Kepler's laws of planetary motion law" is what became the Second Law in the set of three; but Kepler did himself not privilege it in that way. Johannes Kepler published his first two laws about planetary motion in 1609, having found them by analyzing the astronomical observations of Tycho Brahe. Kepler's third law was published in 1619. Kepler had believed in the Copernican model of the solar system, which called for circular orbits, but he could not reconcile Brahe's highly precise observations with a circular fit to Mars' orbit—Mars coincidentally having the highest eccentricity of all planets except Mercury. His first law reflected this discovery.
Planetary civilization is planetary, consuming all energy that is available from a neighboring star, or about 10 watts. A Type II civilization is stellar, consuming all the energy that their star emits, or 10 watts. A type III civilization is galactic, consuming the energy of billions of stars, or about 10 watts. Carl Sagan suggested defining intermediate values (not considered in Kardashev's original scale) by interpolating and extrapolating, according to his calculations, the modern state of the present human civilization is expressed by a value about 0.7. Theoretical physicist Michio Kaku, in a book, "Physics of the Future", published in 2011, stated