THE PHOTO THAT SHOULD DEFINE YOUR ENTIRE LIFE
Those who follow this blog may be aware that about 98% of the photos I post here are my own work. There have been a few times where I have used a generic web image or another photographer’s image citing the original sources. Today is another one of them for I wish to share a photo from the fine folks at NASA, one which some of you most likely have already seen, but perhaps not have been able to truly and fully appreciate its significance. It is the Hubble eXtreme Deep Field image of a starless area in our sky.
With the exception of one or two stars, every thing else in this photo is a distant galaxy.
Image credit: NASA; ESA; G. Illingworth, D. Magee, and P. Oesch, University of California, Santa Cruz; R. Bouwens, Leiden University; and the HUDF09 Team.
And now for a bit of background. Published in 2012, the Hubble eXtreme Deep Field is not a new set of observations, but rather a combination of many existing exposures (over 2000 of them) into one image. Combining the Hubble Ultra Deep Field, the Infrared Hubble Ultra Deep Field and many other images of the same small spot of sky taken over almost 10 years, the Hubble eXtreme Deep Field pushes the limit of what we can see in the visible Universe even further. It is made up of a total of 22 days of exposure time and 50 days of observing time. The photo was assembled by combining the NASA Hubble Space Telescope photographs taken of a patch of sky at the center of the original Hubble Ultra Deep Field. The XDF is a small fraction of the angular diameter of the full Moon.
To obtain the original Hubble Ultra Deep Field photo the telescope was pointed at a patch of sky that, as seen from Earth, had nothing in it. No bright stars, no nebulae, no gas clouds, no known galaxies and no galaxy clusters. Nothing but empty space. But was it really empty? What the astronomers found in their first image of this small region of space, where before absolutely no known galaxies were seen, were around three thousand new galaxies. With the exception of about five or six points in which diffraction spikes could be seen, those picturesque gleaming points of light which identify the objects as stars within our own Milky Way, every single point of light in the image they obtained was a galaxy.
In 2012, an even deeper version was created, using a more advanced set of cameras and optics and that version is what is known as the Hubble eXtreme Deep Field image that you see here. This image, consisting of a region of space barely a thousandth of a square degree of the sky, which is so small that it would take thirty-two-million of them to fill the entire sky, contains an unbelievable 5,500 galaxies, the most distant of which have had their light traveling towards us for some 13 billion years, or for a time equivalent to more than 90% the present age of the Universe. That is one hell of a long road trip.
When this figure is extrapolated over the entire sky, it is conceivable that there are some 170 billion galaxies in the observable Universe, and that is just a low estimate. When one considers that there is an astonishing amount of Universe out there that Hubble is not yet able to observe, and that it can only see the brightest of those most distant galaxies, the estimate may be closer to 10^12, or a trillion galaxies within our visible Universe. A trillion. Think about that for a minute. Or for the rest of your life. A trillion galaxies.
And when one considers that there are hundreds of billions of stars within our own galaxy, that means that number of stars in the Universe could possibly be around 10^23 (10,000,000,000,000,000,000, that is 100 sextillion). That is an unbelievably large amount of stars. And then, take into account that each and every one of those stars has its own unique story, its own development and history, perhaps its own planetary systems, and the ever minuscule and remote chance that on some of those planets life has evolved. Now that is really putting things in perspective.
So, what you are really looking at is a very historical photo, a photo that, all things considered, should define your life as much as it defines your place in this vast amazing Universe. Perhaps if everyone had a copy of this photo hanging in their living room, to remind them of what life really is about and where it is actually taking place, we would make progress in putting aside our petty beliefs, our useless conflicts and incessant preoccupation with all that is truly unimportant in life, and recognize the true meaning of our all too short sojourn here in a sea of trillions of stars and galaxies. Perhaps, for once, we would really open our eyes and see…
Thanks to NASA and to Ethan Siegel, a NASA columnist and professor at Lewis & Clark College for the technical information.
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