Thursday, July 18, 2013

Breaking News from the Outer Planets

1. Neptune has a new moon. Well, new to you. It was discovered by going over old photos from the Hubble Space Telescope. The moon is 12 miles, or 19 kilometers, wide. So think about that for a moment: a telescope in orbit around the earth was able to spot a 12 mile-wide object in orbit around Neptune.

2. Tomorrow, on July 19, the Cassini spacecraft in orbit around Saturn will turn its cameras inward and will take a picture of the earth. From Saturn. It will take the picture between approximately 2:27 and 2:42 Pacific time -- add three hours for the east coast, five more for Great Britain, and one more for continental Europe. So make sure to look up and smile. They've done this before. Here's one,

which is reminiscent of the "pale blue dot" picture that Carl Sagan talked NASA into taking from Voyager 1. Of course, Sagan used this to argue that the earth and humanity are insignificant and that this contradicts the traditional view of humanity as the pinnacle of creation supposedly taught in the Bible -- and I can't help but think he already had the book half written when he asked NASA to take the picture. Unfortunately for Sagan, we've known since at least Aristotle that in comparison to the size of the universe the earth is, for all practical purposes, infinitely small, a mathematical point with zero volume. For more on this, read "Copernicus and the Tale of the Pale Blue Dot" by Dennis Danielson.

Update (26 July): Here's the new picture of earth taken from Saturn:

and here's one taken at about the same time from the Messenger spacecraft in orbit around Mercury:

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