New algorithms to determine eigenstates and thermal states on quantum computers

Image capturing the essence of how the researchers represented imaginary-time evolution by unitary transformations that one can turn into a quantum circuit. Credit: Motta et al.

Determining the quantum mechanical behavior of many interacting particles is essential to solving important problems in a variety of scientific fields, including physics, chemistry and mathematics. For instance, in order to describe the electronic structure of materials and molecules, researchers first need to find the ground, excited and thermal states of the Born-Oppenheimer Hamiltonian approximation. In quantum chemistry, the Born-Oppenheimer approximation is the assumption that electronic and nuclear motions in molecules can be separated.

A variety of other scientific problems also require the accurate computation of Hamiltonian ground, excited and thermal states on a quantum computer. An important example are combinatorial optimization problems, which can be reduced to finding the ground state of suitable spin systems.

So far, techniques for computing Hamiltonian eigenstates on quantum computers have been primarily based on phase estimation or variational algorithms, which are designed to approximate the lowest energy eigenstate (i.e., ground state) and a number of excited states. Unfortunately, these techniques can have significant disadvantages, which make them impracticable for solving many scientific problems.

A research collaboration between the groups of Garnet Chan, Fernando Brandao, and Austin Minnich at the California Institute of Technology (Caltech) has recently led to the development of three new algorithms that could help to overcome the limitations of existing phase estimation and variational methods. These algorithms, dubbed quantum imaginary time evolution, quantum Lanczos and quantum METTS algorithms, were presented in a paper published in Nature Physics.

"Determining ground, excited and thermal states is of course an important problem in quantum computing, but the algorithms to tackle it on contemporary hardware typically require important quantum resources, such as deep quantum circuits (i.e. comprising many quantum gates, and thus prone to decoherence and imperfect implementation) and ancillary (i.e. additional) qubits—or non-linear noisy classical parameter optimizations," Mario Motta, one of the researchers who carried out the study, told Phys.org.

The key aim of the recent study carried out by the researchers at Caltech was to develop new quantum algorithms for determining ground, excited and thermal states on quantum computers. The researchers tried to circumvent the practical limitations of existing techniques for computing Hamiltonian states by leveraging notions from classical computer physics, such as imaginary-time evolution, exact diagonalization and finite-temperature state sampling, ultimately extending these

notions to quantum computing algorithms beyond what previously accomplished.

"Our algorithms are based on the notion of imaginary-time evolution, which is akin to a cooling process," Motta explained. "Suppose that we can prepare a quantum mechanical system in a simple but inaccurate approximation for the ground state, a trial wave function. By applying this cooling process to the system, we can systematically remove spurious excitations from the trial wave function, thereby gradually approaching the ground state. This is the content of the quantum imaginary-time evolution (QITE) algorithm."

The three algorithms developed by the Caltech researchers are somewhat similar to classical techniques for finding ground and excited states. By collecting information as imaginary-time evolution unfolds, however, these algorithms can formulate and solve an eigenvalue problem that provides access to specific excited states, employing a quantum variant of the Lanczos approach, a well-established mathematical technique to compute eigenvalues and eigenvectors.

"Of course, imaginary-time evolution can also be used to cool a system from infinite to finite (greater than zero) temperature, and thus to compute finite-temperature properties, as we do in our QMETTS algorithm," Motta said.

The quantum imaginary time evolution algorithm and Lanczos algorithm proposed by the researchers have several advantages over existing and classical techniques. For instance, as they are rooted in physical intuition, they can be implemented on contemporary quantum hardware and do not require deep circuits, ancillary qubits and complicated parameter optimizations, which are indispensable for other quantum algorithms.

"The most meaningful achievement of our study was the conception of a suite of new algorithms for the study of many-many-body systems on contemporary quantum computers," Motta said. "Our algorithms bring useful insights to the Physics field: in particular, they show how the combination of ideas and techniques from different fields of science can be synergistically combined to produce innovative techniques.''

In their study, Motta and his colleagues demonstrated the effectiveness of the algorithms they developed by implementing them on the Rigetti quantum virtual machine and Aspen-1 quantum processing unit. In these demonstrations the algorithms performed remarkably well, comparing favorably to existing techniques for computing Hamiltonian ground, excited and thermal states.

The new algorithms developed by this team of researchers could be used in a variety of studies that involve quantum simulations and optimization. In addition, they could be refined and extended to meet the needs of individuals research projects.

"Our future research will be directed towards expanding the predictive power of the algorithms we developed," Motta said. "For example, by computing properties beyond the energy, such as density operators and correlation functions, and devising systematic and efficient strategies to study arbitrary many-body systems (comprising bosons and fermions, with particular emphasis on molecules)."

