Evidence For Liquid Water On a Frozen Early Mars 63
Matt_dk writes "NASA scientists modeled freezing conditions on Mars to test whether liquid water could have been present to form the surface features of the Martian landscape.
Evidence suggests flowing water formed the rivers and gullies on the Mars surface, even though surface temperatures were below freezing. Dissolved minerals in liquid water may be the reason."
Re:Warmer? (Score:3, Insightful)
If Mars had a significant amount of water it almost certainly also had an atmosphere, which retained heat.
Early Mars was warmer [Re:Warmer?] (Score:5, Insightful)
Is it possible that mars was warmer at a time? Either with a high level of CO2 or some other greenhouse gas that would have warmed the surface enough for running water?
Yes, that's a good summary of the current scientific thinking. The Viking orbital images show a lot of the surface is sculpted by water-carved features, and the belief is that Mars originally has a much thicker carbon dioxide atmosphere, which provided a significant amount of greenhouse warming (*). With the loss of Mars' magnetic field, this thick atmosphere was slowly eroded away by the solar wind to the very thin atmosphere we see today.
Maybe a little more dramatic but maybe even a slightly closer orbit?
No, that's quite unlikely. Planets are hard to move.
-----
*Footnote: The media likes to pretend that there is some controversy about the fact that carbon dioxide produces greenhouse effect warming (because controversy sells newspapers), but in the science community studying planetary atmosphere, there is no controversy whatsoever. It is just physics.
If you search hard enough, you can find somebody who disagrees, and quote them, and say, "look, not all scientists agree!" And since this is /. I'm sure somebody's about to do that: the miracle of the internet is that these fringe thinkers have just as loud a voice as people who have actually stufied the subject. But nevertheless, the greenhouse effect is just physics. And relatively simple physics.
Re:Early Mars was warmer [Re:Warmer?] (Score:3, Insightful)
My frost-bit annuals, planted well after the last-frost date for this location, beg to differ...
Yeah, this is exactly the kind of irrelevent arguments you tend to hear. To be fair, the idiotic media hype makes it seem as if this really is the argument for global warming: one warmer-than-average summer, and the headlines read "Global warming is here," and one worse-than-average hurricane season and headlines say "Global warming! Hurricanes are getting worse!"
Global warming is a long-term average rise of temperature over time scales of decades. One warm winter, even a handful of warm winters, has nothing to do with it. Temperatures still fluctuate-- climate change doesn't negate the existence of changes in the weather. And we're talking about the average heat balance of the globe-- any particular spot may still be warmer, or cooler, or unchanged.
The rule for northeast Ohio is, don't plant your tomatoes until the end of May. I planted mine at the end of April. Guess what? They're doing fine. Has global warming moved the growing season up by a month? No, you can't conclude that-- one season, one place, that's not relevant. Global warming is about averages, and about time scales of decades. Got that? Averages. Decades.
There is plenty of controversy, except among those taking funds from govt's, companies, etc who have a vested interest in global warming.
Yes, that's an amazing argument that just can't be refuted: just say that all the science that disagrees with your opinion is biased. You don't need to prove it, you can just assert it, and repeat it over and over until people get tired of arguing. It's such a great argument that you can use it to disprove anything, refute any amount of evidence, no matter how much there is. Evolution? The science establishment has a vested interest in saying it's established science! Did we really land on the moon? The science establishment vested interest in saying we did! UFOs in Roswell? The science establishment has a vested interest in pretending that they invented all that technology we stole from crashed saucers! Tesla invented free power and the oil companies had him killed? The science establishment has a vested interest!
Throw out all those studies, and we can talk.
Yep, that's the argument of the AWG deniers, all right. Throw out all the science. Exactly.