The images and our best computer models don't agree.
A trio of intriguing galaxy clusters<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQzNDA0OS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxNTkzNzUyOH0.0IRzkzvKsmPEHV-v1dqM1JIPhgE2W-UHx0COuB0qQnA/img.jpg?width=980" id="d69be" class="rm-shortcode" data-rm-shortcode-id="2d2664d9174369e0a06540cb3a3a9079" data-rm-shortcode-name="rebelmouse-image" />
The three galaxy clusters imaged for the study
Mapping dark matter<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="d904b585c806752f261e1215014691a6"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/fO0jO_a9uLA?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>The assumption has been that the greater the lensing effect, the higher the concentration of dark matter.</p><p>As scientists analyzed the clusters' large-scale lensing — the massive arc and elongation visual effects produced by dark matter — they noticed areas of smaller-scale lensing within that larger distortion. The scientists interpret these as concentrations of dark matter within individual galaxies inside the clusters.</p><p>The researchers used spectrographic data from the VLT to determine the mass of these smaller lenses. <a href="https://www.oas.inaf.it/en/user/pietro.bergamini/" target="_blank" rel="noopener noreferrer">Pietro Bergamini</a> of the INAF-Observatory of Astrophysics and Space Science in Bologna, Italy explains, "The speed of the stars gave us an estimate of each individual galaxy's mass, including the amount of dark matter." The leader of the spectrographic aspect of the study was <a href="http://docente.unife.it/docenti-en/piero.rosati1/curriculum?set_language=en" target="_blank">Piero Rosati</a> of the Università degli Studi di Ferrara, Italy who recalls, "the data from Hubble and the VLT provided excellent synergy. We were able to associate the galaxies with each cluster and estimate their distances." </p><p>This work allowed the team to develop a thoroughly calibrated, high-resolution map of dark matter concentrations throughout the three clusters.</p>
But the models say...<p>However, when the researchers compared their map to the concentrations of dark matter computer models predicted for galaxies bearing the same general characteristics, something was <em>way</em> off. Some small-scale areas of the map had 10 times the amount of lensing — and presumably 10 times the amount of dark matter — than the model predicted.</p><p>"The results of these analyses further demonstrate how observations and numerical simulations go hand in hand," notes one team member, <a href="https://nena12276.wixsite.com/elenarasia" target="_blank">Elena Rasia</a> of the INAF-Astronomical Observatory of Trieste, Italy. Another, <a href="http://adlibitum.oats.inaf.it/borgani/" target="_blank" rel="noopener noreferrer">Stefano Borgani</a> of the Università degli Studi di Trieste, Italy, adds that "with advanced cosmological simulations, we can match the quality of observations analyzed in our paper, permitting detailed comparisons like never before."</p><p>"We have done a lot of testing of the data in this study," Meneghetti says, "and we are sure that this mismatch indicates that some physical ingredient is missing either from the simulations or from our understanding of the nature of dark matter." <a href="https://physics.yale.edu/people/priyamvada-natarajan" target="_blank">Priyamvada Natarajan</a> of Yale University in Connecticut agrees: "There's a feature of the real Universe that we are simply not capturing in our current theoretical models."</p><p>Given that any theory in science lasts only until a better one comes along, Natarajan views the discrepancy as an opportunity, saying, "this could signal a gap in our current understanding of the nature of dark matter and its properties, as these exquisite data have permitted us to probe the detailed distribution of dark matter on the smallest scales."</p><p>At this point, it's unclear exactly what the conflict signifies. Do these smaller areas have unexpectedly high concentrations of dark matter? Or can dark matter, under certain currently unknown conditions, produce a tenfold increase in lensing beyond what we've been expecting, breaking the assumption that more lensing means more dark matter?</p><p>Obviously, the scientific community has barely begun to understand this mystery.</p>
An intriguing theory explains animals' magnetic sense.
- Some animals can navigate via magnetism, though scientists aren't sure how.
- Research shows that some of these animals contain magnetotactic bacteria.
- These bacteria align themselves along the magnetic field's grid lines.
