[null and void]

Is that the Rosetta stone?

[dr_lew]

The asteroids being examined are the metaphorical Rosetta stones which are considered to contain the key to the early history of the solar system. Cf. the Why Rosetta? page at the Rosetta spacecraft site linked in the blurb.

[lurk]

“Is that the Rosetta stone?”

Looks more like a kidney stone.

Pass that bad boy and you’ll be doubled over for a day or two.