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Is Our Planet Going the Way of the Dinosaurs?
We now think the big mass extinctions were caused by hydrogen sulfide bacteria. Two hundred hydrogen sulfide molecules among a million air molecules is enough to kill a human.
Most of the big mass extinctions have been caused by nasty volcanic events. The last one didn’t cause a mass extinction. It was in the Tertiary Period. This was in my own home state, Washington State, the Columbia River Basalts.
Out came all this basalt, as liquid lava, and a lot of the carbon dioxide came out too, but not enough to cause the Earth to go into a really nasty mass extinction. The mass extinctions caused by the basalts happen by simply heating the world. When you heat the world you heat the pole more than you do the equatorial region. When that happens, you start losing circulation. The only reason you have wind now is you have a hot spot and a cold spot and they’re trying to equilibrate. With an ocean current you have the same thing. You have a cold Antarctic and then you warm them up, the ocean circulation system is dampened down. There’s much less heat difference.
We already have very sluggish ocean circulation. The oceans are going oxic - losing their oxygen. They only keep oxygenated now because of this vigorous mixing. Even when you have oxygen in the atmosphere and contact with the surface, once you slow down any circulation, that whole basin can lose this oxygen. The Black Sea is the same case. It’s sits under a 21% oxygen atmosphere, and yet the Black Sea, except for the top several meters, in anoxic. It’s black because it’s producing a lot of sulfur-producing bacteria and there’s very nasty gasses that are produced.
We now think the big mass extinctions were caused by global anoxia. The oceans themselves were so sluggish that the hydrogen sulfide bacteria were produced in huge areas of the ocean. The bottom bubbles up to the surface and starts killing things - rotten egg killing. It would be extremely nasty. Hydrogen Sulfide poisoning is a horrible death. Two hundred hydrogen sulfide molecules among a million air molecules is enough to kill a human. Just breathing in 200 of those little things amid all the million you’re getting in oxygen and boom, you’re down, horribly down.
So, this is a really nasty poison and it was certainly present in past oceans during these short-term global warming events. That’s why it’s really spooky what we’re doing now.
In Their Own Words is recorded in Big Think's studio.
Image courtesy of Shutterstock
Live on Thursday: Learn innovation with 3-star Michelin chef Dominique Crenn
Dominique Crenn, the only female chef in America with three Michelin stars, joins Big Think Live this Thursday at 1pm ET.
22 September, 2020
Big Think LIVE
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<p>
Having been exposed to mavericks in the French culinary world at a young age, three-star Michelin chef Dominique Crenn made it her mission to cook in a way that is not only delicious and elegant, but also expressive, memorable, and true to her experience. Crenn will share the importance of gaining knowledge and inspiration from what and who surrounds you, building a unified and empowered team, and inventing a business model out of inspiration, as well as necessity.
</p><p>
Ask your questions for Dominique Crenn during the Q&A!
</p><p><strong>Join the live stream at 1pm ET on Thursday, September 24.</strong></p><h2>STREAMING LINKS:<br><a href="https://edge.bigthink.com/live_streams/110" target="_self">Big Think Edge</a> | <a href="https://youtu.be/knx4dWkwmd0" target="_blank">YouTube</a> | <a href="https://bit.ly/3kDXywJ" target="_blank">Facebook</a></h2>
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Popular
Physicists solve a 140-year-old mystery
Scientists discover the inner workings of an effect that will lead to a new generation of devices.
13 October, 2019
Carrier-resolved photo-Hall effect.
Credit: IBM
Surprising Science
- 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.
