Physics tip sheet: APS April Meeting

WASHINGTON, D.C., April 9, 2019 — This tip sheet highlights interesting presentations from the upcoming 2019 APS April Meeting in Denver — a major international meeting that features talks and presentations about discoveries in astrophysics, particle physics, energy research and many other areas of modern physics.

The meeting runs from Saturday, April 13 through Tuesday, April 16 at the Sheraton Denver Downtown Hotel, located at 1550 Court Place in downtown Denver. Press registration is open, and information on how to receive press credentials can be found at the bottom of this release.

Many of these speakers will participate in press conferences during the meeting; a schedule will be released next week. Members of the media who are unable to attend in person may register for the live webcasts at https://www.apswebcasting.com.

The first results of the Event Horizon Telescope project, a global network of telescopes that has been working to capture first images of a black hole, will be presented in a dedicated session at the 2019 APS April Meeting in Denver on Sunday morning (http://meetings.aps.org/Meeting/APR19/Session/H04). The results, which have been called groundbreaking, will be announced publicly a few days prior to the APS meeting at a special press conference, hosted by the Event Horizon Telescope project and the National Science Foundation, which takes place on Wednesday, April 10, 2019, 9 a.m. EDT at the National Press Club, 529 14th St NW, Washington, D.C., 20045. For more information on the press conference, see https://www.nsf.gov/news/news_summ.jsp?cntn_id=298155&org=NSF&from=news.

1. Nucleosynthesis in Neutron Star Mergers

2. What Traversable Wormholes Can Tell Us About Quantum Physics

3. Micro-X Sounding Rocket Tests ‘TES’ Detectors

4. Unlocking Home PCs to Advance Binary Black Hole Collision Research

5. Chandra: Exploring Sagittarius A* Event Horizon Dynamics

6. Solving the Mysteries of Ultra-High Energy Cosmic Rays from Another Galaxy

7. COSINE-100 Experiment Tests Claims of Dark Matter Discovery

8. Timing Photons to Improve Medical PET Scans

9. Harnessing Advances in Nuclear Physics to Meet Societal Needs

10. AMEGO: Proposed Mission Opens New Eyes on Energetic Universe

11. Neutron-Freezing of Supercooled Water Discovered

12. Visualizing Complex Dynamics of a Black Hole Merger

13. LISA: Hearing Gravitational Waves in Space

14. NOvA and T2K: Searching for the Universe’s Imbalances with Neutrino Experiments Hundreds of Kilometers Long

15. Time for a Clean Energy Transition16. Slicing Time Gives Insights into the Dynamics of Black Holes

17. North American Power Grid Failure Model

18. Extracting Entanglement in the Quantum World, Cheaply

19. CMB-S4: Experiment to Further Probe Universe’s “Ancient Light”

20. Radical Energy Efficiency by Design

21. The First Stars in the Universe

22. NANOGrav: Looking for Black Holes with a Detector the Size of a Galaxy

23. GRAVITY Collaboration: Best Evidence for the Existence of Massive Black Holes

24. CubeSats: Small but Mighty

The first direct observation of a neutron star collision confirms the presence — and probable production — of heavy elements there. Still, we have no definitive evidence that the heaviest nuclei (gold, platinum, uranium) were produced in the GW170817 merger. We also do not know what fraction of heavy elements observed in the galaxy can be attributed to mergers. Future neutron star events could provide data to improve understanding of the rapid neutron capture events producing elements beyond iron. In particular, an observational signature from a single nucleus — Californium-254 — can potentially confirm that elements up to uranium can be made in mergers. Future astrophysical simulations of mergers will be improved by current and forthcoming data on unstable isotopes, which in combination with astrophysical observations will clarify the role that mergers play in heavy element synthesis.

The presentation, “Nuclear physics and the GW170817 kilonova,” will take place at 10:45 a.m. MT, Saturday, April 13, in room Plaza Court 3 of the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/B14.1

If you drink science fiction, you will eat the worm — or rather, the wormhole. Sending characters though tunnels in curved space-time that connect two places is a well-worn literary device, but it turns out that wormholes may teach us things about quantum physics that not even the best fiction writers could anticipate.

Daniel Jafferis from Harvard University will present findings that wormholes are possible — although not useful for human travel. “From the outside perspective, travel through the wormhole is equivalent to quantum teleportation using entangled black holes,” Jafferis said.

