But just in case you don't need to, might I suggest you post a description of the type of movement you want for your meteors? You might not need to do a loop at all. Depending on what you want them to do there could be an alternate method.
The quetion is not so much on the actual movement but on how to access individual object instances and all object instances. In Python that is.
I am able to find a For each Sprite in python.
It would have been natural for the python part to be able to iterate over all Sprites using something in the lines of [code:38rp9999] for instance in Sprite instance.X += 1 [/code:38rp9999]
or something like [code:38rp9999]Sprite[index] += 1[/code:38rp9999]
Another option would be to use the event picking mechanism and execute the python script as part of the action. Would that be possible. I think it would be a nice option to have the python script as an action of some event.