The Mystery Rock In A Doughnut Shape

According to NASA, this snapshot from the Opportunity rover in December 2013 showing the “jelly doughnut” phenomenon has an explanation. Suddenly, this mysterious object materialized out of nowhere, as if a Martian Homer Simpson had dropped it.

Here’s what it isn’t: Neither fungus-like Martian life nor meteor impact ejecta is responsible for this. But what we have here is geologic roadkill. Researchers have called the white rock “Pinnacle Island” because of its appearance, which resembles a pie filling of sorts. Curiosity’s onboard cameras captured a series of before and after shots, in which it initially seems to be absent and then reappears.