What does a half million galaxies look like? Something like this:
Whoa. That's a part of a huge image just released by the Canada-France-Hawaii Telescope Legacy Survey Deep Field #1, a ginormous mosaic of the night sky... and by ginormous, I mean GINORMOUS. It covers a solid square degree of sky -- 5 times the area of the full Moon -- and tips the scale at a whopping 370 megapixels! It took 5 years and several hundred hours of observing time with the 3.6 meter telescope on top of Mauna Kea to get this massive mosaic.
The image itself may look cool and all, but the true power comes when
you give in to the dark side you use the interactive zoom feature. You can surf the entire mammoth 370 million pixel image, zooming in on galaxies galore. And you won't run out of objects to investigate any time soon: there are an estimated 500,000 galaxies in the image. Like the Hubble image I posted about yesterday, almost everything you see in the image above is a galaxy, not a star.
The images were taken to look for very distant supernovae. It was the investigation of these far-flung stellar explosions that led astronomers to determine the Universal expansion is accelerating, and to postulate the mysterious dark energy that powers this phenomenon. The CFHT is being used to map the same area of the sky over and over again, looking for the tell-tale blobs of light that mark the spots of a distant, dying suns. The more of these we see, the better we can nail down the physical characteristics of the cosmic expansion, and of the dark energy about which we know so little.
Of course, astronomers will squeeze a lot of science from this and other images... but it's also OK to simply scan and pan through them at home, too, marveling that the Universe is so deep and so deeply beautiful.