Head outside and look up at the sky at 2:27 PDT (21:27 UTC) to wave at the Cassini spacecraft as it captures a view of its home planet from orbit around Saturn. That’s in like 20 minutes as I write this post, so seriously, hurry.
If you miss it, or you’re afraid of not being on the correct side of Earth, fear not. NASA realized that the MESSENGER spacecraft around Mercury will also be in position to capture Earth this weekend. It will be doing so tomorrow, July 20 at 4:49 a.m., 5:38 a.m. and 6:41 a.m. PDT (11:49, 12:38, and 13:41 UTC).