Comment on

• Background levels of methane in Mars' atmosphere show strong seasonal variations.

  Webster CR, Mahaffy PR, Atreya SK, Moores JE, Flesch GJ, Malespin C, McKay CP, Martinez G, Smith CL, Martin-Torres J, Gomez-Elvira J, Zorzano MP, Wong MH, Trainer MG, Steele A, Archer D Jr, Sutter B, Coll PJ, Freissinet C, Meslin PY, Gough RV, House CH, Pavlov A, Eigenbrode JL, Glavin DP, Pearson JC, Keymeulen D, Christensen LE, Schwenzer SP, Navarro-Gonzalez R, Pla-García J, Rafkin SCR, Vicente-Retortillo Á, Kahanpää H, Viudez-Moreiras D, Smith MD, Harri AM, Genzer M, Hassler DM, Lemmon M, Crisp J, Sander SP, Zurek RW, Vasavada AR. Webster CR, et al. Science. 2018 Jun 8;360(6393):1093-1096. doi: 10.1126/science.aaq0131. Science. 2018. PMID: 29880682
• Organic matter preserved in 3-billion-year-old mudstones at Gale crater, Mars.

  Eigenbrode JL, Summons RE, Steele A, Freissinet C, Millan M, Navarro-González R, Sutter B, McAdam AC, Franz HB, Glavin DP, Archer PD Jr, Mahaffy PR, Conrad PG, Hurowitz JA, Grotzinger JP, Gupta S, Ming DW, Sumner DY, Szopa C, Malespin C, Buch A, Coll P. Eigenbrode JL, et al. Science. 2018 Jun 8;360(6393):1096-1101. doi: 10.1126/science.aas9185. Science. 2018. PMID: 29880683