Monday, February 29, 2016

A Tale Of A Particle With Two Names

Physics Focus this week has a brief but fascinating history of the J/Psi particle and its discovery that led to it having two different names.

When two separate groups, using different types of accelerators, get practically the same result, it is difficult not to be convinced by something like that. Ah, but back then, way back in the 70's, the US had several high energy physics colliders like this where multiple facilities were producing results.

Now, the US has none, not even one (RHIC and CEBAF are nuclear physics facilities/colliders).


Friday, February 26, 2016

If The Laws Of Physics Don't Apply....

"... what would the law of physics say about such-and-such?"

I've heard of many dumb and stupid things online over the many, MANY years I've been on the 'net (since 1989, if you have to ask!), but somehow, this one caught my eyes more than others.

I'm not going to point out where I recently read it, but this issue is not about physics, but rather with how irrational certain things are, and how irrational people can be without realizing it. If you are in the US and being immersed in the General Election fever, I'm sure you'll understand this. But it doesn't lessen the impact and the surprise for me, because many of these things are so obviously ridiculous. But yet, the people who muttered them don't seem to care how foolish they sounded.

BTW, when this person in question was told that since he is discarding the laws of physics in the first place, why not make up any kind of rules that he wants? And guess what? He didn't want to. He still wanted a "rational" explanation on how physics would explain something that doesn't follow the laws of physics.



Friday, February 19, 2016

LIGO Discovery And The Nobel Prize

Inevitably, the discussion that follows after the LIGO announcement of the detection of gravitational wave is the Nobel Prize. If there is a sure thing with regard to the Nobel Prize, is that this discovery will get someone this prize.

But just like the issue surrounding the discovery of the Higgs, the question comes up on who should deserve the prize for this discovery. Just like the Higgs, thousands of people were responsible in the work, both theorists and experimentalist. And typically, the Nobel committee will give the award to the individuals who either headed the collaboration, or made the most significant contribution to the physics that led to the discovery.

This news article lists the three most likely individuals who might be the front-runner for the Nobel Prize for this LIGO discovery.

"I think that most of the community would agree that the three pioneers of what became LIGO would be Rainer Weiss, Kip Thorne, and Ronald Drever," the head of one of LIGO's observatories in Hanford, Washington, Fred Raab, told Business Insider.

Weiss — who is a professor at MIT's Department of Physics — and Drever — now retired — are both experimentalists who made significant contributions to the concept, design, funding, and eventual construction of LIGO.

On the other hand, Thorne is a theorist, and the Feynman Professor of Theoretical Physics at CalTech. Together with his students, Thorne conducted much of the work on what the detection of a gravitational wave would actually look like and how to identify that signal within the data

Unfortunately, Ronald Drever is in poor health, and the Nobel prize is not awarded posthumously. They may also have missed the deadline for this year's Nobel prize.

The news article discuss on whether the Nobel prize should increase the number of recipient from the maximum of 3 for each prize (outside of the Peace price). I think the change should be more on awarding the prize to deceased individuals. So what if that person is dead? If he/she did make a major enough contribution to warrant a prize, then it should be done. This is especially true for many women scientists who never received their recognition while they were alive back when women were not encouraged or had severe restrictions on their careers as scientists. Posthumous awards can correct these injustices.


Thursday, February 11, 2016

LIGO Reports Detection of Gravitational Wave

LIGO has officially acknowledged of the detection of gravitational wave.

Now, in a paper published in Physical Review Letters on February 11, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaborations announce the detection of just such a black hole merger — knocking out two scientific firsts at once: the first direct detection of gravitational waves and the first observation of the merger of so-called binary black holes. The detection heralds a new era of astronomy — using gravitational waves to “listen in” on the universe.

In the early morning hours of September 14, 2015 — just a few days after the newly upgraded LIGO began taking data — a strong signal, consistent with merging black holes, appeared simultaneously in LIGO's two observatories, located in Hanford, Washington and Livingston, Louisiana.

Notice that this is the FIRST time I'm even mentioning this here, considering that for the past 2 weeks, at least, the rumors about this have been flying around all over the place.

Looks like if this is confirmed, we know in which area the next Nobel prize will be awarded to.

