Thanks to Rob Grigjanis, I got the link to the talk I gave on Saturday on the wildly varying age of the Earth. The full day’s talks are below and mine begins soon after the 5:25:00 mark.
If you do not know how to skip to the part where my talk begins, you can go here where it has already been cued up for you.
Rob and I had a discussion about my discussion of Kelvin’s role in the comments section of my earlier post announcing the talk that those interested can go and read.
(Previous posts in this series: Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8, Part 9, Part 10)
For convenience, let me summarize the results that were arrived at in the previous post of the calculations of the Poynting vector by Rohrlich for a charge Q and detector D for the following five scenarios. S represents an inertial frame (such as freely falling in a uniform gravitational field) while E is the frame of the Earth.
Scenario 1: Both Q and D are floating freely in empty space in the absence of all forces
Conclusion: D will not detect any radiation and and thus Q is said to not radiate.
Scenario 2: Both Q and D are both falling freely in a uniform gravitational field
Conclusion: D will not detect any radiation and and thus Q is said to not radiate.
Scenario 3: Q is freely falling while D is on the floor in E
Conclusion: D will detect radiation and thus Q is said to radiate.
Scenario 4: Q is on the floor in E while D is freely falling
Conclusion: D will detect radiation and thus Q is said to radiate.
Scenario 5: Both Q and D are at rest on the floor in E
Conclusion: D will not detect radiation and thus Q is said to not radiate.
Let us see how Rohrlich’s results affect the two postulates that began this series of posts:
Postulate #1: If we can eliminate all other forces such as friction, all objects that are dropped from the same height in a gravitational field will fall at the same rate and hit the ground at the same time.
Postulate #2: An accelerating charge falling freely in a gravitational field will radiate energy.
The results of Scenario 3 support Postulate #2, that the falling electric charge will radiate and that radiation will be detected by a detector at rest in the frame.
But there are still three (at least) unresolved issues.
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More is emerging about tennis player Novak Djokovic’s crackpot views.
The tennis star has a track record when it comes to questionable scientific claims.
In his book Serve to Win, Djokovic described how in 2010 he met with a nutritionist who asked him to hold a piece of bread in his left hand while he pressed down on his right arm. Djokovic claims he was much weaker while holding the bread, and cited this as evidence of gluten intolerance.
And during an Instagram live, he claimed that positive thought could “cleanse” polluted water, adding that “scientists have proven that molecules in water react to our emotions.”
According to Dr David Nunan, a senior researcher at the Centre for Evidence Based Medicine at the University of Oxford, “on the balance of probabilities it is highly unlikely that such claims are true – at least not by current conventions of scientific theory and practice.”
The last delicate operation in the unfurling of the James Webb Space Telescope was successfully carried out when the two side mirrors were unfolded so that the large 6.5m concave mirror is now complete. This was the last final phase of the telescope assembly, as shown in this simulation.
A few days ago, the secondary mirror (the little mirror that faces the big golden mirror) was unfolded and the support structure for it was successfully locked into place.
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People in the US complain a lot about about the restrictions imposed by the pandemic but they should see what Hong Kong has. This report is from a ProPublica reporter who is a Hong Kong citizen about what she had to go through in order to enter the country, starting with a very restrictive 21-day quarantine in a hotel at her own expense, even though she was vaccinated.
Incoming travelers were greeted by gowned, gloved and masked workers, who directed us through the terminal. As I followed the passengers ahead of me, I was unnerved by the shuttered stores….The terminal was now eerily still. My feet made too much noise as I trudged along the path marked by guardrails.
…A PPE-covered worker sent me to a series of stations. First, I pulled my mask down for a nurse to swab my nose and throat for a PCR test. Then I presented my documents — preflight negative COVID-19 test, proof of hotel booking, Hong Kong resident ID and vaccination card — to an officer who scrutinized them before declaring me up to par.
