The western route, 5th leg after stop at Absecon / Reeds Bay Options

[Poolio]

Yes, the reason is to go back for a look at the rock, Block Island.

True, but in post 52 Tim Parker suggests that there are other reasons as well. We'll just have to wait and see.

(BTW, whenever I see or hear any reference to Ozymandias, all I can think of is Graham Chapman stumbling around drunk in Monty Python's Michael Ellis episode. A bit unfortunate...)

[djellison]

Other reasons we're going to the rock (other than it being big). Not that there are other reasons to go in that direction.

[PaulM]

This is probably a stupid question, but.....

Are meteorites on Mars actually interesting? I'm fully aware that BI may be a piece of deep ejecta, and appreciate why that would make it worth investigating, but the rovers have seen a couple well identified meteorites, and spent some considerable time going over them.

What can we learn from them that is different than what we would learn from meteorites on Earth?

CE

I suspect that each time a cobble is investigated it is hoped that it is not a meteorite but rather a rock from some distance away on Mars. Opportunity has studied hundreds of rather simillar local Meridiani rocks and so a rock from elsewhere on Mars is of great interest.

Such a rock is Bounce Rock which was found by Opportunity in April 2004. The rock was named for the fact that it was struck by Opportunity as the craft bounced to a stop during its landing stage. Bounce Rock bears a striking resemblance to a class of meteorites found on Earth known as shergottites, that are believed to have originated from Mars:

http://en.wikipedia.org/wiki/Bounce_Rock

I think that the Mars rock which would be of most interest would be another fragment of the formation of which the Antarctic meteorite AH84001 formed a part:

http://en.wikipedia.org/wiki/Allan_Hills_84001

The large meteorite which blasted AH84001 into space presumably blasted another million fragments of this formation into space. At least one of these fragments must currently be lying on the plain of Meridiani.

I understand that the most interesting meteorites of all would be fragments of the Earth close to 4 billion years old. Metamophism has severely altered all rocks of this age on Earth but it has been suggested that fresh fragments of Earth rocks of this age could be found on the Moon or Mars.

[fredk]

At least one of these fragments must currently be lying on the plain of Meridiani.

How can we be sure? Even if the ejecta from the AH84001 impact spread globally over Mars, what would be the surface number density of ejecta pieces large enough for Oppy to study, as a function of distance to the impact antipode?

[centsworth_II]

...the rovers have seen a couple well identified meteorites, and spent some considerable time going over them.

The rocks did not become "well identified" until after going over them. An assumption that a rock is a meteorite before inspection could turn out to be wrong. More is learned about the geology of Mars if the rocks turn out to be Martian, but I guess the crater counters are interested in the number of surviving meteors on the surface.

[centsworth_II]

...I think that the Mars rock which would be of most interest would be another fragment of the formation of which the Antarctic meteorite AH84001 formed a part....

It would be as interesting as Bounce rock: A piece of Mars from far away. I wonder if Opportunity would even be capable of detecting the carbonates in AH84001.

My vote for most interesting rock would be a chunk of limestone.

[glennwsmith]

Astrophil, I think your reading is correct -- thanks!

Cryptoengineer, you make a good point re value of Block Island as a meteorite vs. piece of ejecta. But it's hard for us space junkies to ever think about a meteorite as anything but way cool -- even laying on the surface of Mars.

[Stu]

If ever you want proof of how cool a meteorite is, take a piece of Canyon Diablo (the meteorite that blasted out Meteor Crater) into a school classroom full of 6 year olds and let them hold it... "That's from space... it fell from the sky 50,000 years ago...!" Wow...! Then let them hold a piece (or in my case some VERY small pieces!) of a Mars meteorite... "... and that's from the planet Mars..." Cue eyes wide as saucers and a mouth formed into an amazed "o" shape...

Priceless...

[PDP8E]

nothing much happening .... so a super zoomed image of Block Island ...hyper processed
(zounds! the jpeg artifacts are awful!)




oh well...

[CosmicRocker]

...
I understand that the most interesting meteorites of all would be fragments of the Earth close to 4 billion years old. Metamophism has severely altered all rocks of this age on Earth but it has been suggested that fresh fragments of Earth rocks of this age could be found on the Moon or Mars.

What a far-out thought! Those possibilities had not occurred to me, though they should have. Thanks for mentioning that, Paul. Do you have a reference to who first suggested it?

[serpens]

Given that any ejecta from an Earth impact would be going the wrong way in the gravitational well, what would be the probability that it could have the kick off velocity necessary to reach the orbit of Mars? And since Mars sweeps a greater orbit than Earth, wouldn't this further diminish the possibility of impact? Given the resouces available on site, how could we identify the provenance in any case?

[centsworth_II]

Do you have a reference to who first suggested it?

The following is a study reported in 1989 which references previous studies.

Science News Mar 25, 1989
"According to S.A. Phinney... kicking a rock hard enough to free it from Earth's gravity would require a meteorite capable of making a crater more than 60 miles across. In addition, Mars' orbit is much larger than Earth's, so the chance of an Earth rock hitting Mars is about 10 percent that of the same thing in reverse....

...The group found fewer particles seemed likely to get to Mars than suggested by some previous analyses."

[SFJCody]

Looks like an iron meteorite. But a very intimidating one with a strange hole in one side. I hope it doesn't bite!
http://qt.exploratorium.edu/mars/opportuni...ARP0713L0M1.JPG

[djellison]

That is a big ass chunky lump of metal I think. It'd be worth a fortune if it was on Earth

[remcook]

Looks like the Beagle-2! *ducks and runs*