The Lagrangian for the Standard Model

 The Standard Model (SM) is the theory that best explains and describes all the known fundamental particles of nature, and the forces of nature, minus gravity. It is the heart and soul of particle physics. It is built around quantum field theory, which is, as one might expect, is one of the more challenging mathematical theories around. 

The main way to represent all the possible interactions and forces between the different particles is through a Lagrangian operator. Lagrangians are actually a standard way to do classical mechanics, and it can be extended into quantum mechanics, as well. A lagrangian is put together using energy, rather than forces like we would do in Newtonian mechanics. Think of a lagrangian as U - KE, or potential energy - kinetic energy. 

Anyhow, this article allows you to see what the lagrangian in the SM looks like, and breaks it down section by section to show you what the real math looks like for different interactions that build up our fundamental understanding of the universe!! 

"Blue Jet" lightning that goes up, towards outer space

 In electrostatics, we get into the basic concepts for how we think 'normal' lightning is formed. Ice crystals bumping and rubbing together in a storm cloud is the friction needed to separate charge, and turn a cloud into a large battery or capacitor. 

But "blue jet" lightning can be observed both on the ground and from outer space. This article has a wonderful photo from the space station, which captured the flash with certain detectors. Scientists are working on understanding this process fully - the blue glow is due to mostly nitrogen being in the upper reaches of the atmosphere, before heading into outer space. 

A galaxy missing its central supermassive black hole!!

 Thanks to Marc for finding this one. 

Check out a galaxy astronomers are scratching their heads on - missing is a central supermassive black hole! It apparently has drifted out of the main body of stars making up the galaxy, and it is a mystery as to how this could happen. Nothing can out-do Nature as far as variety and having a sense of humor! :-) 

STEM Writing Contest with the NY Times

 For the writers out there: 

New Student Opportunity: 2nd NYTimes/Science News STEM Writing Contest!

Science News in High Schools and The New York Times Learning Network together invite students to participate in the 2nd annual STEM Writing Contest. Students will choose an issue or question in STEM that interests them and then write a 500-word explanation that will engage and enlighten readers. Here is a rubric for the contest, which is open to students ages 11–19. 

Student submissions are due on Tuesday, March 2, 2021 at 11:59 p.m. Eastern time. Winning entries will be published on The New York Times Learning Network. You can read last year’s winning essays  here.

COOL Interactive for 50 gravitational wave events!

 Check out this article, which has an interactive graphic for the 50 detected events of gravitational waves from LIGO! It's cool! 

RC Circuit Lab

 This video shows a series RC circuit, with a 47,000 microfarad capacitor (a large capacitor!) connected to a 10-ohm resistor and a power supply. The capacitor is hooked up to an electronic voltmeter, which can be read out in real time. We can watch the time-dependent behavior of the voltage of the capacitor, which is the same behavior (exponential rise and decay) as the charge being stored by the capacitor. 

Note that as the voltage of the capacitor rises, and the total voltage of the power supply stays constant, then the voltage across the resistor must be decreasing; this means the current in the circuit is decreasing. This is Kirchhoff's voltage rule, V = Vres + Vcap, at all times. And if Rres decreases, then the current must be decreasing because of Ohm's law, I = V/R. 

We first see what happens with a 10-ohm resistor, and then a 200-ohm resistance. Note how much longer it takes the capacitor to charge...this is due to the time constant of the circuit, RC. We can control how quickly or slowly the circuit takes to charge and discharge, which is a key piece of knowledge to have for modern electronics (since everything is basically time dependent). Check it out! 

To see the mathematical derivations we will do in class, check out this one for charging a capacitor in a series circuit; or this one for a discharging capacitor. There is also one for how to think about it if the resistor and capacitor are in parallel. 

Codecademy - FREE platform for learning various programming languages

 Since a number of people have been asking about how to start programming, the most popular platform for a variety of languages, and especially Python, is Codecademy. 

Another option for beginners is a language developed by Northwestern, Netlogo; there is a Web based version of this you should be able to run on Chromebooks.  

Free Competitive Programming course in Java, taught by Alan!!

 For those who are interested in programming, and perhaps have a little beginning knowledge of the Java language, you may want to take senior Alan Wang's Competitive Programming online course. This is an extension to a free, basic Java course he created and ran for over 100 younger students last summer, and is his SDG project. 

The course is free and online, all you need to do is commit to the time to take it!! Registration is open, and we expect it to fill quickly since it is capped at 30 students this time. Check it out if interested!! 

Competitive programming is like math olympiad or science olympiad but for computer science. During competitions, you take a 4-hour test that tests your ability to write code to solve difficult problems. There are 4 divisions bronze, silver, gold, platinum. The class will be introducing how to take the test and going over how to advance from the bronze divisions to silver division. Alan would encourage students who have taken Introduction to Java Programming or know basic Java programming to register. 

Half the observable matter in the universe is in filaments of gas connecting galaxies

 An interesting article about where some 50% of ordinary matter, the observable stuff you and I are made of. is in filaments of gas and plasma connecting galaxies. Some of these filaments are tens of millions of light-years long. Big Bang models of the universe, through computer simulations of the evolution of the universe, predict such filaments, and now astronomers have figured out several ways to finally see them. Truly fascinating! Check it out. 

Help make change for students with special needs in Greece

 If you'd like to again help the 15-year old Greek student, Marios Thomeas, who recently spoke up for equity in education for students with special needs across the globe, he is focusing on trying to help influence the Greek government to make changes. You can sign the petition that will go to the Greek Prime Minister, and if you choose can leave a brief video message stating support for this effort and for better support and resources for kids with special needs, who all have gifts they want to share with humanity.