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Spreading light over quantum computers

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More information:
Mario Motta et al. Determining eigenstates and thermal states on a quantum computer using quantum imaginary time evolution, Nature Physics (2019). DOI: 10.1038/s41567-019-0704-4

© 2019 Science X Network

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New algorithms to determine eigenstates and thermal states on quantum computers (2019, November 29)
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Italy satisfied with outcome of ESA ministerial

SEVILLE, Spain — Italy, one of the largest contributors to the European Space Agency, is pleased with the outcome of the recent ministerial meeting that provided funding for a number of its priorities, including a reusable spacecraft.

In a finally tally of contributions provided by ESA at the end of the Space19+ ministerial meeting here Nov. 28, Italy ranked third among ESA’s 22 member states, contributing 2.28 billion euros ($2.51 billion) or 15.9% of the 14.4 billion in funding provided by ESA members overall at the meeting. Only Germany, at 3.29 billion euros, and France, at 2.66 billion euros, offered more funding. The Italian funding commitment is nearly one billion euros higher than what it provided at the previous ministerial in 2016.

“We are very happy,” Giorgio Saccoccia, president of the Italian space agency ASI, said in an interview after the Space19+ meeting here Nov. 28. “What happened today at the ministerial reflects the priorities the government of Italy and the space agency is putting on space activities, which is considered a sector of great economic return for the country.”

He highlighted roles in several programs, such as Earth observation, technology development, evolution of the Vega small launch vehicle and Mars sample return. A lot of attention, though, was focused on a smaller program, called Space Rider, that seeks to develop a reusable spacecraft that can be launched into orbit and then return for a landing, somewhat similar to the existing X-37B operated by the U.S. Air Force and Sierra Nevada Corporation’s Dream Chaser under development.

Space Rider will build on the Intermediate eXperimental Vehicle, a vehicle that launched on a Vega rocket in 2015 on a suborbital flight, splashing down in the Pacific. ESA foresees launching Space Rider on a Vega C as soon as 2022 into low Earth orbit, where the spacecraft would remain for at least two months. The spacecraft, with its payload of up to 800 kilograms of experiments, would then return to Earth, gliding back to the ground under a parachute.

ESA did not disclose the total value pledged to Space Rider at the meeting, but did state that Italy is providing 75% of the total. That led to questions at the press conference at the end of Space19+ about whether Space Rider is truly a European program rather than a national program.

Jan Woerner, director general of ESA, disagreed, nothing that several countries play key roles in the agency’s overall space transportation portfolio. “Each and every member state has its specific competence, and this is good,” he said.

For Space Rider, he acknowledged that he wanted to see more member states join the program. “But what is more important for me: Space Rider will fly and land,” he said. “It’s not a national program. It’s a program of the European Space Agency within the whole space transportation package.”

Saccoccia said 10 countries decided to participate in Space Rider, pledging funding that oversubscribed the program. “It’s a good demonstration of trust,” he said. “We want to return the commitment that other countries have provided to this program into the proper distribution of activities in order to also produce growth for our partners.”

Another priority for Italy was human space exploration, where ESA committed to start work on two modules for the lunar Gateway, a telecommunications and refueling element known as ESPRIT and an international habitation, or “iHab” module ESA proposes to cooperate with Japan in development.

Both modules would be added to the Gateway in the second, “sustainable” phase of its development after NASA’s planned 2024 human lunar landing. “The reason why we made a very large contribution to the iHab module is that we want to play a role on the sustainable part of Artemis,” he said.

That work, Saccoccia said, will be in parallel with Italy’s plans to cooperate directly with NASA on other elements of Artemis. He noted Italy’s expertise in pressurized modules as one key area. “We intend to use this capacity to contribute to the early modules that will be used for the first phase of Artemis,” he said. That includes the Habitation and Logistics Outpost (HALO) element that NASA plans to award a sole-source contract to Northrop Grumman to develop. That will be based on that company’s Cygnus spacecraft, whose pressurized module is built in Italy.

“In overall terms, our country will give a great contribution to the full Artemis project,” he said.

#Space | https://sciencespies.com/space/italy-satisfied-with-outcome-of-esa-ministerial/

International Space Station Commercialization Heralds A New Era For Human Spaceflight

STS-135 final flyaround of ISS This picture of the International Space Station was photographed from ... [+] the space shuttle Atlantis as the orbiting complex and the shuttle performed their relative separation in the early hours of July 19, 2011. Onboard the station were Russian cosmonauts Andrey Borisenko, Expedition 28 commander; Sergei Volkov and Alexander Samokutyaev, both flight engineers; Japan Aerospace Exploration astronaut Satoshi Furukawa, and NASA astronauts Mike Fossum and Ron Garan, all flight engineers. Onboard the shuttle were NASA astronauts Chris Ferguson, STS-135 commander; Doug Hurley, pilot; and Sandy Magnus and Rex Walheim, both mission specialists.

