Saturday, July 18, 2009

Lessons for my child: power of observation

Cosmos is complex, perhaps too complex to fathom, and many elements of the cosmos are intertwined in nature. However, we can take it from Einstein that ``Subtle is the Lord, but malicious She is not". This means the cosmos, even though complex in detail, operates through very few, and simple and direct rules. The simplicity is of course overshadowed by multiple phenomena operating simultaneously. Careful observation of cosmos may reveal some of the secrets of its laws.
  1. It is not simply ``watching". For example, if you watch a movie, it would be meaningless exercise if you can not narrate its script or story or or meaning later. What a pity it would be, if someone had to watch Deewar or Kaala Pathar, and not remember the actor who made it all so watchable.
  2. One observes with patience. It takes all your drive to be still, and observe a hummingbird in flight while sucking nectar
  3. The devil is always in detail. One has to remember endless nights of observations by Tycho Brahe, whereby positions of Mars were known to such an accuracy, that Kepler could have one, and only one hypothesis satisfying them. One can also remember astute, and precise observations by Charles Darwin or Marie Curie.
  4. One must isolate a phenomenon and observe it away from influence by other factors involved. This sounds like, one has to know a phenomenon beforehand (to isolate it) before observing it. That is true to certain extent. In this regard, science progresses by one step at a time.
There are many exercises from our daily lives which would teach us the power of observation. An incomplete list goes as below.
  • Ants path to/fro sugar
  • Fish and their internal organs
  • Microscopes and micro-organisms in water
  • Plants grow steadily everyday, photograph a plant inside your house from the same angle over a month and make a movie.
  • Magnets and compass: migratory birds fly using their internal compass.
  • Beetles, butterflies and their colours
  • Melting ice, and freezing water.

Tuesday, July 14, 2009

LOFAR first light !

Our telescope has been shown to be completely operational. The electronics worked all in parts, then they conducted tests of individual antennas, measured their responses, then they connected all of them to a massive super-computer.

The voltages from all the antennas are combined locally to 'form beams' and pass on the data to the super-computer, where a program does the job of a traditional 'correlator'. It basically compares (correlates) voltages from one reference antenna with other antennas. That tells us about structure of the astronomical sources, akeen to images of the source. We can also just add up signals from all antennas, say to observe a pulsar, where all the separate antennas will act in conjunction like a single large dish.

Follow the LOFAR on twitter...

Saturday, July 04, 2009

Lesson for my child : Curiosity

Humans are curious about variety of phenomena in our daily lives: rains, fires, hurricanes/ storms, waves, tides. It also applies to things that we can not experience using our senses: clear sky, ocean depths, stars, Sun, Moon, etc.
  1. Throughout their existence humans all over the planet have asked questions about things that were around them: their surroundings, our planet, the cosmos, the origin of all the things, and where were all going to end. वेद, or the Vedas called them पंचमहाभूत, or the five elements: Earth, Water, Fire, Wind, and Sky. Everything is made of them. It is not important if Vedas were correct or not, what matters most is that, humans thought of the cosmos. The surrounding natural elements and cosmos on the larger scale made an impact on those early Hindu thinkers.
  2. Those Hindu thinkers related various phenomena as manifestations of those five elements. This is characteristic of humans: we relate seemingly disparate phenomena using fewer logical elements. At one level, we should understand that those associations are not real, but they allow us to comprehend phenomena in an organized manner; and if the exercise is successful, we can predict certain things using those associations.
  3. Curious human will observe and think about apparent patterns. This is most crucial for the survival of species: food resources, predicting natural phenomena (predicting tides is crucial for fisher-folk, rains are important for farming).
  4. This curiosity also leads to betterment of lives:
-- waves/ tides and fishing
-- rains and paddy farming
-- diseases and micro-organisms

Here is a true story of a Goan boy who was bitten by a snake. The snake was of harmless kind, although very similar to poisonous adder snake in its appearance. A Tantrik was summoned by parents to `cure' their boy of the poison. No wonder, the boy was fine after the Tantrik performed his rituals. It so happened that the boy was bitten by a snake again, however, this time by a real poisonous adder. His parents preferred the Tantrik once more, however, all his rituals took precious time away. The boy died the next morning.

The story is important, in that one has to be curious and understand that poisonous snake alone cause harm. As far as we can make out patterns on the snake-back, we are safe, else we face grave consequences. The same goes for the rest of the nature.

Life is precious and there are no guarantees. However, curiosity and learning allow us to survive in this world better, and also make it a richer experience.

Friday, July 03, 2009

What I want my child to know

I hope to be a father soon. As a good father, I would present the best part of me to my progeny. Apart from my genes, the best thing I can pass on to my child is what I learnt in my long education in my life so far. It is the rational/ scientific thinking and attitude, along with the self-awareness, that identifies humans.

In a series of posts, I will now outline my thoughts on scientific thinking and self-awareness. One day my child would read this, learn something, and perhaps laugh.

Thursday, July 02, 2009

Coherent Dedispersion

Our code to remove dispersion effects from pulsar time series is now in its 5th revision. The major changes are:

1) the code reads one period of pulsar in small chunks of 32k samples
2) the chunks are dedispersed and smoothed with a factor = 4096
3) smoothed chunks are appended to the final time series.