Monday, 6 May 2013
Sunday, 5 May 2013
Tuesday, 30 April 2013
Here is a brief history of Zero.
Numbers were used for thousands of years before they used zero. Egyptian hieroglyphics were used as early as 3500 B.C. Egypt did not have - or need - a zero. Even without zero, Egyptians became masters of mathematics.
The Greeks brought mathematics to its highest point in ancient times. Around 500 BC, the Greeks developed a newer more sophisticated system which avoided repeated letters, but both the Egyptian and Greek number systems still had no zeros.
|And yes, the symbol for 80 is Pi|
In 2500 B.C., the Babylonians started to use Base 60 (which is why there are 60 seconds in a minute, and 60 minutes in an hour). They sometimes used a space to represent an empty position. By about 200 A.D., they used a pair of small triangles to represent an empty position. Although the Babylonians never actually invented a zero, they did make the important first step.
Hindu culture had a positional number system in base ten. They used a dot to represent an empty place, and was called ‘Sunya’ which meant empty. At this point, the early zero was a placeholder and an aid in calculation. By 500 A.D., the Hindus use a small circle to represent Zero, and was recognized as a numeral.
Arabic people recognized the value of the Hindu system and adapted the numerals and calculations. Word then spread the ideas in their travels The zero was named with the Arabic word ‘sifz’. Fibonacci, after learning Hindu-Arabic numerals from his Arabic tutors, brought news of zero and new computational methods to Europe.
Europeans resisted Hindu-Arabic numerals. At first, the numerals, including zero, were not accepted, even to the point where Florence, Italy, passed a law prohibiting the use of the numerals. Slowly, the numbers became accepted
In the history of culture the discovery of zero will always stand out as one of the greatest single achievements of the human race.
Zero is the number that separates positive numbers from negative numbers. It’s even, it’s the integer that precedes one. Happy A to Z Blogging Challenge!
Monday, 29 April 2013
Saturday, 27 April 2013
Friday, 26 April 2013
Whales have lost their hind legs (the front ones are now their flippers), and we have a pretty good fossil record of how they did so, thanks in large part to the work of Phil Gingerich (see his great whale evolutionsite here) and his collaborators.
Although whales lack external hind legs, they do have internal rudiments of the hind limbs and pelvic girdle, as seen at the top of the above image, which goes through the evolutionary process of how whales came to be. I think whales having legs is pretty much the most fool proof way of proving evolution.
Also this, because it made me laugh
Thursday, 25 April 2013
Voyager 1 is on the edge of the solar system! It was lauched in 1977, and is only now reaching the edge of the solar system, or the outer heliosphere to be exact.
Wednesday, 24 April 2013
Tuesday, 23 April 2013
On a more positive note, it seems that Clara and River will meet for the first time. Should be interesting...