Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog – Page 5

Get the latest international news and world events from around the world.

Log in for authorized contributors

How fast is the universe expanding? Supernova could provide the answer

That the universe is expanding has been known for almost a hundred years now, but how fast? The exact rate of that expansion remains hotly debated, even challenging the standard model of cosmology. A research team at the Technical University of Munich (TUM), the Ludwig Maximilians University (LMU) and the Max Planck Institutes, MPA and MPE, has now imaged and modeled an exceptionally rare supernova that could provide a new, independent way to measure how fast the universe is expanding. The studies are published on the arXiv preprint server.

The supernova is a rare superluminous stellar explosion, 10 billion light-years away, and far brighter than typical supernovae. It is also special in another way: the single supernova appears five times in the night sky, like cosmic fireworks, due to a phenomenon known as gravitational lensing.

Two foreground galaxies bend the supernova’s light as it travels toward Earth, forcing it to take different paths. Because these paths have slightly different lengths, the light arrives at different times. By measuring the time delays between the multiple copies of the supernova, researchers can determine the universe’s present-day expansion rate, known as the Hubble constant.

Entangled Ions Measure Time Faster

An optical clock based on a pair of calcium ions achieves a given precision more quickly when the ions are entangled.

What time is it? How precisely you can answer this question might depend on how long you are able to measure. Glance at a clock and you’ll first register the positions of the hour and minute hands. Look for longer and you’ll make out the movement of the second hand, improving your precision 60-fold. The most precise timepieces currently available are state-of-the-art optical clocks, and these also return a more precise result the longer that they are interrogated. But for many applications—in satellite navigation systems, for example, where the position of a fast-moving vehicle needs to be determined quickly—the answer must be prompt as well as precise. Now Kai Dietze at the German National Metrology Institute and colleagues have demonstrated a way to use quantum entanglement to halve the measurement time of an ion-based optical clock without compromising its precision [1].

Optical clocks are the technological successors to microwave atomic clocks, which, for nearly 60 years, have defined the International System of Units (SI) unit of time: the second. Microwave atomic clocks have been refined since they were first invented in the 1950s, but now optical clocks are reaching maturity in the sense that several systems reach or exceed the criteria required by the International Bureau of Weights and Measures for redefining the second. Optical clocks could potentially outperform microwave clocks by 4 orders of magnitude, with implications for fundamental physics and geodesy.

Tin isotopes reveal clues to nuclear stability

Separated by an ocean and more than a decade, innovative experiments with 31 tin isotopes having either a surplus or shortage of neutrons show how neutrons influence nuclear stability and element formation. The experiments, conducted between 2002 and 2012 at Oak Ridge National Laboratory and more recently at CERN, provide knowledge that impacts nuclear energy and national security applications.

The earlier, influential ORNL measurements contributed to the American Physical Society naming ORNL’s Holifield Radioactive Ion Beam Facility a historic physics site in 2016. Several resulting publications by ORNL scientists and collaborators examined nuclear energy transitions of isotopes of tin and its neighbors and established the “doubly-magic” nature of tin-132 —stability resulting from full outer shells of both protons and neutrons.

Recent laser spectroscopy measurements at CERN’s ISOLDE facility by a team of scientists, including Alfredo Galindo-Uribarri of ORNL, combined with ORNL’s earlier Holifield results, have helped physicists understand how nuclear properties change across isotopes. The results, which help theoretical physicists improve models, are published in the journal Physical Review Letters.

Is this glass square the long, long future of data storage?

Scientists at Microsoft Research in the United States have demonstrated a system called Silica for writing and reading information in ordinary pieces of glass which can store two million books’ worth of data in a thin, palm-sized square.

In a paper published today in Nature, the researchers say their tests suggest the data will be readable for more than 10,000 years.

Could a recently reported high-energy neutrino event be explained by an exploding primordial black hole?

The KM3NeT collaboration is a large research group involved in the operation of a neutrino telescope network in the deep Mediterranean Sea, with the aim of detecting high-energy neutrino events. These are rare and fleeting high-energy interactions between neutrinos, particles with an extremely low mass that are sometimes referred to as “ghost particles.”

Recently, the KM3NeT collaboration reported an extremely high-energy neutrino event, which carried an energy of approximately 220 PeV (peta-electron volts). This is one of the most energetic events recorded to date and its cosmological origin has not yet been identified.

Researchers at Universidade de São Paulo and Universidad Autónoma de Madrid carried out a theoretical study exploring one proposed explanation for this remarkable neutrino event, namely that it originated from the explosion of a primordial black hole near Earth.

Quantum entanglement pushes optical clocks to new precision

By replacing single atoms with an entangled pair of ions, physicists in Germany have demonstrated unprecedented stability in an optical clock. Publishing their results in Physical Review Letters, a team led by Kai Dietze at the German National Metrology Institute, hope their approach could help usher in a new generation of optical clocks—opening up new possibilities in precision experiments and metrology.

To measure the passing of time, every clock works by counting oscillations of some reference frequency—whether it’s the swinging pendulum of a clocktower, or the vibrations of an electrified quartz crystal in a modern digital clock. Timekeeping accuracy is directly tied to how reliable these oscillations are: while a pendulum can accrue noticeable variations in its swing, vibrating quartz is far more reliable, making quartz clocks far more accurate.

Today, optical clocks are the most precise timekeepers ever achieved. In these devices, atoms are first “probed” by an ultra-stable laser tuned close to a specific optical transition. When the laser frequency matches the energy difference between two electronic states, an electron is excited to a higher energy level.

Lab-in-the-loop framework enables rapid evolution of complex multi-mutant proteins

The search space for protein engineering grows exponentially with complexity. A protein of just 100 amino acids has 20100 possible variants—more combinations than atoms in the observable universe. Traditional engineering methods might test hundreds of variants but limit exploration to narrow regions of the sequence space. Recent machine learning approaches enable broader searches through computational screening. However, these approaches still require tens of thousands of measurements, or 5–10 iterative rounds.

With the advent of these foundational protein models, the bottleneck for protein engineering swings back to the lab. For a single protein engineering campaign, researchers can only efficiently build and test hundreds of variants. What is the best way to choose those hundreds to most effectively uncover an evolved protein with substantially increased function? To address this problem, researchers have developed MULTI-evolve, a framework for efficient protein evolution that applies machine learning models trained on datasets of ~200 variants focused specifically on pairs of function-enhancing mutations.

Published in Science, this work represents Arc Institute’s first lab-in-the-loop framework for biological design, where computational prediction and experimental design are tightly integrated from the outset, reflecting a broader investment in AI-guided research.

Obstacle or accelerator? How imperfections affect material strength

Imagine a material cracking—now imagine what happens if there are small inclusions in the material. Do they create an obstacle course for the crack to navigate, slowing it down? Or do they act as weak points, helping the crack spread faster?

Historically, most engineers believed the former, using heterogeneities, or differences, in materials to make materials stronger and more resilient. However, research from Georgia Tech is showing that, in some cases, heterogeneities make materials weaker and can even accelerate cracks.

Led by School of Physics Assistant Professor Itamar Kolvin, the study, “Dual Role for Heterogeneity in Dynamic Fracture,” was published in Physical Review Letters this fall.

/* */