The Strongest Affection And Utmost Zeal Should,

Of All Things Visible, The Highest Is The Heaven Of The Fixed Stars.

I Can Easily Conceive, Most Holy Father, That As Soon As Some People Learn That In This Book Which I Have Written Concerning The Revolutions Of The Heavenly Bodies, I Ascribe Certain Motions To The Earth, They Will Cry Out At Once That I And My Theory Should Be Rejected.

For When A Ship Is Floating Calmly Along, The Sailors See Its Motion Mirrored In Everything Outside, While On The Other Hand They Suppose That They Are Stationary, Together With Everything On Board. In The Same Way, The Motion Of The Earth Can Unquestionably Produce The Impression That The Entire Universe Is Rotating.

Mathematics Is Written For Mathematicians.

First Of All, We Must Note That The Universe Is Spherical.