacecraft as part of the effort. Soon, a competition began between the Army, Air Force and Navy to develop a U.S. satellite and launch vehicle capable of reaching orbit.

At that time, JPL, which was part of the California Institute of Technology in Pasadena, primarily performed defense work for the Army. (The “jet” in JPL’s name traces back to rocket motors used to provide “jet assisted” takeoff for Army planes during World War II.) In 1954, the laboratory’s engineers began working with the Army Ballistic Missile Agency in Alabama on a project called “Orbiter.”

The Army team included Wernher von Braun (who would later design NASA’s Saturn V rocket) and his team of engineers. Their work centered around the Redstone Jupiter-C rocket, which was derived from the V-2 missile Germany had used against Britain during the war.

JPL’s role was to prepare the three upper stages for the launch vehicle, which included the satellite itself. These used solid rocket motors the laboratory had developed for the Army’s Sergeant guided missile.

JPL would also be responsible for receiving and transmitting the orbiting spacecraft’s communications. In addition to JPL’s involvement in the Orbiter program, the laboratory’s then-director, William Pickering, chaired the science committee on satellite tracking for the U.S. launch effort overall.

The Navy’s entry, called Vanguard, had a competitive edge in that it was not derived from a ballistic missile program – its rocket was designed, from the ground up, for civilian scientific purposes. The Army’s Jupiter-C rocket had made its first successful suborbital flight in 1956, so Army commanders were confident they could be ready to launch a satellite fairly quickly. Nevertheless, the Navy’s program was chosen to launch a satellite for the IGY.

University of Iowa physicist James Van Allen, whose instrument proposal had been chosen for the Vanguard satellite, was concerned about development issues on the project. Thus, he made sure his scientific instrument payload – a cosmic ray detector – would fit either launch vehicle. Meanwhile, although their project was officially mothballed, JPL engineers used a pre-existing rocket casing to quietly build a flight-worthy satellite, just in case it might be needed.

The world changed on Oct. 4, 1957, when the Soviet Union launched a 23-inch (58-centimeter) metal sphere called Sputnik. With that singular event, the space age had begun. The launch resolved a key diplomatic uncertainty about the future of spaceflight, establishing the right to orbit above any territory on the globe. The Russians quickly followed up their first launch with a second Sputnik just a month later. Under pressure to mount a U.S. response, the Eisenhower administration decided a scheduled test flight of the Vanguard rocket, already being planned in support of the IGY, would fit the bill.

But when the Vanguard rocket was, embarrassingly, destroyed during the launch attempt on Dec. 6, the administration turned to the Army’s program to save the country’s reputation as a technological leader.
Unbeknownst to JPL, von Braun and his team had also been developing their own satellite, but after some consideration, the Army decided that JPL would still provide the spacecraft. The result of that fateful decision was that JPL’s focus shifted permanently – from rockets to what sits on top of them.

The Army team had its orders to be ready for launch within 90 days. Thanks to its advance preparation, 84 days later, its satellite stood on the launch pad at Cape Canaveral Air Force Station in Florida.
The spacecraft was launched at 10:48 p.m. EST on Friday, Jan. 31, 1958.

An hour and a half later, a JPL tracking station in California picked up its signal transmitted from orbit. In keeping with the desire to portray the launch as the fulfillment of the U.S. commitment under the International Geophysical Year, the announcement of its success was made early the next morning at the National Academy of Sciences in Washington, with Pickering, Van Allen and von Braun on hand to answer questions from the media.

Following the launch, the spacecraft was given its official name, Explorer 1. (In the following decades, nearly a hundred spacecraft would be given the designation “Explorer.”) The satellite continued to transmit data for about four months, until its batteries were exhausted, and it ceased operating on May 23, 1958.

Later that year, when the National Aeronautics and Space Administration (NASA) was established by Congress, Pickering and Caltech worked to shift JPL away from its defense work to become part of the new agency. JPL remains a division of Caltech, which manages the laboratory for NASA.

The beginnings of U.S. space exploration were not without setbacks – of the first five Explorer satellites, two failed to reach orbit. But the three that made it gave the world the first scientific discovery in space – the Van Allen radiation belts. These doughnut-shaped regions of high-energy particles, held in place by Earth’s magnetic field, may have been important in making Earth habitable for life. Explorer 1, with Van Allen’s cosmic ray detector on board, was the first to detect this phenomenon, which is still being studied today.

In advocating for a civilian space agency before Congress after the launch of Explorer 1, Pickering drew on Van Allen’s discovery, stating, “Dr. Van Allen has given us some completely new information about the radiation present in outer space….This is a rather dramatic example of a quite simple scientific experiment which was our first step out into space.”

Explorer 1 re-entered Earth’s atmosphere and burned up on March 31, 1970, after more than 58,000 orbits.

TOP IMAGE….Explorer 1 sits atop the Jupiter-C rocket (designated “Juno-1”) in the gantry as its launch date nears. Image credit: NASA

CENTRE IMAGE….The Juno-1 launch vehicle carrying Explorer 1 lifts off from Cape Canaveral, Florida, at 10:48 p.m. EST on Jan. 31, 1958. Image credit: NASA

LOWER IMAGE….America’s First Satellite – America joined the space race with the launch of this small, but important spacecraft.