A major stumbling block in formulating wormholes is the need for negative energy, which seemed to be inconsistent with quantum gravity. However, Jafferis, together with Aron Wall and Ping Gao, has overcome this using quantum effects resulting from direct interaction between the ends of the wormhole.

“The real import of this work is in relation to the black hole information problem and the connections between gravity and quantum mechanics,” Jafferis said.

“It gives a window to the experience of an observer inside a spacetime that is accessible from the outside. I think it will teach us deep things about the gauge/gravity correspondence, quantum gravity, and even perhaps a new way to formulate quantum mechanics.”

The presentation, “Traversable wormholes,” will take place at 11:21 a.m. MT, Saturday, April 13, in room Plaza D of the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/B02.2

The Micro-X sounding rocket became the first program to ever fly transition-edge sensor (TES) microcalorimeters into space with its launch in July 2018. Sounding rockets are essentially missiles and are great for testing out new technologies because you can get the payload back and fly again if necessary. They collect only about five minutes of supernova remnant X-ray data on these flights, but sounding rockets are orders of magnitude cheaper than satellites.

Antonia Hubbard from Northwestern University will describe how she and her colleagues used a sounding rocket to operate TES detectors in space. Microcalorimeters work by measuring heat deposition, but what sets TES apart from anything that’s flown before are the thermometers it uses. TES’s are extremely sensitive to temperature — its materials have a normal resistance at room temperature but are superconducting at very cold temperatures. Although there was a flight mishap (the rocket-supplied pointing system failed), the cryogenics stayed cold. So they got calibration source data in flight and became the first to operate TES in space, which is a huge milestone for the field, Hubbard said.

The presentation, “Micro-X Sounding Rocket: 1st Flight Performance and Future Prospects,” will take place at 11:57 a.m. MT, Saturday, April 13, in Governor’s Square 12 at the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/B10.7

A deeper understanding of binary black hole collisions could lie in thousands of personal computers scattered around the globe. Since the Nobel Prize-winning discovery of gravitational waves from a colliding pair of black holes in 2015, LIGO and Virgo gravitational wave detectors have observed gravitational waves from nine more binary black hole collisions. Learning more about these waves promises to deepen understanding of black holes and gravity at its most extreme. But analyses to date have relied upon a small number of supercomputer simulations.

Looking ahead to future discoveries of gravitational waves from these collisions, the number of simulations will need to be greatly expanded to maximize scientific impact. Now a new distributed computing project spearheaded by a West Virginia University team will allow students, astronomy buffs and the general public help researchers perform these lengthy computer simulations by lending processor time on their home desktop or laptop computers. Zachariah Etienne from West Virginia University will describe the BlackHoles@Home software, which will be available for use later this year. The team’s SETI@Home-like project website is already built (http://www.blackholesathome.net).

The presentation, “The BlackHoles@Home Project: Black Hole Binaries on the Desktop Computer,” will take place at 1:42 p.m. MT, Saturday, April 13, in room Governor’s Square 17 of the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/C11.2

Black holes are simple objects that live in complicated and often extreme environments. The Milky Way’s Sagittarius A* is a supermassive black hole with 4 million times the mass of the Sun. Powerful X-ray telescopes like the Chandra X-ray Observatory reveal that it’s embedded in a hot (100 million C/200 million F) envelope of material swirling around it — falling in and being driven back out by physical processes still not understood.

Daryl Haggard from McGill University and her team use Chandra and every other telescope they can get their hands on to probe Sagittarius A*’s roiling surrounds, where strong gravity plays a key role. One key question about the electromagnetic radiation observed from Sagittarius A* is whether observed bright flashes of light, such as X-ray flares, are coming from near the event horizon or arising instead from interactions further away from the black hole. Haggard’s team is working to peer through the chaos to see what happens to light and matter just before it disappears into the black hole.

The presentation, “Chandra Explores Sagittarius A*’s Event Horizon Dynamics: X-ray and Multi-wavelength Variability,” will take place at 2:06 p.m. MT, Saturday, April 13, in room Plaza F at the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/C04.2

Some cosmic rays arrive at Earth with extraordinarily high energy. The Pierre Auger Observatory, a 3,000-square-kilometer array of detectors in Argentina, is unravelling the mysteries of these ultra-high energy cosmic rays (UHECRs) that hit Earth’s atmosphere less than once per square kilometer per century.

