New experiments find weird quantum activity in supercold gas.
Quantum Mechanics, Onions, and a Theory of Everything<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="036ae7b8dd661df2d125a3421a0299ba"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/bcVruA0AJ-o?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span>
Does time exist? Here's what the debate is all about.
- Everything we do as living organisms is dependent, in some capacity, on time. The concept is so complex that scientists still argue whether it exists or if it is an illusion.
- In this video, astrophysicist Michelle Thaller, science educator Bill Nye, author James Gleick, and neuroscientist Dean Buonomano discuss how the human brain perceives of the passage of time, the idea in theoretical physics of time as a fourth dimension, and the theory that space and time are interwoven.
- Thaller illustrates Einstein's theory of relativity, Buonomano outlines eternalism, and all the experts touch on issues of perception, definition, and experience.
Astronomer Michelle Thaller schools us on what atoms really look, the Big Bang theory, and the speed of light.
- Most people have seen atoms illustrated in textbooks and know about the Big Bang and the speed of light, but there is a good chance what you think you know is not scientifically accurate.
- Michelle Thaller, an astronomer and Assistant Director for Science Communication at NASA, is here to clear up the misconceptions and explain why atoms don't actually look that way, why the Big Bang is a misnomer, and why the speed of light is more than just really fast.
- Is there an edge of space? Does light experience time? Watch this video for answers to those and other interesting questions.
Some people choose alternatives to masks for comfort. A study shows the difference in effectiveness.
- A new study provides a visualization of why face shields are ineffective at stopping the spread of COVID-19.
- Using a mannequin that could simulate coughing, the authors demonstrated how water droplets slide around shields.
- The authors conclude that shields are not an effective replacement for masks.
A cool, if slightly terrifying, visualization.<p>The straightforwardly named "<a href="https://aip.scitation.org/doi/pdf/10.1063/5.0022968" target="_blank"><em>Visualizing droplet dispersal for face shields and masks with exhalation valves</em></a><em>" </em>was published in the journal "<a href="https://aip.scitation.org/journal/phf" target="_blank">Physics of Fluids</a>" and led by Dr. Siddhartha Verma of Florida Atlantic University. In it, the researchers explain that while face shields are very good at blocking the forward motion of larger droplets of water, the large open space in their design allows for smaller droplets to pass them and disperse throughout the room, reducing their potential benefits.</p><p>The authors attached a face shield to a slightly modified mannequin that could simulate coughing to demonstrate this. Small droplets of water and glycerin, comparable in size to the lower end of estimates of what is needed for a virus to travel, were blown through the mannequin's mouth and highlighted with laser sheets as they traveled throughout the room. </p> As illustrated below, small droplets that stop moving forward do not immediately drop to the floor, but instead, they float toward the gap at the bottom of the shield. Following air currents, the droplets eventually made their way around the face shield and began to spread. Given enough time, they'll spread up to a few feet away.
Why you should wear a proper facemask, revisited.<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="232361a0d3ad7a620c9ad6d8eec8fa50"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/UFX9oS2kpUA?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 shortcomings of face shields and other mask alternatives are not shared by the thing they are meant to replace, the basic, well-made face mask.</p><p>As explained above, face masks work to keep others around you from getting your germs by keeping the water droplets you exhale, which may contain viruses, from <a href="https://www.ucsf.edu/news/2020/06/417906/still-confused-about-masks-heres-science-behind-how-face-masks-prevent" target="_blank">spreading</a>. They have also been shown to reduce the number of droplets from other people's breath that reach your face, potentially preventing you from getting <a href="https://www.npr.org/sections/health-shots/2020/06/21/880832213/yes-wearing-masks-helps-heres-why" target="_blank" rel="noopener noreferrer">sick</a>. Given that face masks lack a large hole in them, as shields or masks with valves do, they allow far fewer droplets to escape than the competition. </p><p>The study considered the differences between a cheaply made face mask and a well-made one, with the cheap one proving much less effective. Even the best masks have some degree of leakage, so maintaining social distancing of at least two meters (about six feet) is still necessary. </p><p>No protective mask is perfect, and no set of rules offers complete safety. However, some objects and procedures work better than others at keeping people safe. As this study shows, face shields, masks with exhaustion valves, and cheaply made masks don't work as well as a well-made face mask.</p>
A new study finds the rocks that first formed Earth carried with them enough hydrogen for three times the water we have today.
- Enstatite chondrite meteorites are rare today, but they may have been Earth's basic building blocks.
- A study finds these meteorites contain a surprising amount of hydrogen, nitrogen, and water.
- The implication of the study is that Earth had all of its water from the beginning.
Analyzing E chondrites<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzYwNDUwOC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyNzc0NTg1M30.uL0ziiPPOTZud7L_5IXJt2hEKhiX42qcgKoyb9ADOiE/img.jpg?width=980" id="4d974" class="rm-shortcode" data-rm-shortcode-id="3692b2cf3dcba948cedc8c8d42c7a244" data-rm-shortcode-name="rebelmouse-image" alt="enstatite chondrite" />
Credit: User Captmondo/Wikimedia<p>Lead author <a href="http://recherche.crpg.cnrs-nancy.fr/spip.php?rubrique437&lang=fr" target="_blank">Laurette Piani</a> of CPRG <a href="https://source.wustl.edu/2020/08/meteorite-study-suggests-earth-may-have-always-been-wet/" target="_blank">says</a>, "Only a few pristine enstatite chondrites exist: ones that were not altered on their asteroid nor on Earth." In acquiring samples for study, the researchers went out of their way <em>not</em> to select meteorites holding water: "In our study we have carefully selected the enstatite chondrite meteorites and applied a special analytical procedure to avoid being biased by the input of terrestrial water."</p><p>As to why this team of scientists were the first to identify high concentrations of hydrogen in E chondrites, Piani suggests it's due to previous researchers' bias, saying, "it was commonly assumed that these chondrites formed close to the sun. Enstatite chondrites were thus commonly considered 'dry,' and this frequently reasserted assumption has probably prevented any exhaustive analyses to be done for hydrogen." </p><p>Using conventional <a href="https://en.wikipedia.org/wiki/Mass_spectrometry" target="_blank">mass spectrometry</a> and secondary ion mass spectrometry, the scientists did also find water in the meteorites. Recalls Vacher, "The most interesting part of the discovery for me is that enstatite chondrites, which were believed to be almost 'dry,' contain an unexpectedly high abundance of water." In addition to water, the team found substantial amounts of nitrogen they theorize could have aided in the formation of the Earth's atmosphere, nitrogen being its most abundant element.</p>
Earth's first sip<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzYwNDUyMy9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1NzM4OTQzMn0.-bEMCDbsCNLfE6A-weKvSN4e8nLeb9wmyNTwXD26XZo/img.jpg?width=980" id="b95b9" class="rm-shortcode" data-rm-shortcode-id="a70443a22a624a53b43a6b335c054240" data-rm-shortcode-name="rebelmouse-image" alt="ocean" />
Credit: gunsan gimbanjang/Shutterstock<p>The researchers were also able to add fresh evidence supporting the theory that E chondrites were Earth's basic building blocks: The meteorites' hydrogen and nitrogen isotopes turned out to be the same as the planet's.</p><p>"Our discovery shows," says Piani, "that the Earth's building blocks might have significantly contributed to the Earth's water. Hydrogen-bearing material was present in the inner solar system at the time of the rocky planet formation, even though the temperatures were too high [at the time] for water to condense." </p><p>Where did our water come from? It was always right here.</p>