<p><br></p></div>
<p>New research, led by IBM, made a breakthrough in resolving a mystery that has baffled physicists for 140 years. It promises to lead to a new generation of semiconductor materials and devices that use them.</p><p>The invention of semiconductors was instrumental in bringing on our digital age. You can find these electricity-carrying substances in your smartphone and computer. An improvement in this field could have major ramifications for future gadgetry. </p><p>In 1879, the American physicist <a href="https://en.wikipedia.org/wiki/Hall_effect" target="_blank">Edward Hall</a> discovered the <strong>Hall effect, </strong>showing that you can measure how electricity in a conductor flows. He found that because a magnetic field deflects the movement of electronic charges in a conductor, you can measure the amount of that deflection. This number will describe the voltage perpendicular (or transverse) to the flow of charge. </p>
<p>Modern researchers recognized, that you can also make Hall effect measurements using light in so-called <strong>photo-Hall experiments</strong> that generate multiple carriers (or electron-hole pairs) in superconductors. Unfortunately, while the Hall voltage provides crucial information about these charge carriers in a semiconductor, it is limited to the properties of the dominant (or majority) charge carrier, explain contributing authors <strong>Oki Gunawan</strong> and <strong>Doug Bishop</strong> in a <a href="https://www.ibm.com/blogs/research/2019/10/physics-photo-hall-effect/" target="_blank">post on IBM's research blog.</a></p><p>Figuring out the information about both the majority and minority charge carriers, which impact changes in conductivity, would be key to advancing applications utilizing light, including optoelectronic devices like solar cells, LEDs, and lasers as well as artificial intelligence tech.</p><p>Now a new formula and technique for getting both the majority and minority carrier information was developed by researchers from <a href="https://www.kaist.ac.kr/html/en/" target="_blank">KAIST</a> (Korea Advanced Institute of Science and Technology), <a href="https://english.krict.re.kr/eng/main" target="_blank">KRICT</a> (Korea Research Institute of Chemical Technology), <a href="https://www.duke.edu/" target="_blank">Duke University</a>, and <a href="https://www.ibm.com" target="_blank">IBM</a>.</p><p>The method, dubbed <strong>Carrier-Resolved Photo Hall (CRPH),</strong> measurement, can simultaneously extract information about the majority and minority carriers like density and mobility, carrier lifetimes and lengths of diffusion. In fact, compared to the <strong>three</strong> parameters of measurement traditionally derived by engaging the Hall effect, the novel technique can get up to <strong>seven</strong> parameters of information.</p>
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMTk5MTIxOS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY2MjgxMzcxNn0.KTpkjQP-O--HlZwu3TTM073oyBoyQNvF9SLo1ohy_dM/img.jpg?width=980" id="35dca" class="rm-shortcode" data-rm-shortcode-id="8377019083b984922c4b6537e7883160" data-rm-shortcode-name="rebelmouse-image" />
Credit: Gunawan/Nature magazine
<p>The approach also takes advantage of a tool developed by IBM called the <strong>parallel dipole line (PDL) trap</strong>, which generates an oscillating magnetic field. It works as an ideal system for photo-Hall experiments because of the large amount of space it allocates for sample illumination.<br></p><p>If you'd like to dive more into the subject, check out the new study <a href="https://www.nature.com/articles/s41586-019-1632-2" target="_blank">published in <em>Nature</em> magazine.</a></p>
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Does forgetting a name or word mean that I have dementia?
The number of people with dementia is expected to triple by 2060.
24 September, 2020
Photo by Connor Wang on Unsplash
Mind & Brain
The number of cases of dementia in the U.S. is rising as baby boomers age, raising questions for boomers themselves and also for their families, caregivers and society.
<p> <a href="https://www.cdc.gov/aging/dementia/index.html" target="_blank">Dementia</a>, which is not technically a disease but a term for impaired ability to think, remember or make decisions, is one of the most feared impairments of old age.
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Incidence increases dramatically as people <a href="https://news.umich.edu/one-in-7-americans-over-age-70-has-dementia/" rel="noopener noreferrer" target="_blank">move into their 90s</a>. About 5% of those age 71 to 79 have dementia, and about 37% of those about 90 years old live with it.
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Older people may worry about their own loss of function as well as the cost and toll of caregiving for someone with dementia. A 2018 study estimated that the lifetime cost of care for a person with Alzheimer's, the most common form of dementia, to be <a href="https://www.cbsnews.com/news/alzheimers-costs-americans-277-billion-a-year-report/" rel="noopener noreferrer" target="_blank">US$329,360</a>. That figure, too, will no doubt rise, putting even more burdens on family, Medicare and Medicaid.
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There's also been a good deal of talk and reporting about dementia in recent months because of the U.S. presidential election. Some voters have asked whether one or both candidates might have dementia. But, is this even a fair question to ask? When these types of questions are posed – adding further stigma to people with dementia – it can unfairly further isolate them and those caring for them. We need to understand dementia and the impact it has on more than 5 million people in the U.S. who now live with dementia and their caregivers. That number is <a href="https://www.cdc.gov/aging/dementia/index.html" rel="noopener noreferrer" target="_blank">expected to triple</a> by 2060.
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First, it is important to know that dementia cannot be diagnosed from afar or by someone who is not a doctor. A person needs a detailed doctor's exam for a diagnosis. Sometimes, brain imaging is required. And, forgetting an occasional word – or even where you put your keys – does not mean a person has dementia. There are different types of memory loss and they can have different causes, such as other medical conditions, falls or even medication, including herbals, supplements and anything over-the-counter.