Fred Sarazin from the Colorado School of Mines will present recent results from Auger, and over about 15 years, it has made some remarkable discoveries.

Auger has observed a suppression of the cosmic ray flux at the high-energy end of the spectrum as predicted in the ’60s. However, its nature is not as predicted: Auger has determined that those cosmic rays may not be just protons, but a mix of atomic nuclei possibly up to iron. Also, Auger has established that the origin of UHECRs is outside of our galaxy, but their exact astrophysical sources remain elusive.

As the Auger collaboration celebrates its 20th anniversary this year, the observatory is being upgraded and is set to tackle more UHECR mysteries.

The presentation, “Recent results from the Pierre Auger Observatory,” will take place at 8:30 a.m. MT, Sunday, April 14, in room Governor’s Square 10 of the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/G08.1

One of the holy grails of physics is the detection of weakly interacting massive particles (WIMPs), which are believed to constitute dark matter. Since the DAMA/LIBRA experiment in Italy claimed to detect them years ago, no other group has confirmed the signal DAMA/LIBRA claims to observe. DAMA/LIBRA uses sodium iodide crystals as targets for dark matter particles, but other experiments have used different materials such as liquid xenon. To definitively test whether or not DAMA/LIBRA is observing dark matter, COSINE-100, a detector built 700 meters underground in South Korea, is using the same detector material, sodium iodide crystals. COSINE-100’s initial quest to confirm signs of a particular model of WIMPs turned up no evidence of the signal DAMA/LIBRA reports seeing. While this doesn’t necessarily mean DAMA/LIBRA is wrong, William Thompson from Yale University and COSINE-100 colleagues say their finding is significant because the model used to test DAMA/LIBRA’s result is one of the most widely used benchmark models within the field.

The presentation, “First Results from a Spin-Independent WIMP Search with COSINE-100,” will take place at 9:06 a.m. MT, Sunday, April 14, in the Grand Ballroom II at the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/G17.4

Since PET scans rely on detecting corresponding pairs of gamma ray photons emitted after electron and positrons meet and annihilate each other, a key to improving these valuable diagnostic systems lies with better measurement of time differences between the two photons. More precise determination of that time difference, known as time of flight, can result in higher sensitivity. By taking into account the speed of light and using full width at half maximum spectral analysis, a CERN team has launched what’s known as the 10 picosecond Time-of-Flight PET challenge to obtain a much better 3D tissue image — without the need for tomographic inversion.

Paul Lecoq from CERN said this new class of scanning technology has demonstrated an ability to produce images 16 times better than today’s PET scans. New TOF-based scanners may also reduce the amount of radiation needed for the procedure as well as the required radiopharmaceutical injected into patients. The researchers believe the improved scans could lead to new PET applications in cardiovascular, neurological, metabolic, inflammatory and infectious/metabolic areas, as well as pediatric, neonatal and prenatal situations.

The presentation, “Nanocrystal-based scintillators for TOF-PET with ultimate time resolution,” will take place at 10:45 a.m. MT, Sunday, April 14, in room Plaza D at the Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/H02.1

Advances in nuclear physics have allowed researchers to develop groundbreaking imaging and other systems that deliver critical benefits to society. A team at the U.S. Department of Energy Thomas Jefferson National Accelerator Facility is playing a key role in the effort with development of several applications already paying dividends in medical diagnostics and plant biology.

Andrew Weisenberger from JLAB will describe how by taking advantage of the core principle behind PET and SPECT imaging — detection of radioactive isotope “tags” inside living systems — researchers at the facility have designed a number of handheld and compact systems that can conduct imaging with new capabilities. One such system, called PhytoPET, can track sugar production in a living plant. This is critical to understanding nutrient absorption and could lead to development of better soils that don’t need fertilizers. Another system, called AwakeSPECT, uses single photon emission computed tomography to peer into the active brains of un-anesthetized mice. The team also developed a novel gamma camera imaging system that can be placed much closer to human tissue to detect breast cancer in three dimensions.

