Well I haven't been out for any astronomical observing for this whole week and so can only comment on ongoing physicist wannabe activities and on some of the online meetings and space news.
As many of you physicist wannabes know, making your way through quantum field theory (QFT) is quite difficult. I have tried using several different books in the past, including the class by Peskin and Schroeder and the easier, student friendly text by Klauber, but it is just difficult to keep going and make sense of it all. Now, I might have finally met the text that is easier to understand and make some headway. It might also just be that after struggling with those other texts, the whole thing is starting to sink in? Anyway this next text, "QFT for the Gifted Amateur" by Lancaster and Blundell, looks pretty good. For the first time, I learned why the commutation rules of creation and annihilation operators applies. The secret is of course that the answer can be quite different for the particle count at one point in spacetime if you perform the annihilation operator first and then the creation operator or vice versa. It makes a difference, which is why it is said the operators don't commute. So, if you are struggling with QFT be sure to check out this textbook.
|Is this finally the textbook for learning QFT? (Source: T. Lancaster & S. Blundell)|
While waiting for the online talk by SETI on the search for near Earth asteroids, I found this twitter feed from Eric Weinstein. His post shows other newsfeeds saying that the CDC lied about the general public use of face masks for protection from the pandemic, initially so that more masks would be available for health personnel who really are in more need of masks. What are we to make of this philosophical quandary? Did it really come down to the case that in order to ensure getting masks in the right location for one group of citizens that another group had to be put more at risk and lied too? There was and is so much uncertainty still about masks. Social distancing, or as it more correctly should be described, physical distancing, appears to still be an effective mitigation. I can't decide what the right course of action should have been, but couldn't the request to free up masks been handled differently?
When I first heard about the ineffectiveness of masks policy, back in late March time frame, I said that can't true. We know know, months later, the value of masks. When I first heard the recommendation that wearing mask was not helpful and might actually be dangerous, I had just finished calculating using Stoke's Law how long virus particles would remain suspended in the air following expulsion from an infected person. What I read into the official recommendation was "oh-oh, they have found that the virus is aerosolized and a cloth mask is not going to be useful and that they wanted to reserve the N95 masks for medical personnel." Well, it turned out that the expelled virus particles were mostly in small droplets and wearing a regular cloth mask could be useful, even though medial personnel needed the full range of masks and PPE.
So, it seems the mask issue was some sort of noble lie. It probably worked out the best in the end, but it is not a happy thought to think that CDC scientists can shade what we are told and are asked to believe that it is just scientific opinion. What other areas of science are we also susceptible to scientific opinions being shifted one way or the other to meet some other goal; some other goal that may or may not have our own health interests and our interest in truth in mind! Anyway, I think Eric is right in that this can only increase suspicion about scientific announcements that affect public policy in that now we have to be worried more that the announcement is not just based on science but on some other agenda too.
Sadly the whole issue gets more complicated because some of the social media sites, like Facebook and YouTube said that they would flag or even remove posts that went against the official health pronouncements from the official CDC and WHO. Hmm, so in that case if you said initially that masks would have been helpful, your post could be removed, and now I suppose if you say that masks are not helpful, your post could be removed. This removal of posts is troubling because if that policy extends to other areas too, there can be no free discussion of pros and cons on that or other issues.
|Do noble lies trade lives of one group of people for an overall better solution? (Source: Twitter feed)|
Ok, enough sputtering and ranting about that topic, or more correctly just wondering what is the best policy, where we are in need of more information, we can now get back to one more news article before the SETI presentation which is about ready to begin. You might have seen this full page diagram in the June issue of The Planetary Society newsletter which showed an interesting display of where all of the various solar system probes and observatories are located. Who knew, I had forgotten about many of these probes? Thanks for that!
