In 1929, Edwin Hubble (shown here at Mount Wilson Observatory) showed that more distant galaxies were flying away from us faster than nearby galaxies, which suggested an expanding universe. PICTORIAL PRESS LTD/ALAMY STOCK PHOTO

By Tom Siegfried

SEPTEMBER 20, 2021

From the day Archimedes cut his bath short to shout “Eureka,” science has been a constant source of surprises.

Even after the abundant accumulation of knowledge in the intervening two millennia, science still retains the capacity to astonish, and the century since Science News began reporting has produced its share of shocking discoveries. Some such surprises happened suddenly (if not necessarily with eureka moments); in other cases, revolutionary shifts in understanding took a while to seep slowly into general scientific awareness.

In either case, Science News was sooner or later on the job during the last 100 years, identifying and reporting the never-ending series of surprises, too numerous to mention here, except for my Top 10.

10. Parity violation

In the 20th century, physicists established the importance of mathematical symmetries in the laws of nature. While all sorts of changes occur in the physical world, the equations describing them remain the same. So it seemed obvious that viewing the universe in a mirror — switching left and right — should have no effect on the accuracy of those equations. Hermann Weyl, a prominent mathematician who died in 1955, boldly stated that “there can be no doubt that all natural laws are invariant with respect to an interchange of right with left.”

But then in 1956 physicists Tsung-Dao Lee and Chen Ning Yang published a theoretical paper suggesting otherwise, and almost immediately two teams of experimenters showed that nature did indeed distinguish left from right (in technical terms, violating parity). Radioactive beta decay of cobalt atoms and the decay of unstable particles called muons both exhibited a left-right disparity in the directions traveled by the emitted beta particles — a major surprise. “It was socko!” recalled Leon Lederman, one of the experimenters, in an interview four decades later. “New atomic matter laws” proclaimed the headline in Science News Letter, the predecessor to Science News, with the subhead declaring the results “a revolution in theoretical physics.”

See full text

If today’s successful academics habitually work late in the laboratory, they’re likely to advocate that the next generation does the same.Credit: Thomas Barwick/Getty

Dave Hemprich-Bennett , Dani Rabaiotti & Emma Kennedy

A major flaw in much scientific and academic career advice is survivorship bias. This is a common logical error, involving drawing conclusions based on those who have ‘survived’ a process — and are thus more visible than those who did not. In the case of science careers advice, the bias arises because those who manage to stick to their chosen career path are there to advise the next generation of researchers on how to stay in their field.

As two postdoctoral researchers in ecology (D.H.B., D.R.) and a lecturer in learning and teaching (E.K.), we have seen many examples of worthy but ‘unsuccessful’ colleagues who left their research field against their wishes. On the flipside, the positions we hold in our respective fields are, to some extent, the result of many chance events that we experienced.

Some of our success came from hard work, grit and good judgement. But much of it came from decisions, luck and circumstances that never make it into careers advice. For example, job opportunities for D.R. and her friends have come about through having drinks with senior scientists, and D.R. was invited to publish her first book Does It Fart? thanks to a completely unplanned Twitter hashtag. Chance or serendipitous experiences such as these are impossible to replicate, yet are key to many people’s ability to stay in their chosen career.

Conversely, E.K. had to leave her original field, English literature, because she could not afford to stay in the insecure, low-paid teaching roles that were available. It is therefore important to know not only why some people ‘succeeded’, but also what pushed many more away. Assuming that all aspiring scientists and academics enjoy similar circumstances to those of their colleagues who have ‘survived’ can only damage the prospects of the next generation, and will lead to professions with much less diverse staff than could have been the case.

See full text

Image from a MAYA collaboration numerical relativity simulation of a neutron star-black hole (NSBH) binary merger, showing the disruption of the neutron star. Credit: Deborah Ferguson (UT Ausitn), Bhavesh Khamesra (Georgia Tech), and Karan Jani (Vanderbilt University).

