Tuesday, January 6, 2015

A Stunning Photograph: No Human Has Seen Such a Thing

One of my most vivid memories as a child was the time our family paid a visit to the telescope and observatory on top of Mt. Palomar in Southern California. I'm not sure how old I was, perhaps 8 or so, and I already had a mania for all things astronomy. We bought some postcards that day, two of which I remember clearly. They were actual photographs taken by the Palomar telescope, and included three of the planets (Mars, Jupiter and Saturn) on one card. The other was a photograph of the Andromeda Galaxy. I kept those cards for years, and they may still be in one of the boxes in my closet. I was pleased to find that it only took a moment with a search engine to find the photograph of the Andromeda Galaxy itself:
Many thanks to Palomar Skies for posting this 1959 photograph of the Andromeda Galaxy
At the time (the mid-1960s) I thought one could increase the magnification of the photographs by simply looking at them with a magnifying glass, and later when I had the chance, a microscope. I sadly soon learned the difference between magnification and resolution. The best telescope in the world at the time could only discern the fuzziness of the hundreds of billions of stars, because the atmosphere was too turbulent to allow higher resolution photographs. As far as I knew we'd never be able to resolve individual stars in a galaxy other than our own. I went on to study different things, but I never forgot my desire to see another galaxy up close outside our Milky Way.

That desire became a reality today. With thanks and accolades to NASA and the European Space Agency.

Go to this site: http://www.spacetelescope.org/images/heic1502a/zoomable/. Give it time to load. It is a photograph of the Andromeda Galaxy with 1.5 billion pixels (as noted at IFLS, the average high resolution monitor has just over 2 million pixels). The photograph resolves individual stars in the Andromeda Galaxy. The zoomed photograph contains 100 million stars, and yet covers only about 10% of the entire galaxy. You can download the entire photograph, but you would need around 4.3 gigabytes on your computer to store it. And need around 600 high definition screens to show the entire image.

This is an extraordinary accomplishment, perhaps the most detailed picture ever produced. The first view in human history of the totality of stars in a galaxy outside our own. I doubt that 100 million people have looked at this photo yet, which means you could choose just about any star in the zoomed close up and realize you are the only human who has ever observed this star. The only person who has wondered what planets it has, whether life ever emerged on the planet's surface. Sure, there are enough stars in our own galaxy to do that sort of thing, but before this picture existed, you couldn't do it out there.

In 2018, a new space telescope, the Webb, will launch, which will have mirrors amounting to a diameter of 21.3 feet, compared to Hubble's 7.8 feet. Thirty years elapsed between the best photo ever taken from Earth of the Andromeda Galaxy, the picture from my childhood, and this remarkable image from the Hubble. The Webb Space Telescope represents thirty years of technological advances beyond that of the Hubble Telescope. What incredible things will we see next?

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