Dark matter does not defy gravity

Map of the distribution of galaxies observed by the DESI collaboration, from which it is possible to accurately measure the velocities of galaxies.
Image Credit: © Claire Lamman/DESI collaboration; custom colormap package by cmastro.

Does dark matter follow the same laws as ordinary matter? The mystery of this invisible and hypothetical component of our Universe — which neither emits nor reflects light — remains unsolved.  A team involving members from the University of Geneva (UNIGE) set out to determine whether, on a cosmological scale, this matter behaves like ordinary matter or whether other forces come into play. Their findings, published in Nature Communications, suggest a similar behavior, while leaving open the possibility of an as-yet-unknown interaction. This breakthrough sheds a little more light on the properties of this elusive matter, which is five times more abundant than ordinary matter.

Ordinary matter obeys four well-identified forces: gravity, electromagnetism, and the strong and weak forces at the atomic level. But what about dark matter? Invisible and elusive, it could be subject to the same laws or governed by a fifth, as yet unknown force.

Dark matter falls into gravitational wells in the same way as ordinary matter, thus obeying Euler's equations.

What Is: The Human Microbiome

The Human Microbiome
Image Credit: Scientific Frontline stock image

The Invisible Organ

The human body is not a sterile, solitary entity. It is a dense, complex, and dynamic ecosystem. Each individual serves as a host to a vast community of microorganisms, collectively known as the human microbiota. This community, which resides in and on the body, is estimated to comprise between 10 trillion and 100 trillion symbiotic microbial cells. Early estimates, which have become a cornerstone of the field, suggested these microbial cells outnumber human cells by a ratio of ten to one. While more recent analyses propose a ratio closer to 1:1, the sheer scale of this microbial colonization remains staggering. These microbial cells, though only one-tenth to one-hundredth the size of a human cell, may account for up to five pounds of an adult's body weight.

This vast microbial community is not a passive passenger. It functions as a "virtual organ" of the body, or more precisely, a "metabolic organ". It is so deeply integrated into our physiology that we are dependent on it for essential life functions, including digestion, immune system development, and the production of critical nutrients.

Bowhead whales’ secret to long life may lie in a protein

University of Rochester biologists are considering ways to ramp up in humans the CIRBP protein, which plays a key role in repairing DNA in bowhead whales and other species.
Photo Credit: National Park Service / public domain

As humans age, we become more vulnerable to cancer and other diseases. Bowhead whales, however, can live for up to 200 years while staying remarkably disease resistant.

How does one of the largest animals on Earth stay healthy for centuries? And could their biology hold clues to help humans live longer too?

New research from scientists at the University of Rochester and their collaborators suggests one answer lies in a protein called CIRBP. The protein plays a key role in repairing double-strand breaks in DNA, a type of genetic damage that can cause disease and shorten lifespan in a variety of species, including humans. In a study published in Nature, the researchers—including URochester biology professors Vera Gorbunova and Andrei Seluanov and first authors Denis Firsanov, a postdoctoral researcher, and Max Zacher, a graduate student in their lab—found that bowhead whales have much higher levels of CIRBP than other mammals. The findings offer a new clue to how humans might one day enhance DNA repair, better resist cancer, and slow the effects of aging.

New Species of Spider Discovered, Just in Time for Halloween

A species of trapdoor spider, named Aptostichus ramirezae, was newly identified by UC Davis scientists.
Photo Credit: Emma Jochim/UC Davis

Scientists at the University of California, Davis, have discovered a new species of trapdoor spider lurking in California’s coastal sand dunes. The newly identified Aptostichus ramirezae is a close relative of Aptostichus simus, a species found along the coast from Monterey to Baja California, Mexico. 

The study, published in Ecology and Evolution, shows that what looked like one species, is actually two. 

“While there are over 50,000 species of spiders worldwide, there are probably hundreds of thousands left to be discovered, even along the coast where new spider species may be hiding just underfoot of California beachgoers,” said senior author Jason Bond, a professor in the UC Davis Department of Entomology and Nematology.

Bioinformatics Uncovers Regenerative Therapy for Spinal Cord Injury

Human brain cells are notoriously difficult to culture in the lab, but UC San Diego researchers successfully grew human brain cells, shown here, in order to test a new treatment approach for spinal cord injury.
Photo Credit: Mark H. Tuszynski/UC San Diego Health Sciences

Spinal cord injury (SCI) remains a major unmet medical challenge, often resulting in permanent paralysis and disability with no effective treatments. Now, researchers at University of California San Diego School of Medicine have harnessed bioinformatics to fast-track the discovery of a promising new drug for SCI. The results will also make it easier for researchers around the world to translate their discoveries into treatments.

One of the reasons SCI results in permanent disability is that the neurons that form our brain and spinal cord cannot effectively regenerate. Encouraging neurons to regenerate with drugs offers a promising possibility for treating these severe injuries. 

The researchers found that under specific experimental conditions, some mouse neurons activate a specific pattern of genes related to neuronal growth and regeneration. To translate this fundamental discovery into a treatment, the researchers used data-driven bioinformatics approaches to compare their pattern to a vast database of compounds, looking for drugs that could activate these same genes and trigger neurons to regenerate.

