Cosmic Mirror

You are walking tired and thirsty on an unforgiving desert. Water is not to be found anywhere near. Broken hearted, you suddenly seem to spot an oasis. You rub your eyes, pinch your skin, but yes it is an oasis indeed. Oh NO, its only a mirage, an illusion that played tricks on you. You are crestfallen!

A situation like above occurs quite commonly. Here, for example, the air in the immediate vicinity of the hot sands are much lighter in comparison to that of the above. Just as light bends, due to refraction (changes at the interface, due to differing refractive indices of the medium), when a ray of light is made to pass through water from air, it bends (one can see it using lasers or using a straight rod which appears bent). A similar situation occur in deserts and in very cold climates.

Objects having mass, distort the space time curvature just in a similar way an iron ball would do to a piece of cloth, whose four corners are tied to four poles. There would be an indentation in the middle of the cloth. If one releases a small ball at one of its corners, the ball will proceed towards the dent, in a spiral way. Encircling, it will finally end up in the center. This is what we call gravity, and orbits (paths, the ball traces) have been proposed so that the ball doesn't end up with the ball at the center.

Now imagine a black hole, a very massive and dense object, with such a strong gravitational pull, that even light can not escape its fatal attraction. Thus it it is invisible. The gravitational pull near its surface will be maximum, while the pull will fade out away from it, inversely proportional to the square of the distance (of measurement). Hence we can visualize a situation akin to the mirage illusion already stated. Near the black hole the gravity (space time curvature) is densest, whereas gravity away from it is less so. This reminds us the analogy of refraction we saw with respect to light (electro-magnetic radiation). Thus, you certainly can expect to find gravitational mirrors (total internal reflection) in black holes.

The black hole won't belch out any of its secrets, as theory of quantum gravity prohibits it: it will only show the observer's curious face in its own mirror. Could there be a Grand Unified Theory now? Or, how about combing your hair using this MIRROR?

Frozen frame

When we take photographs of our near and dear ones or that of a beautiful scenery, we freeze the happenings at that moment. Whatever may be the size of the photo (in bytes/pixels), all the informations had to come through the lens via the focal point. If there were no aberrations (spherical/chromatic etc), then all these bits of informations will have passed through the focal point only (theoretically). How is it possible? A point (just a point, mind it) holding so much information? If there be simultaneous data transfer, the information density will be maximum at this point, whereas if we think of sequential data transfer, the speed of data transfer at this point had to be maximum. (We just cannot change the speed of light in a specific medium at will, can we?)

My profound ignorance in optics won't allow throwing any light on this. Perhaps data congestion/bottlenecks in the nodes of the internet may be addressed to when this is found out. (Presently locomotive behavior of ants are being investigated to find the best net traffic algorithm).

Science Can Be Fun

Been busy for a few days. Now almost through with all my assignments.
I worked and fixed some critical EKG/EEG issue to some extent. But the superimposing (background) noise is really bugging the contraption. I put the device within a metal enclosure, used good quality coaxial cable, yet the device seems prone to catch the 50 Hz hum, and the noise from the SMPS (Switched Mode Power Supply) of the computer. I used the scope software to analyze the input and interface it to the computer, so that my computer monitor could behave as a stand alone oscilloscope. I used the 'mic in' jack of the computer for signal input. For power, I used two 9 volt general purpose batteries, to ensure safety and also to eliminate mains hum. Perhaps, they need to be screened further. I'll look into this.

Next I did a kind of magic with a laser pointer! It was a hit among kids and adults alike. All I did was that I got hold of a class 3A, 630-680 nM key chain laser (the light is red at this electromagnetic wavelength), which sells for about 60-70 cents here in Calcutta. I tied one end (the key side) of the laser to the spindle/axle of a DC motor, via a spring. I tied a rubber band across the push button switch of the laser, so that it was constantly on. Then I switched on the 12 V supply of the motor. As the laser pointer rotated, the centrifugal force stretched the spring which increased in length gradually (as per 'Young's modulus') as the motor gathered speed. The resulting beam gave a vivid and bright spiral trajectory on the wall. The persistence of vision gave an added effect. I observed all the necessary precautions needed with lasers, of course!

Then I did a few basic things with polarizers as my young science fans wouldn't let me go. You would be surprised to know that I actually got these little things from my old mobile phone. I found out two remarkable pieces of polarizers in the LCD panel portion (picture on the left). I showed them what they were and the peculiar way they behaved. The color changed as one was rotated with respect to the other. You can watch a medium quality video here (754KB, WMV format). The experiment demonstrates the wave nature of light. Needless to say, they were amused.

Finally, I feel tempted here to mention about mobile flashers, those tiny devices, which flash as one uses the cell phone, without any wiry connections. More about them later, may be in my other blog.