NASA/Wikimedia Commons

Earlier this week, NASA announced that it would purchase seats on commercially organized missions to the International Space Station (ISS) by 2024. Though NASA is expected to release a request for proposals (RFP) for any interested providers to submit bids in early 2020, the likely frontrunners to provide this service are the two companies NASA has already contracted for ISS human spaceflight services: SpaceX and Boeing. The seats purchased on these private missions would be in addition to the test flights and operational missions NASA has already contracted through its Commercial Crew Program. In contrast with “normal” NASA ISS missions with a duration of approximately 6 months, these commercial passenger flights will include an ISS stay of no longer than 30 days.

This announcement is the latest in a series of moves by NASA to open the ISS up for commercialization, as the U.S. government attempts to renew agency focus on missions beyond low-Earth orbit (LEO). The International Space Station (ISS) has been the exclusive destination of government-sponsored astronauts for almost two decades now, and has been continuously inhabited by humans since 2000. Roughly the size of a football field, the ISS orbits the Earth in LEO at an altitude of approximately 400 kilometers and provides a microgravity and space environment research laboratory for crew members to conduct experiments in biology, physics, and astronomy, among other fields. Funding for the laboratory is provided by its participating countries, which include the U.S., Russia, Japan, Canada, and member states of the European Space Agency. Russia’s ROSCOSMOS has been the sole provider of human transportation services to the ISS since the Space Shuttle’s final mission in 2011, although NASA’s Commercial Crew Program expects both SpaceX and Boeing to be able to launch humans to the ISS in 2020.

Boeing's first CST-100 Starliner capsule seen in front of the Vehicle Assembly Building at NASA's ... [+] Kennedy Space Center as it began its journey on Nov. 21, 2019, to Cape Canaveral Air Force Station for its first uncrewed launch.

NASA

The Trump administration initially sought to completely withdraw U.S. funding for the laboratory by 2024, a proposal that was met with criticism from some top NASA officials who argued that astronaut safety could be compromised by the program’s early termination. The ISS’s planned end date was originally 2028, after which the Station would either be taken over by a commercial entity or deconstructed and removed from service. As NASA’s current annual budget for use and maintenance of the ISS is over $3 billion USD, the feasibility of a complete takeover by a commercial entity has been called into question. However, allowing private astronauts onboard the U.S. segment before the Station’s decommissioning would still represent a marked increase in U.S. government support for commercial human spaceflight. In December 2018, the Leading Human Spaceflight Act was passed, extending operation of the ISS until 2030.

By commercializing the ISS, the Trump administration looks to enable continued U.S. human presence in space while freeing up NASA resources for deep space exploration, such as missions to the planned Lunar Orbital Platform - Gateway. In late 2017, the Trump administration issued Space Policy Directive-1, stating that “Beginning with missions beyond low-Earth orbit, the United States will lead the return of humans to the Moon for long-term exploration and utilization, followed by human missions to Mars and other destinations.” The Lunar Orbital Platform - Gateway is a proposed space station in lunar orbit that is intended to serve as a communications hub, science laboratory, short-term human habitation module, and holding area for rovers and robots. Once built, this new Station would be a major component of NASA’s Artemis program, which plans to use the Space Launch System (SLS) rocket and Orion spacecraft to send crew to the lunar south pole region by 2024. Accomplishment of this feat would constitute a major milestone towards returning human presence to the Moon, which saw its last human visitor in 1972.

Artist's concept of the updated configuration of the Lunar Orbital Platform-Gateway, as found on the ... [+] HEOMD presentation of September 6, 2018.

NASA/Wikimedia Commons

Of note, the Trump administration is hardly the first U.S. presidential administration to set its sights beyond LEO. Upon the 20th anniversary of the Moon landing in 1989, George H.W. Bush announced the Space Exploration Initiative, which called for the construction of Space Station Freedom, establishment of permanent presence on the Moon, and a crewed mission to Mars. The price tag of this endeavor was estimated at $500 billion over 20 to 30 years, and the initiative was never implemented due to lack of support from Congress. Later, Bush’s son George W. Bush announced the retirement of the Space Shuttle Program and funding for a new Constellation Program to the Moon. The Constellation program was later canceled by George W. Bush’s successor, Barack Obama, and replaced with plans for a human mission to an asteroid.

