Hawking Radiation

While the following post doesn't quite get me to the point of understanding Hawking radiation, it gets me much closer to the point of understanding what Stephen Hawking was attempting to say in A Brief History of Time: now I know what he means by "virtual particles" and that I need to read up on Feynman diagrams to understand the argument.

Source: https://www.physicsforums.com/threads/higgs-field-and-the-casimir-effect.405738/#post-2736124 

Graphically in a Feynman diagram a virtual particle is a particle that does not escape to infinity; so its line has two ends (two vertices) where it meets with another line or lines. Now draw a circle and two vertices on the circle. This is a vacuum fluctuation where at one vertex a pair of virtual particles is created out of nothing (vacuum); the two particles propagate to the second vertex where they annihilate into nothing (vacuum). Usually this is a mathematical [artifact] and is "subtracted" from the theory.

Near the event horizon something strange happens. One of the two virtual particles tunnels through the horizon whereas the other virtual particle is eventually sucked into the black hole. The particle outside the event horizon does not annihilate with the other particle, so it escapes to infinite and is therefore not a virtual particle. The confusion is due to the fact that we compare a process in flat space (with two virtual particles in a vacuum fluctuation) with another, different process in curved spacetime (with one real particle). That's why its strictly speaking not a virtual particle that becomes a real particle, but a particle that is created by tunneling (similar to the alpha particle that tunnels from a nucleus causing alpha decay).

The mathematical reason is difficult: in order to set up quantum field theory one must define a vacuum state. In curved spacetime this is no longer possible uniquely. So what we call virtual particle when its located inside the event horizon is a real particle when it is located outside the horizon. One can evaluate this vacuum ambiguity mathematically. In doing so one finds that one has to redefine the vacuum state outside the event horizon in such a way that is contains real particles with thermal spectrum.

A similar effect is the so-called Unruh effect. It simply says that if an observer at rest observes vacuum w/o particles then a constantly accelerated observer observes thermal radiation! So the same volume of space contains no particles at all or thermal radiation - depending on the observer. Again the very notion of vacuum is no longer unique. The two effects are closely related as in the Unruh case there is again a "kinematical horizon" which means there is a region of spacetime from which no signal can reach the accelerated observer. This is not due tothe eometry of spacetime but due to the acceleration only, but nevertheless it is a horizon.

Reference: https://www.physicsforums.com/threads/higgs-field-and-the-casimir-effect.405738/#post-2736124

-Max
 

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I could not love thee dear, so much,
Loved I not honor more.

Global warming evidence(?) and positive feedback loops

Article: https://issuesinsights.com/2019/07/29/will-the-global-warming-hysterics-never-tire-of-being-wrong/?fbclid=IwAR2jf6xiN7uOIcjst3kv1mbX4aFKSa954Y3mNmENKxR7cv_hDEJMQ712xkw 

 
But some remember those frenzied forecasts. Following is but a small taste of a smorgasbord of baloney:

Al Gore once declared that "unless drastic measures to reduce greenhouse gases" were taken within the next decade, "the world will reach a point of no return," eventually suffering "a true planetary emergency." That was 13 years ago.

Gore is of course the same fellow who in the mid- to late-2000s kept telling us the Arctic Ocean would soon be ice-free. The ice, which is still there, had grown thicker and had wider coverage in 2014 than when Gore made his prediction. Earlier this year, before the growing season had ended, Wattsupwiththat reported the "2019 Arctic sea-ice extent is already higher than the previous four years and six out of the last 14 years."

In January 2009, former NASA scientist and corporate witch hunter James Hansen swore that the incoming president had a mere four years to save the world.

Later in the year, British Prime Minister Gordon Brown (the Thames, again) said there remained "fewer than 50 days to set the course of the next 50 years and more."

Also in 2009, 124 months ago, the prince of Wales worried out loud the world had "less than 100 months" to save itself.
2009 was a particularly looney year. Elizabeth May, leader of the Greens in Canada, wrote "we have hours to act to avert a slow-motion tsunami that could destroy civilization as we know it. … We need to act urgently. We no longer have decades; we have hours."

