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:probably more common than we think

[frank378]

IIRC it's not just a molten core, but a spinning molten core made up mostly of iron which allows for a significant magnetic field to deflect solar winds.

I *think* I recall hearing that one of the reasons Mars could not "keep it together" the way the Earth did is because the core may have a different atomic/elemental makeup.

Any planetary scientists that can attest to/debunk this?

Re:probably more common than we think

[J'raxis]

Tectonics might not be. One of the prevailing theories of why we have tectonic plates is that a sizeable chunk of the earth's crust got sheared off by a massive impact, leaving the remaining chunks of crust to slowly slide around the surface of the earth. The impactor that struck the earth hit at a particularly fortuitous angle; a little bit off and it would have destroyed the planet instead. Whether or not these kinds of impacts are improbable or not is still an open question -- one theory is that the impactor formed at one of the earth's Lagrange points, and it wasn't just a "random" blow from an asteroid, so it may be more common than it at first sounds.

Incidentally, the impactor blew that crustal material clear into orbit, which ultimately coalesced into the moon. See the giant impact theory entry on Wikipedia.

Re:Breaking News!

[peculiarmethod]

This is a fairly common theory (especially in the wake of the early findings that the other planets in the Solar System are uninhabitable by humans), but our studies of our own solar system suggest it to be untrue. If life were as adaptable as suggested, then we'd find inflatable beings on Jupiter, Crystaline entities on Venus, creepy crawlers on Mars, and other life forms well suited to their environment.

Yet no such creatures have ever been found. Hope is still held that water creatures may be found on Jupiter's Icy Moons (specifically Europa), but we've pretty much exhausted the remainder of the Solar System.


I'm going to have to argue with that. To be perfectly honest with ourselves, we can't say whether life only exists on a physical plane, or a mixture of magnetic, physical, spritual, gaseous.. we have no idea. It could be that life is abundant in forms we just haven't had the opportunity (capability) to discover yet. When one looks at areas that now seem unihabited, it seems impossible that they ever were. At present, desert covers a large part of Australia, The Great Sandy Desert, The Gibson Desert and the Great Victoria Desert combine to fill more than half of Western Australia. It was covered by large sheets of ice before that, and before that by a shallow ocean, which was most defintely teeming with life. The south pole has produced palm tree fossils. To a temporary observer (as we are to the celestial bodies), the south pole seems dead. it was once covered in life. Things change, things move, and accidents happen. Just because our sister and brother planets look devoid of life now, doesn't mean they are or have been. Or will be for that matter.

Best evidence for water

[Council]

To me, the best evidence for water is this map, which they always show at NASA presentations on Mars. It's a topographic map colored by altitude, and you see that the areas below a certain depth are almost completely crater-free, contrasted strongly with the areas above that depth. This, to me, is a really, really strong argument that it was once covered in water and had a coastline.

Looking at that map always makes an Earth-like Mars seem much more real to me.

Re:Breaking News!

[shawb]

Mars' atmosphere is drastically thinner than ours, and that is assumed to be in a large part due to the smaller size. The gravitational pull simply can't maintain a thick atmosphere, and Mars' size is such that the core has cooled off, and techtonic activity has stopped. Lack of techtonic activity means that atmospheric gasses are no longer being replenished. It may be possible that life could exist without an atmosphere, but it seems very unlikely to me. There would at least need to be a liquid medium to distribute metabolic chemicals (such as CO2 and O2 on earth) to allow for life to have the proper energy to survive. On Mars this would have to be on the surface, as the lack of techtonic activity means there would be no thermal vents such as on earth which provide another chemical gradient which allows some forms of life to survive. I don't have a problem seeing that life could have existed at one time on mars, but I highly doubt that it is currently there. There may be some remnant organisms in deep deep stasis which are basically waiting for favorable conditions to revive, but I personally do not call that currently living.