My Weblog

I’m just back from a trip to US where I had the chance to attend LinuxWorld in San Francisco. I greatly enjoyed a presentation on Free Culture by Lawrence Lessig. Great topic and a good place to do it since while we are preoccupied with Open Source we tend to neglect that there’s some thing which is even more important than Open Source and this is Open Content. In the healthcare-related software development area where I sit, opening the content might be far more important than providing free and customizable software applications. The creative commons idea is great. I should probably add “some rights reserved” to the music I publish on this site as a sign of support to this idea.

However, free culture is a big step beyond free content and honestly a tricky thing to leave totally uncontrolled. I grew up in a world, where culture was openly controlled and saw what came in place when this control was removed - not a pretty picture, actually a “mass culture” with very little real value. I guess we need to do some thinking here and I’m afraid I do not have an answer.

The new CD of good friend has been released. James Vernon is great piano player and this time in a marvelous piano trio setup. Jim has put a lot of energy in this disk called “HOUSE OF JAZZ”. I heard it last January at his place in Dallas, TX and to my ears it was ready to be released, but his group kept on working on it to make the best out of the recorded material. It is as he says himself “a synthesis of modern jazz and modern classical sources”. The 7/8 measure of “Cerebral Hemorrhage” is something that even relates to the folk music of my country.

I truely recommend his disk - it is simply great jazz. It is available online at CD BABY and the songs can be listened to on the trio’s web site as well. I’m happy for Jim and his wife Geraldine that they suceeded to get this beautiful thing out. I hope to see them soon and congratulate them in person. Good work, guys.

We just returned back from a short trip to California. We did a great drive from San Francisco (actually started from Palo Alto) down to San Diego on the famous “Highway 1″. The nature, wild life and all that we tried to capture on a few pictures, posted on this server, but it is worth seeing it live. We both liked San Diego very much - it was a surprise to me, but I can easily name it as one of the most beautiful US cities. The combination of nature and civilzation is really unique. I do not know many places where one can walk to the international airport of the city from its downtown area. On my return I actually checked in to LA and then walked back into the city with my boarding pass to have a last stroll before leaving. Is not this great?

I have just read the last book of Kurt Vonnegut - “Man Without A Country”. It is the same old Vonnegut reacting on the recent events in 2004, although as he says there’s nothing so new about our race that has not happened since Prometheus has stolen the fire from the gods and gave it to the humans. The book is short but it synthesizes his views on humanity, socialism, atheism, meaning of life and the likes, that are present in all his other books.

At one point it reminded me about the movie I saw the other day - “Match Point”, the most recent one of Woody Allen. It is a great movie, by the way, perhaps the best one I’ve seen this year. When Vonnegut writes about the rulers of today (presidents, dictators, “guessers”, whatever) I thought of the main character in “Match Point” and how greatly he differs from Dostoyevski’s Raskolnikov. While Raskolnokov went insane after killing the old lady, for Chris (a typical guesser by Vonnegut) killing a loved one and his own baby is just a “collateral damage”!

During the movie I thought “have we all got so inhumane that Raskolnikov’s crime is a just a joke by today’s standards?”. Vonneguts gives a this answer as far as I can tell: “there’s nothing recent about it - it has always been like that”. I’m not sure. There’s surely one thing that differs our world from all previous ones (especially after the collapse of the socialist/communist experiment in the Soviet Union and Eastern/Central Europe), and this is “profit”. The difference is that today we do not leave this world in the hands of humans, but rather in the hands of the anonymous profit. Profit is something measured today, this is why we do not care about the real future.

One of the thinks I liked too - the comparison of today’s world with Poland under occupation.

I’ve started to play with Google Maps API and have created a small page with some locations of interest to me here. Google Maps have some AJAX capabilities that I wanted to experiment with but have not done it yet.

I had the idea to place on a map some of the locations where I have taken the landscape photos in my “Landscapes” album in my gallery. However, from what I know so far, Coppermine is not a very easy gallery to customize, especially if you use it to hold more than pictures - e.g. video and audio files. Seems tough even to modify some of the links within the generated pages. I wanted to have the “home” referring to the top page of my site and after a few minutes going through the php files I gave up - it is not structured in a very intuitive manner.

