Trundling along the ecliptic in Virgo, our satellite hangs near the bright star Spica in the evening sky.
Look southwest after sunset to spot the waxing Moon near the bright star Spica in Virgo. Credit: Stellarium/USGS/Celestia/Clementine
The Moon now passes 0.8° south of Spica at 6 P.M. EDT, with the pairing visible as evening twilight falls. (As with Mars earlier this week, some parts of the world will see Spica disappear behind the Moon in an occultation — this time, southern South America will get that view.)
By 9:30 P.M. local daylight time, the Moon sits to the lower left of Spica in the southwest. The star, which glows at magnitude 1.0, is an incredibly hot, massive star more than 10 times the mass of our Sun, shining with a piercing blue-white light that’s lovely through binoculars or any telescope. Take some time to enjoy the Moon under magnification as well, skimming along the terminator delineating lunar night from day, now centered on the nearside at First Quarter.
Sunrise: 5:36 A.M. Sunset: 8:32 P.M. Moonrise: 2:12 P.M. Moonset: 12:41 A.M. Moon Phase: Waxing gibbous (59%) *Times for sunrise, sunset, moonrise, and moonset are given in local time from 40° N 90° W. The Moon’s illumination is given at 12 P.M. local time from the same location.
For a look ahead at more upcoming sky events, check out our full Sky This Week column.
For the first time, astronomers have obtained visual evidence that a star met its end by detonating twice. By studying the centuries-old remains of supernova SNR 0509-67.5 with the European Southern Observatory’s Very Large Telescope (ESO’s VLT), they have found patterns that confirm its star suffered a pair of explosive blasts. Published today, this discovery shows some of the most important explosions in the Universe in a new light.
Most supernovae are the explosive deaths of massive stars, but one important variety comes from an unassuming source. White dwarfs, the small, inactive cores left over after stars like our Sun burn out their nuclear fuel, can produce what astronomers call a Type Ia supernova.
“The explosions of white dwarfs play a crucial role in astronomy,” says Priyam Das, a PhD student at the University of New South Wales Canberra, Australia, who led the study on SNR 0509-67.5 published today in Nature Astronomy. Much of our knowledge of how the Universe expands rests on Type Ia supernovae, and they are also the primary source of iron on our planet, including the iron in our blood. “Yet, despite their importance, the long-standing puzzle of the exact mechanism triggering their explosion remains unsolved,” he adds.
All models that explain Type Ia supernovae begin with a white dwarf in a pair of stars. If it orbits close enough to the other star in this pair, the dwarf can steal material from its partner. In the most established theory behind Type Ia supernovae, the white dwarf accumulates matter from its companion until it reaches a critical mass, at which point it undergoes a single explosion. However, recent studies have hinted that at least some Type Ia supernovae could be better explained by a double explosion triggered before the star reached this critical mass.
Now, astronomers have captured a new image that proves their hunch was right: at least some Type Ia supernovae explode through a ‘double-detonation’ mechanism instead. In this alternative model, the white dwarf forms a blanket of stolen helium around itself, which can become unstable and ignite. This first explosion generates a shockwave that travels around the white dwarf and inwards, triggering a second detonation in the core of the star — ultimately creating the supernova.
Until now, there had been no clear, visual evidence of a white dwarf undergoing a double detonation. Recently, astronomers have predicted that this process would create a distinctive pattern or fingerprint in the supernova’s still-glowing remains, visible long after the initial explosion. Research suggests that remnants of such a supernova would contain two separate shells of calcium.
Astronomers have now found this fingerprint in a supernova’s remains. Ivo Seitenzahl, who led the observations and was at Germany’s Heidelberg Institute for Theoretical Studies when the study was conducted, says these results show “a clear indication that white dwarfs can explode well before they reach the famous Chandrasekhar mass limit, and that the ‘double-detonation’ mechanism does indeed occur in nature.” The team were able to detect these calcium layers (in blue in the image) in the supernova remnant SNR 0509-67.5 by observing it with the Multi Unit Spectroscopic Explorer (MUSE) on ESO’s VLT. This provides strong evidence that a Type Ia supernova can occur before its parent white dwarf reaches a critical mass.