There is also a sigh of relief, because we have been searching for this darn thing for years, if not decades. It is another aspect of General Relativity that is finally detected.


This Educational Video on Accelerators Doesn't Get It

OK, before you send me hate mail and comments, I KNOW that I'm hard on this guy. He was probably trying to make a sincere and honest effort to explain something based on what he knew. And besides, this video is from 2009 and maybe he has understood a lot more since then.

But still, this video is online, and someone pointed this out to me. I get a lot of these kinds of "references" from folks online, especially with Wikipedia entries. And try as I might to ignore most of these things, they ARE out there, and some of these sources do have not only misleading information, but also outright wrong information.

This video, made presumably by a high-school science teacher, tries to explain what a particle accelerator is. Unfortunately, he described what a particle accelerator CAN do (i.e. use it in high energy physics colliders), but completely neglected the description of a "particle accelerator". This is a common error because most people associate particle accelerator with high energy physics, and think that they are one and the same.

They are not!

As I've stated in an earlier post, more than 95% of particle accelerators on earth has NOTHING to do with high energy physics. One of these things might even be in your doctors office, to generate x-rays to look at your insides. So using high energy physics experiment to explain what a particle accelerator is is like using creme brulee to describe what a dessert is. Sure, it can be a dessert, but it is such a small, SMALL part of a dessert.

A particle accelerator  is, to put it bluntly, a device to accelerate particles! Period. Once they are accelerated, the charge particles can then be used for whatever they are needed for.

Now, that may sounds trivial to you, but I can assure you that it isn't. Not only does one need to accelerate the charge particles to a set energy, but in some cases, the "quality" of the accelerated particles must be of a certain standard. Case in point is a quantity called "emittance". If these are electrons, and they are to be used to generate light in a free-electron laser, then the required emittance, especially the transverse emittance, can extremely low (in fact, the lower the better). This is where the study of beam physics is crucial (which is a part of accelerator physics).

The point I'm trying to make here is that the word "particle accelerator" is pretty generic and quite independent of "high energy physics" or "particle collider". Many accelerators don't even collide these particles as part of its operation (in fact, many do NOT want these particles to collide, such as in synchrotron radiation facilities).

What this teacher neglected to describe is HOW a particle accelerator works. The idea that there are these accelerating structures with a wide range of geometries, and they can have either static electric field, or oscillating electric field insides of these structures, that are responsible for accelerating these charged particles, be it electrons, protons, positrons, antiprotons, heavy nucleus, etc... And even for high energy physics experiments, they don't usually collide with a "fixed" target, as implied in the video. Both LEP, the Tevatron, the LHC, etc. all collide with beams moving in the opposite direction. The proposed International Linear Collider is a linear accelerator that will collide positrons and electrons moving toward each other in opposite direction.

So while the intention of this video is noble, unfortunately, the information content is suspect, and it missed its target completely. It does not really explain what a particle accelerator really is, merely what it can be used for. It also perpetuates the fallacy that particle accelerators are only for these exotic experiments, when they are definitely not.


Friday, February 05, 2016

The Physics of Mirrors Falls Slightly Short

This is a nice, layman article on the physics behind mirrors.

While they did a nice job in explaining about the metal surface and the smoothness effect, I wish articles like this will also dive in the material science aspect of why light, in this case visible light, is reflected better off a metal surface than none metalllic surface. In other words, let's include some solid state/condensed matter physics in this. That is truly the physics behind the workings of a mirror.


Wendelstein 7-X' Comes Online

ITER should look over its shoulder, because Germany's nuclear fusion reactor research facility is coming online. It is considerably smaller, significantly cheaper, but more importantly, it is built and ready to run!

Construction has already begun in southern France on ITER, a huge international research reactor that uses a strong electric current to trap plasma inside a doughnut-shaped device long enough for fusion to take place. The device, known as a tokamak, was conceived by Soviet physicists in the 1950s and is considered fairly easy to build, but extremely difficult to operate.

The team in Greifswald, a port city on Germany's Baltic coast, is focused on a rival technology invented by the American physicist Lyman Spitzer in 1950. Called a stellarator, the device has the same doughnut shape as a tokamak but uses a complicated system of magnetic coils instead of a current to achieve the same result.

Let the games begin!