New 3D computer model shows how far a cough can spread indoors
This unsettling simulation shows how mucus-mist can rapidly spread in a grocery store.
- Finnish researchers have shown how a single cough can blast small aerosolized saliva particles around a grocery store.
- There is an ongoing scientific debate about how the novel coronavirus moves through the air.
- The bigger risk when it comes to COVID-19 is the transmission of larger droplets through close contact with others (three feet or less).
Using a computer simulation, researchers in Finland have shown how a single cough can blast small saliva and mucus particles around a grocery store well beyond a six-foot social distancing radius.
In the 3D simulation, a cloud of green particles originating from a person coughing in one aisle are shown spreading into the next aisle over. The cough releases a turbulent mist of droplets — aerosolized particles — which stay suspended in the air and move over into the parallel row.
These findings highlight an ongoing scientific debate about how the novel coronavirus moves through the air. The simulation's images are certainly concerning, but the risk of actually getting enough of a virus aerosol to contract a respiratory illness like COVID-19 is unknown according to Kumi Smith, an assistant professor of epidemiology and community health at the University of Minnesota. She told Business Insider that while the video "gives the impression that any shared airspace will lead to transmission," evidence has yet to support that.
When it comes to COVID-19, the bigger risk comes from close contact with another person within three feet or less through which larger droplets (larger than five to 10 microns) could be transmitted by talking, coughing, or sneezing. The larger the droplet the more likely it is to fall onto nearby objects or to the ground after expulsion. So if a person touches these droplets and then rubs his or her face, they could contract the virus. (Hence, the importance of frequent hand washing.) William Schaffner, a professor of preventive medicine and infectious diseases at Vanderbilt University Medical Centre, told Business Insider that droplet transmission within three to six feet accounts for a majority of virus transmissions.
But while close interactions between people are much more likely to spread an infectious dose of virus-laden particles, other research indicates the large versus small droplets difference may be irrelevant when it comes to distance between individuals. For example, Lydia Bourouiba, a fluid dynamics scientist at MIT, recently showed that a sneeze can spray droplets of various sizes a whopping 23 to 27 feet from a nose. And while a sneeze is not a typical symptom of coronavirus, an asymptomatic person who randomly sneezes could expel and spread the pathogen.
The importance of distancing
The Finnish simulation and Bourouiba's research emphasize how important social distancing measures, as well as additional precautions like wearing masks, are to public. Earlier this month, the Centers for Disease Control and Prevention (CDC) officially advised that Americans wear masks or other mouth and nose coverings when going out in public to prevent the spread of the virus. If everyone abided by these recommendations, the coronavirus crisis would likely be sufficiently addressed. Facial coverings are most effective at stopping the potential spread of the virus to others, so long as they are properly used, rather than as a way to guard yourself. According to the World Health Organization, there is currently no evidence that wearing a mask protects healthy people from becoming infected with respiratory infections. But since anyone could be asymptomatic and carrying COVID-19, we should all be covering our face by some means while in public areas.However, wearing a mask doesn't mean you should let your guard down. It should supplement social distancing and other protective protocols, not replace them. So continue to maintain that minimum six--foot distance, keep washing your hands, and please cover your mouth when you cough or sneeze.
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Scientists discover the inner workings of an effect that will lead to a new generation of devices.
- Researchers discover a method of extracting previously unavailable information from superconductors.
- The study builds on a 19th-century discovery by physicist Edward Hall.
- The research promises to lead to a new generation of semiconductor materials and devices.
Credit: Gunawan/Nature magazine
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>
Scientists have found evidence of hot springs near sites where ancient hominids settled, long before the control of fire.