Type Ia supernovae are key to our understanding of the Universe. They behave in very consistent ways, and their predictable brightness — no matter how far away they are — helps astronomers to measure distances in space. Using them as a cosmic measuring tape, astronomers discovered the accelerating expansion of the Universe, a discovery that won the Physics Nobel Prize in 2011. Studying how they explode helps us to understand why they have such a predictable brightness.
Das also has another motivation to study these explosions. “This tangible evidence of a double-detonation not only contributes towards solving a long-standing mystery, but also offers a visual spectacle,” he says, describing the “beautifully layered structure” that a supernova creates. For him, “revealing the inner workings of such a spectacular cosmic explosion is incredibly rewarding.”
This research was presented in a paper to appear in Nature Astronomy titled “Calcium in a supernova remnant shows the fingerprint of a sub-Chandrasekhar mass explosion.”
The team is composed of P. Das (University of New South Wales, Australia [UNSW] & Heidelberger Institut für Theoretische Studien, Heidelberg, Germany [HITS]), I. R. Seitenzahl (HITS), A. J. Ruiter (UNSW & HITS & OzGrav: The ARC Centre of Excellence for Gravitational Wave Discovery, Hawthorn, Australia & ARC Centre of Excellence for All-Sky Astrophysics in 3 Dimensions), F. K. Röpke (HITS & Institut für Theoretische Astrophysik, Heidelberg, Germany & Astronomisches Recheninstitut, Heidelberg, Germany), R. Pakmor (Max-Planck-Institut für Astrophysik, Garching, Germany [MPA]), F. P. A. Vogt (Federal Office of Meteorology and Climatology – MeteoSwiss, Payerne, Switzerland), C. E. Collins (The University of Dublin, Dublin, Ireland & GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany), P. Ghavamian (Towson University, Towson, USA), S. A. Sim (Queen’s University Belfast, Belfast, UK), B. J. Williams (X-ray Astrophysics Laboratory NASA/GSFC, Greenbelt, USA), S. Taubenberger (MPA & Technical University Munich, Garching, Germany), J. M. Laming (Naval Research Laboratory, Washington, USA), J. Suherli (University of Manitoba, Winnipeg, Canada), R. Sutherland (Australian National University, Weston Creek, Australia), and N. Rodríguez-Segovia (UNSW).
Geologists from The University of Hong Kong (HKU) have made a breakthrough in understanding how the Earth’s early continents formed during the Archean time, more than 2.5 billion years ago. Their findings, recently published in Science Advances, suggest that early continental crust likely formed through deep Earth processes called mantle plumes, rather than the plate tectonics that shape continents today.
A New Perspective on Earth’s Early Crust
Unlike other planets in our solar system, Earth is a unique planet with continental crust—vast landmasses with granitoid compositions that support life. However, the origin of these continents has remained a mystery. Scientists have long debated whether early continental crust formed through plate tectonics, i.e., the subduction and collision of giant slabs of Earth’s crust, or through other processes that do not involve plate movement.
This study, led by Drs Dingyi ZHAO and Xiangsong WANG in Mok Sau-King Professor Guochun ZHAO’s Early Earth Research Group at the HKU Department of Earth and Planetary Sciences, together with international collaborators, has uncovered strong evidence that a distinct geodynamic mechanism shaped the Earth’s formative years. Rather than the plate tectonic processes we see today, the research points to a regime dominated by mantle plumes—towering columns of hot, molten rock ascending from deep within the Earth. It also identifies a phenomenon known as sagduction, wherein surface rocks gradually descend under their weight into the planet’s hotter, deeper layers. These findings shed new light on the dynamic processes that governed the early evolution of Earth’s lithosphere.
Studying Ancient Rocks to Understand the Deep Past
The team analysed ancient granitoid rocks called TTGs (tonalite–trondhjemite–granodiorite), which make up a large part of the oldest continental crust. These rocks, found in northern China, date back around 2.5 billion years. Using advanced techniques, the researchers studied tiny minerals within the rocks, known as zircons, which preserve chemical signatures from the time the rocks were formed.
