Well, here we are in our social isolation bunker mode at the observatory. The calendar suddenly has lots of open spots, but nowhere to go. So we can follow up on some current news from the journals and take an amateur's look at the biology and effects of the Coronavirus. This pandemic can be so disruptive we might separate events on our calendar, from what we used to do, to what we do now, as BCV and ACV (Before/After CoronaVirus)!
First up, this interesting article in the current issue of New Scientist lists the carbon footprint of data delivery and phone calls. I guess this assumes the current mix of electrical generation sources that still mostly relies on carbon based fossil fuels and for all of the data and internet infrastructure. Anyway who knew that using your cellphone for a day required the equivalent of 47 grams of carbon?
|Ballooning data usage and carbon footprint for cell phone usage (Source: Edd Gent, New Scientist, Mar 14)|
During one of the last physics colloquium on March 4, 2020, Professor Jocelyn Reed mentioned the proposed Cosmic Explorer project which is one of the proposed next generation of gravitational wave detectors. This was the second to last physics colloquium before they were all put on hold because of the corona virus and now we have more time to explore some concepts brought up there.
What is the Cosmic Explorer? She described it as having much longer arms so instead of the current 4 km arm length, the Cosmic Explorer would have 40 km arms. This increased arm length would result in much higher sensitivity and would be able to detect merger events from much further distances. But 40km length arms pose some construction problems in that the Earth's surface is curved and light travels in straight line and the vacuum pipes must also be straight. My calculation is that the two ends of the 40 km pipe will be about 31 meters above the Earths surface (assuming spherical Earth). So finding a location for the Cosmic Explorer will be a challenge that both meets low seismic noise and terrain that minimizes the elevation difference. In the graphic below, you see an artists impression of the tube burrowing through some low hills as part of some construction approach.
|Cosmic Explorer is a planned gravitational wave detector with 40 km arms (Source: CosmicExplorer,org)|
The Cosmic Explorer white paper which lays out some of the scientific benefits of this gravitational wave detector which is higher sensitivity. In a graph from the paper, you can see something almost like a factor of 10 improvement in sensitivity.
|Longer arms increases sensitivity (Source: CosmicExplorer.org, arXiv:1907.04833)|
Another performance table from the table shows some of the other operating parameters. With longer length and other improvements you can see the benefits in higher SNR and early warning time of merger, which can be used to alert other electromagnetic observations of the upcoming event. Pretty neat!
|Stacking of nose cone onto other sections of Starship SN3 (Source: @BocaChicaGal)|
Next, we see the nose cone being gently placed on top of another portion of the Starship. Wow, things are moving so fast in Boca Chica! It is not clear when the Starship proposed test hop of about 12 km altitude will take place, but the new uncertainty is whether we will be allowed to travel there or if if just doesn't make sense to take the risk of travelling there to witness the test launch. Maybe we just have to thank and rely on @BocaChicaGal to keep us informed!
|Nose cone added to other sections of Starship SN3 (Source: @BocaChicaGal)|
Many other study activities have been put on hold or cancelled because of the virus pandemic. This week I had planned to do more study in gauge theory, but instead find that I was more curious about the nature of the corona virus. We have learned that there are several families of coronavirus, some members of which are the common cold virus, while others are responsible for SARS (Severe Acute Respiratory Syndrome coronavirus) and MERS (Middle East Respiratory Syndrome-related coronavirus). We have plenty of news bulletins advising us on the need for washing of hands and maintaining a level of social distance and so many of our planned meetings and conferences have been cancelled or postponed, so I elected to dive a little deeper into the physics and biology associated with the virus.
First up in this topic was to find some easy to understand descriptions of the virus. Now, in the past, I had an interest in microbiology and had spent considerable energy and time studying microbiology and biochemistry. The field of microbiology is really at a very interesting time right now because so much progress has been made in understanding the physical and chemical basis of all of the biological machinery of life. Many mysteries remain but now was the time to go back and take a more introductory look at the biology of viruses.
There are many short videos available on the internet and my favorite so far is from the MedCram website. In the short online video outlined below we see a description of how molecular spines on the coronavirus identify entry points into the host cell. The receptor in this example is called "ACE2" The virus is able to use this entry point into the cell and then commandeer the cell's replication machinery to not only perform the cell's requirements but to make multiple copies of the virus's genetic code.