Magnetotactic bacteria hosts<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQyMTQ2Ny9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY2MDcwMTYxMn0.BZ-cpaTejm38_HCvVoSZ92k58dxnQETahNmKOmB14X4/img.jpg?width=980" id="c6097" class="rm-shortcode" data-rm-shortcode-id="a9f01b7583442ad92a05927c79754f50" data-rm-shortcode-name="rebelmouse-image" alt="whale mother and calf" />
A right whale mother and calf
Credit: wildestanimal/Shutterstock<p>One of the paper's authors, Geneticist <a href="https://sciences.ucf.edu/biology/person/robert-fitak/" target="_blank">Robert Fitak</a>,<a href="https://sciences.ucf.edu/biology/person/robert-fitak/" target="_blank" rel="noopener noreferrer"></a> is affiliated with the biology department of the <a href="https://www.ucf.edu" target="_blank">University of Central Florida</a> in (UCF) Orlando. Prior to joining the department, he spent four years as a postdoctoral researcher at Duke University investigating the genomic mechanisms responsible for magnetic perception in fish and lobsters.</p><p>Fitak tells <a href="https://www.ucf.edu/news/animals-magnetic-sixth-sense-may-come-from-bacteria-new-paper-suggests/" target="_blank">UFC Today</a>, "The search for a mechanism has been proposed as one of the last major frontiers in sensory biology and described as if we are 'searching for a needle in a needle stack.'"</p><p>That metaphorical needle stack may well be the scientific community's largest database of microbes, the <a href="https://bmcgenomics.biomedcentral.com/articles/10.1186/1471-2164-9-75" target="_blank" rel="noopener noreferrer">Metagenomic Rapid Annotations using Subsystems Technology database</a>. It lists the animal samples in which magnetotactic bacteria have been found.</p><p>The primary use of the database, says Fitak, has been the measurement of bacterial diversity in entire phyla. An accounting of the appearance of magnetotactic bacteria in individual species is something that has previously be unexplored. "The presence of these magnetotactic bacteria had been largely overlooked, or 'lost in the mud' amongst the massive scale of these datasets," he reports.</p><p>Fitak dug into the database and discovered that magnetotactic bacteria have indeed been identified in a number of species known to navigate by magnetism, among them loggerhead sea turtles, Atlantic right whales, bats, and penguins. <em>Candidatus Magnetobacterium bavaricum</em> is regularly found in loggerheads and penguins, while <em>Magnetospirillum</em> and <em>Magnetococcus</em> are common among right whales and bats.</p><p>As for other magnetic-field-sensitive animals, he says, "I'm working with the co-authors and local UCF researchers to develop a genetic test for these bacteria, and we plan to subsequently screen various animals and specific tissues, such as in sea turtles, fish, spiny lobsters and birds."</p>
The bacteria-host relationship<p>While the presence of the bacteria in these particular species is intriguing, further study is needed to be sure they're responsible for other animals' magnetic navigation. Their presence in these species <em>could</em> be just a coincidence.</p><p>Fitak also notes that he doesn't know at this point exactly where in the host animal the magnetotactic bacteria would reside, or other details of their symbiotic relationship. He suggests that they might be found in nervous tissue associated with navigation, such as that found in the brain or eye.</p><p>If confirmed, Fitak's hypothesis could suggest that our own sensitivity to the Earth's magnetic field might one day be enhanced via magnetotactic bacteria in our own individual microbiomes, should they be benign to us as hosts.</p>
A study from McGill University reveals the secret of musicians who have excellent time.
- When a person locks onto a beat, it's because their brain rhythms have become aligned with it.
- Listening and physically performing are brain functions not directly related to rhythm synchronization.
- The study tracked EEG brain activity during listening, playing along, and recreating rhythms.
Listening and tapping<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzYyNDIzNS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0MzU4NjIzOH0.vK-N6A-goMccmBsL5xOyrzmWoxsiOHDKV-J9YPfHj7Y/img.jpg?width=980" id="48cf6" class="rm-shortcode" data-rm-shortcode-id="1adaf404031fa0036848a1ba4193c1fd" data-rm-shortcode-name="rebelmouse-image" alt="TR-808 rhythm composer" />
A beat machine that produces notes similar to those used by the researchers
Credit: Steve Harvey/Unsplash<p>Palmer and her colleagues worked with 29 adult musicians — 21 female and 6 males, aged 18 to 30 years old — each of whom was proficient with an instrument, having studied for a minimum of six years. With electroencephalogram (EEG) electrodes affixed to their scalps, the participants listened to and tapped along with different versions of three basic rhythms as the scientists captured their brain activity.</p><p>Each rhythm was preceded by a four-beat count off. </p><ul><li><a href="https://www.mcgill.ca/newsroom/files/newsroom/simple1-1.mp3" target="_blank">Rhythm 1:1</a> — repeatedly played a simple series of evenly spaced clicks.</li><li><a href="https://www.mcgill.ca/newsroom/files/newsroom/moderate1-2.mp3" target="_blank" rel="noopener noreferrer">Rhythm 1:2</a> — repeatedly played a two-beat phrase with a higher-pitched sound for the first beat of each phrase and a lower-pitched sound for the second.</li><li><a href="https://www.mcgill.ca/newsroom/files/newsroom/complex3-2.mp3" target="_blank">Rhythm 3:2</a> — repeatedly played the most complex rhythm of the three, a series of triplets. In this case, the lower-pitched sound played the quarter notes while a higher-pitched sound played the triplet notes.</li></ul><p>(Tap or click each rhythm's name above to listen to its complete version with no beats or sounds omitted.)</p><p>The participants were assigned Listen, Synchronize, and Motor tasks. In the:</p><ul><li>Listen task — participants were played a dozen modified versions of the rhythms and asked to report any missing beats they noticed.</li><li>Synchronize task — individuals played along with a dozen versions of the rhythms, in some cases supplying sounds researchers had removed from the patterns.</li><li>Motor task — participants were asked to reproduce a dozen rhythm variations after hearing each one.</li></ul>