By measuring the water content and oxygen isotope composition of these zircons, the team found that the rocks were formed in dry, high-temperature environments, unlike those typically found in zones where tectonic plates collide and one sinks below the other (subduction zones). The oxygen signatures also indicate a mixture of molten oceanic rocks and sediments, consistent with rocks formed above mantle plumes rather than subduction zones.
The researchers proposed a two-stage model to explain their findings:
Around 2.7 billion years ago, a mantle plume caused thick piles of basalt (Fe- and Mg-rich volcanic rock) to form on the seafloor.
Then, around 2.5 billion years ago, another mantle plume brought heat that caused the lower parts of these basalts to melt partially. This process produced the lighter TTG rocks that eventually formed continental crust.
Implications for Earth and Planetary Science
“Our results provide strong evidence that Archean continental crust did not have to be formed through subduction,” explained Dr Dingyi Zhao, postdoctoral fellow of the Department of Earth and Planetary Sciences and the first author of the paper. “Instead, a two-stage process involving mantle plume upwelling and gravitational sagduction of greenstones better explains the geochemical and geological features observed in the Eastern Block.”
The study distinguishes between two coeval Archean TTG suites—one plume-related and the other arc-related— by comparing their zircon water contents and oxygen isotopes. Professor Guochun Zhao emphasised “The TTGs from the Eastern Block contain markedly less water than those formed in a supra-subduction zone in the Trans-North China Orogen, reinforcing the interpretation of a non-subduction origin.”
“This work is a great contribution to the study of early Earth geodynamics,” co-author Professor Fang-Zhen Teng from the University of Washington added. “Our uses of zircon water and oxygen isotopes have provided a powerful new window into the formation and evolution of early continental crust.”
This study not only provides new insights into understanding the formation of Archean continental crust, but also highlights the application of water-based proxies in distinguishing between tectonic environments. It contributes to a growing body of evidence that mantle plumes played a major role in the formation of the early continental crust.
Journal paper: A two-stage mantle plume–sagduction origin of Archean continental crust revealed by water and oxygen isotopes of TTGs, by Dingyi Zhao et al., Science Advances (2025). DOI: 10.1126/sciadv.adr9513
An image of the coral Stylophora pistillata taken with the new micrsope, BUMP. Each polyp has a mouth and a set of tentacles, and the red dots are individual microalgae residing inside the coral tissue.
view more
Credit: Or Ben-Zvi
The intricate, hidden processes that sustain coral life are being revealed through a new microscope developed by scientists at UC San Diego’s Scripps Institution of Oceanography.
The diver-operated microscope — called the Benthic Underwater Microscope imaging PAM, or BUMP — incorporates pulse amplitude modulated (PAM) light techniques to offer an unprecedented look at coral photosynthesis on micro-scales.
In a new study, researchers describe how the BUMP imaging system makes it possible to study the health and physiology of coral reefs in their natural habitat, advancing longstanding efforts to uncover precisely why corals bleach.
Engineers and marine researchers in the Jaffe Lab for Underwater Imaging at Scripps Oceanography designed and built the cutting-edge microscope with funding from the U.S. National Science Foundation. The microscope is already yielding new insights into the relationship between corals and the symbiotic microalgae that support their health, revealing for the first time how well individual algae photosynthesize within coral tissue.
Their findings were published July 3 in the journal Methods in Ecology and Evolution.
“This microscope is a huge technological leap in the field of coral health assessment,” said Or Ben-Zvi, a postdoctoral researcher at Scripps Oceanography and lead author of the study. “Coral reefs are rapidly declining, losing their photosynthetic symbiotic algae in the process known as coral bleaching. We now have a tool that allows us to examine these microalgae within the coral tissue, non-invasively and in their natural environment.”
Corals are reef-building animals that can’t photosynthesize on their own. Instead, they rely on microalgae living inside their tissues to do it for them. These symbiotic algae use sunlight, carbon dioxide and water to produce oxygen and energy-rich sugars that support coral growth and reef formation.
