PFE031: Thunderstorms

Thunderstorms are awesome am I right?

Lightning! Thunder! Rain [sometimes]! Pretty. Loud. Pretty LOUD!

So why am I looking to muck pretty awesome things up with numbers? Because, I don't know, it's you who's reading this, it's probably more of your fault anyways [see above image].

Right, so we're going to review a common and fairly well known trick: the five second rule.

Not that one, the one about lightning and thunder.

Lightning and thunder happen at basically the same time... at the location of the lightning. So if you get hit by lightning you'll see the flash and hear the thunder at the same time [or you won't because your brain will be rather well-done, I don't know]. But as you move away from the lightning [generally a good idea] everyone knows that the thunder slides away from the lightning too... in time. That is, you see a flash and then... BOOM.

Let's science this up now. Light goes fast. I mean, really fast. Count one second: "one one thousand". Light from the earth is basically to the moon in that time. So we can pretend that light's instantaneous for any distances on earth that we are ever going to care about.

Sound, on the other hand, is comparatively pokey. Since sound travels through something [air in this case] it is a little bit dependent on the properties of that material, but at 50F [a reasonable temperature for a thunderstorm I figured] sound travels at about 1107 feet per second. How fast is that? Well, let's see, it's certainly faster than I can run [thank goodness! Otherwise there would be sonic booms all the time]. If we then convert that into seconds per miles [which might seem like a weird unit unless you're a runner] we get about 4.77 seconds per mile - it takes sound just under five seconds to travel a mile.

BUT WAIT! THERE'S MORE!

So apparently sound travels faster when there's more humidity in the air. This is actually a little bit complicated, but a simple model gives about a half a percent increase. This brings our timing down to an even shorter 4.75 seconds per mile. Whatever.

This gives us our standard five second rule [unlike the food one above, this one is rooted in SCIENCE, YEAAA!!!]. Start counting time as soon as you see lightning and stop as soon as you hear the corresponding thunder [if the storm is too active it can be tough to tell which boom corresponds with which flash - you're on your own in these cases]. Take the number of seconds and divide by five [then round up a teensy bit if you want to be more accurate] and that will tell you how far away the lightning is. If you counted 8 seconds you're looking at ~1.6 miles away. Is it just that easy? It's just that easy.

But... who cares how far away it is? What we really care about is

Shh. I'm counting between the lightning and the thunder to see if the storm is coming or going.

whether the storm is coming, leaving, or passing us by. If we repeat the above process, we can get the distance to the strongest part of the storm over a period of time. If the distances are shrinking head for cover. Of course, you can also probably tell if the lightning is getting brighter and the thunder is getting louder and if it starts pouring on your poor unprotected head - but this way is way more fun.

That's thunderstorms.

PFE030: The Higgs Mechanism Part 3 - The Discovery

The LHC is a pretty awesome machine. It took ten years to build the final component and uses five smaller accelerators to seed it. It is essentially the largest and most complex thing humans have ever built and the largest computing grid we've ever put together is employed to process the largest amount of data ever generated. It's also the largest refrigerator [okay, cryogenic facility but it's more fun to think about how much beer/potato salad would fit inside than super conducting magnets]. It also has reached the highest energy and luminosity in any man-made device ever. Whatever.

Kegs too.

I reiterate these things to emphasize how awesome of a machine it must be and how hard it must be to find whatever it's looking for.

While the Higgs field is everywhere and interacting with most things, it's hard to directly observe it. Luckily it has a side business creating additional particles, the Higgs boson. We can create, observe, measure, and quantify these particles - all those tasty things us physicists like doing. Unfortunately, it's not very good at making them. Lots of other boring particles [the kind of stuff we're made of and a zoo of other yawny stuff] are far easier to make. It's like looking for a needle in a haystack of haystacks [okay it's nothing like that because you or I could eventually suss out the needle and I have no idea how to even turn on an LHC - but it's really really hard].

Luckily, there are piles of physicists sorting out exactly how big the haystack is supposed to be. If it looks even teeny weeny bit [that's a technical term - move along] bigger than it's supposed to, then ta-da! We've got... something!