|Location of all the solar system probes (Source: The Planetary Society, June 2020)|
The SETI online lecture this time was a panel session with three expert astronomers involved with finding and tracking near Earth asteroids. The panelists talked about how a wide consortium of telescopes are used to find and track asteroids. One of the neat surveys is the Atlas survey which is conducted from Hawaii. Atlas database is often used by amateur astronomers in some of their follow up observations of asteroids. Anyway you can probably still find the recorded meeting online at the SETI website.
|Panelists at SETI online talk on the search for near Earth asteroids (Source: www.seti.org)|
During the presentation, the authors showed some of their favorite asteroids. For me, I always liked Itokawa because so much detail was there and you could see how it was probably formed by previous collisions. Dioretsa is interesting because it revolves around the sun in the opposite direction than other asteroids. The authors conducted an online poll of the audience and we all got to vote for our favorite ones. Well, just as I was about to click my vote for Itokawa, Astronomer Assistants Ruby and Danny, interceded and convinced me to vote for Kleopatra. Hmm, yeah I guess I'm pretty happy voting that way and besides it turns out that Kleopatra won the online poll anyway! Thanks for convincing me, Ruby and Danny!
In other news, Aviation Week Magazine, the current issue was a salute to Elon Musk and SpaceX for recent and ongoing successes in getting manned flights back into space and lowering the cost of the access to space. Way to go, Elon!
|Elon Musk and SpaceX are changing access to space (Source: Aviation Week, June 2020)|
Meanwhile, back in the TwitterSphere, we see more photos and news sent in by the army of amateur followers of activity at SpaceX facilities across the country. First up, we see this photo sent in by Reagan, showing a brand new Falcon 9 booster being set up at the McGregor, TX facility for some unknown testing. Thanks for that, Reagan!
|A brand new Falcon 9 shows up in McGregor for testing (Source: Reagan, @bluemoondance74)|
Next up, we get a couple of more photos from Mary at the SpaceX Boca Chica facility. First we see a beautiful sunrise (I think) view at Boca Chica with ongoing Starship fabrication in the foreground.
|Beautiful sunrise? at SpaceX Boca Chica facilities (Source: Mary, @bocachicagal)|
Next up, Mary shows us some of the ongoing fabrication and test preparation on Starship SN7. This time, Mary has added some readable comments so the rest of us get a better understanding of what is in the photo. Thanks for everything, Mary!
Just seeing all the activity going on in Boca Chica is exciting and I am eager to get back there myself. Our previous visit there, way back in March 13-15, which was supposed to be just the start of a trip there and finishing up back in Houston for the Lunar and Planetary Conference, March 15-19, but as you already know it was cancelled due to the coming pandemic lockdown.
Our short visit to Boca Chica convinced us that it would be hard find a convenient place near the rocket ship launch site. There is only one road (Highway 4) out to the area and it would be shutdown during any rocket testing and driving off the highway also did not look too inviting, especially in just a 2-wheel drive rental car. We did make the one hour drive from Boca Chica over to the party place with plenty of hotels and fun on South Padre Island. Could we use South Padre Island as an observation point? Check out the Google Earth map and see that the southern tip is just about 6 miles from the launch site. That might be our best observing spot and still be close to some nice creature comforts and bartenders!
|Google Earth straight distance from Boca Chica to South Padre Island (Source: Palmia Observatory)|
Ok, let's finish up this post with a test for all of you keen eyed astronomers and others who look up at the night sky or in this case down at your feet. This optical illusion has been making the rounds on the internet, so if you haven't seen it yet, here is your chance to take a look and report what you see. About half of the viewers, like Resident Astronomer Peggy and I, both see the sneaker as appearing in greenish and grey color tones. Hey, who said that opposites attract? Anyway, take a look and tell us what colors you see. Apparently the other half of people see the sneaker in pink and white colors. What say you?
|What colors do you see in this sneaker image optical illusion? (Source: Twitter feed)|
Until next time, here from our burrow, stay safe, but it's time to recover more of our freedom,
Resident Astronomer George
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