Galileo discovered how many of jupiters satellites

First, with telescopes, then with satellites, then space rovers, and ultimately with manned spacecraft.

Humans have set foot on the moon, successfully landed rovers on Mars, and even photographed other galaxies. Take your classroom into the great beyond with these out-of-this-world resources. A moon is an object that orbits a planet or something else that is not a star. Encyclopedic entry. An orbit is a regular, repeating path that one object takes around another object or center of gravity.

Orbiting objects, which are called satellites, include planets, moons, asteroids, and manmade devices. Earth and the other seven planets that circle the star we call the sun and smaller objects such as moons make up our solar system. Join our community of educators and receive the latest information on National Geographic's resources for you and your students. Skip to content. Galileo Galilei Galileo explains the topography of the moon, as well as the moons of Jupiter, to two cardinals.

Twitter Facebook Pinterest Google Classroom. Background Info Vocabulary. Satellites can be natural, like moons, or artificial. It took almost two centuries, however, before the models and tables based on them reached satisfactory accuracy. The naming of the satellites provides an interesting example of how such matters were handled before the foundation of the International Astronomical Union in the twentieth century.

As their discoverer, Galileo claimed the right to name the satellites. In his notebooks, Galileo referred to them individually by number, starting with the satellite closest to Jupiter, but he never had occasion to refer to them in this way in print. In Provence, Nicholas Claude Fabri de Peiresc tried to differentiate between the Medicean Stars by assigning them the names of individual members of the family, but this system was not published and thus was never used by others.

First, he himself used the numerical system beginning with the satellite closest to Jupiter. Second, he thought that he might call them after his patron, the Duke of Brandenburg -- a suggestion followed by no one. Third, he suggested naming the farthest satellite the Saturn of Jupiter, the next one the Jupiter of Jupiter, the third one the Venus of Jupiter, and the one nearest the planet the Mercury of Jupiter.

This cumbersome system never caught on. Finally, Marius related a suggestion by Kepler : Jupiter is much blamed by the poets on account of his irregular loves. Three maidens are especially mentioned as having been clandestinely courted by Jupiter with success. Then there was Ganymede, the handsome son of King Tros, whom Jupiter, having taken the form of an eagle, transported to heaven on his back, as poets fabulously tell.

I think, therefore, that I shall not have done amiss if the First is called by me Io, the Second Europa, the Third, on account of its majesty of light, Ganymede, the Fourth Callisto.

This fancy, and the particular names given, were suggested to me by Kepler, Imperial Astronomer, when we met at Ratisbon fair in October So if, as a jest, and in memory of our friendship then begun, I hail him as joint father of these four stars, again I shall not be doing wrong. Following Galileo and Marius, astronomers simply referred to them by number.

With the satellites of Saturn, however, a problem developed. In Huygens discovered the first and largest; then in Giandomenico Cassini discovered two more, and in yet another two. Cracks and streaks crisscross the entire icy surface, which is marked with very few craters. Europa has a high degree of reflectivity, making it among the brightest moons in the solar system. At 20 to million years old, the surface is fairly young.

It is possible that an extensive ocean beneath the surface harbors life. Ganymede is the third Galilean moon from Jupiter and the largest of the four.

This low-density moon is about the size of Mercury but has about half the mass. Its outstanding characteristic is that it is the only moon to have its own magnetic field.

A few, such as a compass that collapses into the shape of a dagger, demonstrate the era's alliance of science and power. But they also illustrate its blending of science and art—the gleaming artifacts rival works of sculpture. They tell, too, of a growing awareness that, as Galileo said, nature was a grand book " questo grandissimo libro " written in the language of mathematics.

Some of his contemporaries refused to even look through the telescope at all, so certain were they of Aristotle's wisdom.

Besides, said Sizzi, the appearance of new planets was impossible—since seven was a sacred number: "There are seven windows given to animals in the domicile of the head: two nostrils, two eyes, two ears, and a mouth From this and many other similarities in Nature, which it were tedious to enumerate, we gather that the number of planets must necessarily be seven.

Some who did deign to use the telescope still disbelieved their own eyes. A Bohemian scholar named Martin Horky wrote that "below, it works wonderfully; in the sky it deceives one. A Jesuit scholar and correspondent of Galileo named Father Clavius attempted to rescue the idea that the Moon was a sphere by postulating a perfectly smooth and invisible surface stretching above its scarred hills and valleys.

The Starry Messenger was a success, however: the first copies sold out within months. There was a great demand for Galileo's telescopes, and he was named the head mathematician at the University of Pisa. In time Galileo's findings began to trouble a powerful authority—the Catholic Church. The Aristotelian worldview had been integrated with Catholic teachings, so any challenges to Aristotle had the potential to run afoul of the church.

That Galileo had revealed flaws in celestial objects was bothersome enough. But some of his observations, especially the changing phases of Venus and the presence of moons around other planets, lent support to Copernicus' heliocentric theory, and that made Galileo's work potentially heretical.

Biblical literalists pointed to the book of Joshua, in which the Sun is described as stopping, miraculously, "in the midst of heaven, and hasted not to go down about a whole day. By , a Dominican friar named Tommaso Caccini preached openly against Galileo, calling the Copernican worldview heretical. These church challenges greatly troubled Galileo, a deeply pious man. It is a common misconception that Galileo was irreligious, but as Dava Sobel says, "Everything he did, he did as a believing Catholic.

Late in , Galileo traveled to Rome to meet with church leaders personally; he was eager to present his discoveries and make the case for heliocentrism. But Baronius' view turned out to be the minority one in Rome.