Friday, September 30, 2011

Physics Lectures On YouTube

Professor Lewin is an engaging lecturer at MIT and I love his Dutch accent.   His stuff is is great..


Enjoy!!
  Prof.V.Balakrishnan, Department of Physics, IIT Madras.  Really fine  lectures.
Bon appetit! 

Thursday, September 29, 2011

Rosh Hashana & The Dead Sea Scrolls On The Web

Rosh Hashana (The "head" of the year) is a Jewish  holiday.  Today is the first day of the year 5772 according to the Hebrew Calendar.    The epoch or reference date of the hebrew calendar is the date of the creation of the universe  -  the Anno Mundi.    Around 160 CE, Jewish scholars worked backwards from "known" events and used time periods mentioned in the Hebrew bible and calculated "year zero" at around 3,920 years before their current time.  So if we are in 2011 CE,  then we get 2011-160+3920 =  5771.  Seems right. 

You won't have to travel spatially to Israel to see the Dead Sea Scrolls.   The Israel Museum, Jerusalem and Google have a project to digitize them, and make them available to all online.   The Official Google Blog has a post  about the project as well.   As of now, you can click on the Great Isaiah scroll and get images and translations to English of the text.   The scrolls were discovered in caves in the Dead Sea area which is usually hot and dry.  Most of the scrolls are badly fragmented - a few are almost complete.  The scrolls were carbon dated in the 1990s with calibrated ages for the oldest scrolls at about 300 BCE  (about 2,300 years ago).    These are the oldest known surviving copies of the Hebrew bible and related texts.

The Hebrew bible starts with Genesis, the creation of the universe.  The biblical creation myth is one of many.   No ancient one is close to the scientific value for the age of the universe.  The Chinese and ancient Egyptians came up with ~40,000 years.  The Hindu's were close at 4.5 billion, but then decided to multiply by fifty. Still, it's pretty good.   Christian estimates range from about 9,000 to 6,000 years.  

Sunday, September 11, 2011

September 11 Attacks - Tenth Anniversary

As I write this, ten years after the September 11, 2001 attacks,  I am doing something similar to that day ten years ago.  I am sitting at my computer.   Most of us remember where we were, and what we were doing,  on that  cool, clear Tuesday morning.   I was on the yahoo news website when the page updated and a small "breaking news"  link appeared in red.  Shortly after,  I tuned in to the CNN cable TV channel and watched,  in fear and fascination,  the events of that day as they unfolded on TV.  Manhattan, being compact and a hub of television production,  had almost instantaneous video coverage after the collision of the first plane with the  World Trade Center's North Tower at 8:46 AM.   At first, I thought it was an accidental collision.  When the second plane collided with the South Tower at 9:03 AM,  I knew immediately it was a coordinated attach by hijackers.  The flight path of the second plane was clearly controlled and targeted - it reminded me of the film footage of the Japanese kamikaze planes flying into our ships in WW2.  The kamikaze fighter planes,  although loaded with high explosives, were tiny and light compared to a modern passenger jet.  Ominously,  all the hijacked planes originated on the East Coast and were flying transcontinental routes to California.  Their size, speed, and the large fuel load made them heavy and as lethal as hundreds of kamikaze fighters.   The choice of flights was far from random.  Someone had designed, organized and implemented a horrible plan.  And the results transcended all the planners expectations by a wide margin.   It started with perfect weather for neophyte pilots.   And then we learned  of the events in Washington, DC and near Shanksville, PA.  How many more were left? Nobody knew.   Fighter jets were scrambled from Otis Air Base.  For days after, a rustic quiet in the skies was punctuated by the roar of military jet engines.

Like many with family and friends in New York, I was concerned about where they were and how they were doing.  I also felt closer to my fellow New Yorkers than I ever before.  My thoughts went first to my mother who used to take the bus down to South Ferry - right past the World Trade Center.  Telephone service became rapidly saturated - especially outgoing service.   I talked with my mother shortly after the attacks - from the downtown bus, she had seen the pall of smoke rising from  the Battery Park area.   In the following days, she told me about the notices, many with color pictures of missing relatives,  taped to the lamp posts in her neighborhood.   The sadness was excruciating.    About two weeks later, I took the train to New York.   It really hit home as I walked past those notices - so many pictures of young and vibrant people - they were never to return.  Shakespeare's most famous soliloquy came to mind -  they never had a choice.   ...The undiscovered country from whose bourn  No traveller returns, puzzles the will,....

The New York Times' coverage was very detailed especially regarding the unraveling of the plot, people and organizations behind the attacks.   And, of course, the local stories were heart-rending.  There were many stories of close-calls:   those who missed flights of the four planes - people with early dentist appointments who arrived later than normal to work - those with flexible working hours .  But mostly there were stories about the victims and their families.  The good news, which is not mentioned enough,  is that over 50,000 people worked in the WTC towers.  At the time of the attacks about 18,000 people were in the towers.  About 200,000 people visited the WTC complex daily.   Three thousand people died -  it could have been much worse.

The planes hit high up on the WTC towers.  greenhorn pilots did not have the skills to fly in low....tbc

Utility Pole Replacement in Cambridge (Riverside)

Last night a wooden  utility pole  cracked at the base and fell toward the neighboring pole across the street. This caused the wires to d...