At just 10 micrometers across, or about one-tenth the width of a human hair, these algae are far too small to be seen with the naked eye. When corals are stressed by warming waters or poor environmental conditions, they lose these microalgae, leading to a pale appearance (“coral bleaching”) and eventual starvation of the coral. Although this process is known, scientists don’t fully understand why, and it hasn’t been possible to study at appropriate scales in the field — until now.
“The microscope facilitates previously unavailable, underwater observations of coral health, a breakthrough made possible thanks to the National Science Foundation and its critical investment in technology development,” said Jules Jaffe, a research oceanographer at Scripps and co-author of the study. “Without continued federal funding, scientific research is jeopardized. In this case, NSF funding allowed us to fabricate a device so we can solve the physiological mystery of why corals bleach, and ultimately, use these insights to inform remediation efforts.”
The new imaging system builds upon previous technology developed by the Jaffe Lab, notably the Benthic Underwater Microscope, or BUM, from 2016. The main component of the BUMP is a microscope unit that is controlled via a touch screen and powered by a battery pack. Through an array of high-magnification lenses and focused LED lights, the microscope captures vivid color and fluorescence images and videos, and it now has the ability to measure photosynthesis and map it in higher resolution via focal scans.
With this tool, scientists are literally shining a light on biological processes underwater, using PAM light measurement techniques to visualize fluorescence and measure photosynthesis, and using imaging to create high-resolution 3D scans of corals.
When viewing the corals under the microscope, the red fluorescence of corals is attributed to the presence of chlorophyll, a photosynthetic pigment in the microalgae. With the PAM technique, the red fluorescence is measured, providing an index of how efficiently the microalgae are using light to produce sugars. The cyan/green fluorescence, concentrated around specific areas such as the mouth and tentacles of the coral, is attributed to special fluorescent proteins produced by the corals themselves and play multiple roles in the coral’s life functions.
The tool is small enough to fit in a carry-on suitcase and light enough for a diver to transport to the seafloor without requiring ship-based assistance. In collaboration with the Smith Lab at Scripps Oceanography, Ben-Zvi, a marine biologist, tested and calibrated the instrument at several coral reef hot spots around the globe: Hawaii, the Red Sea and Palmyra Atoll.
Peering through the microscope, she was surprised by how active the corals were, noting that they changed their volume and shape constantly. Coral behavior that looks like kissing or fighting has been previously documented by the Jaffe Lab, and Ben-Zvi was able to add some new observations to the mix, such as seeing a coral polyp seemingly trying to capture or remove a particle that was passing by, by rapidly contracting its tentacles.
“The more time we spend with this microscope, the more we hope to learn about corals and why they do what they do under certain conditions,” said Ben-Zvi. “We are visualizing photosynthesis, something that was previously unseen at the scales we are examining, and that feels like magic.”
Because scientists can bring the instrument directly into underwater study sites, their work is non-invasive — they don’t need to collect samples or even touch the corals.
“We get a lot of information about their health without the need to interrupt nature,” said Ben-Zvi. “It’s similar to a nurse who takes your pulse and tells you how well you’re doing. We’re checking the coral’s pulse without giving them a shot or doing an intrusive procedure on them.”
The researchers said that data collected with the new microscope can reveal early warning signs that appear before corals experience irreversible damage from global climate change events, such as marine heat waves. These insights could help guide mitigation strategies to better protect corals.
Beyond corals, the tool has widespread potential for studying other small-scale marine organisms that photosynthesize, such as baby kelp. Several researchers at Scripps Oceanography are already using the BUMP imaging system to study the early life stages of the elusive giant kelp off California.
“Since photosynthesis in the ocean is important for life on earth, a host of other applications are imaginable with this tool, including right here off the coast of San Diego,” said Jaffe.
In addition to Ben-Zvi and Jaffe, this study was co-authored by Paul Roberts — formerly with Scripps Oceanography and now at the Monterey Bay Aquarium Research Institute — along with Dimitri Deheyn, Pichaya Lertvilai, Devin Ratelle, Jennifer Smith, Joseph Snyder and Daniel Wangpraseurt of Scripps Oceanography.