While speaking to then-Secretary of State John Kerry in May 2014, French Foreign Minister Laurent Fabius warned that "we have 500 days to avoid climate chaos." Nearly 1,900 days have passed since. The chaos is in the foreign minister's head.

In 2015, mayors from around the world signed a statement that said the "last effective opportunity to negotiate arrangements that keep human-induced warming below 2-degrees" Celsius had arrived.

Almost 20 years ago, in Y2K, the British Independent quoted a climate researcher who said in coming years the children of England "just aren't going to know what snow is." Thirteen years later, that same newspaper told readers to "stand by for icy blasts and heavy snow."

Commentary by Max:

Predictions of climate disaster have always rested upon the implausible assumption that earth's climate is an unstable equilibrium, when everything we know about earth's history and planetary systems indicates it's more likely to be a stable equilibrium. If heating led to further irreversible heating, the Earth would already have turned irreversibly into a furnace way back in the Medieval Warm Period. Climatology's arguments in favor of positive feedback loops are extraordinary claims, and we have yet to see extraordinary evidence. It's hotter than it used to be but in all likelihood this is about as hot as it's ever going to get, and the history of the past two decades bears that out because it's no longer getting even hotter--there is no temperature-driven positive feedback loop.

Also carbon dioxide has diminishing returns. At some point you're already capturing about all the energy in the CO2 bands, and increasing CO2 levels cease to matter (in terms of temperature at least--high CO2 levels do still make air feel less fresh, while increasing plant growth rates, and extremely high CO2 levels can give you a headache or eventually even kill you).

-Max
 
 --

I could not love thee dear, so much,
Loved I not honor more.

Pre-marriage Discussion

[Responding to questionnaire taken from https://www.marriagebuilders.com/choosing-the-right-one-to-marry-2.htm?fbclid=IwAR2lOe9xcmN-U825aaUkY9yhADyYaGLxThLn4DHvM91krQZriQWK7JLpfj8. My responses to B.F. in brackets.]

However, you can make up your own version of the PREPARE test if you like. It won't be as sophisticated as the one a professional counselor would give you, but it could give you a rough idea of where you might have serious conflicts. But more importantly, it would help you understand how you would handle those conflicts after marriage.

Ask yourselves these questions:

1. Do you want to have children, and if so, how many? [Ideally I'd like four daughters named Samantha (Sam), Alexandra (Alex), Riley, and Jill.]
2. What religion do you want for our children? [I would like our family to be completely committed to the teachings of Jesus Christ, especially as taught in the Church of Jesus Christ of Latter-day Saints.]

3. When our children are disobedient, how will you discipline them? [Ideally I'd like to raise my eyebrows and let them suffer the consequences of their own foolishness. I'm open to other approaches, especially when they are very young, but that's how I'd prefer to handle it. I'm a big believer in freedom of agency.]
4. How do you want to spend our vacations and holidays? [I'm not sure. For my own sake I'd probably just want to stay home, read books, and relax, but I expect that for the girls' sakes I'd want to frequently do things that give them new experiences, indoors, outdoors, and in the worlds of the mind.]
5. How much money do you expect me to earn? What if I never earned any money? [It would be fine with me if you never earned any money. In fact as a matter of fiscal discipline I would prefer it if we never, as a family, relied at all upon any money that you happened to earn even if you did feel like getting a professional job. That way you'd feel completely free to take any job you wanted, or leave any job you wanted, without any economic repercussions to family welfare. My goal is to make enough money for you to have that complete freedom.]

6. What kind of house would you like to own? Where would you like to live? [My mild preference is to have a house with no yard so there is no yardwork. If you decide that you want a yard because it looks nice I will do my best, because what's important to you should be important to me, but it's possible I might never learn to enjoy doing yardwork so please be patient.]

