Posts Tagged ‘Blue Marble’

Is this a picture of Earth?

March 21, 2012
One of these images is a photograph of the Earth. The other isn't. So which is which? And what is the other one? (Images courtesy of NASA)

One of these images is a photograph of the Earth. The other isn't. So which is which? And what is the other one? (Images courtesy of NASA)

Friends. Fellow humans. We live on an amazing planet. And I feel priveliged to belong to the first generation in all of Earth’s history who have seen our planet as viewed from space. As we beat ourselves up for our collective failure to safeguard our planet, I feel it is worthwhile to pause and realise just how recently we acquired a truly global perspective.

The image on the left is a photograph of the Earth taken on a Hasslebad camera by an astronaut on Apollo 17 who, 28,000 miles out from Earth, looked out the window and happened to find the Earth illuminated fully. Since you can see Antarctica in daylight you can tell this must be in the southern hemisphere summer. When the camera was returned to Earth, the film was developed and the image revealed – there were no digital previews in 1972!

The image on the right is a fabrication. It uses ‘data’ acquired by a low Earth orbit satellite (Suomi) which is cleverly pasted together as described here.

Illustration of the way in which the right hand image was fabricated

Illustration of the way in which the right-hand image was fabricated. Despite being acquired by a satellite at a height of around 300 miles, it simulates the view from much further away. Image courtesy of NASA.

So what do we conclude? The view is no less amazing for having been simulated. And the whole Earth perspective it represents is as much a philosophical perspective as a physical one. But despite the ubiquity of a similar image as the default iPhone desktop, I find the original more emotionally powerful. The fact that an individual human being took the picture on the boldest adventure of a generation somehow resonates with me.

The six and a half minute video below describes in more detail how the images are made – it is shockingly complicated. Enjoy 🙂

http://www.sciencefriday.com/embed/video/10425.swf


%d bloggers like this: