Friday, June 24, 2011

What an idea, Sirji!

In Why Evolution Is True, there is an example of the kind of things I like reading about. It describes a method to verify the age of a fossil that had been previously dated by a radiometric method.
There are yet other ways to check the accuracy of radiometric dating. One of them uses biology, and involved an ingenious study of fossil corals by John Wells of Cornell University. Radioisotope dating showed that these corals lived during the Devonian period, about 380 million years ago. But Wells could also find out when these corals lived simply by looking closely at them. He made use of the fact that the friction produced by tides gradually slows the earth’s rotation over time. Each day - one revolution of the earth - is a tiny bit longer than the last one. Not that you would notice: to be precise, the length of a day increases by about two seconds every 100,000 years. Since the duration of a year – the time it takes the earth to circle the sun — doesn’t change over time, this means that the number of days per year must be decreasing over time. From the known rate of slowing, Wells calculated that when his corals were alive - 380 million years ago if the radiometric dating was correct - each year would have contained about 396 days, each 22 hours long. If there was some way that the fossils themselves could tell how long each day was when they were alive, we could check whether that length matched up with the 22 hours predicted from radiometric dating.

But corals can do this, for as they grow they record in their bodies how many days they experience each year. Living corals produce both daily and annual growth rings. In fossil specimens, we can see how many daily rings separate each annual one: that is, how many days were included in each year when that coral was alive. Knowing the rate of tidal slowing, we can cross check the “tidal” age against the “radiometric “ age. Counting rings in his Devonian corals, Wells found that they experienced about 400 days per year, which means that each day was 21.9 hours long. That’s only a tiny deviation from the predicted 22 hours. This clever biological calibration gives us additional confidence in the accuracy of radiometric dating.
It is so much more interesting than just asking, "Were you there?" You can find out more about a slowing Earth here.

Monday, June 13, 2011

Face blindness

I saw an interesting discussion about a curious disability called face blindness.

Monday, June 6, 2011

Playing dumb - II

Sometimes people will say some wacky things like, 'All our actions are guided by the spirits of our ancestors.' (Judging by the contents of the conversation, it was not a metaphorical statement.) They will then say, 'What do youngsters know about such things these days'?

When there is a discussion about the relative military strengths of India and Pakistan, emotion is likely to rule the roost and it is not wise to get into an argument. Once I was told that there was a report in some magazine that India had the resources to destroy the whole of Pakistan while Pakistan had the resources to destroy 'only' half of India so in the event of a full fledged conflict India's victory was assured. If I had thought that I just had to say, 'It would be a Pyrrhic victory', and everyone would break out in applause, I might have given it a shot but I knew that it won't be so easy. It is curious that regular folks who have never held a weapon in their lives are fascinated by terrible weapons that cause immense destruction somewhere far away and produce spectacular firework displays on T.V.

Apparently,Daniel Bernoulli thought of the equation that would have predicted my preference for keeping quiet, as per this TED talk by Dan Gilbert. According to Bernoulli's equation, the Expected value, V of an action is given by:
V = (odds of success) x (value of success)
The odds of my being able to convince anybody was very low. It is very difficult to change deeply held beliefs. People tend to tune out disconfirming views. (According to Carol Travis, all of us have a tendency to rationalise our beliefs. I remember reading that we always have a goodly portion of that which we condemn. She also says that the best predictor of memory is one’s current beliefs.) The value that I attach to the success would also be very low. It would take me a very long time to say anything substantial and nobody, least of all me, has the patience to wait that long. It will also waste Jaya's time. I realised long ago that the quickest way to get back to reading about more interesting things was to remain silent.

Thus my expected value for wading into these debates is close to zero and my best option is to keep quiet. (Perhaps it would have been beneficial if I had thought along these lines before my stroke also.) At most times, I try to dictate short sentences omitting many common words, hoping Jaya will guess them. My verbosity is confined to the blog, much to your misfortune!

I am the perfect victim to whom various mythological tales can be told - I will listen quietly with a smile and there was no danger of my walking off in a huff. I had a better appreciation of why Bertie Wooster used to be underwhelmed when Madeline Basset used to tell him that "the stars are God's daisy chain", or that "every time a fairy blows its wee nose a baby is born". Once I was listening to such chatting for over an hour, muttering 'holy shit' a few times because I wanted to watch a cricket match. When I finally managed to get the T.V. switched on, the match had just started - it had been delayed due to rain!

Another situation when it is best for me to remain silent (which I have written about earlier also) is when people talk about business, finance, marketing, etc. I suppose if you are an MBA you cannot escape these things. When a visitor sees me reading a book, he might guess that it is about International Business. If they are told that I sometimes watch T.V., they might assume that I am glued to the business channels. I am reliably informed that my favorite newspaper is The Economic Times. I have not seen it for over a decade. In fact, I rarely read any newspapers these days. I will sometimes be asked for stock tips. If I was asked about the axolotl, I might have been motivated to dictate a few words but about stock tips, the best I can do is say,'I don't know'.

Sometimes a new visitor will come who had never seen me before. He will assume that I am in the depths of depression and will tell me, 'My heart tells me that you will get alright very soon!' I will blink and smile. There is nothing much else that I can do. They will feel encouraged and tell everyone else, 'My heart tells me that he will get alright very soon!' Everyone will nod politely. There is nothing much else that they can do. There will then be 'My friend had...' or 'I heard of a doctor who...' I may be a beneficiary of the identifiable victim bias but it also means that I receive many suggestions of rituals and 'cures' (it has reduced now) from good people who feel compelled to help me in some way.