Cold and Clammy

A fascinating report by the excellent David Chandler in today's New Scientist about the strangely muddy looking texture of some of the ground near Spirit, specifically the places where it seems to have bounced. Apparently some people on the team are speculating there might be some level of brine in the regolith, making it act a bit muddy. Others argue that electrostatic effects may be able to produce the same sorts of textures -- which would be exciting in and of itself. Always cool to see a planet do something deeply unearthly. But the brine explanation is obviously rather sexier, with its implications of possible habitability. The story from the print edition isn't online, but an earlier news report by David looking at other evidence for brine can be found here

For a while I've wondered whether the notion of an early "warm and wet" phase in Mars's history owes part of its appeal to the alliterative simplicity of the phrase. "Warm and wet", or "warmer and wetter", just has a natural ring to it. This may sound silly, but sometimes the way a phrase sounds really does matter. Look at the way debates about the roles of heredity and environment have been shaped by the opposition of "nature and nurture" that Francis Galton borrowed from Shakespeare. Galton found it a "convenient jingle of words". (Shakespeare himself, Matt Ridley informs us, may have borrowed the phrase from Richard Mulcaster, the first headmaster of the Merchant Taylors' school, and the great great great great uncle of the horrendous Boy Mulcaster). "Warm and wet" shaped Mars thinking by insisting that you must have a markedly hotter climate to see effects due to liquid water, and thus any such effects could be relegated to some very ancient climate. In various ways it's becoming fairly obvious that that's not necessarily the case. The ancient climate might not have been that warm, and some recent watery events (for example, the gully-forming process, whatever it is) may have taken place at today's cold temperatures.

The best phrase Ive been able to come up with in an attempt to shake off the dominance of "warm and wet" is "cold and clammy". Unfortunately, its not particularly applicable to the various active but not necessarily very liquid-friendly ideas currently knocking around about ice ages(see this entry for more). If the brine hypothesis takes off, though, maybe "cold and clammy" will be the convenient jingle of the day (he suggested, vainly).

Comments

[Martin]

I remember hearing in a television program on Stephen Hawking that the reason black holes are called black holes is because the physicists who constructed the theory got tired of saying "gravitationally collapsed mass" every other sentence, and this almost certainly accounts for part of the sexiness of black holes. Branding is important, even in science.

[Oliver Morton]

And branding can backfire -- when Fred Hoyle coined the term "Big Bang" he meant it mockingly as a way of putting down the theory that rivalled his own "steady state" theory. But the big bang stuck.

I seem to remember a story somewhere saying that "black hole" took a little time to catch on in international cosmology circles because its literal translation into Russian is a bit rude...

[Bruce Moomaw]

I go for "Cold and Damp" as a more plausible view of Noachian Mars (kind of like the wholly erroneous view of California held by the Lady Who's A Tramp).

The absence of any large amounts of water-weathered rocks there -- and the evidence for significant and widely scattered deposits of stuff like olivine, which CAN'T have been exposed to any significant amount of liquid water -- leads me to think that the Warm and Wet enthusiasts have now been firmly disproven. But I still think there's a very strong chance for a Noachian Mars that had small but significant amounts of surface or near-surface liquid water at near-freezing, which (as Phil Christensen tells me) would vastly slow down its weathering tendencies.

James Head has a series of abstracts for the Vernadsky-Brown Microsymposium providing what looks to me like pretty good morphological evidence that water may have run down from the southern hills through the valley networks (probably under an ice crust), trickled into an underground water table in the southern plains, emerged once more onto the surface in channels erupting from the slopes of the North-South Dichotomy, and finally emptied into an ice-shrouded sea filling the northern plains (which may actually have been mostly an ice sheet, with only a thin layer of geothermally warmed liquid water at its base).

A Noachian Mars in which all the surface liquid water was ice-covered is not a very promising locale for the evolution of life, but it isn't an entirely hopeless one either -- especially considering the possibilities of hot springs. But I now have a strong and creepy suspicion that, if we DO ever find proof of either extant or fossil life on Mars, we may always be totally unable to prove that it wasn't just transferred from early Earth to Mars via meteorite, rather than evolving independently on Mars. Now, if we find life on Europa -- THAT'S a different matter...