Here are two contributions from personal experience to the ever growing list of Internet pictures that go with the “You had one job…” meme.

First, a nice loaf of our favorite nine-gain bread, from a neighborhood Portuguese bakery:

Yes, you are seeing it right: It’s sliced lengthwise. Needless to say, the hapless employee who offered this stunning demonstration of human intelligence did not remain on the job much longer. (Regardless of how it was sliced, the bread was yummy.)

Next, one of my favorite deserts, an Austrian delicacy, a Mozartkugel (Mozart ball):

What’s wrong with it, you ask? Well… the portrait of Mozart is not supposed to be on the bottom of the piece, you know; it usually goes on top!

I know, I know, there have been much bigger fails on the Interwebs. Still, I found these funny.

A short while ago, I turned on a computer. Like several of my other computers, this one is also configured to display a weather widget on the desktop. Here is what it showed:

If only it were true! Alas, the reason for this overly optimistic weather report had to do with the fact that the computer in question has last been turned on more than four months ago, back in September. In reality, this is what our weather is like right now:

And even that is a significant improvement over the −21°C that greeted me early in the morning.

It appears that we are entering the era of flawed democracies.

Our country, Canada, remains firmly in the category of full democracy. But that is no longer true south of the border. In an annual survey by The Economist, the United States slid down the list (and this is based on data from 2016, before Trump’s inauguration). It is now one of the leading flawed democracies, with a democracy score virtually identical to that of Japan.

And even as the number of full and flawed democracies, put together, remains roughly the same (80 in 2008, 75 in 2016 if I counted correctly), the number of full democracies is rapidly shrinking. There were 28 full democracies on the list back in 2008; by 2016, this number shrank to 19, a more than 30% decrease in just eight years.

Meanwhile, the examples of India and Mongolia demonstrate that democracy is not just a privilege for the rich. These countries are decidedly third world economies with GDP per capita roughly one tenth that of Canada or the US, yet they manage to maintain democracies no more flawed than the regimes on the eastern fringes of the European Union, such as Hungary or Romania.

In case anyone is wondering, Canada is not immune to the fear, rage and bigotry that helped Trump to power. A perfect example: Five dead, an unknown number injured in a shooting in a mosque in Quebec City tonight.

I feel like crying tonight.

I promised myself not to blog about politics for a while, but events being what they are, I cannot keep my damn mouth shut or my damn fingers not typing.

These two screen captures speak for themselves.

First, the number of Americans killed by terrorists from the seven Muslim-majority countries that are on Mr. President, Generalissimo, smartest-man-in-the-world Donald J. Trump’s traveler ban:

Next, the number of Americans killed by terrorists from three Muslim-majority countries that are not on the Generalissimo’s oh-so-perfect list to protect Americans:

The difference? As many pointed out, these three countries that are not on Trump’s list have one thing in common: business ties with the Trump empire.

Dear Trump supporters, tell me again how your beloved Tweety Orangeface, heading the bestest and least corruptest American government ever, is draining the swamp and protecting Americans?

Enough blogging about politics. It’s time to think about physics. Been a while since I last did that.

A Facebook post by Sabine Hossenfelder made me look at this recent paper by Josset et al. Indeed, the post inspired me to create a meme:

The paper in question contemplates the possibility that “dark energy”, i.e., the mysterious factor that leads to the observed accelerating expansion of the cosmos, is in fact due to a violation of energy conservation.

Sounds kooky, right? Except that the violation that the authors consider is a very specific one.

Take Einstein’s field equation,

$$R_{\mu\nu}-\tfrac{1}{2}Rg_{\mu\nu}+\Lambda g_{\mu\nu}=8\pi GT_{\mu\nu},$$

and subtract from it a quarter of its trace times the metric. The trace of the left-hand side is $$-R+4\Lambda$$, the right-hand side is $$8\pi GT$$, so we get

$$R_{\mu\nu}-\tfrac{1}{4}Rg_{\mu\nu}=8\pi G(T_{\mu\nu}-\tfrac{1}{4}Tg_{\mu\nu}).$$

Same equation? Not quite. For starters, the cosmological constant $$\Lambda$$ is gone. Furthermore, this equation is manifestly trace-free: its trace is $$0=0$$. This theory, which was incidentally considered already almost a century ago by Einstein, is called trace-free or unimodular gravity. It is called unimodular gravity because it can be derived from the Einstein-Hilbert Lagrangian by imposing the constraint $$\sqrt{-g}=1$$, i.e., that the volume element is constant and not subject to variation.

Unimodular gravity has some interesting properties. Most notably, it no longer implies the conservation law $$\nabla_\mu T^{\mu\nu}=0$$.

On the other hand, $$\nabla_\mu(R^{\mu\nu}-\tfrac{1}{2}Rg^{\mu\nu})=0$$ still holds, thus the gradient of the new field equation yields

$$\nabla_\mu(\tfrac{1}{4}Rg^{\mu\nu})=8\pi G\nabla_\mu(T^{\mu\nu}-\tfrac{1}{4}Tg^{\mu\nu}).$$

So what happens if $$T_{\mu\nu}$$ is conserved? Then we get

$$\nabla_\mu(\tfrac{1}{4}Rg^{\mu\nu})=-8\pi G\nabla_\mu(\tfrac{1}{4}Tg^{\mu\nu}),$$

which implies the existence of the conserved quantity $$\hat{\Lambda}=\tfrac{1}{4}(R+8\pi GT)$$.