The Obama administration was the first in U.S. history to invest in commercial human spaceflight with its backing of the NASA Commercial Crew Program as part of the American Recovery and Reinvestment Act (ARRA) of 2009. By moving towards commercialization of the ISS, the Trump administration appears to be building on the initial groundwork laid by Commercial Crew for further space commerce activities while simultaneously pursuing its own agenda for deep space exploration.

As of today, the timeline for NASA’s Artemis program calls for landing a man or woman on the Moon by 2024, which would coincide with the agency’s timeline for purchasing shorter-duration commercial flights. That said, human spaceflight development programs are notoriously prone to significant delays, suggesting that even with continued funding, the 2024 date for an Artemis launch may be at risk. Still, if the agency continues down its current path, the next decade could be an exciting time for the U.S. space program. For the first time in history, NASA could be sending astronauts to two very different destinations at once: Lunar orbit, and low-Earth orbit.

#News | https://sciencespies.com/news/international-space-station-commercialization-heralds-a-new-era-for-human-spaceflight/

Amazon fires are causing glaciers in the Andes to melt even faster

South America: the Andes mountains run along the western edge of the Amazon basin (centre). Credit: AridOcean / shutterstock

If you have turned on a TV or read the news during the past few months, you have probably heard of the widespread fires that wrought havoc on the Amazon rainforest this year. Fires occur in the rainforest every year, but the past 11 months saw the number of fires increase by more than 70% when compared with 2018, indicating a major acceleration in land clearing by the country's logging and farming industries.

The smoke from the fires rose high into the atmosphere and could be seen from space. Some regions of Brazil became covered in thick smoke that closed airports and darkened city skies.

As the rainforest burns, it releases enormous amounts of carbon dioxide, carbon monoxide, and larger particles of so-called "black carbon" (smoke and soot). The phrase "enormous amounts" hardly does the numbers justice—in any given year, the burning of forests and grasslands in South America emits a whopping 800,000 tonnes of black carbon into the atmosphere.

This truly astounding amount is almost double the black carbon produced by all combined energy use in Europe over 12 months. Not only does this absurd amount of smoke cause health issues and contribute to global warming but, as a growing number of scientific studies are showing, it also more directly contributes to the melting of glaciers.

In a new paper published in the journal Scientific Reports, a team of researchers has outlined how smoke from fires in the Amazon in 2010 made glaciers in the Andes melt more quickly.

When fires in the Amazon emit black carbon during the peak burning season (August to October), winds carry these clouds of smoke to Andean glaciers, which can sit higher than 5,000 metres above sea level.

Despite being invisible to the naked eye, black carbon particles affect the ability of the snow to reflect incoming sunlight, a phenomenon known as "albedo". Similar to how a dark-coloured car will heat up more quickly in direct sunlight when compared with a light-coloured one, glaciers covered by black carbon particles will absorb more heat, and thus melt faster.

By using a computer simulation of how particles move through the atmosphere, known as HYSPLIT, the team was able to show that smoke plumes from the Amazon are carried by winds to the Andes, where they fall as an invisible mist across glaciers. Altogether, they found that fires in the Amazon in 2010 caused a 4.5% increase in water runoff from Zongo Glacier in Bolivia.

Crucially, the authors also found that the effect of black carbon depends on the amount of dust covering a glacier—if the amount of dust is higher, then the glacier will already be absorbing most of the heat that might have been absorbed by the black carbon. Land clearing is one of the reasons that dust levels over South America doubled during the 20th century.

Glaciers are some of the most important natural resources on the planet. Himalayan glaciers provide drinking water for 240m people, and 1.9 billion rely on them for food. In South America, glaciers are crucial for water supply—in some towns, including Huaraz in Peru, more than 85% of drinking water comes from glaciers during times of drought. However, these truly vital sources of water are increasingly under threat as the planet feels the effects of global warming. Glaciers in the Andes have been receding rapidly for the last 50 years.

The tropical belt of South America is predicted to become more dry and arid as the climate changes. A drier climate means more dust, and more fires. It also means more droughts, which make towns more reliant on glaciers for water.

Unfortunately, as the above study shows, the fires assisted by dry conditions help to make these vital sources of water vanish more quickly. The role of black carbon in glacier melting is an exceedingly complex process—currently, the climate models used to predict the future melting of glaciers in the Andes do not incorporate black carbon. As the authors of this new study show, this is likely causing the rate of glacial melt to be underestimated in many current assessments.

With communities reliant on glaciers for water, and these same glaciers likely to melt faster as the climate warms, work examining complex forces like black carbon and albedo changes is needed more now than ever before.

