One for Zigs (and anyone interested in rare pebbles)

Someone has found a new Mars meteorite in Morocco.

http://www.bbc.co.uk/news/science-environment-20900843

Apparently its different to all the other stones that fell on us from Mars.

Here's what I never manage to understand. How do they manage to end up here? If this stone is from Mars, then somehow it must have fallen off Mars at some point. Given that Mars has gravity like every other object with mass, I can't understand how that happens, but there we go.

 

You really have to wonder how they know its from Mars, and not from any of the other billions of places it could have possibly come from in the universe.
I get a 404 error on that link.

 

Probably caused by this character

 

Wash your mouth out with soap, smart arse.

 

Thats very interesting, especially the age & composition.

It fell off of Mars simply because something hit the planet fast enough to make bits of it reach escape velocity. When that happens, not all the rocks go out into space, some are re captured and melt as they fall back down. These are known as Tecktites, a lot of them on earth from past colisions.

This one is interesting as its Basaltic. If Mars once had a hot core we can assume it had the same plate tectonics as Earth. Our continents (Mainly silicas, granites etc) are light compared to Basalt, which is what the continents float on. So this could have come from much lower down, say a place like the mid atlantic ridge where today we have a productive plate boundary spewing out basaltic lava pushing us and America apart.

Also the fact it has a higher water content than later rocks.

This is suggesting that Mars was once a planet with an active plate system, which would indicate a magnetic field caused by a molten core generator, which could have held an atmosphere, which means weather, which means rain, which could have lead to oceans

Blimey, all that from one rock. Think i'll have a drink now.

 

Or it could have been Jack McH
Who took some bits from the Giants Causeway, and casually dropped them, whilst on the Jeep Safari into the desert from Morocco :-)

Jack McH

 

How do we know that this stone is formerly part of Mars, as opposed to part the lump of stone that whacked Mars?

How do we even know it came from Mars at all? Every year we pass close enough to one of the asteroid belts to pull a few in, giving us our annual meteor showers. How do we know this rock is not simply one of those?

This sort of thing fascinates me. Geologists seem to be able to tell a great deal from what to me seems like not very much to go on.

 

The lump that whacked Mars would have been either Stony or Iron, the meteors fall into those 2 types, they've not been cooked in a planet with an active core. Basalts are formed from minerals that have been heated up and have had time to crystalise out.

As to where it came from, its a process of elimination. The other planets are Gas & Ice Giants, Pluto is a captured asteroid, Mercury is too small to have active geology, not sure about Venus, but the surface temperature would mean very different mineralogy.

Some of the moons of Jupiter would be a possiblity, Io for one, but that is pretty active so the rocks would be much younger.

Don't think that it came from here as once somethings reached escape velocity it won't tend to turn around and come back.

 

Had to have a look at those, Titan, possibly, Ceres very unlikely.

 

I say unlikely for Ceres because although it has geological processes going on, they are not the full on hot cooking that would produce a Basalt.