It's the Sun, stupid!

[darrelx]

More recent observations indicate that Mars' south pole is continuing to melt. "It's evaporating right now at a prodigious rate," says Michael Malin, principal investigator for the Mars Orbiter Camera (MOC). The pits in the ice are growing by about 3 meters per year. Malin states that conditions on Mars are not currently conductive to the

Comments

[lizetta]

I don't know why I'm even posting this, but here goes.

Yes, the climate of the earth has always changed. Minor fluctuations are normal, and species are expected to adapt to them. Large scale climate changes have also happened in the history of this planet. The issue here is that this change is happening in a geologically insignificant time frame. Micro-evolution takes place over hundreds, if not thousands of generations. The time frame of a single life is insignificant here.

We have no idea if this change on Mars is normal. We cannot say that this is in fact a change, and not part of the planets cycle. Since Mars does not appear to actually have any life on, these rapid changes might be normal. They might even be the cause of this lack of life.

[roycalbeck]

Mars doesn't have a "cycle". It doesn't, as you've noted, have life, and in fact it never had anything approaching an ecosystem.

We DO know that Mars has polar ice caps, and that those caps are NOW melting. Therefore the planet was cooler in the past than it is in the present.

The simple fact is that Mars exhibits absolutely NONE of the phenomena currently attributed to "global warming": population, major sources of atmospheric pollution, etc. Mars doesn't even have as much volcanic activity as Earth does.

Hence, Ockham's Razor comes into effect: if it isn't being warmed by anything on the planet itself, then it is being warmed by the only other source of heat in the solar system, that being the sun.

[lizetta]

Mars doesn't have a cycle? And you know this how? Can you tell me what size these polar ice caps were 1000 years ago? How about 100 years ago? 10? How many ice ages has Mars had? What was their duration? Is this change in the pits greater than normal? The ice caps there aren't even formed in the same ways that ice caps here are, and they're not chemically the same, being made mostly of CO2 and not H20. I don't see how you can create any correlations with so little data.

[roycalbeck]

Mars doesn't have a cycle because there is nothing there which CAUSES a cycle. You are misplacing the source of the cycle: the sun, which does in fact have known, observed, and measurable changes that provide evidence of a cycle.

"How many ice ages has Mars had?"

Precisely as many as Earth has had, for the same reason: changes in solar activity.

"Is this change in the pits greater than normal?"

What criteria would you possibly list for ABNORMAL changes?

"The ice caps there aren't even formed in the same ways that ice caps here are"

Ice is universally created the same way: by lowering temperatures. It's eliminated in the same way: by raising temperatures. Melting polar caps, regardless of what they're made of, are universally indicative of rising temperatures. The freezing point of a given material doesn't change merely because that material is on Mars.

Now, unless you have an alternate theory as to why the temperatures on Mars are rising, then we're left with solar activity.

[lizetta]

Freezing points do vary because the material is on Mars, since pressure is a component.

I propose that the change in temperatures has to do with the dust to ice ratios in the atmosphere of Mars that affects the amount of solar radiation that reaches the surface. This would cause an decrease in the ice caps until the ratio reaches a critical point, swinging the temperatures back the other direction. Surface recordings on Mars do show evidence that changes have been occuring in the planets history. Of course, complete the picture with basic orbital theory.

Mind you, it's just a hypothesis, but it's as valid as any.