Hello all,


some of us (in the Free! thread) noticed a round dark stain near Oppy:
visible here on the NASA site (look bottom right, just above Oppy's solar panel).
So I open this thread for this.

What such a stain could be? It looks just like a mere change in color, with the same texture than around it.

The more trivial explanation would be a drop of lubricant fallen from the apparatus at the end of Oppy's solar panels, when she passed here just before she got stuck. With a temperature of 20° oil could spread, and certain oil compositions would not evaporate, at least not fast.

But there would be more enthralling explanations. For instance a colony of bacteria could look like this. Or other really unexpected explanation.

In any case we do not know what it is and it may be potentially very interesting. So I think it is worth a bit of examination with the instruments. Just be cautious not to place the microscope right on it, if it is oil it would irremediably dirty the lens.