Maps Show Mars Was Once More Like Earth

vrioux writes "NASA scientists have discovered additional evidence that Mars once underwent plate tectonics, slow movement of the planet's crust, like the present-day Earth. A new map of Mars' magnetic field made by the Mars Global Surveyor spacecraft reveals a world whose history was shaped by great crustal plates being pulled apart or smashed together. ."

Comments

Re:Animation?

[kevn]

You need to be a Spaceflight now premium subscriber to get the extra video content.

Journal link

[brian0918]

Here's the journal abstract:

http://www.pnas.org/cgi/content/abstract/050746910 2v1

"Mars currently has no global magnetic field of internal origin but must have had one in the past, when the crust acquired intense magnetization, presumably by cooling in the presence of an Earth-like magnetic field (thermoremanent magnetization). A new map of the magnetic field of Mars, compiled by using measurements acquired at an 400-km mapping altitude by the Mars Global Surveyor spacecraft, is presented here. The increased spatial resolution and sensitivity of this map provide new insight into the origin and evolution of the Mars crust. Variations in the crustal magnetic field appear in association with major faults, some previously identified in imagery and topography (Cerberus Rupes and Valles Marineris). Two parallel great faults are identified in Terra Meridiani by offset magnetic field contours. They appear similar to transform faults that occur in oceanic crust on Earth, and support the notion that the Mars crust formed during an early era of plate tectonics."

No

[brian0918]

" Seeing as how we do not behave exactly like every other animal, would there be a way that we could have come from Mars? " It would be damn near impossible for humans and chimps to be so similar genetically. Species don't evolve toward eachother genetically.

Liquid Cores

[deathCon4]

All planets (like our own) which have a dynamic liquid core have magnetic fields. The strength of the field depends on how large and dynamic the molten core of the planet remains. When planets form, they start as a liquid lava rock, and slowly cool over millions of years. As they cool, the outer crust (or mantle) solidifies, while the core remains molten. This is true of any solid planet (not gas giant) therefore any rock-type planet would most likely of had a magnetic field at one time. Mars unfortunately is far enough from the sun that it has cooled to great depth inside the planet, reducing its liquid core to a very small percent of its original size, reducing and almost eliminating its magnetic field, which is at present very weak. Another proof of this is the lack of volcanism on Mars, which by examining the topographic features was once very active.

Re:Liquid Cores

[phlegmofdiscontent]

The cooling of Mars's core has nothing to do with insolation. Planetary cores are molten (or not) due to the presence of radioactive elements which release heat as they decay. Mars is less dense than Earth, meaning it's core is much smaller and probably has a smaller proportion of uranium, etc than Earth. Thus, the amount of heat generated by radioactive decay dropped off much faster than here, thus ending most geological activity billions of years ago (not all of it, though, as there are indications of volcanic activity as recent as 100 million years ago which is a small fraction of Mars's lifetime). If solar influx had anything to do with tectonics, we would expect Mercury to be much more active than Earth, but it's not. It's about as dead as the Moon, geologically speaking.

Re:Liquid Cores

[phlegmofdiscontent]

At least some of the heat in the Earth's core is from radioactive decay.

http://www.newscientist.com/article.ns?id=mg187251 03.700

Additionally, planetary formation theories state that during the Earth's formation, it would have melted from the accretion impacts that created it. While pressure alone will melt the metal-silicate materials deep in the Earth, it won't create heat (melting actually costs energy, even if kept at constant temperature). Gravitational contraction will create heat, but the Earth hasn't contracted much in the past 4 billion years (gravitational contraction was a proposed mechanism for the Sun's output, but was shown to be insufficient). While my explanation was simplified and doesn't tell the whole story, it is mostly correct.

Re:Aliens?

[SgtClueLs]

No no you guys have it all wrong. The Flying Spaghetti Monster reached down his noodley appendage and created a Mountain, Trees and a Midget. This ape business are lies spread by the non-FSM Believers. They shall never know what heaven is like, with it's stripper factory and beer volcano!

