Saturday, January 06, 2024


Here's another sci-fi flick you probably never heard of, Europa Report, about a space mission in search of extraterrestrial life to Europa, one of Jupiter's four Galilean Moons.

Shot on a low budget (10 million US$), yet entirely at ease visually with far bigger productions; a cast consisting of unknown actors, yet all of them filling the screen; an unknown Ecuadorian director (Sebastian Cordero Espinosa), yet he holds the reins throughout and the tempo never slacks.

Once in a while jewels are made and yet slip under the radar totally undeservedly. Europa Report is just such a movie. See it.

Good night.


Thursday, January 04, 2024


In Europe anyway.

Hameln, Germany:

Antwerp and Brussels, Belgium:

Milan, Italy:


Berlin, Germany:

Our politicians, who even now flatly refuse to close our borders, indeed, who are now trying to frame declaring illegal immigrants as legal ones through a new 'Migration Pact', deserve to be shot.


Monday, January 01, 2024


If we can forget for a moment the terrible turmoil in the world, what with the biggest war since WW2 going on in Ukraine; Gaza; Darfur; dangerous tensions between China and Taiwan/The Philippines et al, one can only conclude that we seem to be on the cusp of a new Technological Era. Think quantum computers, the imminent return to the Moon and hence the exploration of Mars, AI, Brain Computer Interfacing and its potential to give severely handicapped people a new lease on life...

... and yet none of all that made as much an impression on me as CERN's ALPHA-g experiment last fall. This post's title sums up the essence: matter and antimatter react the same to Earth's gravity, but to find that out requires being able to isolate antimatter of course. I assume that before the experiment took place, antimatter had already been isolated, but I will use ALPHA-g's feat as the reference for that scientific breakthrough.

Antimatter is the opposite of ordinary matter: composed of antiparticles with reversed charge, parity and time. According to physics' laws, any (subatomic) particle should have its own antiparticle: a proton its antiproton, an electron its anti-electron (aka positron), a neutron its antineutron, a quark its antiquark etc etc. These particles were mathematically predicted and experimentally found, e.g. Paul Dirac predicted the positron around 1928 or so, and only 4 years later Carl Anderson found it in an experiment involving cosmic rays. It was Dirac again (what a genius) who theorized the antiproton in 1933, and in 1955 Emilio Segrè and Owen Chamberlain discovered it in in LBNL's (Lawrence Berkeley National Laboratory) Bevatron, a particle accelerator.

But while the consituent components of the most basic antimatter atom, the anti-hydrogen so to say, had thus been isolated, apparently it took until our days to go one step further and assemble them. Ordinary hydrogen, the basic building component of the Universe that we can see, is composed of one proton and one electron circling it. So anti-hydrogen must consist of an antiproton and an anti-electron, which from now on I will refer to as a positron.

Up until learning of this experiment, which relies on having actual antimatter of course, I thought matter's opposite number was the stuff of sci-fi and thrillers, like e.g. in Dan Browns Angels and Demons where the Pope's camerlengo wants to use an antimatter device to wreak havoc and teach humanity a lesson - the antimatter, suspended in a magnetic field sustained by a battery, expected to react in a violent annihilation explosion with matter upon depletion of the battery.

But the sci-fi is already behind us - CERN has an actual Antimatter Factory, and apparently, aside from measurable quantities of antiydrogen, comparable amounts of antihelium have already been produced also, be it at CERNs Large Hadron Collider by a team led by Ivan Vorobyev.

Anyway, the hurdle of assembly of basic anti-atoms now apparently having been taken, let's get back to the subject which was about ALPHA-g's experiment to find out whether antimatter reacts similarly to Earth's gravity as matter:


"Ever since the discovery of antimatter 90 years ago, physicists have striven to measure its properties in new and more precise ways. Experiments at CERN’s Antimatter Factory represent the state of the art. In addition to enabling measurements of properties such as the antiproton charge-to-mass ratio with exquisite precision (recently shown by the BASE experiment to be equal to that of the proton within a remarkable 16 parts per trillion), the ability to trap and store large numbers of antihydrogen atoms for long periods by the ALPHA experiment has opened the era of antihydrogen spectroscopy. Such studies allow precise tests of fundamental symmetries such as CPT. Until now, however, the gravitational behaviour of antimatter has remained largely unknown.

Equivalence principle

Using a modified setup, the ALPHA collaboration recently clocked the freefall of antihydrogen, paving the way for precision studies of the magnitude of the gravitational acceleration between antiatoms and Earth. The goal is to test the weak equivalence principle of general relativity, which requires that all test masses must react identically to Earth’s gravity. While models have been built that suggest differences could exist between the freefall rates of matter and antimatter (for example due to the existence of new, long-range forces), the theoretical consensus is clear: they should fall to Earth at the same rate. In physics, however, you don’t really know something until you observe it, emphasises ALPHA spokesperson Jeffrey Hangst: “This is the first direct experiment to actually observe a gravitational effect on the motion of antimatter. It’s a milestone in the study of antimatter, which still mystifies us due to its apparent absence in the universe.”

