author here.
Some cross bedding features could be wind generated (ha! geography!). But theres also a lot of evidence of hydrous minerals - clays, etc - and evidence of frozen ice, especially in the Northern basin of Mars.
Theres a lot of debate about the efficiency of atmospheric stripping and hence water loss. It apparently depends on a lot of modelling assumptions and there's also a fair amount of evidence for water locked up in the cryosphere of Mars.
However, what we're saying is that irrespective of atmosphere loss or potential water stores, Mars was doomed from the off by virtue of its mantle chemistry. Liquid water would simply react with its surface rocks, forming dense hydrous minerals which then allows a transport mechanism of water to the mantle. This ain't good for the prospects of the evolution of life on Mars and has implications for life on extra solar planets.
And as a LONG time slashdot botherer (yeah, I've lost my UID more than once....) I'm more than happy to answer questions (if I can!)
shit - this is the pinnacle of my science career - SLASHDOT!!!
Its advantages are obvious - each round is cheap, it doesn't get lost and end up as a technology or a munition 'giveaway' (or bad press), and as the article says, reaction time can be rapid. It means that the next class of boats are merely floating powerstations with all the 'goodies' held far away from the action.
Besids, a rail gun is not just line of sight, as with any ballistic weapon, unless you can see over the horizon. I guess the main limiting factors in use would be those of ablation - both to the rail and projectile.
This kind of thing bugs me so much that I actually created a log-in just fro this....agreed - big claims require big evidence, and in this case the micro-analysis is extremely poor, to the point of being worthless. For a start, why did they use arbritrary accelerating voltage of 9.7KeV? Its too low to excite significant Fe X-rays, hence the Fe peak is small....were the samples coated (and they must have been)..if so, theres the carbon contribution...if they were gold coated, then the entire analysis is bunk.....why was this analysis not done on the TEM? The fact the researchers used a tradename as the name of the anayltical technique gives the game away somewhat, but fully quant ED analysis on very small poorly prepeared samples is really not very clever. It should have been rejected until better analysis was available. If there was other evidence to support their claims, then it should have been included. If that evidence has been rejected previoulsy, it strongly suggests desperation on the part of the researchers. This kind of shoddy use of standard analytical techniques by scientists is really symptomatic of either laziness or desperation to get published. Either way, its really not on.
Slashdot Mirror
author here. Some cross bedding features could be wind generated (ha! geography!). But theres also a lot of evidence of hydrous minerals - clays, etc - and evidence of frozen ice, especially in the Northern basin of Mars.
Theres a lot of debate about the efficiency of atmospheric stripping and hence water loss. It apparently depends on a lot of modelling assumptions and there's also a fair amount of evidence for water locked up in the cryosphere of Mars. However, what we're saying is that irrespective of atmosphere loss or potential water stores, Mars was doomed from the off by virtue of its mantle chemistry. Liquid water would simply react with its surface rocks, forming dense hydrous minerals which then allows a transport mechanism of water to the mantle. This ain't good for the prospects of the evolution of life on Mars and has implications for life on extra solar planets.
And as a LONG time slashdot botherer (yeah, I've lost my UID more than once....) I'm more than happy to answer questions (if I can!) shit - this is the pinnacle of my science career - SLASHDOT!!!
Its advantages are obvious - each round is cheap, it doesn't get lost and end up as a technology or a munition 'giveaway' (or bad press), and as the article says, reaction time can be rapid. It means that the next class of boats are merely floating powerstations with all the 'goodies' held far away from the action. Besids, a rail gun is not just line of sight, as with any ballistic weapon, unless you can see over the horizon. I guess the main limiting factors in use would be those of ablation - both to the rail and projectile.
This kind of thing bugs me so much that I actually created a log-in just fro this....agreed - big claims require big evidence, and in this case the micro-analysis is extremely poor, to the point of being worthless. For a start, why did they use arbritrary accelerating voltage of 9.7KeV? Its too low to excite significant Fe X-rays, hence the Fe peak is small....were the samples coated (and they must have been)..if so, theres the carbon contribution...if they were gold coated, then the entire analysis is bunk.....why was this analysis not done on the TEM? The fact the researchers used a tradename as the name of the anayltical technique gives the game away somewhat, but fully quant ED analysis on very small poorly prepeared samples is really not very clever. It should have been rejected until better analysis was available. If there was other evidence to support their claims, then it should have been included. If that evidence has been rejected previoulsy, it strongly suggests desperation on the part of the researchers. This kind of shoddy use of standard analytical techniques by scientists is really symptomatic of either laziness or desperation to get published. Either way, its really not on.