Monday, March 30, 2009

light is a bandit

I've started learning about special relativity in school. I've heard a little about relativity in the past and had previously developed a sort of blind trust that space and time are relative to frame of reference, or something like that. I knew that if you go really fast then time doesn't pass at the same rate, I had no clue how. Recently when working with optics I read that light travels away from the source at a constant speed and even if you were moving away from the source, as far as you are concerned, the light still approaches you at the same speed. This concept totally blew my mind because as you all know: when someone throws a ball at you and you run away, it then appears to you that the ball is coming at you slower than if you just stood still. If the ball behaved as light does then as soon as you start running it would speed up to its initial speed plus your speed. So how is light an exception to the laws of mechanics? Maybe it has something to do with light being a wave of energy stored in electric and magnetic fields, also light has no mass like a ball does. It turns out that this curious behavior of light is Einstein's second postulate of special relativity and because of it, crazy things happen. Things I don't yet understand so I won't try to explain.

I do however want to share what I think is an interesting example of current in a wire from 2 different inertial frames of reference. We have observer 1 who is stationary with respect to the current and observer 2 who is moving with the same direction and velocity as the current.

Observer 1 experiences a magnetic field (it can be calculated by Biot-Savart, or Ampere's Law).

If we imagine the current as individual positively charged particles then to observer 2 the so-called current becomes an electrostatic line of charge.

Observer 2 would experience an electric field due to these charges (we find this by Coulomb's or Gauss' Law). This might lead to a nasty disagreement between the two observers as observer 1 would insist that there was a magnetic field and observer 2 would be quite certain that it was actually an electric field and they both would be right. I must give credit to Gary Adams who showed that to me (and 170 other people in the room) last semester and is a really great physics professor.

Wednesday, March 11, 2009

Radio in my Head

Introductory note: If you are not a very big Radiohead fan I don't expect you to explore all the links in this post but please if you do anything, go here! (I'll remind you again at the end.)

I'm interested in how bands form, I like to read about how groups got started. It's an interesting thing that when I want to find out about a band, the first place I go is Wikipedia. I find that you get a good summary of historical information on groups whereas if you go to the artists official website you usually just get the latest news and things that don't interest me as much. I'm interested in the humble beginnings, the ugly past, the trials and failures gone through before the big break. Wikipedia will usually give you a good start but if you want to know more you have to search for in-depth interviews or maybe someone's put out a book on the band. I've been getting more into Radiohead lately and they have the most confusing official webpage of any band I've seen. None of it really makes sense to me and I can appreciate that maybe the band just wants to express themselves a certain way, they are entitled to it, I just don't get anything from visiting. Since their site left me unfulfilled I searched for content elsewhere and found it.

On youtube there are some videos of the band doing a sort of house concert videocast performance. Actually it looks like they did one on Nov 9 2007 and another Dec 31 2007. The former was entitled "Thumbs Down" and the latter "Scotch Mist". In fact, "Scotch Mist" is a 52 minute video available on youtube including performances of all the songs from their new album. These are live performances but the band is just set up in a house somewhere and the audience is on the other side of the podcast. I totally love it. The Thumbs Down session included them doing covers including The Smiths "Headmaster Ritual" and Joy Division "Ceremony" among others. So maybe you don't want to devote a few hours watching these videos, I understand that. You can also view individual tracks, Radiohead actually has a good youtube profile with some of the songs listed separately. (I just want to squeeze in another link the song there there, a really good video from a live concert).

Portishead also did a similar videocast just before the release of their newest album. The video is called "Portishead in Portishead" I believe. It was available till the release of the album but I've found that if you go to their official site you can register your email with them and they will allow you access to the video. This one was also captivating to me, I loved watching their New York live video, some musicians are just fascinating to watch. They do such interesting things with vintage keyboards and old tape echo effects.

I've been walking around with "Jigsaw Falling Into Place" in my head. It's on Radiohead's latest "In Rainbows" album. I learned the guitar part and fooled around with working the song up myself but I have the problem that my voice is not high enough. Makes me a little frustrated but I've encountered this frequently so I have a procedure: I consider falsetto, I consider transposing, I consider whether it just wasn't meant to be, I try harder to extend my range. The first 3 options have been successful enough to keep me content in the past but the last one still hasn't ever come through for me as well as I want it to. If I end up working it out I'll post a video and you can witness for yourself me trying to fake my way through it.

So in writing this post I have come across yet another set of wonderful performance videos for VH1 Live From The Basement. Much like the other videos mentioned but a little smoother around the edges and with a few different songs. I highly reccomend Where I End and You Begin, this is the link I mentioned at the top and you can see Jonny Greenwood playing the unique instrument the Ondes Martenot, you can play it similarly to a theremin. I've overloaded this post with links and I realize I've gotten out of hand so I'd better end it now. I hope there is music out there that gets you as excited as this gets me.