The uncertainty of science: Though scientists had assumed the presence of an ancient delta that once flowed into Jezero Crater meant a lake once filled the crater, Perseverance data from its first year of roving has so far found no evidence that a lake every existed.

[A] summary of the first year of data from the rover, published in three different papers being released today, suggests that Perseverance has yet to stumble across any evidence of a watery paradise. Instead, all indications are that water exposure in the areas it explored was limited, and the waters were likely to be near freezing. While this doesn’t rule out that it will find lake deposits later, the environment might not have been as welcoming for life as “a lake in a crater” might have suggested.

Jezero Crater, like Gale Crater where Curiosity is roving, is located in the Martian dry equatorial regions. Though the data from Gale suggests a lake had once existed there, the data also suggests strongly that any water there acted more like water in cold climates like Iceland, existing mostly as glacial ice.

The jury is still out, but these results from Perseverance once again point to ice and glaciers as a possible explanation for many of the geological features on Mars that we on Earth automatically assume were caused by liquid water.