Exploration of Jupiter

Too early, humans started to be fascinated by how the sky at night looked like. In the Stone Age, man drew the Sun, the Moon and the stars. But the stars didn't seem to have any dimensions. People noticed that the sky was constantly changing. First the ancient Egyptians (who had thought of the sky as a vast canopy supported by the mountains of the four corners of the Earth) and before the Greek word (which named the light points that became known as "planets", for "wandered"). The biggest planet dominated the sky. It was given many names, depending on the different places, where people lived. The ancient Romans, gave it the name of the king of gods and god of the sky. The European astronomers accepted that, so we call this planet Jupiter.

1.1 Galileo Galilei.

But Jupiter's exploration began with Galileo Galilei .

In 1610, Galileo Galilei, used a new optical instrument, and discovered the biggest satellites of Jupiter (Io, Europa, Ganymede and Callisto). They were named by Marius Simon and probably they were known before Galileo officially discovered them.

He saw four points around Jupiter. First he thought they were stars. But, on the next day, when he looked at the sky he noticed that those points had changed position. This change intrigued him because the stars don't do this at all.

First, Galileo called Jupiter and its moons the Medicine Family, but later, the moons were called Io, Europa, Ganymede and Callisto. In honour of Galileo, they are now called the Galilean moons.

Of course his telescope wasn't powerful, but in the next three hundred years, the telescope was continually perfected, and became very important for observing the stars and planets.

1.2 Pioneers' Mission.

Before Pioneer 10 and Pioneer 11, no spacecraft had travelled to a planet more distant than Mars. In 1972 Pioneer 10 was launched and in 1973 Pioneer 11. The first one went to Jupiter and it was the first to be sent to the outer Solar System, and the second went to Saturn.

Of course there were many serious questions and the scientists didn't know how to answer them.

There are thousands of big asteroids between Mars and Jupiter. Could it navigate through those ones safely? They didn't known... Could the spacecraft resist to the Jupiter's radiation?

Well, Pioneer 10 and 11 travelled safely through the asteroid belt and resisted to Jupiter's radiation, so, we got to known that we could explore the outer planets of our solar system. That was a great advance to astronomy.

1.3 The Voyager and Ulysses missions.

As we saw before, the Pioneers were a success. After those, we had a new type of spacecraft navigating in the Solar System in 1977 (Voyager 1 and Voyager 2). Voyager 1 went to Jupiter and continued on to Saturn. Voyager 2 did the same, but continued by Uranus and Neptune.

The Voyagers made a lot of important discoveries about Jupiter and also took pictures of Jupiter's moons (among those images, were those showing volcanoes erupting on the moon Io) and the incredible cloud system (with the Great red spot).

The spacecraft Ulysses (in the 1980s), used Jupiter's gravity to explore the poles of our Sun and it found that gravity was changed and also discovered there were fewer volcanoes erupting in Io.

All these discoveries made scientists wish to examine Jupiter more closely. So they started thinking about the Galileo mission.

Galileo Galilei spacecraft.

On October 18, 1989, the spacecraft Galileo (named in honour of the first modern astronomer - Galileo Galilei - he made his telescope and made the first observation of the firmament using a telescope in 1610), made the ground shake and left Earth. The six-year journey to that giant planet began.

Galileo arrived at Jupiter on December 1995. That was just the beginning of the journey.

Recent Discoveries

The most recent discoveries took place between 1990 and 2000. The Galileo spacecraft took images from Jupiter's Galilean Moons (Callisto, Ganymede, Europa and Io) and made the astronomers revise their ideas about them. So they examined Jupiter's moons in detail with an eletronic camera and a spectrometer.