An RAC/CSO may be physically realizable using a black hole. Just fly near a black hole and drop a computer into it, preferably one that runs Microsoft software. As it falls down you'll observe a CSO. Or leave the computer behind and YOU take the plunge. As you get nearer the BH the computer will look like an RAC. Of course this doesn't take into account quantum effects.
If you are really "dying" to know the answers to a problem that only an RAC could do, then you could try this little experiment. Good luck, send me a post card. (Unfortunately, it will never reach me, and I won't get it) George Levy