The presentation, “Compact and Handheld Radioisotope Imaging Systems for Bio-medicine,” will take place at 11:09 a.m. MT, Sunday, April 14, in room Plaza D of the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/H02.2

Many of the most energetic extreme objects in the universe have their peak energy output in a part of the electromagnetic spectrum known as the medium-energy gamma-ray band — an energy range that is lower than that currently measured with NASA’s Fermi Gamma-ray Space Telescope. The international team behind the proposed All-sky Medium Energy Gamma-ray Observatory, or AMEGO, hopes to open a new window into this poorly explored region of the EM spectrum.

AMEGO, the team said, would be able to detect the gamma ray counterparts to both high-energy neutrinos and neutron-star mergers that produce gravitational waves, among other astronomical sources. Operating in an all-sky survey mode, the observatory could shed light in key questions including the formation, evolution and acceleration mechanisms in astrophysical jets; measure the properties of element formation in dynamic systems; and test models that predict dark matter signals in this energy band.

The presentation, “All-sky Medium Energy Gamma-ray Observatory (AMEGO) – A Discovery Mission for the MeV Band,” will take place at 2:06 p.m. MT, Sunday, April 14, in room Governor’s Square 10 of the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/J08.4

Supercooled water has been studied for many decades by chemists and condensed matter physicists — down to -40 C (-40 F). But now, thanks to inspiration from the Disney movie “Frozen,” Matthew Szydagis from the University at Albany, State University at New York and colleagues managed to discover a new property of it.

They found that some particles (neutrons) but not others (gamma rays) trigger freezing. This discovery was made while testing out a theory that if striking a bottle of supercooled water can trigger it to freeze, it might also apply to a subatomic particle like dark matter. To their surprise, it worked, and they established a new way to detect fundamental particles, potentially even dark matter, since neutrons are thought to emulate it. This discovery has wide-ranging potential implications, including for the detection of nuclear weapons in cargo for homeland security, understanding cloud formation, and providing clues about how certain mammalian species hibernate by somehow supercooling their blood.

The presentation, “The Snowball Chamber: Using Supercooled Water to Search for Low-Mass Dark Matter,” will take place at 2:54 p.m. MT, Sunday, April 14, in room Governor’s Square 11 at the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/J09.8

The Laser Interferometer Gravitational-Wave Observatory (LIGO) hunts for gravitational waves from co-orbiting black holes. Black holes lose energy through gravitational waves, spiral in toward each other and eventually merge. To analyze data from detections, an accurate model of expected gravitational waves is crucial. Today, numerical simulations involving Einstein equations are used to predict the gravitational waves — the downside is that they’re costly because they require months on a supercomputer.

So Vijay Varma from Caltech and colleagues created “surrogate models” that use techniques akin to machine learning to interpolate between hundreds of existing numerical simulations. These models reproduce the simulations accurately, while taking only a fraction of a second to evaluate. They also built a Python package that uses surrogate models to help visualize the complex dynamics involved. This includes precession — wobbling caused when the black holes’ rotation axes aren’t perpendicular to the plane of the orbit. Researchers and the general public can use it to generate a visualization of a merging black hole within seconds on a laptop.

The presentation, “Numerical relativity surrogate waveform model for precessing binary black holes,” will take place at 4:06 p.m. MT, Sunday, April 14, in the Grand Ballroom I at the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/L16.4

The Laser Interferometer Space Antenna (LISA), a collaboration between the European Space Agency and NASA set for launch in 2034, will be the first space-based gravitational wave observatory, listening, as does its ground-based counterpart LIGO, for ripples in the fabric of space-time produced by violent events in the universe. LISA will detect lower-frequency waves than LIGO (around 10 megahertz, as opposed to around 100 hertz for LIGO), thus providing information about different sources.

LISA will consist of three spacecraft separated by 2.5 million kilometers in a triangular formation, following Earth in its orbit around the sun. Emanuele Berti from Johns Hopkins University will describe how the trio of satellites will open a new observational window on gravitational wave sources such as the mergers of massive black holes at the centers of galaxies, or black holes and neutron stars falling into massive black holes. It will also perform precision tests of Einstein’s general relativity, and may reveal clues into the nature of dark matter and the origin of the universe.

