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On September 17th, 1998 the Ithaca Journal ran its first "Ask A Scientist!" article in which Professor Neil Ashcroft , who was then the director of CCMR, answered the question "What is Jupiter made of?" Since then, we have received over 1,000 questions from students and adults from all over the world. Select questions are answered weekly and published in the Ithaca Journal and on our web site. "Ask A Scientist!" reaches more than 21,000 Central New York residents through the Ithaca Journal and countless others around the world throught the "Ask a Scientist!" web site.

Across disciplines and across the state, from Nobel Prize winning scientist David Lee to notable science education advocate Bill Nye, researchers and scientists have been called on to respond to these questions. For more than seven years, kids - and a few adults - have been submitting their queries to find out the answer to life's everyday questions.

Published: 17 September, 1998 Next Week's Question
Inside massive Jupiter is pressurized hydrogen
Question
What is Jupiter made of?

Question
Jupiter is very large, about 11 times bigger than the Earth, and over 300 times more massive. But the stuff it contains is very different; over 9 out of 10 atoms in Jupiter are hydrogen atoms: the lightest of all atoms. Under ordinary conditions we think of hydrogen as a gas. If we cool hydrogen gas enough it forms an electrically insulating liquid and if we cool it even more, it forms a solid (just like the progression of steam to water to ice). Inside Jupiter, the hydrogen is under enormous pressures because of the gravitational forces in such a large planet.

One observation that must be explained is that Jupiter has a whopping magnetic field, very much larger than the one we have on our own earth. Many years ago it was predicted that under very high pressures hydrogen has the electrons ripped off it and thus can become a conductor of electricity. Electrical currents in the interior can then produce the observed magnetic field of Jupiter.

An exciting development was made earlier this year by physicists at Lawrence Livermore National Laboratory in California. With shock-waves they managed to duplicate in hydrogen not only the pressure in parts of Jupiter, but also the temperature. And, they managed also to measure the conductivity of hydrogen; it was indeed in the range of certain liquid metals!

The most abundant element in our entire planetary system is hydrogen. It now appears that more than half of it is in a metal form!

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