Journal
Methods in Ecology and Evolution
Method of Research
Observational study
Subject of Research
Animals
Article Title
The Benthic Underwater Microscope Imaging PAM (BUMP): A Non-invasive Tool for In Situ Assessment of Microstructure and Photosynthetic Efficiency
The moon is looking bright in the sky tonight, and that’s for good reason. It’s all down to where we are in the current lunar cycle.
What is the lunar cycle, you ask? This is a recurring series of eight unique phases of the moon’s visibility. The whole cycle takes about 29.5 days (according to NASA), and these different phases happen as the Sun lights up different parts of the moon whilst it orbits Earth. The moon is always there, but what we see on Earth changes depending on how much is lit up.
See what’s happening with the moon tonight, July 3.
What is today’s moon phase?
As of Thursday, July 3, the moon phase is Waxing Gibbous. According to NASA’s Daily Moon Observation, 57% of the moon will be lit up and visible to us on Earth. This is also day eight of the lunar cycle.
Tonight there is plenty to see with the naked eye, so keep your fingers crossed for a clear sky.
With the naked eye, you’ll be able to spot the Mare Crisium, Mare Tranquillitatis, and the Mare Fecunditatis on the moon’s surface. If you’re in the Northern Hemisphere, these will be positioned in the top right of the moon. If you’re in the Southern Hemisphere, they’re on the bottom left.
If you have binoculars, you’ll also spot the Endymion Crater, the Posidonius Nectaris, and the Mare Nectaris.
If you have a telescope, the Apollo 16 and Apollo 11 landing spots will be visible, as well as the Caucasus Mountains, a 323-mile-long mountain range.
Mashable Light Speed
When is the next full moon?
This month’s full moon will take place on July 10. The last full moon was on June 11.
What are moon phases?
Moon phases are caused by the 29.5-day cycle of the moon’s orbit, which changes the angles between the Sun, Moon, and Earth. Moon phases are how the moon looks from Earth as it goes around us. We always see the same side of the moon, but how much of it is lit up by the Sun changes depending on where it is in its orbit. This is how we get full moons, half moons, and moons that appear completely invisible. There are eight main moon phases, and they follow a repeating cycle:
New Moon – The moon is between Earth and the sun, so the side we see is dark (in other words, it’s invisible to the eye).
Waxing Crescent – A small sliver of light appears on the right side (Northern Hemisphere).
First Quarter – Half of the moon is lit on the right side. It looks like a half-moon.
Waxing Gibbous – More than half is lit up, but it’s not quite full yet.
Full Moon – The whole face of the moon is illuminated and fully visible.
Waning Gibbous – The moon starts losing light on the right side.
Last Quarter (or Third Quarter) – Another half-moon, but now the left side is lit.
Waning Crescent – A thin sliver of light remains on the left side before going dark again.
SYDNEY, July 3 (Xinhua) — Australian scientists have identified a group of proteins that could transform approaches to treating cancer and age-related diseases.
Researchers at the Children’s Medical Research Institute (CMRI) in Sydney have discovered that these proteins play a crucial role in controlling telomerase, an enzyme responsible for protecting DNA during cell division, according to a recent statement by the CMRI, which led the research.
This breakthrough clarifies how telomerase both supports healthy aging and fuels cancer cell growth, highlighting new possibilities for treatments that slow aging or stop cancer by targeting these newly identified proteins.
Telomerase helps maintain the ends of chromosomes, known as telomeres, which are vital for genetic stability. While telomerase is essential for the health of stem cells and certain immune cells, cancer cells often exploit this enzyme to grow uncontrollably, said the study published in Nature Communications.
The team discovered that three proteins — NONO, SFPQ, and PSPC1 — guide telomerase to chromosome ends; disrupting them in cancer cells prevents telomere maintenance, potentially stopping cancer cell growth.
“Our findings show that these proteins act like molecular traffic controllers, making sure telomerase reaches the right destination inside the cell,” said Alexander Sobinoff, the lead author of the study.
Hilda Pickett, head of CMRI’s Telomere Length Regulation Unit and the study’s senior author, noted that understanding how telomerase is controlled opens new possibilities for developing treatments targeting cancer, aging, and genetic disorders linked to telomere dysfunction. Enditem
SYDNEY, July 3 (Xinhua) — Australian scientists have identified a group of proteins that could transform approaches to treating cancer and age-related diseases.