One very interesting point made in the video was that people on high blood pressure medicine have the side effect that it increases the number of ACE2 sites in their cells. This means that they unintentionally become more receptive to the coronavirus. It turns out that older, senior citizens are more likely to required blood pressure medicine and we see at the same time they seem to be more affected by the corona virus. Hmm, could this be part of the connection between the high infection and mortality rate of senior citizens? Anyway, this video, perhaps quite basic according to serious biologists, was very easy to gain some understanding of how virus's operate.
|Easy to follow, conceptual introduction to virus entry into cells (Source: www.MedCram.com)|
Another video, by the same doctor, Dr. Seheult, described what the impact of the virus is on the infected patient. This was quite interesting, even if not a topic we like to cover and discuss, in that the effect on the oxygen transfer capability in the lungs is impacted and this is the major cause of death. Check out this video if you want to get into the technical, but not gory, details.
Finally, one more video addressed a concern that is quite common on TV news and that is if enough hospital ventilators will be available for those patients that have breathing compromised by the virus. We have already seen how oxygen transfer is impeded by the virus and the ventilator is design to help overcome this effect. But what is a ventilator?
The video describes how a tube is inserted in the patient's throat and sealed in the throat with a balloon so that only air can get into the lungs. The tube is then connected to a machine that has many control knobs and can control the pressure or volume of air that is forced into the lungs. There are various controls to operate all automatically or allow some control by the patient as to when to take a breath. The video goes into the ideal gas law and how the ventilator adjusts pressure and volume to meet the requirements of supporting breathing by mechanical means. So, it was pretty interesting to see all of the details that go into using a ventilator. Of course, the actual operation of the ventilator is much more detailed but it was neat to see the mechanical principles by which it is operated.
So besure to check out the latest updates on MedCram. If you are more interested in current statistics on infected and number of deaths, then check out the John Hopkins Dashboard. It provides a lot of good data. For instance at this instance, China reports 81,000 cases and the US reports just 14,000 cases. For me, I am skeptical of predictions that say that some countries will experience over 50% of their population becoming infected. Even the California governor says that the state could eventually have over 50% infected, which would mean about 20 million persons. This infection strikes me as way too high of an estimate. Why? Not because of any special knowledge, but just look at the statistics for China, where the virus originated, and after their draconian measures to stop the propagation of the virus, their numbers are pretty much stabilized. How was this 50% estimate derived? Time will tell, of course, but if you are interested in tracking these numbers then check out the John Hopkins webpage: https://coronavirus.jhu.edu/map.html
|John Hopkins Dashboard (Source: John Hopkins, https://coronavirus.jhu.edu/map.html)|
The tracking of disease and developing models and procedures to explain and mitigate disease propagation is called epidemiology. Its goal is public health and its goal is to identify causes and risks and control of disease. This field is an interesting field for me in terms of the modelling. It is like we have interacting physical systems and we model possible interactions between the particles of this system and then predict outcomes that can be measured. I had hoped that this book would cover more of the modelling techniques but it is pretty light on that, but does cover some statistics and definitions of mortality rates, etc. So, it is not quite what I was looking for, but if you are the curious amateur, it still might be for you.
|Good introductory textbook for the curious (Source: R. Merrill, "Introduction to Epidemiology")|
There are many other videos on similar topics available but if you want a more structured and university level introduction to viruses then the book, "Molecular and Cellular Biology of Viruses" is a good place to start. You can rent this book on Amazon if you want to take a dive into this topic. For me, it was just at the right level to be able to follow what was being described. So far, the text does not require any biochemistry, but an introduction to molecular biology is a goo plan. At least, I had heard mentioned many of the terms, even if I had forgotten what they actually meant.
|For more technical details of biology of viruses (Source: P. Lostroh, "Molecular and Cellular Biology of Viruses")|
So, we find ourselves in essentially government mandated "shelter at home" situation and are tying to keep busy with ongoing studies. No more physics luncheons out; no more pre-meeting diners; no more Taco Tuesday get togethers. Then there are people who have lost their jobs, which has much more serious impact than our little inconveniences. We can order food out to sort of support our local restaurants, but what about our barbers and bartenders? Our social world has indeed divided into BCV and ACV. Maybe if the weather clears up we might be able to get out and do some solo nighttime observing. We had hoped to again see the string of pearls of the latest Starlink launch of March 18, but so far the satellite orbits are such that no visible observations are predicted for OC.
Until next time (from the bunker),
Resident Astronomer George
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