7. Do you expect me to make love to you whenever you want? If not, would you EVER expect me to make love to you? Would you leave me or have an affair if I never made love to you? [I don't think I would feel cheated if you never made love to me as long as we had a good friendship. That would obviously be inconvenient for our daughters, because they'd never get born, but as far as I'm concerned it's not something I feel like I need. I am not saying I won't feel physical desire for you and won't WANT to reach out to you that way, because you're super-cute and very desirable--but I don't think I would resent it if you hypothetically said "You're my best friend Max but I'm just not into touching and I think I never will be." I could be completely happy, I think, with a 100% verbal relationship with you, as long as I can count on you when I need you.]

8. If you don't like one of my friends, would you want me to give up the friendship? [I'm really not sure. At minimum I'd want to understand why we have different perceptions of this person. How is it possible for me to not like someone you like? I can imagine circumstances where I might try to persuade you that someone is bad for you, and if I successfully persuade you then I expect that you would give up that friendship voluntarily, but I don't think I would expect you to give up a friendship without being persuaded first.]

9. What should our budget priorities be? How will we make financial decisions? [This is a complicated subject. Let's talk about it at more length.]

10. Would you support me financially if I wanted to educate myself for a new career? [Sure. I know you've sometimes considered becoming a veterinarian, for example. If you want to, we'll make it happen, in as many different careers as you feel interested in.]

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I could not love thee dear, so much,
Loved I not honor more.

Pre-Copernican geocentrism

Something I learned from the book Lost In Math, by physicist Sabine Hossenfelder:

People love to make fun of pre-Copernican geocentric models of the universe, but it turns out that there were some interesting arguments against heliocentrism, back in the day.

For one thing, scientists back then knew how to do trigonometry, and they noticed that the stars (unlike the planets) didn't seem to move, which meant that either (1) the stars were fixed in position relative to the earth, not the sun, or else (2) the stars were implausibly far away, thousands of times farther away than any of the planets, far enough away that their parallax motion was impossible to detect.

It wasn't until much later that we developed instruments sensitive enough to detect that yes, the stars really do show parallax motion as the earth goes around the sun. But if you went back in time to the 16th century, and you didn't bring any of those modern instruments with you, you'd have a pretty tough time answering that argument.

This is good in the sense that it teaches you something true about the way human beings search for knowledge, including the fact that people can be wrong without being stupid.

It's an interesting book.

-Max

Ref: https://www.amazon.com/Lost-Math-Beauty-Physics-Astray-ebook/dp/B0763L6YR7/ 

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I could not love thee dear, so much,
Loved I not honor more.

What Is Pornography?

The definition of "pornography" I would give to my kids is "pornography is material produced by one person in an attempt to gain power (money, attention, etc.) over another person by manipulating their physical desires."

This definition makes it possible to talk clinically about accidental exposure to pornographic material, and without feeling shame. Case in point: I was on a web site today, skimming an article about Soviet whaling practices, and I kept seeing these highly-inappropriate bikini ads from a company called Venus. The body language of the models was aggressively sexual, and unlike most Google ads, these ones didn't have a little X in the corner for easily closing the ad and opting out of seeing it in the future. The ad bugged me enough that I held up my hand to cover the screen while I searched for ways to disable it, which I _think_ I was able to eventually do after some trial and error. (I clicked on Google Ad Choices, which sent me to Criteo's web page, and I told Criteo not to show me that product again, and reloaded the page--no luck, still the bikini porn. So I clicked on Google Ad Choices again and opted out of Criteo entirely, and reloaded the page, and this time I saw some ad for a hotel or something, so maybe it worked.)

Whoever was selling those bikinis is clearly trying to gain power (money, attention) by manipulating physical desires (aggressively sexual stances, making it hard to opt out), and therefore it's pornography. To them it's just business, probably, but they don't care about the damage they inflict on other people as long as they get their money. And if I had kids, I would want them to know that, and to be able to react to ads like that one by (1) realizing that they're under attack, (2) taking countermeasures, (3) feeling free to calmly discuss the attack with family members without feeling ashamed of the experience.

Am I always successful in fending off such attacks so calmly and disinterestedly? No. I was just lucky today. Do I want my kids to be even better than me at my best? Yes, I do.

-Max
 
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I could not love thee dear, so much,
Loved I not honor more.