[X] My Assistant

[dvandorn]

As we all know, Martian meteorite ALH84001 has interesting structures that have now been debated endlessly as to their origins. The more interesting point, however, is that these structures occur within carbonate inclusions in the rock.

Carbonate Martian rocks have generally not been found from orbit by remote sensing equipment. And in ALH84001, the carbonate "nuggets" are rather tiny inclusions.

If there *are* carbonate rocks on Mars, how the heck do we find them? And if they tend to exist merely as tiny inclusions in other rocks, how do we analyze them (or even see that they're there) in situ?

-the other Doug

[edstrick]

Yep. It's an odd coincindence... CCD's specifically have a long-wave limit roughly the same as infrared film's extreme limit.

Infrared terminology tends to vary from sub-field to subfield, with everybody having different ideas of what short, middle and long-wave IR are. I tend to think of wavelengths from beyond far red to about 1.1 micrometers as Photographic Infrared.

I think Near-IR tends to be a hopelessly confused term at times, including photo-IR and wavelenfths up to 1.8 or 2-point-someting.... say 2.5, 2.8 micrometers <seems to depend on whoever's detectors, optics transmission, etc.)

I call anything beyond 1.1 up to around 5 micrometers as middle IR. You need special detectors, maybe special optics. Solar energy declines with wavelength and thermal emission increases till they cross over somewhere near the 5 micrometer window.

I call 5 to 20 micrometers thermal IR, where everything from room temperature to dry ice emits heat. There's two atmosphere windows, short and long, divided by the 15 micron CO2 band which is opaque on venus, earth and mars.

Everything beyond 20 mm is far infrared out to some ill-defined start of sub-millimeter waves, maybe 100 to 200 microns.. atmosphere's opaque except for short distances or at ultra-extreme altitudes for most of that band.

[marsbug]

Can't say how important this is but it's connected to searching for martian carbonates so I'll post it here. I trust doug to remove it if it owes more to good PR than science!