In The Midst Of All

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.

Finally We Shall Place The Sun Himself At The Center Of The Universe.

When, Therefore, I Had Long Considered This Uncertainty Of Traditional Mathematics, It Began To Weary Me That No More Definite Explanation Of The Movement Of The World-machine Established In Our Behalf By The Best And Most Systematic Builder Of All, Existed Among The Philosophers Who Had Studied So Exactly In Other Respects The Minutest Details In Regard To The Sphere.

Since, Then, There Is No Objection To The Mobility Of The Earth, I Think It Must Now Be Considered Whether Several Motions Are Appropriate For It, So That It Can Be Regarded As One Of The Wandering Stars. For The Fact That It Is Not The Centre Of All Revolutions Is Made Clear By The Apparent Irregular Motion Of The Wandering Stars, And Their Variable Distances From The Earth, Which Cannot Be Understood In A Circle Having The Same Centre As The Earth.

Yet The Widespread Planetary Theories, Advanced By Ptolemy And Most Other Astronomers, Although Consistent With The Numerical Data, Seemed Likewise To Present No Small Difficulty. For These Theories Were Not Adequate Unless They Also Conceived Certain Equalizing Circles, Which Made The Planet Appear To Move At All Times With Uniform Velocity Neither On Its Deferent Sphere Nor About Its Own Epicycle's Center.