The News
Egg trick shows Mercury has fluid core
By Randolph E. Schmid The Associated Press
Article Last Updated: 05/04/2007 12:13:12 AM MDT
Washington - Researchers have cracked a mystery at the core of Mercury - and say there's molten fluid inside the tiny planet.
They did it by using the same trick as cooks who want to know if an egg is raw or hard-boiled.
The finding helps explain the unexpected discovery several years ago that Mercury has a small magnetic field.
The discovery of the magnetic field by the Mariner 10 spacecraft puzzled scientists, who believed that because of its small size the planet's core had long ago solidified.
But the most common explanation for a magnetic field is a molten interior, such as on Earth. The moon and Mars, for example, show evidence only of ancient magnetic fields.
The Messenger spacecraft is on its way to Mercury and is expected to arrive next year, but in the meantime researchers led by Jean-Luc Margot, an assistant professor of astronomy at Cornell University, launched their own attempt to learn about the planet's core.

The Research
Read the research behind this story in the journal Science.