The presentation, “Low-frequency gravitational waves from massive black holes: implications for fundamental physics and astrophysics,” will take place at 10:45 a.m. MT, Monday, April 15, in room Plaza D of the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/Q02.1

Studies of neutrinos could provide the key to why the universe exists, thanks to the neutrino’s deviation from the original Standard Model of particle physics. In contrast with predictions, neutrinos have mass, and they oscillate between three types. Understanding this behavior may help modify the Standard Model and solve one of the few failings of this successful model: a prediction of equal amounts of matter and antimatter, which should have all annihilated, leaving nothing instead of a matter-filled universe.

Patricia Vahle from William & Mary will review results from two long-baseline neutrino oscillation experiments: NOvA (800-kilometer baseline between Illinois and Minnesota) and T2K (295-kilometer baseline between Tokai and Kamioka in Japan).

The two experiments are searching for differences between the behavior of neutrinos and anti-neutrinos. They are also improving measurements of the splitting between the masses of the three neutrinos as well as determining the ordering of the masses, a crucial unknown. Their cutting-edge experimental techniques will be the basis for the next generation of neutrino experiments.

The presentation, “Recent Results from NOvA and T2K,” will take place at 10:45 a.m. MT, Monday, April 15, in room Plaza E of the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/Q03.1

The climate science community has cautioned the world about the need for immediate action to reduce human greenhouse gas emissions and to work toward a 1.5 C or lower global climate warming target. Energy and transportation technologies are moving rapidly to enable this tremendously challenging goal, but the U.S. currently stands as the sole denier of this path forward. Our planet must reduce human greenhouse gas emissions by 90 percent or more within 30 years to prevent truly horrendous environmental change, said Daniel Kammen from the University of California, Berkeley, who is working to determine how to achieve this gargantuan task of essentially creating a new industrial revolution within just a few decades.

Despite negativity and pushback from “climate deniers” and those resisting change, he said that this massive energy transition is not only possible but can also all be done with an increase in jobs, a new era in research and development, and a push to make society more equitable and just.

The presentation, “An energy plan the Earth can live with,” will take place at 10:45 a.m. MT, Monday, April 15, in room Governor’s Square 16 at the Sheraton Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/Q07.1

Interesting subtleties arise when studying the dynamics of black holes — and, in particular, their event horizons. Adel Rahman of the University of Chicago will present new insights into the dynamics of black hole event horizons that arise as a result of a particular choice of time slicing, or “foliation.”

Rahman and his collaborator Robert Wald show that when a black hole is stationary (not changing with time), there is a natural way to slice up the event horizon — an unambiguous prescription for doing so that is naturally determined by the event horizon’s geometry. This may be useful for the analysis of quantum phenomena involving black holes.

The work also investigates how to characterize the “black hole memory effect” suggested by Hawking, Perry and Strominger, which concerns changes occurring on the event horizon of a black hole after the passage of a gravitational wave.

The presentation, “Horizon Foliations and Black Hole Memory,” will take place at 10:57 a.m. MT, Monday, April 15, in room Governor’s Square 17 at the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/Q11.2

The North American power grid includes more than 100,000 linked transmission lines. The network is a remarkably reliable system responding to both planned and unplanned variations in supply and demand. Single-point failures are accommodated keeping most effects localized. Occasionally, system corrections overload adjacent elements expanding the issue into a large and costly problem.

Adilson E. Motter from Northwestern University will describe a continental-scale model of the power grid capable of describing its dynamics under various conditions. The model identifies vulnerabilities to cascading effects, Motter said. Although most of the power grid is robust, a few central and heavily connected elements are prone to propagating their failures. The model offers an ideal platform for evaluating upgrades and changes to the grid as our electrical system evolves.

The presentation, “North American Power-Grid Network: Failures and Opportunities,” will take place at 11:21 a.m. MT, Monday, April 15, in room Governor’s Square 16 at the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/Q07.2

The subatomic world of quantum physics exhibits many exciting phenomena. One of the most fascinating is “entanglement” — the state in which two particles are connected, or correlated, with each other even if they’re far apart. This discovery has fueled intriguing applications such as quantum teleportation, in which the state of one particle is transmitted from one place to another. Applications such as teleportation, however, require acquisition of entangled systems in the lab.

