Reviews Astronomy Mirror Earth The Search for Our Planet's Twin by Michael D. Lemonick Share this:FacebookTwitterPocketRedditPrint By Sid Perkins December 13, 2012 at 10:12 pm This article is only available to Science News subscribers. Subscribers, enter your e-mail address to access our archives. Client key* E-mail* Log in Not a subscriber? Science News is a nonprofit. Support us by subscribing now. Subscribe