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Older people wonder and worry about so-called senior moments and the memory loss they perceive in themselves and others. <a href="https://uvahealth.com/findadoctor/profile/laurie-r-archbald-pannone" rel="noopener noreferrer" target="_blank">I see patients like this</a> every week in my geriatric clinic, where they tell me their stories. They forget a word, get lost in a story, lose keys or can't remember a name. Details vary, but the underlying concern is the same: Is this dementia?
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<h2>Normal memory loss</h2><p>As we age, we experience many physical and cognitive changes. Older people often have a decrease in recall memory. This is normal. Ever have trouble fetching a fact from the deep back part of your "mind's Rolodex"? Suppose you spot someone at the grocery store you haven't seen in years. Maybe you recognize the face, but don't remember their name until later that night. This is normal, part of the expected changes with aging.</p><p>What's more of a <a href="https://geriatricscareonline.org/" target="_blank" rel="noopener noreferrer">potential problem</a> is forgetting the name of someone you see every day; forgetting how to get to a place you visit frequently; or having problems with your activities of daily living, like eating, dressing and hygiene.</p><p>When you have troubles with memory – but they don't interfere with your daily activities – this is called mild cognitive impairment. Your primary care doctor can diagnose it. But sometimes it gets worse, so your doctor should follow you closely if you have mild cognitive impairment.</p><p>You want to note the timing of any impairment. Was there a gradual decline? Or did it happen all of a sudden? This too you should discuss with your doctor, who might recommend the MoCA, or <a href="https://www.mocatest.org/" target="_blank" rel="noopener noreferrer">Montreal Cognitive Assessment</a> test, which screens for memory problems and helps determine if more evaluation is needed.</p><p>Also, the Centers for Disease Control and Prevention lists problems in these areas as <a href="https://www.cdc.gov/aging/dementia/index.html" target="_blank" rel="noopener noreferrer">possible signs of dementia</a>:</p><ul><li>Memory</li><li>Attention</li><li>Communication</li><li>Reasoning, judgment and problem solving</li><li>Visual perception beyond typical age-related changes in vision</li></ul>
<h2>More severe issues</h2><p>When memory loss interferes with daily activities, see your doctor about what to do and how to make sure you're safe at home.</p><p>There are numerous types of severe memory loss. Dementia tends to be a slow-moving progression that occurs over months or years. Delirium is more sudden and can occur over hours or days, usually when you have an acute illness. Depression can also cause memory changes, particularly as we get older.</p>
<h2>Dementia and other brain issues</h2><p>Alzheimer's dementia is the most common type of dementia, followed by vascular dementia. They have similar symptoms: confusion, getting lost, forgetting close friends or family, or an inability to do calculations like balance the checkbook. Certain medical conditions – thyroid disorders, syphilis – can lead to dementia symptoms, and less common types of dementia can have different kinds of symptoms. Alzheimer's has a distinct set of symptoms often associated with certain changes in the brain.</p><p>Focusing on safety and appropriate supervision, particularly in the home, is critical for all people with dementia. Your doctor or a social worker can help you <a href="https://www.alz.org/" target="_blank" rel="noopener noreferrer">find support</a>.</p><p>It's also important to be aware of two other things that can lead to decreased mental functioning – delirium and depression.</p><p>Delirium, a rapid change in cognition or mental functioning, can occur in people with an acute medical illness, like pneumonia or even COVID-19 infection. Delirium can occur in patients in the hospital or at home. Risk for delirium increases with age or previous brain injuries; symptoms include decreased attention span and memory issues.</p><p>Depression can happen at any time, but it's more common with aging. How can you tell if you're depressed? Here's one simple definition: when your mood remains low and you've lost interest or joy in activities you once loved.</p><p>Sometimes people have recurring episodes of depression; sometimes, it's prolonged grieving that becomes depression. Symptoms include anxiety, hopelessness, low energy and problems with memory. If you notice signs of depression in yourself or a loved one, see your doctor. If you have any thoughts of harming yourself, call 911 to get help instantly.</p><p>Any of these conditions can be frightening. But even more frightening is unrecognized or unacknowledged dementia. You must, openly and honestly, discuss changes you notice in your memory or thinking with your doctor. It's the first step toward figuring out what is happening and making sure your health is the best it can be.</p><p>And, as with any disease or disease group, dementia is not a "character flaw," and the term should not be used to criticize a person. Dementia is a serious medical diagnosis – ask those who have it, the loved ones who care for them or any of us who treat them. Having dementia is challenging. Learn <a href="https://www.alz.org/alzheimers-dementia/facts-figures" target="_blank" rel="noopener noreferrer">what you can do </a>to support those with dementia in your own community.<img src="https://counter.theconversation.com/content/144565/count.gif?distributor=republish-lightbox-basic" alt="The Conversation"></p><p><a href="https://theconversation.com/profiles/laurie-archbald-pannone-894205" target="_blank">Laurie Archbald-Pannone</a>, Associate Professor Medicine, Geriatrics, <em><a href="https://theconversation.com/institutions/university-of-virginia-752" target="_blank" rel="noopener noreferrer">University of Virginia</a></em></p><p>This article is republished from <a href="https://theconversation.com/" target="_blank" rel="noopener noreferrer">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/does-forgetting-a-name-or-word-mean-that-i-have-dementia-144565" target="_blank" rel="noopener noreferrer">original article</a>.</p>
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New Hubble images add to the dark matter puzzle
The images and our best computer models don't agree.
