How a Nose from Mainz Sniffed out Water on Mars
Water on Mars means, maybe, life on Mars. Now, as you know, we haven't found little green men on the red planet. But this year, a Mars rover took a small step on the planet's soil and made a giant leap for Mars exploration: very strong evidence that, in the past, at least part of Mars was "drenched with water." That means Mars was the kind of place, maybe like that back bottom shelf of your refrigerator, where life might have had a chance to flourish. The Mars rover, from NASA, is called "Opportunity", and at the Max Planck Institute for Chemistry (MPIC), in Mainz, Germany, scientists built the machine which measured the chemical composition of dust and stones where Opportunity rolled.
It's named the Alpha Particle X-ray Spectrometer, but you can just call it APXS, or the "Good Nose" ( Spürnase), as they call it in Mainz. Here's a picture; the Good Nose is the round piece staring out from the rover.
This friendly looking little machine can handle some tough environments, like rocky outcroppings on the Martian surface below -500C. To tell us about the chemistry of Mars, the Good Nose sends out alpha particles and X-rays and senses the characteristic X-rays that are scattered back from the dust or rocks. You'll hear more about those when you click on the audio interview below with Dr. Lugmair, whose Group at the MPIC built the APXS.
One of the objects that the Good Nose sniffed at were the so-called "blueberries" – those are small berry-shaped rocks which were found in a depression on a Martian rock, called the "Berry Bowl".
Mars Blueberries closeup
It turned out that inside the "blueberries", there was something that you wouldn't find in real blueberries: hematite, a kind of iron mineral. Where there's hematite, there's probably been water. If you want to know why, Dr. Günter Lugmair will tell you – and about how the Good Nose found it and other interesting objects.