Re:Based on the site photos...

[meringuoid]

Giant purple spiders aside, does the image show actual spots where the remnant magnetic flux is particularly strong? It seems like those spots might be an interesting place to site the first few Mars colonies. Since shielding from the solar wind is a big issue, a location with just a little help from the residual field (even if weak) might have some advantages over a spot with no help at all from the dead crust.

It probably wouldn't help much. The local magnetic remnants would be tiny, not enough to significantly shield an area.

You'd plant your colonies where there are sites of scientific interest, or resources of value to the colonists, and put up with the radiation. One thing you won't be short of on Mars is rock. Lots and lots of rock. Dig a great big tunnel into the side of Mariner Valley, end of radiation problem...

A map!

[Zinged]

Don't know if this is THE map, but it is a map of Mars Crustal Magnetic Field Remnants: http://photojournal.jpl.nasa.gov/catalog/PIA02819

Please assist with the upkeep of civilization...

[ScentCone]

by thinking before you type. It's not "fishers," it's "fissures." You know, from the same root word that gives us "fission" (as in splitting the atom).

And why go to all the trouble of typing that extra apostrophe in "volcano's" when it forces people to then ask, "The volcano's what?" You're saying that something belongs to a volcano? Or did you mean to just use the plural, and simply say "volcanos" (as in, more than one volcano)?

I don't normally bother with this, but since you're asking a useful question that I can only hope some geologists will answer, I'm just hoping you'll include some more helpful spelling/syntax/punctuation next time around. It elevates the conversation, and reminds the IM kiddies that words actually mean something.

Re:Breaking News!

[VStrider]

There are just so many little things about the Earth that are balanced in favor of life (e.g. Distance from Sun, size of star, size of planet/gravity, magnetic field strength, atmosphere composition, etc.)

The distance from the sun, is not as important as it seems to be. The habitable zone has not been at 1AU at all times and it's going to change again in the future. There was a time when Mars was in the habitable zone and Earth was not. Similarly, when the sun will get older and on its way of becoming a red giant, Mars will again be in the habitable zone while Earth will be as hot as Venus.

The size of a planet and its gravity doesn't necessarily favor or hinder the development of life, as long as you don't take the extremes into account(ie. life would most likely not develop on an asteroid or a gas giant, though there could be exceptions). Mars is a small rocky planet with a gravity of 0.376 Gs which is quite low for humans. But that doesn't mean life didn't exist there. Earth's 1G is not some kind of universal standard for life. It's just the gravity, earth species live on. The same goes for atmospheric composition and magnetic field strenght. It's the enviroment we evolved and live in, not a universal standard. Humans would have as hard a time adapting to a lower/higher G enviroment, or to a deviant atmospheric composition, as a lifeform from somewhere else would have on Earth.

Also don't forget evolution. Life can adapt to a changing enviroment. If we send humans to live on Mars, after several generations, their successors won't be able to live on Earth's gravity. Which btw I think it's the key for colonization of other planets. If we ever find a way to accelerate evolution changes on ourselves, it'd be easier to do this instead of terraforming other planets.

Re:Mars' orbit once crossed Earth's?

[MightyMartian]

That wasn't an astronomer, it was a quack named Velikovsky.

Re:Mars-Earth comparison offends Martians deeply

[D'Eyncourt]

Actually the original poster (digitaldc) is correct. Everest is 8.8 km above SEA LEVEL (which obviously cannot apply to Mars). To make a fair comparison with Olympus Mons you should ignore the water on earth and measure from its lowest point (the Mariana Trench, 10.9 km below sea level) and with this you get 19.7 km for Everest.

Re:Aliens?

[Shotgun]

It is very uncommon, and the idea that they're from Mars is a VERY tenous idea at best. According to http://en.wikipedia.org/wiki/Martian_meteorite the idea is basically, "It doesn't look like it is from here, IT MUST BE FROM MARS."

Not exactly what I'd call science. I'd tend more to calling it "making shit up".