Do the Living outnumber the Dead?

In a word, no.
However, it is an interesting thing to think about.  For so long, the population of homo sapiens sapiens was extremely low, then the scientific revolution came along, allowing modern medicine & agriculture to develop and BOOM!  the population explosion we are in happens.  Check out this graph from http://www.sustainablescale.org:

Even if you were to extend the time axis backwards to around 200,000 BC when we think our subspecies evolved from the simpler, archaic homo sapiens, the populations were so low that there would not be much area under the curve.  However, the popular number for all homo sapiens sapiens dead is around 60 billion (that's for around 7500 generations between you and the first "modern" man).  That's less than 10 dead for each one of us alive today.  Kind of creepy the way we are swarming the surface of this planet, eh?

Yes - life can be this good!

Chongers sees the next wave coming

Moonths

Time for Earth to orbit the Sun: 365.25 days

Time for Moon to orbit Earth: 27.3 days

365.2/27.3 = 13.38

And therein lies the problem. There is no neat way to make lunar –based time (“moonths”) mesh with solar-based time (“years”).

I have blogged about various aspects of time ( days of the week, lunar vs. solar calendars, origin of 60 seconds and 60 minutes as units of time), but Irene brought my attention to another arbitrary unit: that of 12 months. Since the Romans decided to go with a solar calendar, I always wondered why they didn’t go with a nice, round ten months. Well, they did:

1.Martius (March)

Mars - god of War

2. Aprilis (April)

Aphrodite- goddess of love & beauty

 

 

 

 

 

 

 

 

 

 

 

3. Maius (May)

Maia - goddess of spring

4.  Junius (June)

Juno - goddess of marriage

 

5.  Quintilis (July)

Fifth Month, renamed by Julius Caesar

6.  Sextilis (August)

Sixth Month - renamed by Augustus Caesar

  

7. September  - the seventh month

8.  October - the eighth month

9.  November  - the ninth month

10.  December - the tenth month

A nameless winter stretch of days followed to round out the solar year until Numa Pompilius, the second king of Rome circa 700 BC, added the two winter months at the end of the year:

Januarius "January" (Janus is the Roman god of gates and doorways, depicted with two faces looking in opposite directions) and

Februarius "February" (Februa is the Roman festival of purification).

The nameless stretch of days needed to keep the seasons lined up was kept at the end of the year (after February). This “filler” period was not used every year and was sometimes called Intercalaris "intercalendar" or Mercedinus (“payment for work” was the time when property lessees paid rents due to their landlords). This is the reason leap days come at the end of February even in modern times.

After the introduction of January, Romans began to transition the beginning of the year to Jan 1, but the process took 100's of years to become standard and official.

In modern times we still have to work hard to keep our lunar cycles and solar cycles lined up.  We have our complicated leap year rules and our leap seconds

They let me teach this stuff?

During a very successful pilgrimage to Storyland, I noticed the rear hatch of the minivan (AKA the "Swaggerwagon") would not stay up.  Upon our return, I decided to change out the supporting struts myself. 


Of course the friction force between the hatch and the supporting plank is dependent on a strong normal force at that point of contact, duh! 

Of course the glass in the hatch window is thin and will break as the plank slips and hits it!

A little shaking of the car while replacing a strut and you get this:

In the end, my insurance covered the window replacement.  Next time, I'll draw a force diagram first!

Well, Put Me in the Zoo!

A bedtime favorite at the Riddy house is Robert Lopshire's "Put me in the zoo".
We own the one below subtitled "A book of Colors".  In a store today, Sebastien spotted the book on the left.
Oh my!  All these years, we have been missing parts of the story and the colors were so different.  Apparently, the "Bright and Early Board Books" are abridged and scaled down in more ways than just size! .
Foolish me, I had always assumed it was the full book, just in a different format.
Buyers of books for little ones, beware!

Invisible Gorillas

There is a new book out, brought to you by the same people (Christopher Chabris and Daniel Simons) that brought us the famous "count the number of times the ball gets passed" experiment (see video below). 

I haven't read the book, but just from this review from Scientific American, I know these guys are on the money: (all italics lifted from the SA review)
We think we see things as they really are, but “our vivid visual experience belies a striking mental blindness,” [the authors] write.


They cover the illusion of memory, how often our memories are born from our own embellished stories; the illusion of knowledge, we think we know much more than we actually do; the illusion of cause, we quickly assume correlation means causation.


Perhaps the worst illusion of all, the failing that leads to others, is the illusion of confidence. We profoundly overestimate our ability to see things as they are. As the physicist Richard Feynman famously said: The first principle is you must not fool yourself, and you are the easiest person to fool.


If that one was too easy for you, try this one:

Bohr vs. Hegel

I made a timeline for my class of the "light is wave / light is a particle" battle, started by Huygens and Newton; ended by Bohr over 200 years later:

Bohr is often quoted on this subject:

“There exist two sorts of truth:

trivialities, where opposites are obviously absurd, and

profound truths, recognised by the fact that the opposite is also a profound truth.”

This strikes me a slightly more profound and deep version of old Hegelian Dialectic:

 

Sometimes there is no satisfactory synthesis - the thesis and antithesis stay opposites while both remaining true.  The interesting thing to me is the apparent contradiction is only in our own minds, not out there in nature...