Selection of free books in pdf

Books are free when copyright expire. Here we are a selection of free books, Digital, ready to download. In pdf format. And also articles, papers, famous writers. SOME FREE BOOKS 1 Fundamental ideas and problems of the theory of relativity (in english) Albert Einstein 2 Does the inertia of a body depend upon its energy-content? (in english) […]

Book from Einstein about relativity, The special and general theory

Few years ago was time for the 100 anniversary of the publication of paper written by Albert Einstein about General Theory of relativity. We want to celebrate offering all of you for free other book wrote by Albert Einstein: Relativity, The Special and General Theory. Wrote to in 1916 and revised in 1924. CLICK HERE TO […]

Gravitational waves

It is said that the gravitational waves are a consequence of the  theory of relativity, of   Albert Einstein, but it is difficult to find texts in which they argue why this relationship, except that they are arising from the study of the Einstein field equations. Let’s try to apply a little logic and some knowledge of relativity […]

The cientific method

The scientific method is a method of investigation used primarily in the production of knowledge in the sciences. It is intended to be a pattern that allows researchers to go from the initial point of an investigation until conclusions with confidence to obtain valid knowledge. The scientific method is supported by two pillars. The first of […]

Introducction to black holes

We are studying an object, that people may think from recent conception, but that it was conceived more than two centuries ago. In their initial conception, a black hole was an object with a gravity force in their surface so big that nothing could escape from him; not even light if it were affected by […]

How a black hole is formed

Suppose a star like the sun that is exhausting its nuclear fuel turning its hydrogen into helium and this into carbon, oxygen and finally iron coming a time when the heat produced by nuclear reactions is short to produce a dilation of the Sun and thus compensate the force of gravity. Then the sun collapses […]