Cassini Offers A New Glimpse Of The Pale Blue Dot
Given my fascination with the universe, my love for Carl Sagan, and my hopes that the reboot of Cosmos will take viewers by storm, it’s only appropriate that my last post of the year would be about space — and more specifically, about a planetary scientist who arranged a pretty awesome photo op of Earth from the Cassini spacecraft.
Carolyn Porco, leader of the Cassini Imaging Science team and professor of astrophysics and planetary scientists, is following in Carl Sagan’s footsteps, especially when it comes to appreciating the significance of Earth as the “pale blue dot.” The phrase refers to a photograph taken in 1990 by the Voyager 1 probe on its way out of the Solar System, nearly four billion miles from Earth. At Sagan’s request, NASA had the probe turn around and take a photo of Earth, which Sagan then elegantly wrote about. While the photo provides some perspective on the enormity of the universe and the relative smallness of Earth, the original image wasn’t actually that good, and Porco has been wanting to update that image for a long time.
Last month, at a Library of Congress dedication for Carl Sagan, Porco revealed a new photo called “The Day the Earth Smiled” that puts the old one to shame. The image was taken by Cassini, carefully timed to capture Saturn while it blocked the sun. In the scaled-down image below, Earth isn’t visible (it would be beneath and to the right of Saturn), but in the close-ups, such as the image at the top of the post, the Pale Blue Dot is indeed visible.
Porco didn’t just get the shot — she choreographed it. She did something that NASA has never done before, which is to let people know ahead of time that the shot was going to be taken. On July 19, Cassini took the choice photo, and people from all over the world were ready. Porco asked them to go outside at a specific time, and to:
…look up, think about our cosmic place, think about our planet, how unusual it is, how lush and life-giving it is, think about your own existence, think about the magnitude of the accomplishment that this picture-taking session entails. We have a spacecraft at Saturn. We are truly interplanetary explorers. Think about all that, and smile.
Apparently, thousands of people did just that. And while those people aren’t visible in the photograph, when we look at it, we know they’re there. That statement actually sums up a lot about space, as well as about belief. Porco’s idea here is spot on — what could be more perfect than a photograph that captures the glory of Saturn and the smallness of Earth? Sagan would be proud.