The Hubble Space Telescope had a shaky start, indeed the images that it first sent back looked as though the whole thing had been shaken into a blurry mess. It was a disaster and hugely embarrassing for NASA. It took a few years to construct a corrective mirror to be tacked on to the end of the scope but, once in place, Hubble was able to send back some of the most scientifically valuable and awe inspiring pictures that anyone had ever seen. It opened up the cosmos to us.
It would be very difficult to pick my favourite Hubble images, lots of such lists are out there for you to see as the telescope reached its quarter century in space this year. Right up there, though, would be the Deep Field images. The first was taken of the northern sky in the 90s and was solid evidence that the universe is pretty uniform over large distances. A follow up image was done in the southern hemisphere some years later and it looked broadly the same, showing that earth occupies are rather nondescript location in the universe. I’ve chosen to show the eXtreme Deep Field image taken in 2012 for no other reason than it is the most recent.
The original Deep Field image involved pointing the space telescope at a bland, not especially interesting spot in the sky and then letting it have a very long look at that spot. The exposure was crazy long. Days at a time. This allowed it to pick up photons from the most distant, oldest galaxies in the universe. The eXtreme Deep Field, above, is like the third generation of this picture. The exposure time was 23 solid days and that’s why there is such incredible detail to be seen.
So what are we actually looking at here and why is this one of the greatest achievements of mankind as I believe it to be? With the exception of a half dozen or so stars in the foreground, which you can spot as they have a sort of twinkle radiating out of them, every single light that you can see in this picture is a galaxy. Some of them are obviously so, they look like galaxies; but all the other objects too, every little speck of light is an entire galaxy. There are thousands of them just in this one picture, each one of them will have billions of stars. And all of this is just from one tiny, uninteresting patch of night sky. To give you a sense of how much sky we’re looking at I have included the picture below.
As you can see, we’re looking at a small fraction of 1% of the sky (remember, you can cover the entirety of the moon with an outstretched thumb) and yet there is all this stuff in it; several trillion stars. The mind boggles. The scale of the universe is staggering. There are those who believe that this entire edifice has been built for our gratification, that we are the only ‘people’ present in it and that we, in all this immensity, are special. Personally I don’t go for that. Leaving aside the absence of any evidence in the affirmative, I cannot accept that this universe was created, deliberately, just so we can run around killing each other on it, I’m not that self-absorbed. Whilst I acknowledge that that is an argument from personal incredulity I don’t think it is without merit, I just don’t think there is any omnipotent, omniscient being out there that cares about us. We are alone. Some people find that thought a scary one. I find it empowering. I know that it’s all up to me. If I want something I have to work to make it happen. There’s no one going to bail me out, there are no second chances. If I fail at something it’s because I wasn’t good enough, but equally if I succeed at something it’s because I earnt it. What could be more empowering, and liberating, than that?