science

nice color pics from far-side, Chang’e-6

Even as a flying squid, I'm repulsed.

The frequency and magnitude of extreme wildfires around the globe has doubled in the last two decades due to climate change, according to a study released Monday.

The analysis, published in the journal “Nature Ecology & Evolution,” focused on massive blazes that release vast amounts of energy from the volume of organic matter burned. Researchers pointed to the historic Australia fires of 2019 and 2020 as an example of blazes that were “unprecedented in their scale and intensity.” The six most extreme fire years have occurred since 2017, the study found.

The latest insight comes from a study on butterflies in the Midwest, published on Thursday in the journal PLOS ONE. Its results don’t discount the serious effects of climate change and habitat loss on butterflies and other insects, but they indicate that agricultural insecticides exerted the biggest impact on the size and diversity of butterfly populations in the Midwest during the study period, 1998 to 2014.

humans must be optimized for hand tools and short life spans.

clickbait headline but interesting materials research. 'a unique magnetic transition phenomenon known as the "spin-fluctuating devil's staircase."'

Tl;dr an undergraduate paper last year claiming females hunt just as often as males got picked up by the media and amplified before it was discovered their analysis was deeply flawed and unreliable. Here several anthropologists present a very gracious rebuttal.

High-temperature fusion plasma experiments conducted in the Large Helical Device (LHD) of the National Institute for Fusion Science (NIFS), have renewed the world record for an acquired data amount, 0.92 terabytes (TB) per experiment, in February 2022, by using a full range of state-of-the-art plasma diagnostic devices.

The International Thermonuclear Experimental Reactor (ITER), which is currently under construction in France through the international collaboration of seven parties, is expected to generate approximately 1 TB of data per experiment in 10 years, and LHD is currently the only experiment in the world that produces data closely aligned to ITER.

The promotion of "Open Science," in which large-scale research data assets are utilized and shared across society, was adopted as a joint statement at the G7 meeting held in Sendai, Japan in 2023. NIFS started full-fledged efforts toward Open Science by establishing the "Open Access Policy" in February 2022 and the "Research Data Policy" in October 2022.

Since 2023, all the data obtained from LHD experiments are open to the public immediately after acquisition and analysis is completed. All computing program source codes for data analysis are also openly available.

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Chose a title that reflects what the article actually discusses!

A new study by astrophysicist Richard Lieu suggests that gravity can exist without mass, proposing thin, shell-like layers of 'topological defects' as an alternative to dark matter for explaining the gravitational binding of galaxies. This theory posits that these defects create a gravitational force without detectable mass, potentially eliminating the need for dark matter in current cosmological models

Lieu started out trying to find another solution to the Einstein field equations, which relate the curvature of space-time to the presence of matter within it. As Einstein described in his 1915 theory of general relativity, space-time warps around bundles of matter and streams of radiation in the Universe, depending on their energy and momentum. That energy is, of course, related to mass in Einstein's famous equation: E=mc2. So an object's mass is linked to its energy, which bends space-time -- and this curvature of space-time is what Einstein described as gravity, a notch more sophisticated than Newton's 17th-century approximation of gravity as a force between two objects with mass. In other words, gravity seems inextricably linked to mass. Not so, posits Lieu.

In his workings, Lieu set about solving a simplified version of the Einstein field equations that allows for a finite gravitation force in the absence of any detectable mass. He says his efforts were "driven by my frustration with the status quo, namely the notion of dark matter's existence despite the lack of any direct evidence for a whole century." Lieu's solution consists of shell-shaped topological defects that might occur in very compact regions of space with a very high density of matter. These sets of concentric shells contain a thin layer of positive mass tucked inside an outer layer of negative mass. The two masses cancel each other out, so the total mass of the two layers is exactly zero. But when a star lies on this shell, it experiences a large gravitational force dragging it towards the center of the shell. "The contention of my paper is that at least the shells it posits are massless," Lieu says. If those contentious suggestions bear any weight, "there is then no need to perpetuate this seemingly endless search for dark matter," Lieu adds.

The next question, then, is how to possibly confirm or refute the shells Lieu has proposed through observations. "The increasing frequency of sightings of ring and shell-like formation of galaxies in the Universe lends evidence to the type of source being proposed here," Lieu writes in his paper. Although he admits that his proposed solution is "highly suggestive" and cannot alone discredit the dark matter hypothesis. "It could be an interesting mathematical exercise at best," Lieu concludes. "But it is the first [mathematical] proof that gravity can exist without mass."

The study has been published in Monthly Notices of the Royal Astronomical Society.

cross-posted from: https://slrpnk.net/post/10495324

https://bjsm.bmj.com/content/58/11/586.abstract

We haven’t pinned down the masses of any individual neutrino, and we don’t even know which ones are heavier than the others. When it comes to our ability to collect raw data, neutrinos present a triple threat: they’re incredibly lightweight (even the electron weighs over 5 million times more than all the neutrinos combined), they shift their identity as they travel (and their rate of flavor oscillation changes as they travel through different substances, so there’s no one-size-fits-all solution), and they barely interact with anything in the first place...

Scientists have traced the ancestry of the modern horse to a lineage that emerged 4,200 years ago and quickly became dominant across Eurasia.