Data from a U.S. space agency probe flying over Mercury’s surface suggest the planet has greater levels of activity that scientists suspected, as reported on many astronomy based newsgroups.

The National Aeronautics and Space Administration’s Mercury Surface, Space Environment, Geochemistry and Ranging spacecraft, known as Messenger, has measured the planet’s atmosphere, the interaction of its surrounding magnetic field with the solar wind, and its geological past. The probe also discovered a previously unknown impact basin about 430 miles in diameter.

The ever-present supersonic gale from the sun creates never-before-seen magnetic “twisters” that “dance” across Mercury’s magnetic field and occasionally touch down on its surface, new observations have revealed.

Until recently, scientists who participate on science and astronomy newsgroups say the closest planet to the sun remained the least understood of the four terrestrial planets – Mercury, Venus, Earth and Mars. For a long time it was thought to be very similar to Earth’s moon in composition, since both worlds have a similar gray, pockmarked appearance.

The second messenger flyby uncovered new chemicals in Mercury’s tenuous atmosphere, including magnesium, which was not previously known to exist there. The discovery confirms that magnesium is an important constituent of Mercury’s surface. Understanding the different elements present on Mercury helps scientists reconstruct the planet’s history and its formation.

Usenet newsgroups also reporting that during the spacecraft’s second close approach to Mercury, it also measured a much more dynamic magnetic field around the planet than was seen during the first flyby. These changes in magnetic field are tied to the powerful radiation streaming off the nearby sun, and drive variability in Mercury’s atmosphere.