Just 365 short days ago [really they were all pretty average length days] on July 4, 2012 - it was announced that they had found something. It was definitely a boson, probably spin zero [remember that the Higgs is the only spin zero particle so far], and was consistent with the expected properties of the Higgs boson.

Put out the flag, grill some hot dogs, and call it a day, right?

If you look very closely you can see the SSC - the experiment that would have made this discovery an American one instead of a European one.

It's not done. We're not satisfied that easily. See, the predictions for this particle aren't just that they're a pain to make, but super specific. It should be this tall, this fast, this smart - it should have have these friends and hate those people. So on and so forth. But there are a bunch of crazy people who make things up [cough cough like me] who suspect it could be very slightly different. And to rule them out, or confirm their theories, they need measurements far more accurate than the general properties determined so far. Lot's more to do!

That's how you find a Higgs!

Spoiler alert: next week is both practical and not about particle physics!

PS - that isn't quite the end of the story. It appears that things could be rather more complicated than previously expected as indicated in my signoff. There may already be evidence of a second Higgs - don't go telling your friends or anything yet - but this is a key component of many popular theories whatever that means.

PFE029: The Higgs Mechanism Part 2 - How It Acts

Last week, we heard about why we need the Higgs mechanism to fit in with everything else we know about little things. This week we are going to look at "how it interacts with stuff".

Personally I've always been a fan of this

graphic but whatever, it's super confusing. Let's start with the Higgs at the bottom. The line connecting it to itself means that it interacts with itself. The rest of the lines coming out of it means that it interacts with quarks, W and Z bosons [the weak bosons] and some of the leptons [in particular, the electron plus two others]. Notably absent from that list are gluons, photons, and those other leptons [neutrinos].

Okay, what?

It turns out that these are the particles that have mass. Of course, this is what was mentioned last week. Particles that have mass - a resistance to motion - interact with the Higgs. So the Higgs must somehow resist motion. Since the mass of a particle is proportional to how strongly it interacts with the Higgs, it appears that the Higgs itself, somehow, causes a resistance to motion.

Remember that pushing a monster truck is hard even in space with no gravity and no friction - that's because it still has a giant mass.

At this point people usually try to describe the Higgs as something like "sand that we are all moving through that slows us down - the heavier we are, the more we slow down". Of course this is a terrible description. Okay, not terrible, but still misleading.

The problem is that now everyone is thinking about aerodynamics - a frisbee flying in the regular fashion or flopping through this "Higgs sand" all sideways. But of course, that has nothing to do with it. The frisbee interacts with the Higgs field in the same way no matter how its moving.

Let's think of it a different way - in terms of what doesn't interact with the Higgs. Well there are gluons, but no one wants to have to think about those if they don't have to. There are neutrinos, but since the question of their mass is rather complicated and unclear, we'll ignore them too. Luckily, we still have photons or light - something that we are all familiar with!

Light particles don't interact with the Higgs - they may cross paths, but won't even notice it. What evidence of that do we see? They go at the speed of light!

"Wow, thanks there. Light goes at the speed of light? Great one. Now it all makes perfect sense."

Don't think of "the speed of light" as, well, "the speed of light" quite so much - think of it as the universal speed limit. The fastest that anything is allowed to go.

And since photons don't interact with the Higgs, they are always cruising along at a chill 669 million miles per hour.

But everything else [people and cars and toasters are made up of quarks and electrons] travels slower because they keep interacting with the Higgs field so much.

At this point its somewhat important to differentiate between the Higgs field and the Higgs boson. The field exists everywhere. It is here. It is there. It is in a box. It is in a fox. At any time and at any place, any particle that is allowed to interact with it [quarks, airplanes, electrons,... but not photons] does. This constant uniform behavior makes sure that all electrons have the same mass everywhere.

The boson - the particle - associated with all this nonsense, is a result of the fact that the field interacts with itself. A field doesn't have to do this, but because this one does, the Higgs boson itself has a mass.

That's how the Higgs acts.

PFE028: The Higgs Mechanism Part 1 - The Need

Some of you may think that my recent hiatus was due to laziness, forgetfulness, boredness, etc. I have actually been waiting on CERN to write a post on the Higgs - I wanted to wait for it to reach discovery status. It is that time. This is the first in a three part series walking you through the need for the Higgs mechanism, what the Higgs mechanism is like, and the road to discovery.

