After six months of orbiting Mercury, the planet closest to our sun, Messenger, a NASA spacecraft, is sending back data that is challenging long-held assumptions about the planet.

While the information is leaving scientists with more questions than answers, according to csmonitor.com data from the probe is answering some questions and providing the potential for concrete findings about some others.

“Mercury is not the planet described in the textbooks,” James Head III, a mission team member and geologist at Brown University in Providence, R.I. told csmonitor.com

“Messenger’s instruments are capturing data that can be obtained only from orbit,” says Messenger Principal Investigator Sean Solomon, of the Carnegie Institution of Washington in a press release. “We have imaged many areas of the surface at unprecedented resolution, we have viewed the polar regions clearly for the first time, we have built up global coverage with our images and other data sets, we are mapping the elemental composition of Mercury’s surface, we are conducting a continuous inventory of the planet’s neutral and ionized exosphere, and we are sorting out the geometry of Mercury’s magnetic field and magnetosphere. And we’ve only just begun. Mercury has many more surprises in store for us as our mission progresses.”

For Messenger to even make it to Mercury is a major astronautic success. The probe, launched in 2004, traveled for 6.2 billion miles over a 6 ½ year period, according to Scitechstory.com, passing Earth and Venus twice and Mercury three times, in an effort to settle into an orbit around the planet close enough to gather data and long enough to allow a cool-down from fiery passages between the planet and the sun. In March, it began doing the work it traveled all that way to do.

Some of the information transmitted shows volcanic deposits on the planet that scientists are characterizing as flood lava flows. Messenger is also sending information that many hope will confirm the presence of water ice on the planet, according to the csmonitor.com.

Messenger is also sending data that relates to the foundation of the planet. It appears the iron core is larger, than expected, based on the size of the planet, according to the Monitor. Scientists have several theories regarding why, and hope additional information from Messenger will help unlock some mysteries. .

 “These revelations emphasize that Mercury is a fascinating world that is unmatched in the solar system,” says David Blewett, a staff scientist at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., in a press release. “We have barely begun to understand what Mercury is really like and are eager to discover what Mercury can tell us about the processes that led to formation of the planets as we see them today.”

The probe will orbit Mercury for one Earth year.