23 September, 2020
Surprising Science
Scientists can detect the gravitational effects of invisible dark matter. Dark matter causes visual distortions of what's behind it. The greater the distortion, the greater the amount of dark matter. Maybe.
<ul class="ee-ul"></ul>
<p>Dark matter is believed to be important stuff, the glue that holds together the dust, gas, and stars that make up galaxies. It's the organizing force for the universe's large-scale structure, the shape you'd see if you were able to zoom way, way out, and it comprises most of a galaxy's mass.</p><p>We don't know precisely what dark matter is, since it doesn't emit or reflect light, or absorb it for that matter, rendering it invisible to our instruments. However, we can see what dark matter does, insofar as light from objects behind dark matter warps and is magnified as it makes its way toward us. That visual distortion is referred to as dark matter's "lensing" effect, as it's similar to what you might see passing a magnifying glass over an object.</p><p>Now a new <a href="http://dx.doi.org/10.1126/science.aax5164" target="_blank">study</a> of images from the <a href="https://www.spacetelescope.org" target="_blank" rel="noopener noreferrer">Hubble Space Telescope</a> combined with <a href="https://imagine.gsfc.nasa.gov/science/toolbox/spectra1.html" target="_blank">spectra</a> from the European Southern Observatory's <a href="https://www.eso.org/public/teles-instr/paranal-observatory/vlt/" target="_blank" rel="noopener noreferrer">Very Large Telescope</a> (VLT) in Chile finds that there's either a lot more dark matter than computer models predict, or there's a major puzzle piece missing from what we thought we knew about dark matter's behavior.</p>
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
<p>The discrepancy has to do with images of three galaxy clusters captured by Hubble's <a href="https://www.spacetelescope.org/about/general/instruments/wfc3/" target="_blank">Wide Field Camera 3</a> and <a href="https://www.spacetelescope.org/about/general/instruments/acs/" target="_blank">Advanced Camera for Surveys</a> as part of two Hubble projects: The Frontier Fields and the Cluster Lensing And Supernova survey with Hubble (CLASH) programs. The three clusters are called <a href="https://spacetelescope.org/images/heic1115a/" target="_blank">MACS J1206.2-0847</a>, <a href="https://www.spacetelescope.org/images/heic1416a/" target="_blank">MACS J0416.1-2403</a>, and <a href="https://www.spacetelescope.org/images/heic1615a/" target="_blank">Abell S1063</a>.</p><p>Such imagery can be used for authenticating — or exposing flaws in —predictive computer models of dark matter's behavior, locations, and concentrations. </p><p>Lead author <a href="https://www.unibo.it/sitoweb/massimo.meneghetti/en" target="_blank" rel="noopener noreferrer">Massimo Meneghetti</a> of the INAF-Observatory of Astrophysics and Space Science of Bologna, Italy, <a href="https://www.spacetelescope.org/news/heic2016/" target="_blank" rel="noopener noreferrer">says</a> that "galaxy clusters are ideal laboratories in which to study whether the numerical simulations of the Universe that are currently available reproduce well what we can infer from gravitational lensing."</p>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>
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Culture & Religion
Did our early ancestors boil their food in hot springs?
Scientists have found evidence of hot springs near sites where ancient hominids settled, long before the control of fire.
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