News Release • June 29, 2021

For the first time, researchers have confirmed the detection of a collision between a black hole and a neutron star. In fact, the scientists detected not one but two such events occurring just 10 days apart in January 2020. The extreme events made splashes in space that sent gravitational waves rippling across at least 900 million light-years to reach Earth. In each case, the neutron star was likely swallowed whole by its black hole partner.

Gravitational waves are disturbances in the curvature of space-time created by massive objects in motion. During the five years since the waves were first measured, a finding that led to the 2017 Nobel Prize in Physics, researchers have identified more than 50 gravitational-wave signals from the merging of pairs of black holes and of pairs of neutron stars. Both black holes and neutron stars are the corpses of massive stars, with black holes being even more massive than neutron stars.

Now, in a new study, scientists have announced the detection of gravitational waves from two rare events, each involving the collision of a black hole and a neutron star. The gravitational waves were detected by the National Science Foundation's (NSF's) Laser Interferometer Gravitational-Wave Observatory (LIGO) in the United States and by the Virgo detector in Italy. The KAGRA detector in Japan, joined the LIGO-Virgo network in 2020, but was not online during these detections.

The first merger, detected on January 5, 2020, involved a black hole about 9 times the mass of our sun, or 9 solar masses, and a 1.9-solar-mass neutron star. The second merger was detected on January 15, and involved a 6-solar-mass black hole and a 1.5-solar-mass neutron star. The results were published today, June 29, in The Astrophysical Journal Letters.

See full text

Link to ApJ publication

A Hubble Space Telescope image (left) of a galaxy known to host a ‘fast radio burst’ helps ID where in the galaxy the blast originated (oval). After image processing (right), the burst’s origin appears centered on one of the galaxy’s spiral arms. NASA, ESA, ALEXANDRA MANNINGS/UNIVERSITY OF CALIFORNIA SANTA CRUZ, WEN-FAI FONG/NORTHWESTERN UNIVERSITY, ALYSSA PAGAN/STSCI

Locating the bursts’ homes suggests a connection to ordinary, young stars

By Lisa Grossman  JUNE 1, 2021 

Five brief, bright blasts of radio waves from deep space now have precise addresses.

The fast radio bursts, or FRBs, come from the spiral arms of their host galaxies, researchers report in a study to appear in the Astrophysical Journal. The proximity of the FRBs to sites of star formation bolsters the case for run-of-the-mill young stars as the origin of these elusive, energetic eruptions.

“This is the first such population study of its kind and provides a unique piece to the puzzle of FRB origins,” says Wen-fai Fong, an astronomer at Northwestern University in Evanston, Ill.

FRBs typically last a few milliseconds and are never seen again. Because the bursts are so brief, it’s difficult to nail down their precise origins on the sky. Although astronomers have detected about 1,000 FRBs since the first was reported in 2007, only 15 or so have been traced to a specific galaxy.

See full text

Fourteen celestial sources of gamma rays (colored dots in this all-sky map of the Milky Way; yellow indicates bright sources and blue shows dim sources) may come from stars made of antimatter. SIMON DUPOURQUÉ/IRAP

If true, the preliminary find might mean some antimatter survived to the present day

By Maria Temming
APRIL 26, 2021

Fourteen pinpricks of light on a gamma-ray map of the sky could fit the bill for antistars, stars made of antimatter, a new study suggests.

These antistar candidates seem to give off the kind of gamma rays that are produced when antimatter — matter’s oppositely charged counterpart — meets normal matter and annihilates. This could happen on the surfaces of antistars as their gravity draws in normal matter from interstellar space, researchers report online April 20 in Physical Review D.

“If, by any chance, one can prove the existence of the antistars … that would be a major blow for the standard cosmological model,” says Pierre Salati, a theoretical astrophysicist at the Annecy-le-Vieux Laboratory of Theoretical Physics in France not involved in the work. It “would really imply a significant change in our understanding of what happened in the early universe.”

See full text

F. Elavsky and A. Geller/Northwestern Univ./LIGO-Virgo Collaboration

May 7, 2021• Physics 14, 67

The latest dataset from gravitational-wave observatories has enough events to allow researchers to study properties of the whole population of black holes.

