Photographs of two different locations on the surface of Mars showing a small impact crater (top) and a similarly sized hollow (bottom)
Example of degraded impact structures or hallows as observed by different spacecraft on the surface of Mars. (a) Image mosaic of a small impact crater ~10 m in diameter at the Mars Exploration Rover Spirit site. The rover landed in 2004 and operated until 2011. (b) Image mosaic of a similarly sized hollow at the InSight landing site. The InSight spacecraft landed in 2018 and continues to operate on Mars. Credit: Weitz et al. [2020], Figure 5
Source: Journal of Geophysical Research: Planets

Weather on Earth is characterized by microclimates, which are differences in the weather conditions over short distances caused by local conditions such as elevation and amount of sunlight received. Mars, in contrast, appears to experience similar climates over long distances.

Such is the implication of Weitz et al. [2020] who examine the evolution of the Martian landscape at two landing sites, NASA’s Sprit rover and InSight lander, that are separated by thousands of kilometers. The study compared the shape of small impact craters or hallows at the two landing sites, and also used returned images to measure the size and shape distribution of small rocks present at the surface of the Martian soil.

The similarities in morphology and physical properties of hollows and rocks at two different landing sites suggest current environmental conditions that degrade and infill impact craters are comparable and pervasive across Mars.

Citation: Weitz, C. M., Grant, J. A., Golombek, M. P., Warner, N. H., Hauber, E., Ansan, V., et al. [2020]. Comparison of InSight Homestead hollow to hollows at the Spirit landing site. Journal of Geophysical Research: Planets, 125, e2020JE006435.

—Bradley J. Thomson, Editor, JGR: Planets

Text © 2020. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.