Beat markers<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzYyNDQyNi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyNDA5NDU4OX0.GKl27Ed_kuwLg0r_eh_s6yUoes8RN_QS2fMHLBx0vBI/img.jpg?width=980" id="b927a" class="rm-shortcode" data-rm-shortcode-id="b73b2bdc7bb4f9b3c4499fab78b7c5f6" data-rm-shortcode-name="rebelmouse-image" alt="chart with wave lines" />
Credit: Chaikom/Shutterstock<p>The scientists were able to identify neural markers representing each musician's beat perception, revealing the degree of synchronicity between the researchers' rhythms and the brain's own rhythms. Surprisingly, this synchronicity turned out to be unrelated to brain activity associated with either listening or playing.</p><p>Said the study's first authors, PhD students Brian Mathias and Anna Zamm, "We were surprised that even highly trained musicians sometimes showed reduced ability to synchronize with complex rhythms, and that this was reflected in their EEGs."</p><p>While the musician participants were all reasonably competent at tapping along to the rhythms, the degree to which the markers aligned to the beats was what separated the good players from the best. "Most musicians are good synchronizers," say Mathias and Zamm. "Nonetheless, this signal was sensitive enough to distinguish the 'good' from the 'better' or 'super-synchronizers,' as we sometimes call them."</p><p>When Palmer is asked whether a person can develop the ability to become a super-synchronizer, she answers: "The range of musicians we sampled suggests that the answer would be 'yes.' And the fact that only 2-3% of the population are 'beat deaf' is also encouraging. Practice definitely improves your ability and improves the alignment of the brain rhythms with the musical rhythms. But whether everyone is going to be as good as a drummer is not clear."</p>
German researchers have just solved the mystery of how these substances work.
- As pathogens' resistance grows, scientists are searching for a class of drugs that could replace antibiotics.
- Antivitamins that switch off vitamins in bacteria are being investigated.
- Scientists have been struggling to understand how naturally occurring antivitamins do what they do.
Shutting down the dance of the proteins<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzU3Nzk5OS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzMDk4NzI5NX0.FPVenf2jQ4I4raQqn5EpK_DxCGoYRSw3wzIzryl2ys0/img.jpg?width=980" id="27eb8" class="rm-shortcode" data-rm-shortcode-id="6cfa008038077a6fbcab3f53d2af6cf8" data-rm-shortcode-name="rebelmouse-image" alt="Vitamin B1" />
Image source: Ekaterina_Minaeva/Shutterstock<p>The study was led by <a href="https://www.uni-goettingen.de/en/89703.html" target="_blank">Dr. Kai Tittmann's</a> group from the Göttingen Center for Molecular Biosciences at the University of Göttingen in collaboration with <a href="https://www3.mpibpc.mpg.de/groups/de_groot/bgroot.html" target="_blank">Bert De Groot's Computational Biomolecular Dynamics Group</a> from the Max Planck Institute for Biophysical Chemistry Göttingen, and with <a href="https://www.chem.tamu.edu/rgroup/begley/" target="_blank">Tadhg Begley's group</a> from Texas A&M University in College Station, Texas.</p><p>The B1 antivitamin is naturally occurring, and is produced by bacteria as a means of killing off competing bacteria. Its critical atom appears in an apparently unimportant location, deepening the mystery.</p><p>To see how that single atom was doing such an effective job, the researchers used <a href="https://www.pnas.org/content/97/7/3171" target="_blank">high-resolution protein crystallography</a>. This allowed them to observe the interaction between the B1 antivitamin and B1 on an atomic level.<br></p><p>What they saw was that the antivitamin completely interrupted the "dance of protons" that's seen in functioning proteins. Tittmann <a href="https://www.uni-goettingen.de/en/3240.html?id=5964" target="_blank">says</a>, "Just one extra atom in the antivitamin acts like a grain of sand in a complex gear system by blocking its finely tuned mechanics." (Tittmann's group was the first to document this "dance" in <a href="https://www.technologynetworks.com/proteomics/news/dance-of-the-protons-discovery-shows-proteins-instant-message-324139" target="_blank">2019</a>.)</p>
Antivitamins don’t bother humans<p>One particularly significant finding of the new research is that, although the B1 antivitamin prevents B1 from functioning in bacteria, it doesn't interfere with the vitamin for humans. This offers hope that antivitamins can be developed that target and neutralize pathogens without doing harm to patients.</p><p>De Groot's team created computer simulations to learn why humans are unaffected by the errant atom, and found that, "The human proteins either do not bind to the antivitamin at all or in such a way that they are not 'poisoned.'"</p><p>The possibility that antivitamins may at some point be ready to step in and replace failing antibiotics is not totally unexpected. Antivitamins were <a href="https://chemistry-europe.onlinelibrary.wiley.com/doi/epdf/10.1002/cbic.201500072" target="_blank">actually used</a> in the development of antibiotic and <a href="https://www.sciencedirect.com/topics/medicine-and-dentistry/antiproliferative-drug" target="_blank" rel="noopener noreferrer dofollow">antiproliferative</a> drugs such as prontosil and aminopterin. And there are already some antivitamin medicines in use, notably antagonists for vitamins B12, B9, and K.</p>
A clever new study definitively measures how long it takes for quantum particles to pass through a barrier.
