Cartography Of The Cosmos

There are hundreds of billions of stars in our own Milky Way galaxy. Estimates indicate a similar number of galaxies in the observable universe, each with its own large assemblage of stars, many with their own planetary systems. Beyond and between these stars and galaxies are all manner of matter in various phases, such as gas and dust. Another form of matter, dark matter, exists in a very different and mysterious form, announcing its presence indirectly only through its gravitational effects.

This is the universe Salman Habib is trying to reconstruct, structure by structure, using precise observations from telescope surveys combined with next-generation data analysis and simulation techniques currently being primed for exascale computing.

“We’re simulating all the processes in the structure and formation of the universe. It’s like solving a very large physics puzzle,” said Habib, a senior physicist and computational scientist with the High Energy Physics and Mathematics and Computer Science divisions of the U.S. Department of Energy’s (DOE) Argonne National Laboratory.

Habib leads the “Computing the Sky at Extreme Scales” project or “ExaSky,” one of the first projects funded by the recently established Exascale Computing Project (ECP), a collaborative effort between DOE’s Office of Science and its National Nuclear Security Administration.

From determining the initial cause of primordial fluctuations to measuring the sum of all neutrino masses, this project’s science objectives represent a laundry list of the biggest questions, mysteries and challenges currently confounding cosmologists.

There is the question of dark energy, the potential cause of the accelerated expansion of the universe, called inflation. Another question is the nature and distribution of dark matter in the universe.

These are immense questions that demand equally expansive computational power to answer. The ECP is readying science codes for exascale systems, the new workhorses of computational and big data science.

Initiated to drive the development of an “exascale ecosystem” of cutting-edge, high-performance architectures, codes and frameworks, the ECP will allow researchers to tackle data and computationally intensive challenges such as the ExaSky simulations of the known universe.

In addition to the magnitude of their computational demands, ECP projects are selected based on whether they meet specific strategic areas, ranging from energy and economic security to scientific discovery and healthcare.

“Salman’s research certainly looks at important and fundamental scientific questions, but it has societal benefits, too,” said Paul Messina, Argonne Distinguished Fellow. “Human beings tend to wonder where they came from, and that curiosity is very deep.”

HACC’ing the night sky

For Habib, the ECP presents a two-fold challenge — how do you conduct cutting-edge science on cutting-edge machines?

The cross-divisional Argonne team has been working on the science through a multi-year effort at the Argonne Leadership Computing Facility (ALCF), a DOE Office of Science User Facility. The team is running cosmological simulations for large-scale sky surveys on the facility’s 10-petaflop high-performance computer, Mira. The simulations are designed to work with observational data collected from specialized survey telescopes, like the forthcoming Dark Energy Spectroscopic Instrument (DESI) and the Large Synoptic Survey Telescope (LSST).

Survey telescopes look at much larger areas of the sky — up to half the sky, at any point — than does the Hubble Space Telescope, for instance, which focuses more on individual objects. One night concentrating on one patch, the next night another, survey instruments systematically examine the sky to develop a cartographic record of the cosmos, as Habib describes it.

Working in partnership with Los Alamos and Lawrence Berkeley National Laboratories, the Argonne team is readying itself to chart the rest of the course.

Their primary code, which Habib helped develop, is already among the fastest science production codes in use. Called HACC (Hardware/Hybrid Accelerated Cosmology Code), this particle-based cosmology framework supports a variety of programming models and algorithms.

Unique among codes used in other exascale computing projects, it can run on all current and prototype architectures, from the basic X86 chip used in most home PCs, to graphics processing units, to the newest Knights Landing chip found in Theta, the ALCF’s latest supercomputing system.

As robust as the code is already, the HACC team continues to develop it further, adding significant new capabilities, such as hydrodynamics and associated subgrid models.

“When you run very large simulations of the universe, you can’t possibly do everything, because it’s just too detailed,” Habib explained. “For example, if we’re running a simulation where we literally have tens to hundreds of billions of galaxies, we cannot follow each galaxy in full detail. So we come up with approximate approaches, referred to as subgrid models.”

Even with these improvements and its successes, the HACC code still will need to increase its performance and memory to be able to work in an exascale framework. In addition to HACC, the ExaSky project employs the adaptive mesh refinement code Nyx, developed at Lawrence Berkeley. HACC and Nyx complement each other with different areas of specialization. The synergy between the two is an important element of the ExaSky team’s approach.

A cosmological simulation approach that melds multiple approaches allows the verification of difficult-to-resolve cosmological processes involving gravitational evolution, gas dynamics and astrophysical effects at very high dynamic ranges. New computational methods like machine learning will help scientists to quickly and systematically recognize features in both the observational and simulation data that represent unique events.

