- Ancient Mars may have had a carbon cycle − a new study suggests the red planet may have once been warmer, wetter and more favorable for life https://theconversation.com/ancient-mars-may-have-had-a-carbon-cycle-a-new-study-suggests-the-red-planet-may-have-once-been-warmer-wetter-and-more-favorable-for-life-255207 7 comments space