Astronomers claim to have found structures so large, they shouldn’t exist. With such biased, incomplete observations, perhaps they don’t.
A brief flash of green light was recently spotted coming from Venus in the night sky. The colorful shimmer has only been seen a handful of times before.
In a new study published in Science today, JILA and NIST (National Institute of Standards and Technology) Fellow Jun Ye and his research team have taken a significant step in understanding the intricate and collective light-atom interactions within atomic clocks, the most precise clocks in the universe.
Using a cubic lattice, the researchers measured specific energy shifts within the array of strontium-87 atoms due to dipole-dipole interactions. With a high density of atoms, these mHz-level frequency shifts—known as cooperative Lamb shifts—were spectroscopically studied. These shifts were studied spatially and compared with calculated values using imaging spectroscopy techniques developed in this experiment.
These cooperative Lamb shifts, named because the presence of many identical atoms in a tightly confining space modifies the electromagnetic mode structure around them, are an important factor as the numbers of atoms in clocks continue to grow.
The EnVision Venus orbiter could help explain why the hellish planet ended up so different from our own hospitable world.
The U.S. Naval Research Laboratory and the Fermi Large Area Telescope Collaboration have discovered nearly 300 gamma ray pulsars, advancing pulsar research and contributing to gravitational wave studies and navigation applications. The findings also include insights into “spider” pulsars, where a neutron star interacts intensively with its binary companion.
The U.S. Naval Research Laboratory (NRL), in conjunction with the international Fermi Large Area Telescope Collaboration, has announced the discovery of almost 300 gamma ray pulsars. This announcement was made in their Third Catalog of Gamma Ray Pulsars, marking a significant achievement 15 years after the 2008 launch of the Fermi telescope. At the time of Fermi’s launch, there were less than ten known gamma-ray pulsars.
“Work on this important catalog has been going on in our group for years,” said Paul Ray, Ph.D., head of the High Energy Astrophysics and Applications Section at NRL. “Our scientists and postdocs have been able to both discover and analyze the timing behavior and spectra of many of these newfound pulsars as part of our quest to further our understanding of these exotic stars that we are able to use as cosmic clocks.”
“The changes we see preserved in the rock record are driven by large-scale changes in the Martian environment,” said Dr. David Paige. “It’s cool that we can see so much evidence of change in such a small geographic area, which allows us extend our findings to the scale of the entire crater.”
NASA’s Perseverance (Percy) rover has been exploring Jezero Crater on Mars since it landed there in February 2021. During that time, it has made some truly remarkable discoveries and helped us better understand the history of the Red Planet and whether it could have once supported life long ago. It has long been hypothesized that Jezero Crater was once home to a massive lake of liquid water billions of years ago, and a recent study published in Science Advances by the University of California, Los Angeles (UCLA) and the University of Oslo might have confirmed the most precise data to date regarding this hypothesis.
For the study, the researchers used the RIMFAX ground penetrating radar, which can take radar images up to 20 meters (65 feet) below Percy’s location, to analyze the geologic layers underneath the rover. These images gave researchers a first-time glimpse into the former crater floor that has been slowly buried over vast periods of geologic time.
The discovery of an ancient lake bed beneath the Perseverance rover’s location on Mars could mean the robotic scout has already scraped up microbial fossils. But we won’t know for sure until we fetch the sample.
Jonathan Oppenheim at University College London has developed a new theoretical framework that aims to unify quantum mechanics and classical gravity – without the need for a theory of quantum gravity. Oppenheim’s approach allows gravity to remain classical, while coupling it to the quantum world by a stochastic (random) mechanism.
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For decades, theoretical physicists have struggled to reconcile Einstein’s general theory of relativity – which describes gravity — with quantum theory, which describes just about everything else in physics. A fundamental problem is that quantum theory assumes that space–time is fixed, whereas general relativity says that space–time changes dynamically in response to the presence of massive objects.
In 1948, Schwinger developed a local Lorentz-covariant formulation of relativistic quantum electrodynamics in space-time which is fundamentally inconsistent with any delocalized interpretation of quantum mechanics. An interpretation compatible with Schwinger’s theory is presented, which reproduces all of the standard empirical predictions of conventional delocalized quantum theory in configuration space. This is an explicit, unambiguous, and Lorentz-covariant “local hidden variable theory” in space-time, whose existence proves definitively that such theories are possible. This does not conflict with Bell’s theorem because it is a local many-worlds theory.