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Amazon fires 'quicken Andean glacier melt'

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Amazon fires are causing glaciers in the Andes to melt even faster (2019, November 29)
retrieved 29 November 2019
from https://phys.org/news/2019-11-amazon-glaciers-andes-faster.html

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A new theory for how black holes and neutron stars shine bright

Here, a massive super-computer simulation shows the strong particle density fluctuations that occur in the extreme turbulent environments that host black holes and neutron stars. Dark blue regions are low particle density regions, while yellow regions are strongly over-dense regions. Particles are accelerated to extremely high speeds due to the interactions with strongly turbulence fluctuations in this environment. Credit: Image from published study

For decades, scientists have speculated about the origin of the electromagnetic radiation emitted from celestial regions that host black holes and neutron stars—the most mysterious objects in the universe.

Astrophysicists believe that this high-energy radiation—which makes neutron stars and black holes shine bright—is generated by electrons that move at nearly the speed of light, but the process that accelerates these particles has remained a mystery.

Now, researchers at Columbia University have presented a new explanation for the physics underlying the acceleration of these energetic particles.

In a study published in the December issue of The Astrophysical Journal, astrophysicists Luca Comisso and Lorenzo Sironi employed massive super-computer simulations to calculate the mechanisms that accelerate these particles. They concluded that their energization is a result of the interaction between chaotic motion and reconnection of super-strong magnetic fields.

"Turbulence and magnetic reconnection—a process in which magnetic field lines tear and rapidly reconnect—conspire together to accelerate particles, boosting them to velocities that approach the speed of light," said Luca Comisso, a postdoctoral research scientist at Columbia and first author on the study.

"The region that hosts black holes and neutron stars is permeated by an extremely hot gas of charged particles, and the magnetic field lines dragged by the chaotic motions of the gas, drive vigorous magnetic reconnection," he added. "It is thanks to the electric field induced by reconnection and turbulence that particles are accelerated to the most extreme energies, much higher than in the most powerful accelerators on Earth, like the Large Hadron Collider at CERN."

When studying turbulent gas, scientists cannot predict chaotic motion precisely. Dealing with the mathematics of turbulence is difficult, and it constitutes one of the seven "Millennium Prize" mathematical problems. To tackle this challenge from an astrophysical point of view, Comisso and Sironi designed extensive super-computer simulations —among the world's largest ever done in this research area—to solve the equations that describe the turbulence in a gas of charged particles.

The rapidly spinning neutron star embedded in the center of the Crab nebula is the dynamo powering the nebula's eerie interior bluish glow. The blue light comes from electrons whirling at nearly the speed of light around magnetic field lines from the neutron star. The neutron star, the crushed ultra-dense core of the exploded star, like a lighthouse, ejects twin beams of radiation that appear to pulse 30 times a second. Credit: NASA, ESA, J. Hester (Arizona State University)

"We used the most precise technique—the particle-in-cell method—for calculating the trajectories of hundreds of billions of charged particles that self-consistently dictate the electromagnetic fields. And it is this electromagnetic field that tells them how to move," said Sironi, assistant professor of astronomy at Columbia and the study's principal investigator.

Sironi said that the crucial point of the study was to identify role magnetic reconnection plays within the turbulent environment. The simulations showed that reconnection is the key mechanism that selects the particles that will be subsequently accelerated by the turbulent magnetic fields up to the highest energies.

The simulations also revealed that particles gained most of their energy by bouncing randomly at an extremely high speed off the turbulence fluctuations. When the magnetic field is strong, this acceleration mechanism is very rapid. But the strong fields also force the particles to travel in a curved path, and by doing so, they emit electromagnetic radiation.

"This is indeed the radiation emitted around black holes and neutron stars that make them shine, a phenomenon we can observe on Earth," Sironi said.

The ultimate goal, the researchers said, is to get to know what is really going on in the extreme environment surrounding black holes and neutron stars, which could shed additional light on fundamental physics and improve our understanding of how our Universe works.

They plan to connect their work even more firmly with observations, by comparing their predictions with the electromagnetic spectrum emitted from the Crab Nebula, the most intensely studied bright remnant of a supernova (a star that violently exploded in the year 1054). This will be a stringent test for their theoretical explanation.

"We figured out an important connection between turbulence and magnetic reconnection for accelerating particles, but there is still so much work to be done," Comisso said. "Advances in this field of research are rarely the contribution of a handful of scientists, but they are the result of a large collaborative effort."

Other researchers, such as the Plasma Astrophysics group at the University of Colorado Boulder, are making important contributions in this direction, Comisso said.

