Jupiter: The Sun-Like Planet
The planet Jupiter is the largest planet in the solar system [no kidding]. While earth is 8,000 miles wide, Jupiter is more than 88,000 miles across! In fact, all of the other planets could fit inside Jupiter and still have extra storage room.
As fascinating as Jupiter is, when people from NASA propose a multi-million dollar project to send a spacecraft to Jupiter, the question comes to mind: What is so important about Jupiter anyway? It is over 400 million miles away and has absolutely no effect on the way we live our lives… so why explore!?
The answer: we're just curious. Jupiter's main chemical components are hydrogen and helium, similar to the Sun's. Jupiter is producing 2.5 times more heat than it is absorbing from the sun. Although this is a relatively small amount because the planet is so far away from the sun, it means that the planet is producing its own energy deep within the layers of gases and clouds. Scientists believe that Jupiter may be in the early phases of becoming a star!
Another subject of curiosity are the 16 moons that orbit Jupiter. The four largest ones were discovered by Galileo Galilei and were appropriately named Galilean moons. These moons contain deep groves, sulfur compounds, ice, and active volcanoes. Additionally, the Galilean moons are so large that we would consider them as planets if they orbited the Sun. Dr. Wesley T. Huntress, NASA's associate administrator, stated, "Jupiter is like a miniature solar system in itself. A mission to Jupiter may uncover new clues about how the Sun and planets formed and interacted."
The Voyage To Jupiter
The space shuttle, Atlantis, roared off the launch pad on October 18, 1989 with the spacecraft Galileo. The launch and release went perfectly and soon enough, the rocket booster was pushing Galileo out of Earth's orbit and on its way to Jupiter! As exciting as it was, the world had to wait six more years before it reached Jupiter… before they found out whether the project was successful.
During this six-year period, Galileo took advantage of its advanced instruments to discover many things on the way. The spacecraft confirmed the presence of lightning below the clouds of Venus. On its passage through the asteroid belt, Galileo discovered that the asteroid Ido had its own moon! The moon, later named Dactal, was the first moon ever to be found in orbit around an asteroid.
In the July of 1994, when the Shoemaker-Levy comet collided with Jupiter, Galileo had a front-seated view of the "fireworks show." The explosion caused a fireball larger than the entire Earth. At 121 million miles away, Galileo pointed its instruments toward Jupiter and recorded many detailed photos and other information, while telescopes on Earth did their best to record the impact as well. For astronomers, this was a once-in-a-lifetime event and Galileo contributed to it.
The Final Stage
Galileo had two main parts: the atmospheric probe and the orbiter. The atmospheric probe would descend as far as it could (before getting crushed by the immense amount of gravity) into the thick upper atmosphere of Jupiter and transmit various data to the orbiter. The orbiter would orbit Jupiter and relay the information back to Earth. Galileo's atmospheric probe and the orbiter separated 147 days before reaching Jupiter and headed on separate courses.
On the day in which Galileo would descend, the group of scientists and engineers at NASA waited nervously in the Jet Propulsion Laboratory. Most of them had spent a large portion of their life working on the Galileo Project and that was the day where they would find out whether their work would pay off. The air was thick with excitement and anticipation.
Since the spacecraft was 400,000,000 miles away from Earth, they received the news of the landing 52 minutes after it happened. When the Galileo's radio signal came through… the room was filled with a sudden silence… followed by waves of loud cheering and celebration! The atmospheric descent was a success!
After that event, the Galileo orbiter continued to orbit Jupiter and transmit countless amounts of valuable data about Jupiter and its moons. Today, although the well-traveled Galileo has lost contact with mission control, it still silently orbits Jupiter, as a monument of the contributions it has made toward our knowledge of the Universe.
