) But Galileo was fond of the argument and devoted the " Fourth Day " of the discussion to it.

Except for the Antikythera mechanism, an " out of the time " astronomical device, development of computing tools arrived in the beginning of the 17th century: Geometric-military compass by Galileo, Logarithms and Napier Bones by Napier, slide rule by Edmund Gunter.

Marius discovered the moons independently at the same time as Galileo, and gave them their present names, which were suggested by Johannes Kepler, in his Mundus Jovialis, published in 1614.

The names that eventually prevailed were chosen by Simon Marius, who discovered the moons independently at the same time as Galileo: he named them at the suggestion of Johannes Kepler after lovers of the god Zeus ( the Greek equivalent of Jupiter ): Io, Europa, Ganymede and Callisto, in his Mundus Jovialis, published in 1614.

One of the reasons given for developing Galileo as an independent system was that position information from GPS can be made significantly inaccurate by the deliberate application of universal Selective Availability ( SA ) by the US military ; this was enabled until 2000, and can be re-enabled at any time.

It remained the mainstream scientific paradigm in Europe until the time of Galileo Galilei and Isaac Newton.

The Italian physicist and astronomer Galileo brought together the ideas of other great thinkers of his time and began to analyze motion in terms of distance traveled from some starting position and the time that it took.

Galileo proposed a method of establishing the time of day, and thus longitude, based on the times of the eclipses of the moons of Jupiter, in essence using the Jovian system as a cosmic clock ; this method was not significantly improved until accurate mechanical clocks were developed in the eighteenth century.

At the latter time, Galileo had been showing sunspots to astronomers in Rome, and Christoph Scheiner had probably been observing the spots for two or three months using an improved helioscope of his own design.

The Italian physicist Galileo Galilei is credited with being the first to measure speed by considering the distance covered and the time it takes.

Galileo defined speed as the distance covered per unit of time.

Astronomers of the era expected that changes over time in the apparent separation and relative location of these stars would provide evidence for both the proper motion of stars and, by means of parallax shifts in their separation, for the distance of stars from the Earth ( a method first suggested by Galileo Galilei ).

For example, Galileo Galilei was able to accurately measure time and experiment to make accurate measurements and conclusions about the speed of a falling body. Antoine Lavoisier was a French chemist in the late 1700s who used experiment to describe new areas such as combustion and biochemistry and to develop the theory of conservation of mass ( matter ).

Many astronomers after the time of Galileo built their own telescopes out of necessity, but the advent of amateurs in the field building telescopes for their own enjoyment and education seems to have come into prominence in the 20th century.

At the time, such speculation was of a rather rarefied sort, and was limited to astronomers like Christiaan Huygens who wrote a book, Cosmotheoros ( 1698 ) considering the possibility of life on other planets ; or to philosophers like Campanella, who wrote in defense of Galileo.

Both Newton and Galileo, as well as most people up until the 20th century, thought that time was the same for everyone everywhere.

The Galileo engineering review speculated ( but was never able to prove conclusively ) that this longer flight time coupled with the stronger sunlight near Venus caused lubricant in Galileo's main antenna to fail, forcing the use of a much smaller backup antenna with a consequent lowering of data rate from the spacecraft.

Catholic theology was well integrated with scientific knowledge from the time of Aquinas to the time of Galileo, and that too was a deliberate program.

At the time of its publication, Galileo was a mathematician at the university of Padua, and had recently received a lifetime contract for his work in building more powerful telescopes.

Their most bitter dispute concerned finding the equation for the path followed by a particle from one point to another in the shortest time, if the particle is acted upon by gravity alone, a problem originally discussed by Galileo.

In his experimental thinking, Galileo reasoned as follows: if two objects with the same weight are released from the same height at the same time, they will hit the ground simultaneously, having fallen at the same speed.

At that time, the college's teachings were based on those of Aristotle, whom Newton supplemented with modern philosophers such as Descartes and astronomers such as Copernicus, Galileo, and Kepler.