The ALPHA collaboration creates antihydrogen by binding antiprotons produced and slowed down in the Antiproton Decelerator and ELENA rings with positrons accumulated from a sodium-22 source. It then confines the neutral, but slightly magnetic, antimatter atoms in a magnetic trap to prevent them from coming into contact with matter and annihilating. Until now, the team has concentrated on spectroscopic studies with the ALPHA-2 device. But it has also built an apparatus called ALPHA-g, which makes it possible to measure the vertical positions at which antihydrogen atoms annihilate with matter once the trap’s magnetic field is switched off, allowing the antiatoms to escape.

The ALPHA team trapped groups of about 100 antihydrogen atoms and then slowly released them over a period of 20 seconds by gradually ramping down the top and bottom magnets of the trap. Numerical simulations indicate that, for matter, this operation would result in about 20% of the atoms exiting through the top of the trap and 80% through the bottom – a difference caused by the downward force of gravity. By averaging the results of seven release trials, the ALPHA team found that the fractions of antiatoms exiting through the top and bottom were in line with simulations. Since vertical gradients in the magnetic field magnitude can mimic the effect of gravity, the team repeated the experiment several times for different values of an additional bias magnetic field, which could either enhance or counteract the force of gravity. By analysing the data from this bias scan, the team found that the local gravitational acceleration of antihydrogen is directed towards Earth and has magnitude ag = [0.75 ± 0.13 (stat. + syst.) ± 0.16 (sim.)]g, which is consistent with the attractive gravitational force between matter and Earth.

The next step, says Hangst, is to increase the precision of the measurements via laser-cooling of the antiatoms, which was first demonstrated in ALPHA-2 and will be implemented in ALPHA-g in 2024. Two other experiments at CERN’s Antimatter Factory, AEgIS and GBAR, are poised to measure ag  using complementary methods. AEgIS will measure the vertical deviation of a pulsed horizontal beam of cold antihydrogen atoms in an approximately 1 m-long flight tube, while GBAR will take advantage of new ion-cooling techniques to measure ultra-slow antihydrogen atoms as they fall from a height of 20 cm. All three experiments are targeting a measurement of ag  at the 1% level in the coming years.

Even higher levels of precision will be needed to test models of new physics, say theorists. “The role of antimatter in the ‘weight’ of antihydrogen is very little, since practically all the mass of a nucleon or antinucleon comes from binding gluons, not antiquarks,” says Diego Blas of Institut de Física d’Altes Energies and Universitat Autònoma de Barcelona. “Any new force that couples differently to matter and antimatter would therefore need to have a huge effect in antiquarks, which makes it difficult to build models that are consistent with existing observations and where the current measurements by ALPHA-g would be different.” Things start to get interesting when the precision reaches about one part in 10 million, he says. “This is the start of a new avenue of experimental exploration that pushes the development of trapping and other techniques. If you compare the situation with the sensitivity of the first prototypes of gravitational-wave detectors 50 years ago, which had to be improved by six or seven orders of magnitude before a detection could be made, anything is possible in principle.”

Notice what Prof Diego Blas says: “The role of antimatter in the ‘weight’ of antihydrogen is very little, since practically all the mass of a nucleon or antinucleon comes from binding gluons, not antiquarks”. But I assume this holds true for ordinary matter also. A proton e.g. is composed of two up quarks and one down quark (and an antiproton of two anti-upquarks and one anti-downquark. Yet: an up quark weighs some 2.01 +/- 0.14 megaelectron-volts, and a down quark 4.79 +/- 0.16 MeV. That's 0.214% and 0.510% of the mass of the proton (some 940 MeV), respectively. Or the two upquarks and the one down quark which 'make' a proton constitute about 2 + 2 + 5MeV = 9MeV or... somewhat less than one percent of a proton's mass!!! It was to be expected that the same would hold true for an antiproton.

Some more videos:

And be sure to check out this one:

I wonder whether, after antihydrogen and antihelium, Mankind will also be able to build progressively heavier anti-elements? Will we one day be able to see a block of, say, 1 kg of anti-iron suspended in a magnetic field? And what would happen if that magnetic field suddenly fell away and the block boinked against the glass and metal of the device containing it?

One thing is sure, exciting days in physics ahead!


Sunday, December 31, 2023


To all our readers, we wish you a heartfelt Happy New Year and may the Farce be with you!

It's hard to believe, but 2023 marked DowneastBlog's 20th anniversary. I don't know where I am going with this, and company chores being what they are, siphoning off too much time and strength, but I still intend to keep DB online, even though I'm less than pleased with the frequency and quality of my own posts. It's just that I feel a presence is still needed, an outpost if you will, a humble bastion/trench/foxhole of conservative thought and common sense. Or even a modest bridgehead, from whence to launch a counterattack once I will no longer be bothered by the necessity to keep the firm afloat. Can't let go yet, however.

Enjoy yourselves, but if you have to drive this evening/night, drink with moderation!