Dust Storms Linked to Gas Escape from Mars Atmosphere Some Mars...

Wed, 24 Jan 2018 16:49:59 +1100

Dust Storms Linked to Gas Escape from Mars Atmosphere

Some Mars experts are eager and optimistic for a dust storm this year to grow so grand it darkens skies around the entire Red Planet.

This biggest type of phenomenon in the environment of modern Mars could be examined as never before possible, using the combination of spacecraft now at Mars.

A study published this week based on observations by NASA’s Mars Reconnaissance Orbiter (MRO) during the most recent Martian global dust storm – in 2007 – suggests such storms play a role in the ongoing process of gas escaping from the top of Mars’ atmosphere. That process long ago transformed wetter, warmer ancient Mars into today’s arid, frozen planet.

“We found there’s an increase in water vapor in the middle atmosphere in connection with dust storms,” said Nicholas Heavens of Hampton University, Hampton, Virginia, lead author of the report in Nature Astronomy. “Water vapor is carried up with the same air mass rising with the dust.”

A link between the presence of water vapor in Mars’ middle atmosphere – roughly 30 to 60 miles (50 to 100 kilometers) high – and escape of hydrogen from the top of the atmosphere has been detected by NASA’s Hubble Space Telescope and the European Space Agency’s Mars Express orbiter, but mainly in years without the dramatic changes produced in a global dust storm. NASA’s MAVEN mission arrived at Mars in 2014 to study the process of atmosphere escape.

“It would be great to have a global dust storm we could observe with all the assets now at Mars, and that could happen this year,” said David Kass of NASA’s Jet Propulsion Laboratory, Pasadena, California.

He is a co-author of the new report and deputy principal investigator for the instrument that is the main source of data for it, MRO’s Mars Climate Sounder.

Not all Mars watchers are thrilled with the idea of a global dust storm, which can adversely affect ongoing missions. For instance: Opportunity, as a solar powered rover, would have to hunker down to save energy; the upcoming InSight lander’s parameters would need to be adjusted for safe entry, descent and landing in November; and all the cameras on rovers and orbiters would need to deal with low visibility.

Decades of Mars observations document a pattern of multiple regional dust storms arising during the northern spring and summer. In most Martian years, which are nearly twice as long as Earth years, all the regional storms dissipate and none swells into a global dust storm. But such expansion happened in 1977, 1982, 1994, 2001 and 2007. The next Martian dust storm season is expected to begin this summer and last into early 2019.

The Mars Climate Sounder on MRO can scan the atmosphere to directly detect dust and ice particles and can indirectly sense water vapor concentrations from effects on temperature. Heavens and co-authors of the new paper report the sounder’s data show slight increases in middle-atmosphere water vapor during regional dust storms and reveal a sharp jump in the altitude reached by water vapor during the 2007 global dust storm. Using recently refined analysis methods for the 2007 data, the researchers found an increase in water vapor by more than a hundred-fold in the middle atmosphere during that global storm.

Before MAVEN reached Mars, many scientists expected to see loss of hydrogen from the top of the atmosphere occurring at a rather steady rate, with variation tied to changes in the solar wind’s flow of charged particles from the Sun.

Data from MAVEN and Mars Express haven’t fit that pattern, instead showing a pattern that appears more related to Martian seasons than to solar activity. Heavens and coauthors present the dust storms’ hoisting of water vapor to higher altitudes as a likely key to the seasonal pattern in hydrogen escape from the top of the atmosphere. MAVEN observations during the stronger effects of a global dust storm could boost understanding of their possible link to the escape of gas from the atmosphere.

Photo

Wed, 24 Jan 2018 13:46:16 +1100

startswithabang: The Three Meanings Of E=mc^2, Einstein’s Most...

Wed, 24 Jan 2018 13:44:28 +1100

startswithabang:

The Three Meanings Of E=mc^2, Einstein’s Most Famous Equation

“Even masses at rest have an energy inherent to them. You’ve learned about all types of energies, including mechanical energy, chemical energy, electrical energy, as well as kinetic energy. These are all energies inherent to moving or reacting objects, and these forms of energy can be used to do work, such as run an engine, power a light bulb, or grind grain into flour. But even plain, old, regular mass at rest has energy inherent to it: a tremendous amount of energy. This carries with it a tremendous implication: that gravitation, which works between any two masses in the Universe in Newton’s picture, should also work based off of energy, which is equivalent to mass via E = mc^2.”

When it comes to equations, few can lay claim to being ‘the most famous one’ of all time, but right up there is Einstein’s greatest and simplest: E = mc^2. Yet it doesn’t simply state that mass and energy are equivalent, or that the relationship between them is given by the constant c^2. Sure, it says those things, but there’s also a vital physical meaning behind them. Understanding E = mc^2 has led to a variety of tremendous discoveries and breakthroughs, from nuclear power to the creation of new particles in particle accelerators. It even led directly to discovering that Newtonian gravity was theoretically unsound, ushering in the era of General Relativity, as well as the fact that any theory of gravity needs to include a gravitational redshift/blueshift.

How did it all come about? Find out the three meanings of Einstein’s most famous equation, and what it means for our Universe.