The Perseverance rover on Mars discovered a boulder field where one rock in particular stood out as being different from everything they've found on Mars so far. Credit: NASA / JPL-Caltech / ASU / MSSS If looking at this Mars vista conjures up childhood memories of the song, "One of these things is not like the others," NASA scientists are right there with you. Perseverance, a car-size lab on six wheels, traveled into the Red Planet's Neretva Vallis last week. Though this region may look like a ...