One new mystery about MU69, presented by @AlanStern at #SBAG today: These five mounds on its big lobe, all similar in size. A sign of past accretion or caused by space weathering? Stay tuned. pic.twitter.com/8WQCqT62Rg

— Paul Voosen @voooos@sciencemastodon.com (@voooos) January 29, 2019