Black holes (blue), neutron stars (orange), and compact objects of uncertain nature (gray) detected via gravitational waves through September 2019. Each binary merger involves three compact objects: the two coalescing objects and the final remnant. The vertical scale is in solar masses.

Less than six years after the first detection of gravitational waves, observations are becoming routine, with LIGO and Virgo logging black hole mergers more than once per week. At the APS April meeting, the LIGO-Virgo Collaboration (LVC) reported using their catalog of nearly 50 events to estimate the typical properties and histories of black holes. Measurements of black hole spins, for example, suggest that at least two different formation mechanisms are common for black hole binaries. These black hole “population” studies—akin to astronomers’ star surveys—are becoming a prized tool for gravitational-wave scientists, in addition to studies of individual events.

The black holes in the LVC catalog are stellar-mass black holes—the remnants of giant stars after they explode as supernovae. In the past, astronomers could spot these black holes only when they were in a binary orbit with a normal star, but the LIGO and Virgo observatories have revolutionized the field since 2015. “The vast majority of the stellar-mass black holes that we know about in the Universe [were detected via] gravitational waves,” said Carl Rodriguez of Carnegie Mellon University, Pennsylvania, in his presentation at the conference. So gravitational waves are now the main source of data from which astrophysicists will learn about these objects. “For the first time, we’re able to do astronomy” using gravitational waves, said Maya Fishbach of Northwestern University, Illinois, a member of the LVC. “We’re really going to learn more about star formation in general.”

See full text

Researchers bombarded lead nuclei electrons at the Thomas Jefferson National Accelerator Facility. DOE JEFFERSON LAB

By Adrian Cho Apr. 27, 2021

Say what you want about lead, it’s got a surprisingly thick skin—of neutrons, that is. In fact, the layer of neutrons on the outside of a lead nucleus is twice as thick as physicists thought, according to a new study. The seemingly abstruse result could have out-of-this-world implications: Neutron stars, the ultradense spheres left behind when stars explode in supernova explosions, could be stiffer and bigger than theory generally predicts.

“It’s a fantastic experimental achievement,” says Anna Watts, an astrophysicist at the University of Amsterdam who studies neutron stars. “It’s been talked about for years and years and years, and it’s so cool to finally see it done.”

An atom’s nucleus consists of protons and neutrons stuck together by the so-called strong nuclear force. Neutrons generally outnumber protons. Not by too much, however, as a large imbalance in the number of protons and neutrons increases a nucleus’ internal energy and can make it unstable. Theory generally predicts a large nucleus consists of a nearly equal mixture of proton and neutrons surrounded by a skin of pure neutrons.

See full text

Similar article in APS

Paper PREX

Paper PREX Tidal Radius

Scientists think neutron stars are layered. As shown in this illustration, the state of matter in their inner cores remains mysterious.
Credits: NASA’s Goddard Space Flight Center/Conceptual Image Lab

Apr 17, 2021

Matter in the hearts of neutron stars ­– dense remnants of exploded massive stars – takes the most extreme form we can measure. Now, thanks to data from NASA’s Neutron star Interior Composition Explorer (NICER), an X-ray telescope on the International Space Station, scientists have discovered that this mysterious matter is less squeezable than some physicists predicted.

The finding is based on NICER’s observations of PSR J0740+6620 (J0740 for short), the most massive known neutron star, which lies over 3,600 light-years away in the northern constellation Camelopardalis. J0740 is in a binary star system with a white dwarf, the cooling remnant of a Sun-like star, and rotates 346 times per second. Previous observations place the neutron star’s mass at about 2.1 times the Sun’s.

"We're surrounded by normal matter, the stuff of our everyday experience, but there’s much we don’t know about how matter behaves, and how it is transformed, under extreme conditions,” said Zaven Arzoumanian, the NICER science lead at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “By measuring the sizes and masses of neutron stars with NICER, we are exploring matter on the verge of imploding into a black hole. Once that happens, we can no longer study matter because it’s hidden by the black hole’s event horizon."

