schoolme_straying t1_jeg658f wrote on March 31, 2023 at 7:46 PM

Reply to comment by SpiralSuitcase in ELI5: Is there a time difference everywhere? by squidwards_noze

> The earth spins at a ~~constant~~ rate,

Constant-ish rate.

Great American Gladys West developed her model of the world to take into account variations in the earth's spin to ensure that sat nav is accurate.

SpiralSuitcase t1_jeg7x0s wrote on March 31, 2023 at 7:58 PM

How much does the rotation of the earth vary, and is it significant enough to warrant this detour in an explanation to a 5-year-old?

schoolme_straying t1_jegno5c wrote on March 31, 2023 at 9:45 PM

> How much does the rotation of the earth vary, and is it significant enough to warrant this detour in an explanation to a 5-year-old?

ELI5 is not for actual 5 year olds. It's for an intelligent layperson.

Day length fluctuations explains all in a depth that is beyond me.

When I went with my son to Greenwich observatory on the River Thames, London.

We looked at our GPS co-ordinates we found that the zero meridian was 100m or so further east than the observatory. This was explained as being caused by the earth slowing more than anticipate and so the 0° meridian moves further east.

Every so often there is a leap second when this occurs the GPS data resets the zero meridian back to the observatory

SpiralSuitcase t1_jegp2uc wrote on March 31, 2023 at 9:55 PM

So answer the question I was obviously asking.

schoolme_straying t1_jegruqf wrote on March 31, 2023 at 10:15 PM

Not sure exactly what you are asking - could you rephrase it for me?

SpiralSuitcase t1_jegtvpw wrote on March 31, 2023 at 10:30 PM

You explained that ELI5 isn't literal. But I was clearly asking if the clarification you're making is necessary within this kind of explanation. Was my technical inaccuracy negatively impacting the explanation I gave in any way?

schoolme_straying t1_jegvrxz wrote on March 31, 2023 at 10:44 PM

We're that far down in the weeds nobody is interested in our conversation

I think the idea that the time the earth takes to rotate 360° varies and is thus not constant is important and it has consequences that are verifiable to anyone with a mobile phone and GPS.

In terms of science etc I think the idea of a constant should only be used for things that do not change. IE π e and the speed of light in a vacuum.

Obviously I thought it was important or I wouldn't have mentioned it.

As a distraction here's a man in the 1970s with a GPS wondering about the implications of a better organised society

SpiralSuitcase t1_jegvypo wrote on March 31, 2023 at 10:46 PM

Your response was to my TOP LEVEL COMMENT.

But I also want to make it clear that I am also part of the nobody that is interested in this conversation.

ETA: actually, that wasn't clear at all. I am not interested in this conversation and I think your correction is absolutely unnecessary.

schoolme_straying t1_jegx62f wrote on March 31, 2023 at 10:55 PM

I thought my comment was warranted. You didn't. Fine. Good people may agree to differ.