ERATOSTHENES

How Eratosthenes measured the circumference of the Earth

Questions from young children

Please visit my blog to read few questions I received from young children and my answers to them:

PALE BLUE DOT REIMAGINED

SOLAR NEBULA THEORY

“The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of star stuff.” – Carl Sagan