You must have seen this picture before.
This picture was taken with the Hubble and it’s called the Hubble Ultra Deep Space picture. What I knew from a visit to the Griffith Observatory a couple years back was that this picture represents what happens when you hold a needle at an arm’s length towards the sky — the round tip of it would represent approximately the area of space that this picture covers — an impressive thought!
But here’s the whole story behind the picture. Now the first thing you might remember was that this picture was taken by the Hubble telescope, and that telescope seems to be a miracle in itself.
When Galileo first discovered the telescope, that instrument was barely two pieces of glass put together. When I say discover, I do mean discover, not invent – because the telescope per se was actually first introduced in Northen Europe for naval wars on ships. It quickly spread throughout the continent, from France to Italy, where Galileo Galile finally set his hand on it, and saw all the potential it could yield for astronomy.
Since then, humans struggled to make telescopes that could be increasingly more clear. You see, the images you used to get were very blurry, because the focal point for the different colors that were caught by the telescope varied from color to color. The effect was all the more accentuated as the telescope was short. So people started building ridiculeously long telescopes, measuring sometimes up to 45 meters, in order to get crisp pictures. But those telescopes were very approximate, and could be swung and lose their positions with the smallest gust of wind.
That is, until someone had the brilliant idea to create a telescope using two mirrors which would focalize the image without needing this much length. Many subsequent changes happen to make the process better. But all of them had the similar concept of the mirrors reflecting the ligth and directing it into an eye piece.
At that time, I think it must have been around the 1970s, astrophotogrpahy is born. Daguerre’s process to take a still picture of a life scene (which took hours of exposure — you can see the first picture ever taken and read about it in the previous article I wrote on photography), is suddenly recognized as being a perfect tool for astronomy, where long exposures are actually needed.
Now all this you may or may not have known but what I’m about to tell you is really marvelous and knowing the previous things helps us realize just what a little miracle the Hubble telescope is in the history of astronomy.
Following these first pictures like the one you saw before, the telescopes became bigger and bigger, the pictures became more and more sophisticated with colors, and the places humans were physically capable of putting all those installations in became higher and higher in desert mountains. The air in those places is very dry and the altitude, sometimes even higher than the clouds, allows for more crisp images as the athmosphere on earth distorts the data less and less.
And that’s when Hubble came in. One day, they had the idea to send a telescope into space, to escape all the issues of interference with earth’s athmosphere. Hubble was big, it was about the size of a schoolbus. Now they sent it up there and it was all very exciting, and the crew down on earth was impatiently waiting for the delivery of Hubble’s first pictures. What they got was a real shock to all the scientists – and put a lot of people – from astronomers to politicians who had founded the project – into deep trouble. Here’s what they saw. On the right is what they SHOULD have seen, and on the left, the picture they got.
In fact, Einstein himself, when he came up with his theory of relativity, knew that he was “wrong”. He knew that, if the universe was staying constant (which was the assumption back then) then his calculations were off. He countered that by a little variable, which I think he called Comsmic variable or something of the sort, to account for the “expanding force of the universe” — because if the mass of the universe at its center was big enough to pull everythign in towards its center, for the universe to stay still (although today we know it actually does more than just resist that gravity and stay still – it actually is growing and expanding), it had to have some force that would balance that gravity off. That force, he said, was neglectible on earth but added up throughout space, it really did have an incidence.
And so if Einstein’s theory was right and gravity was pulling things together, then with the mass we could see and estimate through spectroscopy (you look at special light emissions and decompose the spectrums to figure out which elements the body you’re observing is made of), the scientists could not explain why the universe was growing. According to gravity it should be slowing down after that big bang, maybe even leading to an implosion eventually as the gravity pulled back everything in the center.
That marked the discover of Dark Matter, this invisible mass in the sky that is currently the only thing the scientists can think of to explain the picture taken by Hubble.
“Either Dark Matter is this new physics phenomenon which we’ve been unaware of for a really long time”, a scientist explains, “and if it really does exist, it’s a very thrilling and exciting discovery we’re about to experience, or Dark Matter does not exist and Einstein was wrong – or maybe not entire right – and we will have to revisit our models and understand how to adapt them to better describe the reality, which is also a thrilling prospect. Either way, we’re on that treshold of an astronomical revolution.”
We live in exciting times! And all this started by a telescope, and its deep sky photography.