Hilbert’s Hotel shows why some infinities are bigger than others

Here is an entertaining video that has a nice explanation of a seeming paradox about infinities.

In 1924, the German mathematician David Hilbert raised a peculiar and seemingly paradoxical question: are some infinities bigger than others? The answer he arrived at – yes, actually – might have been impenetrable to non-mathematicians if not for the thought experiment he devised involving a hotel with an infinite number rooms. This video from the Australian filmmaker and educator Derek Muller builds Hilbert’s ‘infinite hotel’ and populates it with some strange, fuzzy creatures to demonstrate how the mathematician arrived at his groundbreaking conclusion, and touches on the real-world implications of his discovery.

Would I stay or would I go?

The horrific collapse of a 12-story beachfront condominium building in Florida consisting of 136 units has resulted in 16 people being killed and another 149 still missing. While it will take some time to determine the cause of the collapse, suspicions are focused on problems with the foundations or that the salty air caused the steel used in the framework to corrode. A letter written by the president of the condominium association three months before the collapse said that the building needed $15 million in major maintenance and repairs.

There is another identical building just one block away that was built by the same company at the same time forty years ago and now those residents have to make the decision as to whether to stay or leave. This is not an easy decision and would depend on many factors. These units are expensive but their value would have dropped now and some people may not be able to sell and find another place. It would also depend on whether they lived alone (in which case they would only be risking their own demise) or whether they lived with loved ones which might tilt the decision towards moving. It would also depend upon age. Older people find it harder to move and may also feel that they have less to lose by staying.
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The Covid Delta variant is hitting the unvaccinated

The Delta variant of the SARS-CoV-2 virus is now rapidly becoming the dominant strain. This variant is more easily transmissible and more dangerous, and Dhruv Kullar warns that from the evidence gained so far from the UK, it poses a greater risk to the unvaccinated.

Earlier this year, scientists estimated that lineage B.1.1.7-the Alpha variant, first isolated in England-could be some sixty per cent more transmissible than the original version of sars-CoV-2. Now experts believe that the Delta variant is sixty per cent more transmissible than Alpha-making it far more contagious than the virus that tore through the world in 2020. It hasn’t yet been conclusively shown that Delta is more lethal, but early evidence from the U.K. suggests that, compared to Alpha, it doubles the risk of a person’s being hospitalized. Even if the variant turns out to be no deadlier within any one person, its greater transmissibility means that it can inflict far more damage across a population, depending on how many people remain unvaccinated when it strikes.

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The UFO/UAP story will never die

The US government has released its much awaited (by UFO enthusiasts at least) report on what it calls Unidentified Aerial Phenomena and it is just what you might expect.

The mystery of UFOs seen in American skies is likely to continue following the release of the US government’s highly anticipated UFO report.

The report released on Friday afternoon made clear that while American intelligence officials do not believe aliens are behind the UFOs – or what scientists prefer to call unidentified aerial phenomena (UAP) – that were observed by navy pilots, they cannot explain what the flying objects are.

The report confirms that the observed phenomena are not part of any US military operations.

The Pentagon studied over 140 incidents reported by navy pilots of UAP seen over the last two decades for the report. Many were seen from the summer of 2014 into the spring of 2015.

While the report said that some incidents could be the result of technological errors in sensors or observers, it noted that most of the UAP reported “probably do represent physical objects” since they were registered across multiple sensors.

The only UAP intelligence officials were able to identify “with high confidence” turned out to be “a large, deflating balloon”.

“The others remain unexplained,” the report reads.

There are two things to keep in mind. (1) There are always unexplained phenomena. (2) One can never rule out a favored hypothesis for any unexplained phenomena. Those two will ensure that people who believe that extraterrestrials are, for some reason, choosing to buzz around us without making contact will never run out of reasons to believe.

I for one am going to wait until one of them unambiguously contacts us before getting all excited.

Ohio anti-vaxxers want the freedom that vaccination brings

Now that the numbers of people who have been vaccinated has reached more than half the US population, there are places that require proof of vaccination before you can enter. Where I live in Monterey, CA, the local bridge club opened for face-to-face play on Tuesday but you have to show proof of vaccination before you are allowed to do so. The first time you go, you show the proof and your name is entered in a register and that eliminates the need to show proof each time. Masks are not required but you can choose to wear one if you like. There are bottles of hand sanitizer at each table and players are encouraged to use it frequently, especially since they are exchanging cards. I went on Tuesday and there were about a dozen people, about half of them being those who had been starved of bridge because they either were not comfortable enough with technology to play online or they had eye issues that prevented them from looking at a screen for any length of time. It was nice to meet them again.
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The origins of the SARS-CoV-2 virus

Recently there has been an upsurge of interest into the origins of the SARS-CoV-2 virus, the one that causes covid-19, with speculation that it may not have originated by mutating spontaneously into a form that could transfer from animals to humans but that it may have been leaked from a research laboratory that does work on such viruses. Most proponents of the lab leak theory have suggested that the leak was accidental but a few have suggested a darker possibility of deliberate release.

