• PNAS Subscriptions
  • Sign-up for PNAS eTOC Alerts
September 2, 2014; 111 (35)

Cover image

Cover image expansion

Cover image: Pictured are representations of the orbits and relative physical sizes of 1,475 extrasolar planet candidates discovered by NASA's Kepler mission since 2009, including an excerpt of the 589 systems with two or more transiting planet candidates. More than half of the planet candidates shown have been statistically confirmed as true planets. The Exoplanets Special Feature, appearing in this issue, presents recent findings regarding the diversity of exoplanet sizes, compositions, and orbital distances, as well as the conditions likely to support life on exoplanets and potential methods for remotely detecting evidence of biological activity. See the Introduction to the Special Feature by Adam S. Burrows and Geoffrey W. Marcy on pages 12599–12600. Image courtesy of Daniel Fabrycky (University of Chicago, Chicago).

Online Impact

                                                        1. 956115858 2018-01-22
                                                        2. 730379857 2018-01-22
                                                        3. 346624856 2018-01-22
                                                        4. 201609855 2018-01-22
                                                        5. 72549854 2018-01-21
                                                        6. 795928853 2018-01-21
                                                        7. 752345852 2018-01-21
                                                        8. 566508851 2018-01-21
                                                        9. 615722850 2018-01-21
                                                        10. 689612849 2018-01-21
                                                        11. 846903848 2018-01-21
                                                        12. 674896847 2018-01-21
                                                        13. 11197846 2018-01-21
                                                        14. 986896845 2018-01-21
                                                        15. 667601844 2018-01-21
                                                        16. 385442843 2018-01-21
                                                        17. 496686842 2018-01-21
                                                        18. 915288841 2018-01-21
                                                        19. 885256840 2018-01-21
                                                        20. 726268839 2018-01-21