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Mix master: Modeling magnetic reconnection in partially ionized plasma

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More information:
Luca Comisso et al, The Interplay of Magnetically Dominated Turbulence and Magnetic Reconnection in Producing Nonthermal Particles, The Astrophysical Journal (2019). DOI: 10.3847/1538-4357/ab4c33

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#Space | https://sciencespies.com/space/a-new-theory-for-how-black-holes-and-neutron-stars-shine-bright/

An Alien Comet From Another Star Is Soaring Through Our Solar System

Something strange is sailing toward us. Something small and cold and extraordinarily fast. No one knows where it came from, or where it is going. But it's not from around here. This is an interstellar comet - an ancient ball of ice and gas and dust, formed on the frozen outskirts of a distant star, which some lucky quirk of gravity has tossed into our path. To astronomers, the comet is a care package from the cosmos - a piece of a place they will never be able to visit, a key to all the worlds they cannot directly observe.

It is only the second interstellar interloper scientists have seen in our solar system. And it's the first one they've been able to get a good look at. By tracking the comet's movement, measuring its composition and monitoring its behaviour, researchers are seeking clues about the place it came from and the space it crossed to get here. They have already found a carbon-based molecule and possibly water - two familiar chemicals in such an alien object.

As the Sun sinks behind the Tennessee mountains, and stars wink into view, astronomer Doug Durig climbs onto the rooftop of his observatory, powers up his three telescopes and angles them skyward.

Every night, the comet grows bigger and brighter in the sky, expelling streams of gas and dust that may offer up clues to its history. On Dec. 8, it will make its nearest approach to Earth, offering researchers an up-close glimpse before it zooms back into the freezing, featureless void.

Far below in the darkness, Durig will be waiting.

Each star in the night sky represents a possible solar system. Every light in the universe is, more likely than not, some alien planet's sun.

This is the chief lesson of two decades of studying exoplanets. Scientists have identified thousands of worlds beyond our solar system: gas giants and tiny rocky spheres, worlds lit by dim red suns and ones that orbit the spinning remains of collapsed stars. There are even planets circling medium-size yellow suns like ours - though nothing found so far can match the breathable atmosphere and deep, blue oceans of Earth.

Yet even when viewed through the most powerful telescopes, exoplanets are not discernible as anything more than specks of light. And no human alive has a hope of travelling to another star - merely approaching the nearest one would take 40,000 years.

Scientists' best hope for closely examining another solar system was to wait for a piece of one to come to us.

It was August 30, in the quiet moments before dawn, when a self-taught astronomer in a Crimean mountain village spotted a faint smudge low on the horizon, barely distinguishable against the glittering background of stars.

Gennady Borisov submitted his observations to the Minor Planet Center, the astronomers' clearinghouse for information about small bodies in the solar system, so other scientists could take a look.

One night later, halfway across the planet, the strange report caught Durig's eye.

"I was the second person to observe it," Durig said. "That confirmed the comet was real."

Within a couple of weeks, scientists had collected enough observations to calculate the comet's orbit. But they did not find the oval path that comets typically make around the sun. Instead, the orbit was hyperbolic - it did not close in on itself. The object was also traveling at the blistering speed of 93,000 miles per hour, far faster than any comets, asteroids or planets orbiting our sun.

"Wow," said Davide Farnocchia, a navigation engineer at NASA's Jet Propulsion Laboratory, who was among the first people to determine that the comet came from another star. "I was not expecting to see anything like that."

Comet's straight path slightly deflected by the sun's gravitational pull (L), position relative to Earth (R)
Photo Credit: NASA, ESA, J. Olmsted, F. Summers (STScI)

There has been only one other interstellar object spotted in our solar system: a cigar-shaped rock named 'Oumuamua, a Hawaiian word that translates to "messenger from afar."

But 'Oumuamua was already on its way out of the system when it was discovered in October 2017, and it was so faint that scientists were never able to view it as more than a single pixel of light. They were not quite sure what they had seen - was it a metallic, rocky asteroid or an icy, dusty comet? And they were unsure whether the detection was just a lucky fluke, never to be repeated, or a harbinger of things to come.

So researchers were thrilled when, less than two years later, another interstellar traveler arrived.

The new comet, which has been named 2I/Borisov (indicating its discoverer and its status as the second known interstellar object), is expected to be within reach of telescopes until fall 2020. At its closest approach, next month, it will be twice as far from Earth as Earth is from the sun.

Though it entered the solar system from the direction of the constellation Cassiopeia, scientists do not know yet where 2I/Borisov came from, or how long it has drifted through the desolation of interstellar space. Given its current speed, it has certainly been traveling for millions, if not billions, of years.