A team of researchers from the Max Planck Harvard Center for Quantum Optics and the University of Copenhagen is developing such a process with an eye on one primary issue: the energy cost associated with extracting entanglement from other systems. Extraction changes the energy state of the system and raises its energy, said Lucas F Hackl from the Max Planck Institute of Quantum Optics. To help quantum researchers, the team derived how to achieve the cheapest energy change theoretically possible. This allows researchers to determine the cost of extracting entanglement and to benchmark the efficiency of entanglement sources. These quantitative findings hold promise in the areas of cold atoms and quantum fields.

The presentation, “Energy cost of entanglement extraction from quantum fields,” will take place at 11:45 a.m. MT, Monday, April 15, in room Governor’s Square 17 of the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/Q11.6

Since its discovery in 1964, measurements of the Cosmic Microwave Background (CMB) — microwave-wavelength light generated when the universe was in its infancy — have revolutionized our knowledge about the origins and history of the universe and hold promise for probing its earliest moments, the nature of space and time and fundamental particle physics. The ultimate ground-based measurement of this ancient light will come from the $500 million-plus CMB-S4 (or “stage 4”) experiment, which, when it becomes operational in 2027, will consist of dedicated telescopes equipped with half a million highly sensitive superconducting detectors operating at the South Pole and the high Chilean Atacama plateau.

The 200-plus members of the CMB-S4 team anticipate that the experiment will illuminate cosmological inflation, the origins and evolution of the universe, and its matter distribution; place precise constraints on the number and masses of neutrinos; help to reveal the nature of dark energy and dark matter; and test general relativity on large scales. Nils W. Halverson from the University of Colorado Boulder will describe this experiment and what it will reveal about the young universe.

The presentation, “Next Decade Ground: The CMB-S4 Experiment,” will take place at 11:57 a.m. MT, Monday, April 15, in room Plaza Court 1 of the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/Q12.4

The United States uses energy about sevenfold less efficiently than physics permits, in part because many energy-using components are designed suboptimally and separately. But according to Amory Bloch Lovins from the Rocky Mountain Institute, optimally choosing, combining, timing and sequencing parts can save severalfold more energy than normally assumed, and at lower cost.

Lovins will show empirical examples of such integrative design, across many sectors and uses, that demonstrate dramatic savings of energy and money. Often this yields increasing returns (the more you save, the cheaper it gets), contrary to common assumptions from economic theory.

Integrative design — optimizing buildings, vehicles, factories and equipment as whole systems, not as isolated components — can greatly shrink the country’s energy appetite and pollution, not at a cost but at a profit, Lovins said. The same orthodox engineering principles apply, but asking different design questions in a different order yields breakthrough results. The main obstacles are between our ears, Lovins added.

The presentation, “Integrative Design for Radical Energy Efficiency,” will take place at 11:57 a.m. MT, Monday, April 15, in room Governor’s Square 16 of the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/Q07.3

One of the keys to better understanding the origins of our universe is learning more about the first stars formed in the cold, dark expanse that followed the Big Bang. Researchers are attempting to identify stars formed when the only elements present were nonheavy hydrogen, helium and a tiny amount of lithium. Since observational discovery of first stars would require extremely large telescopes, a University of Tokyo team is producing theoretical models that attempt to explain the pattern of heavier elements observed in so-called metal-poor stars, which are very different than our sun.

Ken’ichi Nomoto from the University of Tokyo will describe how in those stars, carbon-iron and zinc-iron ratios are much higher than in the sun. These ratios could be explained by elements ejected during supernova explosions of first stars — many of which were 10 times more energetic than ordinary supernovae. This theory suggests a large fraction of first supernovae of the first stars in our universe were like energetic stars associated with gamma ray bursts.

The presentation, “First Stars: Their Supernova Explosions and Connections to Extremely Iron-Poor Stars,” will take place at 1:30 p.m. MT, Monday, April 15, in room Plaza F of the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/R04.1

Joseph Simon from NASA’s Jet Propulsion Laboratory will present data from a galactic-scale gravitational wave detector called NANOGrav, which harnesses a network of pulsars, highly magnetized neutron stars that rotate thousands of times a second with astonishing regularity. Gravitational waves can disrupt the regularity of the pulsar signals: By searching through years of data for many pulsars, the NANOGrav team believes it’s possible to pick out the miniscule gravitational waves caused by supermassive black hole pairs with nanohertz frequencies, equating to orbits years or even decades long.