New nanomedicine wipes out leukemia in animal study

The real-time cellular uptake of spherical nucleic acids (SNAs) and fusion with leukemia cells’ lysosomes, where the SNAs degrade and release potent chemotherapeutics. SNAs are shown in red; cells’ cytoskeletons are green; and cells’ nuclei are blue.
Video Credit: Chad A. Mirkin Research Group

In a promising advance for cancer treatment, Northwestern University scientists have re-engineered the molecular structure of a common chemotherapy drug, making it dramatically more soluble and effective and less toxic.

In the new study, the team designed a new drug from the ground up as a spherical nucleic acid (SNA) — a nanostructure that weaves the drug directly into DNA strands coating tiny spheres. This design converts a poorly soluble, weakly performing drug into a powerful, targeted cancer killer that leaves healthy cells unharmed.

Sublethal antibiotic levels found to boost spread of resistance genes in the environment by up to 45 times

Photo Credit: Daniel Quiceno M

A new study has found that exposure to sublethal levels of antibiotics, amounts too low to kill bacteria, can increase the spread of antibiotic resistance genes of Escherichia coli (E. coli) found in the environment by up to 45 times.

The study led by researchers from the University of Nottingham and Ineos Oxford Institute for antimicrobial research (IOI) analyzed 39 E. coli strains from a UK dairy farm that were resistant to a group of widely used human critical antibiotics called cephalosporins.

Their findings published in Frontiers journal, showed that all 39 cephalosporin resistant E. coli strains carried the same resistance gene- blaCTX-M-15, which protects bacteria from penicillin and cephalosporin antibiotics

Genetic testing showed the bacteria were almost identical, suggesting a single strain had spread across the farm. Researchers also found that the resistance gene wasn’t fixed in place- it could jump from the bacterial chromosome onto separate small circular double-stranded DNA molecules called plasmids, which can move between bacteria.

Climate report: Earth on dangerous path but rapid action can avert the worst outcomes

Palisades Fire. Photo taken Jan. 8, 2025.
Photo Credit: Cal Fire.

2024 was the hottest year on record and likely the hottest in at least 125,000 years, according to an annual report issued by an international coalition led by Oregon State University scientists.

“Without effective strategies, we will rapidly encounter escalating risks that threaten to overwhelm systems of peace, governance, and public and ecosystem health,” said co-lead author William Ripple. “In short, we’ll be on the fast track to climate-driven chaos, a dangerous trajectory for humanity.”

Despite the sixth annual report’s ominous findings – 22 of the planet’s 34 vital signs are at record levels – Ripple stresses that “it’s not too late to limit the damage even if we miss the temperature mitigation goal set by the 2015 Paris Agreement,” an international treaty that set targets for reducing greenhouse gas emissions.

But with many vital signs, including greenhouse gas concentrations in the atmosphere, ocean acidity and ice mass, continuing to trend sharply in the wrong direction, the authors note that time is definitely of the essence.

Dopamine increases willingness to wait for rewards

L-DOPA, a precursor of the neurotransmitter dopamine, makes humans wait longer for rewards, as new research addresses gaps in earlier studies
Photo Credit: Tim Mossholder

A research team from the University of Cologne conducted one of the most comprehensive studies on dopamine and decision-making in humans so far, providing evidence for effects of the former on the latter. Dopamine is a neurotransmitter involved in several functions, including motivation and reward. The team at the Psychology Department led by Dr Elke Smith and Professor Dr Jan Peters found that L-DOPA, a precursor of dopamine that increases dopamine levels in the brain, slightly increased the study participants’ willingness to wait for larger delayed rewards, decreasing impulsivity by about a 20 percent compared to placebo. This modest effect challenges some earlier influential findings from much smaller studies, which had found that L-DOPA increased impulsive choices. The study “Dopamine and temporal discounting: revisiting pharmacology and individual differences” has appeared in the Journal of Neuroscience.

International research collaboration finds solar gamma rays could unlock the mystery of the Sun’s hidden magnetic fields

AIA Image 193 from Solar Dynamics Observatory (SDO)
Compiled from 97 still images.
Video Credit: Scientific Frontline

New research conducted by an international team of physicists has found that high-energy gamma rays might offer the key to unlocking the mysteries of the Sun’s magnetic fields.

The study, led by the Chinese University of Hong Kong, the University of Exeter and the University of Amsterdam, concludes that teraelectronvolt (TeV) gamma rays, observable from specialist facilities on Earth, could be the result of this magnetic field interacting with cosmic rays.

By studying these TeV rays, say the researchers, it could be possible to identify where the fields are located, with their initial findings suggesting they are just beneath the solar surface.

“Magnetic activity of the Sun is the driver behind the space weather and as a consequence the effects space weather has on our society,” says Professor Andrew Hillier, one of the authors of the paper at Exeter. “However, it is not possible to see beneath the solar surface to investigate the Sun’s magnetic field before they manifest on that surface. Our study provides a new method by using cosmic rays to peer beneath the solar surface.