A trillion particles of light

The work produced under the ECP will serve several purposes, benefitting both the future of cosmological modeling and the development of successful exascale platforms.

On the modeling end, the computer can generate many universes with different parameters, allowing researchers to compare their models with observations to determine which models fit the data most accurately. Alternatively, the models can make predictions for observations yet to be made.

Models also can produce extremely realistic pictures of the sky, which is essential when planning large observational campaigns, such as those by DESI and LSST.

“Before you spend the money to build a telescope, it’s important to also produce extremely good simulated data so that people can optimize observational campaigns to meet their data challenges,” said Habib.

But the cost of realism is expensive. Simulations can range in the trillion-particle realm and produce several petabytes — quadrillions of bytes — of data in a single run. As exascale becomes prevalent, these simulations will produce 10 to 100 times as much data.

The work that the ExaSky team is doing, along with that of the other ECP research teams, will help address these challenges and those faced by computer manufacturers and software developers as they create coherent, functional exascale platforms to meet the needs of large-scale science. By working with their own codes on pre-exascale machines, the ECP research team can help guide vendors in chip design, I/O bandwidth and memory requirements and other features.

“All of these things can help the ECP community optimize their systems,” noted Habib. “That’s the fundamental reason why the ECP science teams were chosen. We will take the lessons we learn in dealing with this architecture back to the rest of the science community and say, ‘We have found a solution.'”

Vanuatu: Volcanic Eruption Forces At Least 6,000 People To Evacuate Ambae Island

The Manaro volcano has been active since 2005, but a recent increase in activity has raised fears of a major eruption.

The national government also approved a $2 million fund to provide food, shelter and water to those affected.

The volcano’s activity measure was raised to Level 4 for the first time over the weekend, which indicates a “moderate eruption” and is the second highest level in Vanuatu’s volcanic alert system.

“There’s ash, fire, stones and lava being thrown out from the mouth of the volcano,” Shadrack Welegtabit, the director of Vanuatu’s National Disaster Management Office, said.

He said it was difficult to say whether there will be a major eruption, and that those who have been evacuated will just have to sit and wait.

“With the seismic machine, we can measure what’s happening but we can’t really predict what the volcano will do next,” he said.

About 10,000 people live on the island, and those in the north and south are most vulnerable.

The Vanuatu Red Cross said those villagers have been moved to the eastern and western sides of the island.

“The priority now is shelter, water and food, and also looking at health,” said Augustine Garae, the organisation’s disaster management coordinator.

Evacuees struggling to get information

Georgia Tacey, the Vanuatu country director for non-governmental organisation Save the Children, said those affected are struggling without reliable information about the eruption.

“They’re incredibly distressed, there isn’t a great deal of mobile cell coverage over the island so [they] rely on word of mouth. Radio coverage is also very little,” she said.

Vanuatu’s Meteorology and Geohazards Department said in an alert that villagers within 6.5 kilometres of the volcano face the biggest risk from airborne rocks and volcanic gas.

The department warned that acid rain could damage crops across a broader area.

Ms Tacey said authorities have a contingency plan in place for if the volcanic activity increases.

“They would be looking at evacuating the entire island to nearby islands,” she said.

“Obviously no one wants that to happen because apart from that being incredibly distressing it would be logistically challenging and would displace people for a very long time.”

Vanuatu is considered one of the countries most prone to natural disasters, with a half-dozen active volcanoes as well as regular cyclones and earthquakes.

It sits on the Pacific’s Ring of Fire, the arc of seismic faults around the Pacific Ocean where earthquakes and volcanoes are common.

Deep 6.4 Quake Strikes Near Fiji And Tonga

The Pacific Tsunami Warning Centre says there is no threat of a tsunami from a 6.4 earthquake which struck near Fiji and Tonga.

The US Geological Survery measured the quake, which occurred today at 1619 Fiji Time, at a depth of 98 kilometres.

According to disaster response authorities in Fiji, the quake’s epicentre was 846km south east of Suva, which is just to the west of the Tongan trench.

The co-ordinates of the quake are 23.713°S 176.937°W.

Giant Atlantic Superstorm Set To Smash Into Britain Next Week

Violent gales and torrential downpours will bring chaos across the country with power and transport networks facing severe disruption.

The latest weather models show Hurricanes Lee and Maria – currently located off the east coast of the United States – merging in the mid-Atlantic Ocean to form a colossal new storm.

Both Hurricanes are currently at Category One strength as they make their way across the Atlantic. Latest GFS tracks released this morning show the projected path of the newly formed storm hitting the UK early next week.