- Quantum particles can tunnel through seemingly impassable barriers, popping up on the other side.
- Quantum tunneling is not a new discovery, but there's a lot that scientists don't know.
- By super-cooling rubidium particles, researchers use their spinning as a magnetic timer.
When it comes to weird behavior, there's nothing quite like the quantum world. On top of that world-class head scratcher entanglement, there's also quantum tunneling — the mysterious process in which particles somehow find their way through what should be impenetrable barriers.
Exactly why or even how quantum tunneling happens is unknown: Do particles just pop over to the other side instantaneously in the same way entangled particles interact? Or do they progressively tunnel through? Previous research has been conflicting.
That quantum tunneling occurs has not been a matter of debate since it was discovered in the 1920s. When IBM famously wrote their name on a nickel substrate using 35 xenon atoms, they used a scanning probe microscopes to see what they were doing. And tunnel diodes are fast-switching semiconductors that derive their negative resistance from quantum tunneling.
"Quantum tunneling is one of the most puzzling of quantum phenomena," says Aephraim Steinberg of the Quantum Information Science Program at Canadian Institute for Advanced Research in Toronto to Live Science. Speaking with Scientific American he explains, "It's as though the particle dug a tunnel under the hill and appeared on the other."
Steinberg is a co-author of a study just published in the journal Nature that presents a series of clever experiments that allowed researchers to measure the amount of time it takes tunneling particles to find their way through a barrier. "And it is fantastic that we're now able to actually study it in this way."
Frozen rubidium atoms
Image source: Viktoriia Debopre/Shutterstock/Big Think
One of the difficulties in ascertaining the time it takes for tunneling to occur is knowing precisely when it's begun and when it's finished. The authors of the new study solved this by devising a system based on particles' precession.
Subatomic particles all have magnetic qualities and they spin, or "precess," like a top when they encounter an external magnetic field. With this in mind, the authors of the study decided to construct a barrier with a magnetic field, causing any particles passing through it to precess as they did so. They wouldn't precess before entering the field or after, so by observing and timing the duration of the particles' precession, the researchers could definitively identify the length of time it took them to tunnel through the barrier.
To construct their barrier, the scientists cooled about 8,000 rubidium atoms to a billionth of a degree above absolute zero. In this state, they form a Bose-Einstein condensate, AKA the fifth-known form of matter. When in this state, atoms slow down and can be clumped together rather than flying around independently at high speeds. (We've written before about a Bose-Einstein experiment in space.)
Using a laser, the researchers pushed about 2,000 rubidium atoms together in a barrier about 1.3 micrometers thick, endowing it with a pseudo-magnetic field. Compared to a single rubidium atom, this is a very thick wall, comparable to a half a mile deep if you yourself were a foot thick.
With the wall prepared, a second laser nudged individual rubidium atoms toward it. Most of the atoms simply bounced off the barrier, but about 3 percent of them went right through as hoped. Precise measurement of their precession produced the result: It took them 0.61 milliseconds to get through.
Reactions to the study
Scientists not involved in the research find its results compelling.
"This is a beautiful experiment," remarked Igor Litvinyuk of Griffith University in Australia. "Just to do it is a heroic effort." Drew Alton of Augustana University in South Dakota tells Live Science, "The experiment is a breathtaking technical achievement."
What makes the researchers' results so exceptional is their unambiguity. Says Chad Orzel at Union College in New York, "Their experiment is ingeniously constructed to make it difficult to interpret as anything other than what they say." He calls the research, "one of the best examples you'll see of a thought experiment made real." Litvinyuk agrees: "I see no holes in this."
As for the researchers themselves, enhancements to their experimental apparatus are underway to help them learn more. "We're working on a new measurement where we make the barrier thicker," Steinberg said. In addition, there's also the interesting question of whether or not that 0.61-millisecond trip occurs at a steady rate: "It will be very interesting to see if the atoms' speed is constant or not."