Tag » Eratosthenes

The Shadows of Alexandria

On this, the summer solstice, I have to post an animation I made a long time ago: The Shadows of Alexandria

In the third century BC, Eratosthenes was able to use the shadows cast during the summer solstice along with some simple measurements to accurately calculate the size of the Earth. 375 kata lagi

The Girth of the Earth: How do we know?

Recently I wrote about the circumference of the Earth, and how long it would take you to travel right round it. But how do we even know that? 774 kata lagi

How Big Is It?

A play on primes - Part 2

In a previous post, I shared some thoughts on a couple of generation techniques for prime numbers. This post is about implementing them.

First implementation of the Sieve of Eratosthenes in JAVA. 334 kata lagi


L4: Apennines

Impressive mountain range on the southern shores of Mare Imbrium and stretching northeast from Eratosthenes. The highest peaks reaches well over 5000 meters. 14 kata lagi


L69: Copernicus secondary craters

So far this is one of the most fascinating objects I have observed on the moon. These chains of craterlets were formed when rubble following the Copernicus impact rained down on Mare Insularum. 63 kata lagi


A play on primes - Part 1

So what does a geek like me do with his free time? Play around with primes. Today I wanted to share some thoughts on prime numbers, the oh so mysterious members of the number system. 328 kata lagi


"They All Laughed at Christopher Columbus...." 1

Image from Ptolemy’s data 2

Actually, it is unlikely that anyone laughed.

Scholars had abandoned the “flat earth” idea almost two thousand years before Columbus lived.   1.112 kata lagi