Researchers at the Children’s Medical Research Institute (CMRI) in Sydney have discovered that these proteins play a crucial role in controlling telomerase, an enzyme responsible for protecting DNA during cell division, according to a recent statement by the CMRI, which led the research.
This breakthrough clarifies how telomerase both supports healthy aging and fuels cancer cell growth, highlighting new possibilities for treatments that slow aging or stop cancer by targeting these newly identified proteins.
Telomerase helps maintain the ends of chromosomes, known as telomeres, which are vital for genetic stability. While telomerase is essential for the health of stem cells and certain immune cells, cancer cells often exploit this enzyme to grow uncontrollably, said the study published in Nature Communications.
The team discovered that three proteins — NONO, SFPQ, and PSPC1 — guide telomerase to chromosome ends; disrupting them in cancer cells prevents telomere maintenance, potentially stopping cancer cell growth.
“Our findings show that these proteins act like molecular traffic controllers, making sure telomerase reaches the right destination inside the cell,” said Alexander Sobinoff, the lead author of the study.
Hilda Pickett, head of CMRI’s Telomere Length Regulation Unit and the study’s senior author, noted that understanding how telomerase is controlled opens new possibilities for developing treatments targeting cancer, aging, and genetic disorders linked to telomere dysfunction. ■
In the face of growing global energy demands and environmental concerns, developing sustainable technologies for energy conversion and carbon dioxide (CO₂) utilization is crucial. Photocatalytic CO₂ reduction, which leverages solar energy to convert CO₂ into valuable chemicals, stands out as a promising solution. However, existing photocatalysts face challenges such as insufficient light absorption, poor charge separation, and high energy barriers for CO₂ reduction.
Metal halide perovskites (ABX₃) have shown potential in photocatalysis due to their excellent light absorption and charge transport properties. Lead-containing perovskites, however, face issues like degradation and toxicity, prompting researchers to explore lead-free alternatives like bismuth (Bi)-based materials. Cs₃Bi₂I₉, a lead-free halide perovskite, has attracted attention for its high optoelectronic performance but is limited by aggregation and insufficient oxidation ability.
A research team led by Jie Chen from Xi’an Jiaotong University has developed a novel visible-light-driven (λ > 420 nm) Z-scheme heterojunction photocatalyst composed of 0D Cs₃Bi₂I₉ nanoparticles on 1D WO₃ nanorods for photocatalytic CO₂ reduction. The catalyst was synthesized using an in situ growth approach, where Cs₃Bi₂I₉ nanoparticles were grown on WO₃ nanorods. The research team conducted extensive experiments and characterizations to evaluate the catalyst’s performance and understand its underlying mechanisms.
Enhanced CO₂ Reduction Activity: The catalyst achieved a CO production rate of 16.5 μmol/(g·h), approximately three times higher than that of pristine Cs₃Bi₂I₉ (5.3 μmol/(g·h)), with a CO selectivity of 98.7%.
Stability: The catalyst maintained stable performance after three cycles of 3-hour reactions, with no significant structural changes observed.
Charge Transfer Mechanism: In situXPS and ESR measurements revealed a Z-scheme charge transfer pathway, where electrons transfer from WO₃ to Cs₃Bi₂I₉ under light illumination, facilitating efficient charge separation and reducing recombination.
Photophysical and Photoelectrochemical Properties: The heterojunction exhibited efficient charge carrier transfer and separation, as evidenced by surface photovoltage spectroscopy, electrochemical impedance spectroscopy, and time-resolved photoluminescence measurements.
This work provides valuable insights into the design of efficient heterojunctions for photocatalytic CO₂ reduction. The successful construction of the 0D/1D Z-scheme heterojunction not only enhances the performance of lead-free halide perovskites but also offers a promising strategy for developing advanced photocatalysts. By combining morphological engineering with the Z-scheme heterojunction design, this study paves the way for more efficient and stable photocatalytic materials, contributing to sustainable energy solutions and carbon emission reduction efforts.
Original source: https://journal.hep.com.cn/fie/EN/10.1007/s11708-025-0989-1
