Reflections on reflections

My four-year old niece from Otago phoned her grandmother in Bay of Plenty:

"Grandma, do you have reflections in the North Island?"

"I think so dear, why?"

"Well, find a spoon and have a look."

Now, I think it most likely that niece was intruiged by the right-way-up / upside-down reflections from the convex and concave faces of the spoon, but she has also hit on an important issue in physics: are the laws of physics the same everywhere (and everywhen)?

While it is amusing to imagine that in one corner of a remote paddock out beyond Te Kuiti there is patch of zero gravity, my experience tells me that the truth is rather more boring – gravity, and the rest of physics, remains the same everywhere on Earth you go.

Is that true also in far-flung corners of the universe? Maybe, in a galaxy far, far away, there are some differences in the laws of physics from what we experience here. This is something that has been studied; for example astronomers have looked at the spectrum of light arriving from distant quasars to determine whether the ratio of the masses of the proton and electron are the same there as they are here. Of course when you look into the distant regions of the universe, you are also looking back in time, since the light takes so long to reach us. That means the question of ‘where’ cannot be separated from the question of ‘when’, but that is another issue.

So, did they find any differences between here and there?

Regrettably for the sci-fi authors, the answer appears to be no. But, if some day you do happen to come across a herd of cows hovering three metres above their paddock, do give me a call.

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