The reality of what we cannot see

What is the true nature of the  universe in which we live? As we all try to make sense of the physical universe that is around us, we are limited by what we can actually see, or detect with instruments. We are also limited by what our brains and eyes are able to decode.

If you remember from previous posts, astronomers are looking further and further out in space with stronger and stronger optical and radio telescopes. They are trying to map the whole universe in 3d. That is, they are mapping what we can actually detect and see of our universe.

There is however a physical limit to how far we can see. Our laws of physics say we cannot see all of it. We can only see light, and light travels at a certain speed. So as we look further and further out we are looking back in time. There is only so far we can go back in time, so there is only so far we can see. What we can see is known as the observable universe.  It is as if we are enclosed in a bubble, there may be much more out there, an  infinite universe has been suggested, or there may be nothing at all. Only time will tell!!

I watched a science program (Horizon BBC) recently that explained this all very nicely. The big question that sprung to my  mind was, what else could be there in our universe, that we simply cannot see?

Detection of the invisible

One of the only ways we can begin to detect what we cannot see is in the areas where our known laws of physics seem to break down.  Gravity is apparently not strong enough to do the job it seems to do in holding our 3D universe together. Thus they came to the concept of dark matter between all heavenly objects, which helps explain our stability. It even seems to be responsible for 5/6th of the matter in the universe.  How do they know this exists and that our laws of physics are not just wrong?

A very nice American scientist intimated that it is detectable by the distortions it creates when  looking at the universe we can see. He gave the example of a photographing an object underwater. The image is distorted by the water, but by the distortions we know that the water exists. Thus they know that dark matter exists.

The only problem with this was that the dark matter was supposed to be holding the universe together. The post big bang expansion of the universe was being slowed down. In fact, they now understand that every object in the universe is moving away from every other object at faster and faster speed. The concept of dark energy, a force unknown and  undetectable but pulling the universe apart, was thus conceived to explain this.

The whole story?

As ever, I have to ask if this is the whole story?  Where next do our rules of physics break down, and what other  undetectable concepts will arise to fill the gaps. I am not anti science but I do not think we are anywhere near the real story of our universe, even the bits we can see.

Aspects of reality

What else does science not know? What else is around us that we cannot see?






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