Thinking - Gravity

Space is a funny thing.

I keep thinking I don't have enough of it on my desk, but that doesn't really tell the entire story.

The world really is an unlikely place.

Take this for example....

If you put something really, really flat, and I mean flat, not earth flat... so say an imaginary flat billiard table...put an imaginary flat billiard table on earth. A really really big imaginary flat billiard table.

Now throw a ball on it.

It will roll around and around like something going down a drain until it settles in the middle.

At the lowest point.

The lowest point of a flat thing.

See. That's just silly.

But that's what would happen. When seen in 2D like my expert drawing, a flat thing would actually make a valley on earth. The sides of the flat thing would be the top of mountains.

If we strike out at 90 degrees from my 2D drawing, and consider it in 3D, it would form a crater with the centre being the lowest point.

So when you throw a ball into the picture, a ball... a ball on earth, would experience a perfectly smooth crater with the centre forming the lowest point, and the edges of the billiard table forming the rim. I was going to say "a perfectly smooth rectangular crater", but I'm not sure it would still be a rectangle.

I'm not sure of anything any more.

Similarly silly is what would happen if you drilled a perfectly straight hole through the earth's crust.

If you drilled an imaginary perfectly straight hole through the Earth's crust and threw a ball into it, it would eventually settle out somewhere around point C.

At the lowest point.

An imaginary straight tunnel, is really (whatever "really" means) an arc shaped tunnel.

Or at least it is as far as a ball is concerned.

Or a person.

If you entered the tunnel at point A, you would be entering a tunnel cut into the earth at say 35 degrees.

A steep decent.

But point C is the lowest point, so after passing point C, you would be climbing again. I think that means that points B and D would be a gentle slope compared with points A and E.

Personally I think this example makes a lot more sense than the previous one, but that might be simply because I'm getting the hang of it, or it could be because I used some letters of the alphabet.

There's nothing like the familiar to sooth the nerves.

But turn your back on the universe for even a second, and space gets all curved and confusing.

120 Things in 20 years - Thinking gravity? Think perfectly flat billiard valleys.


  1. The tunnel example is brilliant. I don't think I could have figured out what you meant without that. The "flat thing" bit doesn't make sense until you imagine what it would look like to be on the Earth looking up at the flat thing. Then suddenly I see what you mean about the sides being like mountains. Because from where we are, the Earth looks flat, so in comparison, the flat thing would look curved. Which hurts my brain.


  2. It's kooky isn't it.

    But keep in mind I may well be totally wrong :)

    1. At least, if you're wrong, you're *impressively* wrong.

  3. I'll settle for *impressively* wrong. Every time:)


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