Mars Polar Cap Mystery Solved

Matt_dk writes "Scientists are now able to explain why Mars' residual southern ice cap is misplaced, thanks to data from ESA's Mars Express spacecraft (the same probe running the 'Mars Webcam'). It turns out the martian weather system is to blame. And so is the largest impact crater on Mars — even though it is nowhere near the south pole. Like Earth, Mars has frozen polar caps, but unlike Earth, these caps are made of carbon dioxide ice as well as water ice. During the southern hemisphere's summer, much of the ice cap sublimates, a process in which the ice turns straight back into gas, leaving behind what is known as the residual polar cap. The mystery was that while the winter cap is symmetrical about the south pole, the residual cap was offset, and scientists couldn't figure out why."

Comments

What do they mean 'misplaced'?

[Tumbleweed]

It's right where I left it.

Re:What do they mean 'misplaced'?

[Anonymous Coward]

In the sofa cushions? That's where I usually find my keys. Did NASA find their keys, too? What about the TV remote?

Re:What do they mean 'misplaced'?

[morgan_greywolf]

In the sofa cushions? That's where I usually find my keys. Did NASA find their keys, too? What about the TV remote?

Yep. You should always look in the couch cushions. And under the couch. That's where I found Jesus.

Re:What do they mean 'misplaced'?

[Anonymous Coward]

Yep. You should always look in the couch cushions. And under the couch. That's where I found Jesus.

You work for the Border Patrol or the Bureau of Immigration?

The answer is simple

[Weaselmancer]

Mars did the calculation for one pole in Metric and the other one in Imperial. That's why they don't line up.

Of all people, NASA should know this.

Re:The answer is simple

[isBandGeek()]

Actually, that's Lockheed Martin for using Imperial units.

Alien planet

[Dan East]

It seems absurdly simple, but it is quite foreign to meteorology on our planet to have an impact crater affecting the global climate and weather patterns. That will be just another of those little things that will give future astronauts the "this isn't Kansas anymore" feeling as they live on another planet.

Re:Alien planet

[mmalove]

"It seems absurdly simple, but it is quite foreign to meteorology on our planet to have an impact crater affecting the global climate and weather patterns."

Tell that to the dinosaurs...

Re:Alien planet

[Anne_Nonymous]

>> it is quite foreign to meteorology on our planet to have an impact crater affecting the global climate and weather patterns.

An impact crater, yes, but other geographic features (both much smaller and much larger than 2300 km) have a huge effect on terrestrial weather.

Re:Alien planet

[fizzup]

Tell that to the dinosaurs...

They aren't in Kansas anymore, either...

Re:Alien planet

[ianare]

You seem to be confusing two different effects of a large asteroid impact - initial and long term.

One of the initial effects will be a huge cloud of dust, blocking almost all sunlight for years at at time - this is what caused the mass extinction at the end of the cretaceous. Others include giant tsunamis (if it crashes into a liquid), 'rain' of molten rock and ash, earthquakes, ect ...
However, on Earth, there are few long term effects, none of which include altering global weather patterns long term. This is due to our planet's ever-changing surface, with new land being created, land being destroyed, and of course continental drift. Mars has no active volcanism and no continental drift, therefore a surface feature which would be rapidly (in geological terms) altered on Earth would last for a very, very long time on Mars.

Another thing is that we have a much thicker atmosphere, reducing the size of the asteroid before impact, AND the probability of it hitting solid ground as opposed to water is about 30/70.

Re:Alien planet

[DinDaddy]

Finally, someone has solved the mystery of why weather prediction is called meteorology.

Marvin vindicated

[UnknowingFool]

In a press statement, Marvin the Martian's publicist told reporters that Marvin felt joy that hey was vindicated by the scientists' report. "Marvin has said all along that the missing polar cap had nothing to do with his lifestyle decision in owning 12 Hummers or related to his Illudium Pu-36 Explosive Space Modulator factory emissions." The publicist did answer allegations that the factory used illegal cartoon workers that were drawn and not colored. A spokesduck from the leading cartoon union said, "For cartoons to be drawn and not colored, that's dessssssspicable!"

The real reason is that...

[KiwiCanuck]

Mars prefers to where it's winter cap, gangsta style.

Martian atmosphere

[fprintf]

I don't know why, but I always though of Mars as a planet without an atmosphere. Perhaps like our Moon, just much bigger. So when first reading the article, I thought that as soon as the carbon dioxide gas sublimated, it would be lost to space.

However, the atmosphere is just really thin: http://starryskies.com/solar_system/mars/martian_atmosphere.html

So, thanks to Slashdot, I once again expand my knowledge of the universe and learned something new today!

Maybe now the ending scene in Total Recall makes some more sense? I'll have to rewatch it and see...

Re:Martian atmosphere

[meringuoid]

Maybe now the ending scene in Total Recall makes some more sense?

The ending of Total Recall makes perfect sense. It only causes problems if you insist that the ludicrously over-the-top secret agent action hero scenario was actually real, as opposed to what your man had in fact paid for at the very beginning.

Re:Martian atmosphere

[hawkfish]

Maybe now the ending scene in Total Recall makes some more sense? I'll have to rewatch it and see...

No, that won't help...

Still not answered...

[ivandavidoff]

Is the angle of offset rakish or merely jaunty?

Two mysteries linked by Rossby waves

[exp(pi*sqrt(163))]

The important phenomenon at work here is that of Rossby waves. It's interesting that this type of polar standing wave may also be implicated in the famous Saturnian hexagon.

Re:Carbondioxide-ice

[morgan_greywolf]

I heard that it's sublime!

Kim Stanley Robinson's Mars Trilogy

[OverZealous.com]

I don't know if anyone else has read this trilogy, but I'm currently finishing the last book in the Red/Green/Blue Mars trilogy.

This series follows a group of scientists as they inhabit and eventually terraform (partially) Mars. It's fantastic how accurate this book has been, covering complex topics on the effort to get to Mars, benefits and detriments to the explorers' health, even engineering feats such as how one might build a true space elevator (by anchoring it to a geostationary asteroid).

He specifically discusses and explains the polar-cap phenomenon caused by a massive meteorite strike. He explains and discusses the weather patterns, atmosphere and insolation issues. Recently, every "discovery" made on Mars has felt like a bit of déja vu, because he has written about it — even “predicted” it — in these books.

But what really impresses me is that the first book (containing all of these elements) was written in 1992. 16 years ago!

Check them out if you like complex, deep science fiction. These are on the complexity order of the Dune trilogy, but far more grounded in current technology.

We knew this already

[volcanopele]

Once again, ESA has discovered something we have know about for years now: http://www.nature.com/nature/journal/v435/n7039/full/nature03561.html First, they discover water ice on Mars... The paper itself is quite interesting actually. I don't understand why the press outreach for ESA needs to come up with claims like "Mars Polar Cap Mystery Solved."