Meteorologists fear an extremely violent post-tropical cyclone – Storm Brian – will form and head straight for the UK.

The current projected path of Storm Brian – as it will be called if it severely threatens the UK – shows it making landfall next Monday, with the churning vortex smashing first into Ireland, then mainland Britain.

Britons should brace themselves for “a bang” according to experts who warn the nation faces “significant” disruption.

Jim Dale, forecaster for British Weather Services, said megastorm caused by Maria and Lee coming together could give rise to the UK’s second named storm of the season.

He said: “Both hurricanes are located around the northeast coast of America but we expect them to get together around Sunday.

“The jet stream is powering up and as it swings southwards towards the end of the week it will help steer the remnants of these storms towards us.

“Both of these are powerful systems and when they get caught up in the jet stream they could be given more life.”

Meteorologists are keeping a very close eye on developments over ocean waters and the track of the jet stream over the next few days.

Mr Dale added: “We do have the potential for major winds next week. A significant October storm is not out of the question.

“It is likely we will see severe gales, perhaps not right across the whole country, but certainly one to watch.”

The US National Hurricane Center issued a revised forecast warning that Hurricane Maria would turn east-northeastward towards Britain – and Lee – and accelerate within 48 hours.

It said hurricane-force winds currently extend outward up to 105 miles from the centre of Maria and tropical-storm-force winds up to 240 miles. Lee is smaller, with a hurricane force wind field of 15 miles and tropical-storm-force winds extending outward up to 45 miles.

Lee and Maria are currently causing 75 to 100mph winds offshore the mainland US. Latest ECM TC tracks also show both hurricanes heading East North East.

WX Charts tweeted: “The GFS again showing remnants of #Maria and #Lee combining with an extra-tropical low and heading towards the British Isles by Sunday.”

Weather forecaster Jim Cantore said: “Lee is firing up and trying to meet up with Maria before they both take off for a trip and transition on the way to Europe.”

Maria and Lee are expected to make an extratropical transition by combining with low pressure in the Atlantic later heading toward the UK by Sunday.

Maria is still much bigger in size than Lee despite both being Category One hurricanes however wind speeds are at similar levels in both.

Latest NOAA update on Maria and Lee show Maria weakening slightly as it continues northward while Lee is still strengthening and moving at high speed.

Both are forecast to make an abrupt northeastwards turn later this week before Maria engulfs Lee to form a new, major storm.

This will give rise to one deep low pressure system which, helped by the jet stream, will then hurtle towards the west coast of Britain.

Eleanor Bell, forecaster for The Weather Company, said: “We expect Maria to curve back over the Atlantic before joining with Lee and forming one deep low pressure system.

“The latest models are showing a significant low moving across the UK next Monday bringing some very wet and windy conditions.

“It is going be a very unsettled period of weather for the UK.

“It is difficult at this early stage to say where will see the most impact, and while everywhere is likely to see something, we think the north and the west will be most unsettled.

“Nowhere is really going to escape the wind and rain, and we are looking at gale-force winds.”

The impact from Monday’s assault threatens to unleash a worse assault than Storm Aileen which struck mid-September.

While there was some disruption including loss of power and transport delays, the impact was less severe than first thought.

It will be a shock to the system to many in the UK after the relatively calm, settled and unusually warm start to autumn.

While stirring up gales this side of the Atlantic, the remnants of the storms will also drag a swath of warm air across the UK.

Temperatures are expected to start creeping up at the beginning of next week although it will feel cool in the wind and rain, experts say.

Worrying forecasting models project the storm system rapidly deepening before hitting the west coast of Britain next Monday.

Brian will be named as the second storm of the season if the likely impacts are deemed by the Met Office to be severe enough.

Britain and the US have separate systems for naming autumn storms, so when Maria and Lee reach the UK as one storm they will be re-named Brian.

The Met Office said with one week to ago before the remnants of both system are due to hit the UK, the impact is still uncertain.

Spokesman Grahame Madge said: “Some of the model outputs are suggesting the hurricanes may merge to form a new depression in the Atlantic.

“There are also various predictions of the track it will take, so there is still much uncertainty at this stage.

He added: “However, if the two systems merge, they will bring air of tropical origin into the north Atlantic giving energy to low pressure systems closer to the UK.

“Putting warm, tropical air into these serves to modify them and this happens there is the potential for rising humidity and winds in the UK.”

Britain’s largely settled weather over the past few weeks has been driven by a huge area of high pressure stretching across Europe from Russia.

This is expected to start weakening over the next few days opening the doors to stormy conditions from the Atlantic.

