QUOTE (djellison @ Feb 27 2006, 12:03 PM)
Because it looks like one. That's about it. I mean - what do you WANT it to look like to classify it as a crater?
Tiny craters do have raised rims - even Fram had one. A small rise at its rim, but it's a small crater so you'd expect that. Eagle and it's sister a few hundreds meters SW - both appeared as raised rims from a distance.
Tjere are hundreds of thousands of these things around the planet - what makes you think they're NOT craters?
It's not that I think they're *not* impact craters, just that I have an open mind about some of the features which we see!
Obviously, Mars is covered with impact craters. Big and small, no problem.
But, at Meridiani, we have seen other sorts of holes in the ground, ranging from the infamous (and dynamically somewhat improbable) mini-craters right up to Anatolia (and perhaps the Payson depression). Fram looked more like a traditional small Lunar crater, to my mind, than does Eagle.
Eagle was characterised as an impact feature *before* we saw the other holes, so the natural assumption was made that it was due to something which fell from the sky. However, there are few bits of direct evidence to support that belief, just habit: round hole = impact crater.
I'm not being contrary for the sake of it - I simply got thinking about holes in the ground, and began to ask myself whether we'd all jumped the gun.