Wood for Trees

click for the detail

I’m not a huge one for detail. Not that I don’t notice things; just that I’m more interested in the bigger picture and the human dynamic these days.

It turns out my psychometric profile (in the jargon) always has one big question in mind: 

Will this work?

So I’m mostly only interested in the details which guide the answer to that question: is this a good idea, is it do-able, are people likely to go for it, can I get my bit of it done?

That means I tend to want to break big problems down into smaller ones; ‘chunking up’ (also in the jargon). 

So what is murderous for me?  

Impractical idealists, detail-minded questioners and incessant talkers… I need time and space to think and I like people who take the time to listen – as my finest friend did this week.

As the old song goeseverybody’s talkin at me’ at the moment. But the good news is, I cope better with it these days than I once did. I’m better at seeing what matters; and what I just need live with.

Which brings me onto my remarkable factiod of this week – why is the night sky dark? 

If the universe is infinite and full of an infinite number of stars, the night sky should be saturated with starlight. But it isn’t…  Roger Barlow explains all on The Conversation

Imagine you are deep in a forest. All around you there are trees. Wherever you look, you are looking at a tree. Maybe a big tree close up or a bunch of small trees further away. 

Surely it should be the same with stars. We’re deep in the universe and whatever direction we look in, there ought to be stars there – billions and billions and billions of them. You would have thought that they’d fill the whole night sky, with the more distant ones fainter but more numerous.

The reason the night sky isn’t just a blaze of light is because the universe isn’t infinite and static. If it were, if the stars went on forever, and if they had been there forever in time, we would see a bright night sky. The fact that we don’t tells us something very fundamental about the universe we live in.

A limit to the universe may seem a natural explanation – if you were in a forest and you could see a gap in the trees, for example, you might surmise that you were near the edge. But it’s dark on all sides of us, which would mean not just that the universe is bounded, but that we’re in the middle of it, which is pretty implausible.

Alternatively, the universe could be limited in time, meaning that light from far-away stars hasn’t had time to reach us yet.

But actually the explanation is neither of these. Light from the far-away stars gets fainter because the universe is expanding.

Edwin Hubble discovered in 1929 that distant galaxies and stars are travelling away from us. He also found that the furthest galaxies are travelling away from us at the fastest rate – which does make sense: over the lifespan of the universe, faster galaxies will have travelled further.

And this affects how we see them. Light from these distant, fast-moving galaxies and stars is shifted to longer wavelengths by the Doppler effect. In the case of these stars, the effect shifts visible light into invisible (to the human eye) infra-red and radio waves, essentially making them disappear. 

The blackness of the night sky is direct evidence of an expanding universe.

Fascinating – a fine example of seeing the wood for the trees. 


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