It’s no easy task to separate the gravitational wave effects on the pulsar timing from other perturbations, such as the Earth’s movement through the solar system and the dispersion caused by wisps of gas the pulsar radiation has passed through on its journey across the galaxy. However, improvements in the data set and advanced noise-modeling techniques are enabling the NANOGrav team to set constraints on the population of supermassive black holes binaries with unprecedented accuracy.

The presentation, “Results from the search for a stochastic gravitational wave background in the NANOGrav 12.5-year data set,” will take place at 3:30 p.m. MT, Monday, April 15, in Grand Ballroom 1 of the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/T16.1

Black holes are thought to be objects so massive and compact that not even light can escape — regions of space-time irreversibly locked away from the outside world. Albert Einstein’s theory of general relativity predicts black holes, but how do we know they really exist? To test the black hole paradigm, Frank Eisenhauer from the Max-Planck-Institute for Extraterrestrial Physics and colleagues from the GRAVITY collaboration combined the four Very Large Telescopes of the European Southern Observatory with the GRAVITY instrument to create the world’s largest telescope.

Eisenhauer will describe how this “super telescope,” with a diameter of 130 meters and a collecting area of more than 200 square meters, offers an unprecedented combination of sharpness and sensitivity. In 2018, the researchers directly measured the gravitational redshift around the massive black hole in the center of our galaxy, and tested in situ the fundamentals of Einstein’s theory of general relativity around such an object. To their great surprise, they observed hot gas orbiting the black hole at 30 percent the speed of light just outside the point of no return (its event horizon). These GRAVITY observations provide the best evidence so far for the existence of massive black holes.

The presentation, “General relativistic effects around the Galactic Center black hole,” will take place at 3:30 p.m. MT, Monday, April 15, in room Plaza D at the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/T02.1

TUESDAY HIGHLIGHTS

Only a few years ago, the astronomy and heliophysics communities were skeptical about whether CubeSats could obtain scientifically relevant data. But these breadloaf-size satellites have proven their ability to return useful data. The twin Miniature X-ray Solar Spectrometer (MinXSS) CubeSats are the first solar science-oriented CubeSat missions flown for the NASA Science Mission Directorate, and they observe soft X-rays from the Sun, which can disrupt Earth’s upper atmosphere and hamper radio and GPS signals traveling through the region. MinXSS data is consistent with inferences from large satellites, allowing these combined data sets to study solar flare, active regions and quiet Sun temperature, density, and elemental abundance variations.

Christopher S. Moore from the Harvard-Smithsonian Center for Astrophysics worked on the MinXSS CubeSats as part of his doctoral research at the University of Colorado Boulder and believes they provide excellent opportunities to train future leaders in technology and science because students commonly play pivotal roles in design, development, testing, mission operations and science analysis. More than 40 graduate students contributed to MinXSS over its lifetime.

The presentation, “Using the Miniature X-ray Solar Spectrometer (MinXSS) CubeSats to Probe HOT Plasma in the Atmosphere of a COOL Star,” will take place at 10:57 a.m. MT, Tuesday, April 16, in room Governor’s Square 10 at the Sheraton Denver Downtown Hotel. ABSTRACT: http://meetings.aps.org/Meeting/APR19/Session/X08.2

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APS will provide free registration to all staff journalists representing media organizations, professional freelance journalists on assignment, and student journalists who are attending the meeting for the express purpose of gathering and reporting news and information. Press registration grants full access to all scientific sessions, to the press room, and to the press conferences. We will also provide complimentary press registration to university press officers, PIOs and other professional media relations staff.

Press registration grants full access to all scientific sessions, to the press room, and to the press conferences. Press credentials are approved at the sole discretion of APS. For press related questions about the APS April Meeting, email [email protected]>.

A series of press conferences will be held during the meeting at the Sheraton Denver Downtown Hotel. A complete schedule will be released the week before the meeting. The press conferences will be live webcast, and members of the media who are unable to attend the meeting in person may register to view the live webcasts at https://www.apswebcasting.com.

The American Physical Society is a nonprofit membership organization working to advance and diffuse the knowledge of physics through its outstanding research journals, scientific meetings, and education, outreach, advocacy, and international activities. APS represents over 55,000 members, including physicists in academia, national laboratories, and industry in the United States and throughout the world. Society offices are located in College Park, Maryland (Headquarters), Ridge, New York, and Washington, D.C. https://www.aps.org/