Arzoumanian and members of the NICER team presented their findings on Saturday, April 17, at a virtual meeting of the American Physical Society, and papers describing the findings and their implications are now undergoing scientific review.

See full text

The storage-ring magnet used for the g – 2 experiment at Fermilab.Credit: Reidar Hahn/Fermilab

30 March 2021

 Long-awaited muon physics experiment nears moment of truth

A result that has been 20 years in the making could reveal the existence of new particles, and upend fundamental physics.

After a two-decade wait that included a long struggle for funding and a move halfway across a continent, a rebooted experiment on the muon — a particle similar to the electron but heavier and unstable — is about to unveil its results. Physicists have high hopes that its latest measurement of the muon’s magnetism, scheduled to be released on 7 April, will uphold earlier findings that could lead to the discovery of new particles.

The Muon g – 2 experiment, now based at the Fermi National Accelerator Laboratory (Fermilab) in Batavia, Illinois, first ran between 1997 and 2001 at Brookhaven National Laboratory on Long Island, New York. The original results, announced in 2001 and then finalized in 20061, found that the muon’s magnetic moment — a measure of the magnetic field it generates — is slightly larger than theory predicted. This caused a sensation, and spurred controversy, among physicists. If those results are ultimately confirmed — in next week’s announcement, or by future experiments — they could reveal the existence of new elementary particles and upend fundamental physics. “Everybody’s antsy,” says Aida El-Khadra, a theoretical physicist at the University of Illinois at Urbana-Champaign.

See full text

Wormholes are fascinating (but theoretical) cosmological objects that can connect two distant regions of the universe. They would allow one to create “shortcuts” through space in order to travel vast distances in a shorter period of time. They are predicted by the general Theory of Relativity, and are what Einstein referred to as “bridges” through space-time. Wormholes are mathematically predicted, if not proven, and a new study illustrates how scientists have taken these theoretical anomalies – which many physicists believe to be real – and created one for them.

Researchers in Spain, from the physics department at the Autonomous University of Barcelona, have actually created a magnetic wormhole in a lab that tunnels a magnetic field through space.
Using matematerials and metasurfaces, our wormhole transfers the magnetic field from one point in space to another through a path that is magnetically undetectable. We experimentally show that the magnetic field from a source at one end of the wormhole appears at the other end as an isolated magnetic monopolar field, creating the illusion of a magnetic field propagating through a tunnel outside the 3D space.

See full text

 A view of the M87 supermassive black hole in polarised light  EHT Collaboration/ESO

The first picture of a black hole’s shadow just got even more interesting. The Event Horizon Telescope (EHT) collaboration released the first direct image of a black hole in 2019, and while the picture on its own was impressive, it wasn’t the scientific smorgasbord some had hoped for. Now, researchers have added polarised light to the picture, giving us an idea of how magnetic fields around a supermassive black hole create powerful jets of matter.

“It was not a lot of information about the actual physics of the gas around the black hole,” says Sara Issaoun, an EHT team member at Radboud University in the Netherlands. “Looking at it in polarised light told us information about the magnetic field of the black hole.”

Read more

Journal references

The Large Hadron Collider at Cern, where scientists are studying the decay of a subatomic particle known as the ‘beauty quark’
(EPA)

23.3.2021

Harry Cockburn : INDEPENDENT

Scientists ‘cautiously excited’ as experiment points towards new era in our understanding of the universe

Unexpected behaviour of subatomic particle known as the ‘beauty quark’ turns standard model of particle physics on its head

Scientists studying the fundamental forces which govern the universe and everything in it are “cautiously excited” recent experiments could lead to a “new era” in our understanding of physics.

While much scientific experimentation confirms existing hypothesis, it seems what gets scientists really bursting with enthusiasm is the discovery of something which confounds their existing theories.