Volcanic Eruption Fears Prompt 75,000 to Evacuate in Bali

Thousands of people have scattered to all corners of the Indonesian island of Bali, fleeing a possible eruption of volcanic Mount Agung.

The mountain, situated on the northeast section of the island, last erupted in 1963 killing about 1,100 people, and a dramatic increase seismic activity has officials worried it may be about to blow again.

“The latest analysis indicates that Mount Agung’s seismic energy is increasing and has the potential to erupt,” the National Vulcanology Center said in a statement to Reuters. “However, no one can predict exactly when there will be an eruption.”

Most people are choosing not to risk staying in the area. More than 75,000 have relocated to areas further away from the peak, and some have crossed to the neighboring island of Lombok, The Associated Press reports.

“Our staff are combing the area and urging everyone to evacuate,” said Indonesian National Disaster Mitigation Agency spokesman Sutopo Purwo Nugroho said at a news conference. “There are some who are staying behind because the volcano hasn’t erupted yet or because of religious beliefs.”

Thousands of evacuees are living in temporary shelters, sports centers, village halls and with relatives or friends, according to the AP. Some return to the danger zone, which extends up to 7.5 miles from the volcano, during the day to tend to livestock.

“There are many livestock in our village but nobody is taking care of them,” Nengah Satiya, who is one of several who volunteered to feed the pigs and chickens in his village, told the South China Morning Post. “We take turns going back to feed them.”

Others have given up on their livestock.

“We have already sold our cattle, because we thought it was better than leaving them there for nothing,” villager Wayan Merta, whose home is just 4 miles from the summit, told the AP. “My feeling is the mountain will erupt. But no one knows, we just pray.”

Meanwhile, in the evacuation centers, the government is distributing hundreds of thousands of face masks and thousands of mattresses and blankets, Nugroho told the AP.

“The biggest challenge is we can’t predict the number of evacuees,” Putu Widiada, head of the local disaster management agency in Klungkung district told Reuters. “If the number of evacuees exceeds our maximum capacity, we have asked that every public hall in the district be prepared to become evacuation camps.”

Officials have said there’s no immediate threat to tourists and a spokeswoman for the Sheraton Bali Kuta told The Australian that as of Monday, “travelers are still coming in. We haven’t had any postponement or cancellations.”

She went on to say that the hotel is advising guests to monitor information from local authorities and travel advisories, a significant eruption would force the closure of Bali’s international airport, stranding thousands.

(MORE: Eight Straight Hurricanes Have Formed in the Atlantic Basin, a First Since the Late 1800s)

Fearing just such an occurrence, some tourists had already decided to leave.

“It’s obviously an awful thing,” an Australian woman who identified herself as Miriam told the AP at Bali’s international airport. “We want to get out of here just to be safe.”

When the volcano last erupted in 1963, it hurled ash as high as 12 miles, according to volcanologists, and remained active for about a year. Lava traveled 4.7 miles and ash reached Jakarta about 620 miles away.

UPDATE : Hurricane Maria: Path Keeps Large Storm Off The East Coast

Hurricane Maria continued on a path northward on Tuesday morning and will pass offshore of North Carolina over the next few days.

Maria is barely a hurricane as of Tuesday morning with 75 mph winds, according to the National Hurricane Center. Hurricane force winds start at 74 mph.

Tropical storm warnings remained in effect for parts of the coast of North Carolina, where the effects of the large storm could be felt starting later today.

In addition there’s the possibility of storm surge along parts of the Outer Banks, and a storm surge watch is in effect for some areas.

As of the last advisory from the hurricane center, at 7 a.m. CDT, Hurricane Maria was located about 190 miles southeast of Cape Hatteras, N.C., and was moving north at 7 mph.

A tropical storm warning is in effect along the North Carolina coast from Bogue Inlet to the Virginia border as well as Albemarle and Pamlico Sounds.

In addition, a storm surge watch is in effect from Cape Lookout to Duck. The hurricane center said storm surge flooding, especially along the sound side of the North Carolina Outer Banks, will be possible starting later today.

One of the most widespread effects from Maria is dangerous surf. Forecasters said waves from the storm are affecting beaches from Florida through southern New England. Rough surf and deadly rip currents will be possible over the next few days.

Maria could weaken to a tropical storm as soon as today, the hurricane center said. Former Hurricane Jose is to thank for that.

Maria is moving over cooler waters that Jose stirred up last week, and forecasters said Maria is showing the effects.

Maria is looking less organized, its strongest winds are on its eastern side and its central pressure is rising, according to the hurricane center on Tuesday morning.