I have been trying to make sense of the debate and found this article by Mara Hvistendahl to be helpful in sorting through the various claims. Hvistendahl had been in China when the avian flu virus broke out in 2013 and she had visited the lab of a prominent researcher and avian flu expert Chen Hualan who had been doing the so-called ‘gain of function’ research that is seen by some as an indicator that the covid-19 virus did not come about by accident.
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E-scooters

These electrified versions of a child’s toy are becoming a popular form of adult transportation, able to travel at speeds up to 30mph (50km/h) and even carry two people. One can see their appeal, especially in urban areas, since they reduce traffic congestion, are maneuverable, easy to learn, and do not take up much space. But because of the reckless riding of some people, they are posing a risk to pedestrians.

French police are searching for two women after the death of a pedestrian who was hit by an electric scooter in Paris, officials say.

The 31-year-old victim, an Italian citizen named only as Miriam, was walking along the Seine early on Monday when she was hit by the e-scooter.

The pair were reportedly travelling at high speed, and did not stop.
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The case has renewed the debate over e-scooters in Paris, where there have been concerns for the safety of pedestrians.
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In 2019, the French government introduced rules after hundreds of incidents, including several deaths. Riders are required to be at least 12 and cannot ride their scooter on the pavement.

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The need for double-blind methods in police lineups

One of the methods that police use to identify people they suspect may have committed a crime is to put them in a lineup with other people and have eyewitnesses pick them out. But Laura Smalarz writes that the way this is often done is fraught with problems.

On the strength of six eyewitnesses’ lineup identifications, Lydell Grant was sentenced to life in prison in 2012 for the murder of a young Texas man, Aaron Scheerhoorn, who was stabbed to death outside a Houston nightclub in 2010.

All six of those eyewitnesses were wrong.
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Thanks to the work of the Innocence Project of Texas, new DNA testing on biological material collected from underneath the victim’s fingernails cleared Grant and implicated another man, Jermarico Carter, who police said confessed to the killing. Carter has now been indicted for the murder by a grand jury, and Lydell Grant was released from prison.

But faith in eyewitnesses runs so deep that despite the overwhelming proof of Grant’s innocence, the Texas Court of Criminal Appeals initially refused his exoneration request. Instead, they asked that the six eyewitnesses who originally testified against Grant respond to his claims of innocence. Finally, almost a year later, the Texas Court of Criminal Appeals declared Grant “actually innocent” on May 19, 2021.

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Can robot animals help treat loneliness?

Katie Englehart writes about the problem of loneliness that afflict a large number of older people in the US.

Older people are more likely to live alone in the United States than in most other places in the world. Nearly thirty per cent of Americans over sixty-five live by themselves, most of them women.
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In 2017, the Surgeon General, Vivek Murthy, declared loneliness an “epidemic” among Americans of all ages. This warning was partly inspired by new medical research that has revealed the damage that social isolation and loneliness can inflict on a body. The two conditions are often linked, but they are not the same: isolation is an objective state (not having much contact with the world); loneliness is a subjective one (feeling that the contact you have is not enough). Both are thought to prompt a heightened inflammatory response, which can increase a person’s risk for a vast range of pathologies, including dementia, depression, high blood pressure, and stroke. Older people are more susceptible to loneliness; forty-three per cent of Americans over sixty identify as lonely. Their individual suffering is often described by medical researchers as especially perilous, and their collective suffering is seen as an especially awful societal failing.

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Debunking UFOs

Mick West, who has long studied UFOs (or Unidentified Aerial Phenomena as the US government calls them) is not impressed with the recent flurry of reports that have given hope to believers that the ‘truth is out there’ that we are being visited by extraterrestrials. (I wrote about a recent New Yorker article that profiled a credulous journalist.) The seeming support, if qualified, given by high profile individuals has added to the expectation that the report that the US government will release later this month will vindicate their beliefs. West says that upon closer examination, these mysterious events invariably turn out to have mundane explanations.
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