This is what has happened following recent work by an international team conducting a study on subatomic particles at the Large Hadron Collider (LHC) at CERN, the European Organisation for Nuclear Research, near Geneva in Switzerland

The LHC is the world’s largest and most powerful particle accelerator. It is a 27-kilometre long ring of superconducting magnets buried 100 metres deep below the Alps, where physicists fire streams of particles through the tube at close to the speed of light, before crashing them headlong into one another and examining the results of these impacts.

A long-term experiment examining a type of subatomic particle called a beauty quark has revealed that when it is observed in the LHCb experiment, it breaks down into other subatomic particles at an uneven rate.

See full text

Link to the arXiv article 

The photo of Einstein sticking out his tongue is world-famous

It’s been 70 years since the genius physicist stuck out his tongue at pesky reporters. The photo turned him into an icon. But what's the story behind it?

It was March 14, 1951, the day Albert Einstein turned 72. The famous physicist, who was born in Ulm, Germany, had already been living in the United States for many years. At the time, he was working at the Institute for Advanced Study in Princeton, New Jersey. A birthday celebration was held in his honor at the research center.
The paparazzi were lurking outside the venue when he left, hoping to hear one of the world-famous professor's witty quips about the global political situation — and to take the perfect birthday photo.
Not a fan of media hype, and growing weary of being a spokesperson, Einsteinwas annoyed by their presence. Yet there he was, stuck in the back seat of a limousine, sandwiched between the institute's former director, Frank Aydelotte, and his wife, Marie, unable to escape the flashing bulbs. "Enough is enough..." he is said to have repeatedly shouted at the pushy reporters. "Hey, Professor, smile for a birthday photo, please," one shouts.

See full text

Europe’s proposed Einstein Telescope, an early design of which is shown here in an artist’s conception (not to scale), would comprise six detectors in a triangular arrangement of tunnels. ET CONCEPTUAL DESIGN TEAM

By Adrian Cho   Mar. 10, 2021

Just 5 years ago, physicists opened a new window on the universe when they first detected gravitational waves, ripples in space itself set off when massive black holes or neutron stars collide. Even as discoveries pour in, researchers are already planning bigger, more sensitive detectors. And a Ford versus Ferrari kind of rivalry has emerged, with scientists in the United States simply proposing bigger detectors, and researchers in Europe pursuing a more radical design.

“Right now, we’re only catching the rarest, loudest events, but there’s a whole lot more, murmuring through the universe,” says Jocelyn Read, an astrophysicist at California State University, Fullerton, who’s working on the U.S. effort. Physicists hope to have the new detectors running in the 2030s, which means they have to start planning now, says David Reitze, a physicist at the California Institute of Technology (Caltech). “Gravitational wave discoveries have captivated the world, so now is a great time to be thinking about what comes next.”

See full text

The globular cluster NGC 6397 is one of the closest to Earth at a distance of 7,800 light years. Analysis of multiple observations over several years with the Hubble Space Telescope reveals the gravitational effects of multiple stellar-mass black holes. Image: NASA, ESA, T. Brown, S. Casertano, and J. Anderson (STScI)

11 February 2021 Astronomy Now

Black holes are thought to range between two extremes: from stellar-mass black holes that form when single, massive stars collapse to the supermassive behemoths millions to billions of times the mass of the Sun. Intermediate-mass holes, with the gravitational heft of hundreds to tens of thousands of stars, are thought to bridge the gap between the two extremes, but only a few candidates have been identified to date.

Likely habitats for intermediate black holes are the cores of globular clusters, the concentrated assemblies of ancient stars that are nearly as old as the cosmos. Researchers using the Hubble Space Telescope observed one of the closest globulars to Earth – NGC 6397 – looking for stellar motions that might indicate the gravitational influence of an intermediate black hole.

Instead, they were surprised to find signs of multiple stellar-mass black holes.

“We found very strong evidence for an invisible mass in the dense core of the globular cluster, but we were surprised to find that this extra mass is not ‘point-like’ but extended to a few percent of the size of the cluster,” said Eduardo Vitral of the Paris Institute of Astrophysics.

See full text