Forecasters expect Maria to weaken to a tropical storm in less than 24 hours.

The hurricane center is forecasting Maria to track northward for the next 36-48 hours then turn eastward and pick up speed. That should keep the center of the storm well away from the coast.

Forecasters said most forecast models agree on this scenario.

There is one other storm in the Atlantic on Tuesday: Hurricane Lee.

As of Tuesday morning Lee was located about 745 miles east of Bermuda and was moving west at 10 mph.

Lee is a small storm and is no threat to land.

Hurricane Lee had winds of 100 mph, making it a Category 2 hurricane, and could get a bit stronger before beginning to weaken on Wednesday, the hurricane center said.

Lava Tubes: Hidden Sites For Future Human Habitats On The Moon And Mars

Lava tubes, underground caves created by volcanic activity, could provide protected habitats large enough to house streets on Mars or even towns on the Moon, according to research presented at the European Planetary Science Congress (EPSC) 2017 in Riga. A further study shows how the next generation of lunar orbiters will be able to use radar to locate these structures under the Moon’s surface.

Lava tubes can form in two ways: ‘overcrusted’ tubes form when low-viscosity lava flows fairly close to the surface, developing a hard crust that thickens to create a roof above the moving lava stream. When the eruptions end, the conduit is drained leaving a tunnel a few metres beneath the surface. ‘Inflated’ tubes are complex and deep structures that form when lava is injected into existing fissures between layers of rock or cavities from previous flows. The lava expands and leaves a huge network of connected galleries as it forces its way to the surface. Lava tubes are found in many volcanic areas on Earth, including Lanzarote, Hawaii, Iceland, North Queensland in Australia, Sicily and the Galapagos islands. Underground networks of tubes can reach up to 65 kilometres. Space missions have also observed chains of collapsed pits and ‘skylights’ on the Moon and Mars that have been interpreted as evidence of lava tubes. Recently the NASA GRAIL mission provided detailed gravity data for the Moon that suggested the presence of enormous subsurface voids related to lava tubes below the lunar ‘Maria’, plains of basalt formed in volcanic eruptions early in the Moon’s history.

Now, researchers from the University of Padova and the University of Bologna in Italy have carried out the first systematic comparison of lava tube candidates on the Earth, Moon and Mars, based on high-resolution Digital Terrain Models (DTM) created from data from spacecraft instrumentation.

“The comparison of terrestrial, lunar and martian examples shows that, as you might expect, gravity has a big effect on the size of lava tubes. On Earth, they can be up to thirty metres across. In the lower gravity environment of Mars, we see evidence for lava tubes that are 250 metres in width. On the Moon, these tunnels could be a kilometre or more across and many hundreds of kilometres in length,” says Dr Riccardo Pozzobon, of the University of Padova. “These results have important implications for habitability and human exploration of the Moon but also for the search of extraterrestrial life on Mars. Lava tubes are environments shielded from cosmic radiation and protected from micrometeorites flux, potentially providing safe habitats for future human missions. They are also, potentially, large enough for quite significant human settlements — you could fit most of the historic city centre of Riga into a lunar lava tube.”

The work by Pozzobon and colleagues is already being used in the European Space Agency’s astronaut training programme. The teams lead a planetary geology training course called PANGAEA for the European Space Agency’s astronauts and engineers. The PANGAEA project has included a field trip and a test campaign in lava tubes in the Canary Island to familiarise the astronauts with geological research they could carry out during future missions to the Moon or Mars, as well as to test technical and operational systems. In particular, PANGAEA has focused on using laser technologies to characterise the Corona lava tube, an 8-kilometre long tunnel on Lanzarote.

However, analysis of lava tubes with DEMs requires that a collapse or a puncture from a meteorite reveals the presence of the hidden tunnel. Conventional remote sensing instruments cannot detect and characterise the lava tubes, as they cannot acquire measurements beneath the surface.

In a separate talk at EPSC, Leonardo Carrer and colleagues of the University of Trento presented a concept for a radar system specifically designed to detect lava tubes on the Moon from orbit. The radar probes beneath the lunar surface with low frequency electromagnetic waves and measures the reflected signals. This radar instrument could determine accurately the physical composition, size and shape of the caves and obtain a global map of their location.

“The studies we have developed show that a multi- frequency sounding system is the best option for detecting lava tubes of very different dimensions. The electromagnetic simulations show that lava tubes have unique electromagnetic signatures, which can be detected from orbit irrespective of their orientation to the radar movement direction. Therefore, a mission carrying this instrument would enable a crucial step towards finding safe habitats on the Moon for human colonisation,” says Carrer.