Martian Microbe Markers - Maybe - and Mysterious Mark on Mercury

"How Mars Rocks Could Preserve Signs of Life "
Space.com (October 2, 2009)

"They haven't yet figured out how to draw blood from stones, but a group of French researchers is offering new insight that could change how scientists search for signs of life in Martian rocks.

"By studying the laboratory fossilization of microorganisms, scientists have caught a glimpse into how early Earth and potential Martian life might be preserved in rocks. The scientists focused on Pyrococcus abyssi and Methanocaldococcus jannaschii, extremophiles which thrive in piping hot (up to 176°F), oxygen-lacking (<0.2% of current levels) environments.

"Some believe this sort of hot, anoxic environment is where life may have originated on Earth, and perhaps even on Mars.

" 'Environmental conditions were similar on the young terrestrial planets and traces of early Martian life may have been similarly preserved as silicified microfossils,' the scientists write in their study, which appeared in the September issue of the journal Geobiology...."

Okay: An article with "Methanocaldococcus jannaschii" in the second paragraph isn't going to be particularly light reading: and the idea of spending time learning about how some bunch of eggheads plan to look for teeny, tiny fossils of bugs that died a few billion years ago might not appeal to everybody.

Me? I read the thing.

But then, when I was a boy I'd read the ingredients list of cereal boxes. I can get along without reading longer than I can make do without breathing - but I really like to read.

Back to the article.

When something the size of a T. Rex dies, there's a reasonable chance that its bones will get fossilized - turned to stone. For a long time, bones, shells, and other hard parts of animals were just about the only sort of fossil known. Knowing what to look for, and a whole lot of legwork has turned up fossils of plants and animals without hard parts.

But they're not all that easy to find.

When it comes to single-celled organisms, it gets even harder.

One thing mentioned in this article is a sort of chemical signature - starchy chemicals called "extracellular polymeric substances," EPS for short. Finding EPS in a rock may mean that microorganisms were in the dirt before it turned to stone - or that microorganisms got inside the rock later.

It's not an ideal test - but if EPS showed up in Martian rocks that hadn't been exposed to Earth's lively ecosystem, that'd be an exciting development.

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And now, for something completely different.

"Mercury's Mysterious Bright Spot Photographed Up Close"
Space.com (October 1, 2009)

"During its most recent flyby of Mercury, NASA's MESSENGER spacecraft caught another glimpse of the innermost planet's mysterious bright spot.

"The MESSENGER probe skimmed just 142 miles (228 km) above Mercury at its closest approach as it whipped around the planet during the flyby, the last of three designed to guide the spacecraft into orbit around the planet in 2011.

"The $446 million probe snapped several new images of Mercury during the flyby, despite a minor data hiccup that delayed the downlink of some of the images.

"One of the new images shows a bright spot on the planet's surface, a feature that scientists cannot yet explain...."

"...cannot yet explain..." - it's exciting when that phrase shows up. It's an indication that humanity's knowledge is going to be expanded a bit - sooner or later.

The bright spot? It may be associated with a hole that was made by volcanic processes. Or, something else.