This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
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The Andromeda galaxy holds a particular fascination. Not just because it's the nearest large galaxy to our own, some 2.5 million light years away, but because it shares a destiny with us. Eventually there will be no more Milky Way and Andromeda, they will merge into something that is both new and old, some 4 billion years in the future.
Until that time though, we can continue to enjoy the magnificent display of Andromeda's trillion or so stars, a hazy conglomeration stretching across our sky (a display that would be visible in its totality to our human eyes if only they were a little more sensitive).
Now a new camera on the Japanese Subaru Telescope atop Mauna Kea in Hawaii has captured one of the most detailed images of our galactic neighbor. This device, the Hyper Suprime-Camera (HSC), is a beast. Its 870 Mega-pixel detector is housed at the end of a lens barrel that's 1.65 meters in length.
With a field of view of about 1.5 degrees the HSC can snap Andromeda all in one, an extraordinary accomplishment for such a high-resolution instrument. It makes for an incredible portrait. The full (albeit merely a 36 mega-pixel reduction) image is here.
It's well worth spending some time zooming into this chart of another galactic system, descending to its stars and gas, its plains and mountains of stellar matter.
One cannot help but wonder if, among so many other suns, there is not someone else, something else, staring back at our own home, a sister galaxy looming out of the void.
Maybe one day we'll find out.