The apparent paradox formed part of a great dispute over the nature of infinity involving many of the key thinkers of the time including Thomas Hobbes, John Wallis and Galileo Galilei.

* 1609 – Galileo Galilei demonstrates his first telescope to Venetian lawmakers.

The four moons were discovered sometime between 1609 and 1610 when Galileo made improvements to his telescope, which enabled him to observe celestial bodies more distinctly than had ever been possible before.

Galileo ’ s discovery showed the importance of the telescope as a tool for astronomers by proving that there were objects in space that cannot be seen by the naked eye.

As a result of improvements Galileo Galilei made to the telescope, with a magnifying capability of 20 ×, he was able to see celestial bodies more distinctly than was ever possible before.

Galileo ’ s discovery proved the importance of the telescope as a tool for astronomers by showing that there were objects in space to be discovered that until then had remained unseen by the naked eye.

Actual proof of the Milky Way consisting of many stars came in 1610 when the Italian astronomer Galileo Galilei used a telescope to study the Milky Way and discovered that it is composed of a huge number of faint stars.

The Italian mathematician, astronomer, and physicist Galileo Galilei ( 1564 – 1642 ) was the central figure in the Scientific Revolution and famous for his support for Copernianism, his astronomical discoveries, and his improvement of the telescope.

Additionally, he did fundamental work in the field of optics, invented an improved version of the refracting telescope ( the Keplerian Telescope ), and mentioned the telescopic discoveries of his contemporary Galileo Galilei.

The first person to use a telescope to observe the night sky and record his observations was the Italian scientist Galileo Galilei in 1609.

File: Justus Sustermans-Portrait of Galileo Galilei, 1636. jpg | Galileo Galilei ( 1564-1642 ): discovered the uniform acceleration rate of falling bodies, improved on the refracting telescope, discovered the four largest moons of Jupiter, described projectile motion and the concept of weight ; known for championing of the Copernican theory of heliocentricism against Church opposition.

* Galileo Galilei ( 1564 – 1642 ) improved the telescope, with which he made several important astronomical discoveries, including the four largest moons of Jupiter, the phases of Venus, and the rings of Saturn, and made detailed observations of sunspots.

* August 25 – Galileo Galilei demonstrates his first telescope to Venetian lawmakers.

Neptune is not truly discovered until 1846, about 234 years after Galileo first sights it with his telescope.

* 1610 — Galileo Galilei uses a telescope to determine that the bright band on the sky, the " Milky Way ", is composed of many faint stars

Ever since Galileo took a Dutch invention and adapted it to astronomical use, astronomical telescope making has been an evolving discipline.

Before Galileo turned his telescope to the heavens, the planets of the Solar System were not recognized as worlds, or places where a person could potentially set foot ; they were visible to observers merely as bright points of light, distinguishable from stars only by their motion.

* Telescopio Nazionale Galileo, a 3. 58m Italian telescope located on the island of San Miguel de La Palma

His description of the center stars as different from a comets head in that they were a " rectangle " may have been an early description of the Trapezium Cluster ( The first detection of three of the four stars of this cluster is credited to Galileo Galilei in a February 4, 1617 although he did not notice the surrounding nebula — possibly due to the narrow field of vision of his early telescope.

Galileo improved the construction of a telescope, which he used to observe the night sky and the moon.

In observing the stars, Galileo reported that he saw at least ten times as many stars through the telescope as with the naked eye, and he published star charts of the belt of Orion and the Pleiades showing some of the newly observed stars.

This report was issued in October 1608 and distributed across Europe, leading to experiments by other scientists, such as the Italian Paolo Sarpi, who received the report in November, the Englishman Thomas Harriot, who was using a six-powered telescope by the summer of 1609, and Galileo Galilei, who soon improved the device.

19th century painting depicting Galileo Galilei displaying his telescope to Leonardo Donato in 1609.

Galileo states that he solved the problem of the construction of a telescope the first night after his return to Padua from Venice and made his first telescope the next day by fitting a convex lens in one extremity of a leaden tube and a concave lens in the other one.