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On Monday, the US recorded over a million new covid-19 cases, a new record, largely driven by the Omicron variant, and we may have not yet reached the peak, which is expected to be reached around mid-January. That statistic is a bit misleading since it includes corrections for delays in reporting over the holidays. In general, I do not pay attention to the daily numbers but instead focus on the averages taken over seven days. But that too has reached a record level of around 575,000, easily surpassing the previous high of around 250,000 set back on January 11, 2021.
Given this grim news, it may be hard to find a silver lining but there is one in that the death and hospitalization rates have not kept pace with the rise in case rates, even allowing for the usual two-week lag. The seven-day average of the death rate is currently around 1,200, compared to its previous peak of 3,400 a year ago. That may be an indication that Omicron is the first phase of the virus transitioning to an endemic, flu-like virus of the kind that we are accustomed to. Some indications of this are that the earlier symptoms of Covid-19, such as loss of a sense of smell and taste and low blood oxygen levels, are no longer as common with the new variant. It also appears that Omicron affects the upper respiratory tract more and is less like to affect the lungs.
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The annual Monterey Skepticamp is being held on Saturday, January 8th from 9:46am to 5:46pm California time. I will be giving a talk at 2:30pm.
Title: Why the age of the Earth has oscillated wildly over time
Summary: The age of the Earth seems to be a settled question in the scientific community, But estimates of its age have oscillated wildly in the past, starting with it being considered really old (even infinitely old) to becoming very young (of the order of thousands of years) to becoming sort of old (hundreds of millions of years) to younger again (tens of millions of years) to the current view of it being really old (of the order of billions of years). This talk will look at the interplay of scientific and religious thinking that was driving this fluctuation.
You can see the full schedule of speakers here.
It is free. You can RSVP here.
The Zoom link to join is https://us02web.zoom.us/j/88526995782
Tennis star Novak Djokovic has said that he is opposed to vaccinations. Australia now requires people entering the country to be vaccinated or apply for a special exemption. Djokovic had applied for and got an exemption from the Australian tennis body that issues such exemptions so that he could play in the Australian Open that takes place starting on January 17th. But later it turned out that he had applied for a visa that does not allow for medical exemptions. This caused a furore with people complaining that he was being given special treatment.
Australian prime minister Scott Morrison then stepped in and said only the federal government has the authority to decide who is allowed into the country and under what circumstances and that he was not eligible to enter. The Victorian state government also refused to weigh in in support of Djokovic’s exemption. Meanwhile, Djokovic and his entourage had already departed for Australia on a long flight and upon arrival he was separated from the rest and held isolated under an armed guard at the Melbourne airport while his case was deliberated. In the end, his visa was cancelled and he was asked to leave.
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(Previous posts in this series: Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8, Part 9)
In the previous post, I quoted Fritz Rohrlich who said that asking whether an accelerated charge really radiates is meaningless and that we need to also look at the value of the Poynting vector at the location of the detector. In discussing the radiation from an electric charge that is freely falling in a gravitational field, the state of motion of the charge and the detector both have to be taken into account. and this requires transformations between frames and will depend on whether the detector is an inertial observer or not. The transformations to accelerating frames requires the use of the mathematical machinery of general relativity.
With that. in mind, let us consider a charge Q and a radiation detector D and see what happens under various scenarios that describe different states of motion of each. There are five possible scenarios of interest to consider. It should be borne in mind that these scenarios are hard to test experimentally and, as far as I am aware, have not been tested.
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We have people who are opposed to vaccinations on ideological grounds, on partisan political grounds, on religious grounds, and who think that it undermines their ‘wellness’ attitude to health and believe that various dietary and mental therapies are the key to avoiding the disease and that vaccines interfere with that protection.
But there are those who do not fit into any of those categories and say that they are not opposed to vaccines as such but don’t get vaccinated because they think that vaccines are unnecessary if one lives a healthy lifestyle and do not have the comorbidities that make one a risk for serious illness and death, such as age or being immunosuppressed or having lung ailments. Younger and otherwise healthy people are likely to fall into this category of the unvaccinated.
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