As the object gets closer to the sun's warmth, ices on its surface turn into gas. This creates the characteristic halo-like "coma," which scientists can scrutinize to determine what the comet is made of. Already, 2I/Borisov has been observed more than 2,000 times.

"That's going to be fun, in terms of looking at this object . . . as it comes in from the deep freeze for the very first time," said Michele Bannister, an astronomer at Queen's University Belfast. "Let's open it up and see what we have with this particular present from another star."

Astronomer Doug Durig waits in darkness for images of the celestial object 2I/Borisov
Photo Credit: Washington Post photo by Sarah Kaplan

Exoplanet discoveries revealed we live in a crowded cosmos. But they also awakened Earthlings to how lonely we are. Mostplanetary systems discovered in recent decades are wildly unfamiliar, and the most common type of exoplanet - a body larger than Earth but smaller than Neptune - doesn't exist near our home.

When astronomers had only our own solar system to go by, "it used to seem like planet formation was solved,"said Malena Rice, an astrophysicist at Yale University. "And then all of a sudden there are all these strange systems that don't fit our picture."

Interstellar comets are uniquely useful for confronting this conundrum. They are born of the same swirling disk of gas and dust that produces planets around an infant star. But then they get stranded at the icy edges of solar systems, where they can preserve the early ingredients of planet formation.

Comets in our own solar system have been found to contain some of the basic ingredients for life: water, carbon, even complex organic compounds. Now 2I/Borisov could tell us whether life's essential molecules were among the building blocks of a world beyond our own.

This fall, Bannister's colleague Alan Fitzsimmons produced the first-ever detection of a chemical compound emitted by an interstellar comet. Separating light from 2I/Borisov into its component parts, his team found a signature of cyanogen, a molecule made of a carbon atom and a nitrogen atom bonded together. The gas is common in comets around this sun.

"When I saw that, I shouted in my office . . . something not repeatable in a respectable newspaper," Fitzsimmons recalled.

A few weeks later, astronomer Adam McKay detected oxygen streaming off the comet, an indicator that sunlight is striking water on the surface and breaking up the molecule. If confirmed, this would be the first-ever detection of alien water in our solar system. It is also another sign that 2I/Borisov is much like the comets we know.

"Even in these other systems where their architectures are very different, maybe the underlying physics and chemistry is still pretty similar," said McKay, a research scientist at NASA's Goddard Space Flight Center.

Models of our solar system suggest that about 90 percent of the leftover material from planet formation was ejected into interstellar space. The space beyond Neptune still harbours millions of icy bodies, which over millennia can be knocked out of orbit and slung away from the sun.

If any of these scattered fragments happen to be pulled into another system and start to glow in the heat of its star, they will appear as interstellar comets to whoever might be watching.

"There's a universality to that, which is amazing," Bannister said. "Our planetary system is woven together with another planetary system by these little wanderers roving across the galaxy."

With just an hour to go until daybreak, 2I/Borisov is due to appear above the horizon and make its way across the eastern sky. Durig's long night is almost over.

Sewanee: The University of the South, the 1,600-student liberal arts college where Durig works, does not have the massive instruments needed to resolve faint night-sky objects. Instead, he must take hundreds of images of the same spot, then use a computer program to layer them so dim lights become clear.

The astronomer checks the focus of his 12-inch Schmidt-Cassegrain telescope and sets it to work, snapping pictures of the place where the interstellar comet is expected to be. He rubs a hand across his eyes, itchy from hours spent beneath the dim red lights he uses to protect his night vision.

It is tiring and often tedious work. Unlike discoverers, follow-up observers do not get to put their names on anything. And unlike researchers working at the world's largest observatories, someone such as Durig faces real hurdles in achieving the findings that get published in prestigious journals.

Still, extraordinary discoveries must be confirmed and refined, again and again, by ordinary people. News may be made by breakthroughs, but knowledge is cemented in the follow-ups.

Here in Sewanee's cramped observatory, cluttered with stacks of observation records and piles of broken equipment he hopes to one day refashion into something usable, "we're doing essential science," Durig says. "We're filling in all the gaps."

Once his telescope has captured an hour's worth of snapshots, Durig compiles them into stacks of 100. In the images that emerge, colours are inverted, so stars appear as black smears on a white background. In the lower left is a dark dot encircled in a halo of fuzz.

Durig clicks forward to the next stack, and the dot moves by a centimetre. Another click, and it moves again.

That's how he knows he is looking at the comet, something swift and surrounded by dust, something that does not behave like anything else in the sky.