There have been, recently, a few posts on the internet discussing the Higgs boson, the recent announcement from CERN, and what it all means. While many of them have stuck strictly to the facts many more [by my entirely unscientific count] have taken numerous liberties with said facts. Here at PFE you get the fair and balanced full story.

First, if you haven't already, go take a look at my last post on mass. Done?

Next, what are we talking about? Let's think about some vocabulary.

1. Mass as discussed in this post will be that of inertial mass. Particle physics does not describe how gravity works [yet, we have some ideas though!]. Moreover, the mass of particles in question is so incredibly small that measuring their gravitational effects is overly tricky. As such the Higgs mechanism has nothing to do with gravity.
2. The Standard Model is a collection of ideas put together over the 1960's and the 1970's, but the ideas themselves have been in progress for much longer. It describes everything we know about particle physics and unites three of the four forces [electromagnetic, strong, and weak - but not gravity]. It has been incredibly predictive and people are still working out all of the implications of the theories put together.
3. "The God Particle" is a completely incorrect name often assigned to the Higgs boson. In 1993, Nobel laureate Leon Lederman wrote a book about, among other things, the Higgs boson. Apparently, he wanted to use the phrase "The Goddamn Particle" in the title due to the difficulty in tracking down the particle, but his publisher wouldn't let him. This name has led to a vastly increased media coverage distorting the facts. One popular myth goes along the lines of, "the particle is everywhere and interacts with everything so it is called 'The God Particle'". In fact, it does not interact with everything, and the particle is a consequence of a field that exists everywhere. There are multiple other fields [that which gives rise to light for instance] that exists everywhere.
4. A boson is a classification of particles. All particles are either fermions or bosons. There are a few interesting properties and consequences of each, but they are not relevant for this Higgs discussion.

Before we get into the nitty-gritty details, I should first explain the history of the discovery. In particular, the name Higgs is associated with the man Dr. Peter Higgs

My namesake has some great moves as shown by the blurriness here.

but there were as many as six or more people who came up with the same idea at the same idea. While no Nobel prizes have been awarded on the subject, the Sakurai prize [some nerdy physics prize] was given to Higgs along with Kibble, Guralnik, Hagen, Englert, and Brout.

Enough physics history, that's even duller than physics itself, right?

Where does the Higgs mechanism fit in with everything else? As people were putting together the standard model, they kept awing themselves with the amazing predictions it made: cross sections, scattering angles, branching ratios, electric charges and magnetic moments among many more. But who cares about those? You all just read about mass, it's mass you want to know about. The thing is, there was no real way to sort out the mass of all of these particles. I know what you're thinking: "This great theory doesn't even tell you what mass the particles should have?" It looks like the theory is lost and we are nowhere.

A number of physicists [those six I mentioned above, plus a few others] put together a theory that allowed particles to have masses within the standard model. The problem is not just that particles need to acquire mass, but that they are all different. In a sense, before you add mass into the theory, all of the particles have a sort of symmetry in that they are all massless. But their masses had already been well-measured. Adding in something else to the theory allowed for an elegant means to allow for particles to have masses.

So this seems pretty straightforward - you don't have mass, so you add mass! But, alas, it's not. You can't just add stuff willy-nilly. I mean, you can of course. But see, the standard model is pretty much amazing. It is been heralded as the greatest scientific achievement. Ever. I mean, it was probably physicists making that claim, but still, pretty big. So if you just "add in mass" - which you can, you lose the beauty that is the standard model. So it has to be done carefully, it has to be done right. It has to be the Higgs.

The final note about the Higgs mechanism and the Higgs field that it describes, is that the field that allows for the mechanism to work "interacts with itself". Okay, that made no sense, but the effect is that you get the Higgs boson. Like how liquid water sort of condenses out of the air from gaseous form in some circumstances, a "condensate" of the Higgs field forms into a real particle just like the rest. It is through this particle that people hope to probe the nature of the Higgs field.

That's why we need the Higgs mechanism.