I have put several photos from our vacation in Sharm El-Sheikh in my gallery here. The last two dives I did were with a an instructor that has a camera, so we did some underwater photos too. Some of them are in my gallery and they are all from Ras Mohammed - Yolanda Reef, Shark Reef and Ras Ghozlani.

Here’s the list of the dives I did (not impressive for a pro, but great for me):

I had my first real tennis lesson today. I would have never thought that one hour of “playing” will make me so tired. I was exhausted, so this is indeed a fantastic way to keep your weight in control without restricting yourself from the good thinks in life, such as beer.

We’ve just come back with Eli from the scuba diving course when we did our first two dives in the Red Sea. I’ve got my PADI Scuba Diver License but I did not continue to get the Open Water Diver one because Eli was not feeling comfortable diving. Diving is really a great experience. The feeling of being down there at the mere 15m to some real diver measures, is opening a new world. This is probably the only kind-of-natural way on earth to escape from the grip of the gravitation and feel as if you are floating in space - and what a space it is. It’s a pity that I could not take pictures as the variety of corals and fish in the Red Sea is truly amazing. We saw a turtle resting on the surface, but the photo I took of it turned to be blurry - the creature was probably a meter long. The Ras Mohammed peninsula and the area around it where we dived is a natural reservation park and I hope that we human would preserve the living creatures here - they are so precious.

Sharm el-Sheikh is really a diver’s paradise, as it is also a great place to rest. Our hotel “Magic Life” seems to be one of the best in the region and is the nicest resort I’ve ever been too. Egyptian beer is good, local red wine is more or less ok if you do not have any expectation, but white and rose wines are worth avoiding (perhaps the problem is that people tend to mix it with water, which if not mineral is undrinkable). All is inclusive ands it is really all - diving practice in the pool, tennis lessons for various skill levels, horse riding, mountain biking, aerobics, etc. There’s a private quay that is only available for the hotel guests and the fish and corals to be seen when snorkeling are numerous - parrot-fish, napoleon-fish, various angel-fishes, just name it - it’s there.

The question I posed before is explained with “length contraction”, which occurs in the direction of the motion, so the normally oriented clock is not affected by it, while any orientation that has a non zero length projection of the photon path on the axis of motion will have to have the length contraction taken into account:

This time, imagine the light clock lying on its side (in other words, Fig. 1 rotated by 90 degrees counter-clockwise). Now the motion of the light pulse is back and forth in the same direction that the whole clock is moving. What happens this time? Well, as the light pulse leaves one mirror and heads toward the other, that mirror advances forward to meet it. This trip is shorter than when the clock is stationary. On the way back, though, the light pulse is chasing a retreating mirror, and the trip takes longer than it would in a stationary situation. This round trip period, T'’, is longer than T’ by the factor 1/γ. (This is similar to the case where an airplane traveling across the Atlantic with a steady headwind against it, and then returning with the same wind at its back, will take a longer time for the round trip than if there were no wind at all. I leave the simple math here as an exercise for the reader.)

Now if this were all there is to the story, the amount of time dilation would depend on the orientation of the clock relative to the direction of motion, but then this would violate the Principle of Relativity. What prevents this violation is a shortening of lengths along the direction of motion. The distance between the two mirrors would thus contract by the factor 1/γ, reducing T'’ to the correct value T’ as it should be. So, lengths are observed to contract along the direction of motion by a factor of 1/γ. Again, this only becomes noticeable at very high speeds, approaching c.

I liked “The Fabric of the Cosmos” so much that started reading “The Elegant Universe” by Brian Greene. I’ve pause now at chapter two where he explains the time dilation with the light clock placed on a moving platform from the viewpoint of a static observer. This is I guess the classical explanation given by Einstein, which is well synthesised here. The computation of the time dilation is indeed straight-forward as it is based on simple geometry, but it is based on the fact that the photon’s direction of movement is perpendicular to the direction of the movement of the platform - this is how the light clock is positioned. Were we to place the light clock in such a way so that the photon’s path is on the same axis as the platform movement, then we will find that there’s no time dilation at all because the sum of the forward and the backwards photon movements between the two mirrors will be same as in a static situation. To clarify the positioning - the direction of movement of the platform is normal to the plane of the mirrors, making the photon motions forward and backward for the observer.

Furthermore, placing the light clock at an arbitrary angle with respect to the direction of motion will yeild other formulas for the time dilation. Is this a paradox or I am missing something?