Durig sends his images and a record of the comet's location to the Minor Planet Center - another drop of data in the bucket of scientific knowledge.

Consistent observations like this, conducted by the same people using the same instruments every night, will be even more important once the comet becomes visible in the Southern Hemisphere, where many of the world's biggest telescopes are positioned. They need to be pointed with extreme precision, so astronomers must have a firm handle on the comet's trajectory and things that might subtly alter it, such as outbursts of gas.

An accurate orbit is also key to astronomers' most ambitious plan for the comet.

"If we can get the best possible trajectory, so we can trace it back with the exact direction it's coming in . . . maybe we can find out what the origin system is," said Farnocchia, the Jet Propulsion Laboratory engineer.

Identifying the comet's parent star would be a tremendous feat, the astronomical equivalent of tracing a message in a bottle back to the person who sent it millions of years ago from billions of miles away. It may not turn out to be possible, most scientists acknowledge.

But maybe that's okay, they say. Because the comet will have already revealed so much else. It will have told us something about the birth of solar systems. It will have connected our home to the workings of the wider galaxy. And now that we have seen it, it is easier to believe that more are out there to be found.

Here on Earth, together in the darkness, Durig and his fellow astronomers will be waiting.

© The Washington Post 2019

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Why Cloud Constellation turned down $100 million

In December, Cloud Constellation was finalizing receipt of a $100 million investment that would help the startup deploy a ring of secure data-storage satellites in low Earth orbit.

By spring, Cloud Constellation had walked away from the deal, citing a review by the Committee on Foreign Investment in the United States, or CFIUS, as one of the reasons.

Cloud Constellation CEO Cliff Beek. Credit: Cloud Constellation

Cliff Beek, CEO of Cloud Constellation, said that the funds — roughly a third of what the company estimates it needs to build and launch its satellite constellation — were too difficult to accept because they came from a Chinese company.

“We did not close the round for various reasons,” Beek said in an interview. “One very important reason was our desire to do business with the U.S. government. And of course, other strategic relationships questioned the source of our funding as well.”

The Chinese company poised to invest in Cloud Constellation was Hong Kong-based HCH Group, a former Hughes Network Systems subsidiary the U.S. satellite communications company spun off in 2013.

Beek said the U.S. Commerce Department, one of seven federal agencies with a seat on CFIUS, was wary of the HCH Group investment.

Cloud Constellation’s satellite manufacturing partner, LeoStella of Seattle, was also leery of the HCH Group funds, Beek said.

CFIUS reviews can delay or cancel investment activity deemed a threat to U.S. national security. Prior to the Foreign Investment Risk Review Modernization Act of 2018, CFIUS focused primarily on mergers, acquisitions and investments where a foreign entity claimed 10 percent or more of a U.S. business. Under the new law, CFIUS can review any foreign investment in critical technologies if the foreign investor obtains certain rights, including access to information that is not publicly available and membership on a company’s board of directors.

The Foreign Investment Risk Review Modernization Act does not target China specifically, but it is widely seen as an attempt to limit Chinese investment in advanced technology, critical infrastructure and businesses that collect personal data on U.S. citizens. Chinese deals are likely to garner significant CFIUS attention, according to entrepreneurs, investors and attorneys who specialize in international trade.

CFIUS, which is chaired by the U.S. treasury secretary and draws its members from the State, Defense, Justice, Commerce, Energy and Homeland Security departments, thwarted a $416 million investment in satellite connectivity provider Global Eagle from Beijing Shareco Technologies in 2017. This year, the U.S. Federal Communications Commission blocked China Mobile’s application to provide cellular services in the U.S. following a negative CFIUS review.

Beek said Cloud Constellation still benefited from working with HCH Group, because while the equity investment didn’t close, it showed the potential of Cloud Constellation’s business.

“The experience was helpful, but it was clear early on — when the inbound calls were coming in from certain customers and vendors, and of course the U.S. government — that this investment was not the path for us to go down,” he said.

Cloud Constellation is in discussion with three separate groups that could invest without raising CFIUS concerns, Beek said.

Cloud Constellation still could count HCH Group as a customer one day, Beek said, and is working with the company on Asia-Pacific service offerings.

Beek said the difficulty CFIUS presents for U.S. startups courting foreign investment should trigger a broader policy discussion about how the United States can offset lost opportunities.

“If foreign investment is precluded into companies deemed as developing critical technologies, can economic incentives be legislatively made for private equity groups engaging in early stage investments?” he asked. “How do we create a pathway that legislates incentives for new investments in our space companies?”

This article originally appeared in the Oct. 7, 2019 issue of SpaceNews magazine.

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