(Image: Estelle Greenwood)
Would you like to own a little piece of the red planet? Well now you have the chance. New Scientist magazine are currently running a competition in which the star prize is a Martian meteorite. It goes by the not very spectacular name of NWA 2975.
By now you are probably asking: So what’s the deal? Why this plug for a magazine competition? Well in order to verify that their sample really was from Mars New Scientist came to the Open University and asked us to run some tests on the prize to check that it is the real thing. We were very happy to help out. We took a very small piece from the prize and analysed its oxygen isotope composition. This test is a 100% reliable when it comes to identifying bits of Mars.
And the result?
Happily for all concerned it really is a chip off the old red planet. The plot below shows how you can tell.
Oxygen has three stable isotopes 16-O, 17-O and 18-O. Rocks from Mars are slightly enriched in 17-O compared with terrestrial samples. So when analyses of rocks from Mars and Earth are plotted on an oxygen three-isotope diagram, like the one below, they form two distinct horizontal lines. Our analysis of NWA 2975 plots close to other analyses of meteorites from Mars, the so-called SNCs, and well away from terrestrial rocks. Interestingly, NWA 2975 falls a little bit below other Mars rocks, and that’s probably because it has suffered weathering on Earth prior to being collected.
To learn more about what Mars rocks can tell us about the red planet why not read Colin Pillinger’s recent New Scientist article.
You can have a look at the sample of NWA 2975 using the Open University Virtual Microscope.