Using this quantity to eliminate $$T$$ from the unimodular field equation, we obtain

$$R_{\mu\nu}-\tfrac{1}{2}Rg_{\mu\nu}+\hat{\Lambda} g_{\mu\nu}=8\pi GT_{\mu\nu}.$$

This is Einstein’s original field equation, but now $$\hat{\Lambda}$$ is no longer a cosmological constant; it is now an integration constant that arises from a conservation law.

The vacuum solutions of unimodular gravity as the same as those of general relativity. But what about matter solutions? It appears that if we separately impose the conservation law $$\nabla_\mu T^{\mu\nu}$$, we pretty much get back general relativity. What we gain is a different origin, or explanation, of the cosmological constant.

On the other hand, if we do not impose the conservation law for matter, things get interesting. In this case, we end up with an effective cosmological term that’s no longer constant. And it is this term that is the subject of the paper by Josset et al.

That being said, a term that is time-varying in the case of a homogeneous and isotropic universe surely acquires a dependence on spatial coordinates in a nonhomogeneous environment. In particular, the nonconservation of $$T_{\mu\nu}$$ should lead to testable deviations in certain Parameterized Post-Newtonian (PPN) parameters. There are some reasonably stringent limits on these parameters (notably, the parameters $$\alpha_3$$ and $$\zeta_i$$ in the notation used by Clifford Will in the 1993 revision of his book, Theory and experiment in gravitational physics) and I wonder if Josset et al. might already be in violation of these limits.

It is well known that the despicable Biff Tannen character from the Back to the Future movies was based on a certain real-life despicable mogul by the name of Donald J. Trump. In particular, the “rich Biff” of 1985, having established a casino and real estate empire after receiving a sports almanac from the future back in 1955, was modeled after everyone’s favorite Trump.

In light of this and today’s historic events, it is only appropriate to imagine how the real-life Biff, I mean Trump, would have fared in one of the movies’ iconic scenes:

I hate manure…

Yes, I know it is more than a little crass to share this tweet. Even so, it is far less distasteful than the many racist caricatures that followed Obama’s inauguration and frankly, it makes it a lot easier to deal with this historic day.

I really have no words to describe how I feel about today. But a picture is worth a thousand words.

So here is another thing I don’t expect to see from Donald Trump: Publishing an article in the highly respected multidisciplinary journal Science.

His predecessor, the still sitting Barack Obama did just that: his article about “The irreversible momentum of clean energy” was published yesterday, January 13, 2017. In it, he makes the case that economic growth does not depend on energy-related emissions, and that combating climate change does not require accepting lower growth or a reduced standard of living.

I just saw this US Defense Department video about a swarm of high speed drones released at altitude by an F/A-18. The drones communicated with each other, self-organized, and went on to execute predetermined tasks autonomously.

In case anyone is wondering why I worry about the future of AI, this is a perfect demonstration.

Meanwhile, the Defense Department is also continuing its trials of the Sea Hunter, a 132-ft, 145-ton unmanned, autonomous vessel designed to hunt submarines.

Don’t worry, the brave new world is coming…

I just finished listening to Obama’s farewell address.

Now why do I have the feeling that this may be the very last time in my life that I’ll be hearing an American President preach goodness and decency instead of contempt and hate? Uplifting thoughts instead of fear and loathing?

Meanwhile, there appears to be a multitude of clowns on the Interwebs who think repealing Obamacare is okay, because they are insured through the Affordable Care Act:

What can I say? Enjoy your improved healthcare starting next month, folks. Glad I live in pinko commie Canada where we have had decent (albeit far from perfect) medicare for half a century. Of course once Trump, along with his BFF Putin, manage to blow up the world, none of this will matter anymore.

Here is a quote from one of my favorite novels, Jack London’s Smoke Bellew:

“The world’s gone smash. There’s nothin’ regular an’ uniform no more. The multiplication table’s gone loco. Two is eight, nine is eleven, and two-times-two is eight hundred an’ forty-six—an’—an’ a half. Anything is everything, an’ nothing’s all, an’ twice all is cold-cream, milk-shakes, an’ calico horses.”

Why this particular quote? Because I was reading about Trump’s infamous medical report, prepared by a Harold N. Bornstein, MD, from the great city of New York. The doctor is real, but the medical report is… weird (reproduced below.) Apparently, Mr. Trump tests positive for everything.

But what is even weirder is the doctor himself and his Web site. Once a respectable site advertising a family practice, today it redirects to a site that sells an annoying teddy bear.

I kid you not. A site that sells “The Original Annoying Happy Birthday Teddy, the bear that never stops singing ‘Happy Birthday to you…'”.

So perhaps that explains why I think that anything is everything, an’ nothing’s all, an’ twice all is cold-cream, milk-shakes, an’ calico horses.

Or maybe I got high on something without realizing it.

I mean… is there anything about America’s esteemed President-Elect that is not a boldfaced lie?

The Emperor has no clothes.

Sycophants praise his choices. The lush fabric. The elegant, fashionable tailoring. The beautiful stitching.

Yet the Emperor has no clothes.

Unfortunately, even his critics no longer acknowledge this fact. They criticize his clothes. They question his taste in garments. They reject the gaudy colors. They ridicule the bad workmanship.

But none have the courage to tell the world the truth: This Emperor is naked.

And thus it came that the lessons of history are once again forgotten, and all its mistakes are yet again set to be repeated.

I captured this close captioning gem several days ago but then promptly forgot about it.

I know, I know, it’s not easy to caption a conversation in real time. But it was still hilariously funny. Thanks for a good morning laugh.

For what it’s worth, as I recall the word that was actually used was “agree”. How that turned into “pee”, I have no idea.