Van Morrison, Newton and Einstein

Enlightenment, don’t know what it is“; so says van Morrison. But what about ‘understanding’? Well, just the other day I was taking to my son…


Be careful there, Leo, you might fall.

Dad, how come if I step off this wall, I’ll fall to the ground?

That’s because of gravity, son.

What’s gravity?

Well, all objects attract each other. So when you step off the wall, the earth and you attract each other and you actually accelerate towards the ground. If the wall is very high you’ll accelerate to quite a high speed so you’ll hit the ground with a bit of a bump.

Ok, but how does the earth actually attract me?

Well, that’s a tricky one. A great scientist named Isaac Newton was able to describe exactly what happens when two objects attract each other. For example he said that the heavier each object is, the stronger the attraction will be, and the further away the objects are from each other, the weaker the attraction will be. He was right but he didn’t really say what gravity actually is.

So we still don’t  know what really happens when two objects attract each other?

We do actually. Albert Einstein came up with the idea that when two objects come close to each other, it’s a bit like what happens when two people are sleeping on a soft mattress. They both make a big dip in the mattress and they end up rolling towards each other. Einstein said that space is a bit like the soft mattress and objects make dips in space that cause them to roll towards each other.

But space is nothing!

I know, it’s weird, isn’t it.

Do you really understand it all, Dad?

I do and I don’t. Understanding is a bit like an onion; you know the way you can peel an onion apart, layer by layer? So somebody who has very little understanding might only have one layer of knowledge; like me telling you that if you step off the wall you’ll fall because of gravity. Somebody with a bit more ‘understanding’ might remember some stuff about Isaac Newton and seem a bit cleverer to you. Somebody else might have seen a science programme on TV  and learned all about Albert Einstein and his theory of gravity, and that will make them seem that they understand things even better. But in the end most of us run out of layers of knowledge and at that point we say we don’t understand something.

So the mattress is the end of the story?

It is for me, I’m afraid!


About Greg Foley

A lecturer in Biotechnology in Dublin City University for more than 25 years. Trained as a Chemical Engineer in UCD (BE and PhD) and Cornell (MS). Does research on analysis and design of membrane filtration systems.
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