Getting rid of Greenwich Mean Time

Have you actually seen it in person?

No, but I go by there every couple of weeks so I'm going to look for it, now.

Conservation Voice wrote:

Nobody that matters wrote:

Conservation Voice wrote: I'm not understanding what keeping atomic time and GMT have to do with each other.

GMT is basically where the time "starts" in the world, not how the time is kept.

It's fun going to the Greenwich Observatory though. They have the GMT line (Rose Line) in the courtyard and you can straddle it, standing in both hemispheres at the same time.

Without the leap seconds, they'll have to make the rose line mobile to allow for small fluctuations in the rotational speed of the earth. Couple of centuries from now and it could be somewhere out in Russia.

Not really. The Rose Line is for hours, not for seconds, NTM. GMT or CUT is the 0 hour.

The rose line represents where the sun is directly over at 0 hour. If the earth slows it's rotation by one second, either the line or the 0 hour needs to move. Leap seconds move the 0 hour. If we go with atomic clocks (meaning the 0 hour becomes inflexible) then the line must move in order for the sun to be directly over it at the now inflexible 0 hour.

Basically, somethings gotta give. Einstein would love this debate - which is relative, location or time?

Regardless of location, some of my relatives are never on time

Nobody that matters wrote: The rose line represents where the sun is directly over at 0 hour. If the earth slows it's rotation by one second, either the line or the 0 hour needs to move. Leap seconds move the 0 hour. If we go with atomic clocks (meaning the 0 hour becomes inflexible) then the line must move in order for the sun to be directly over it at the now inflexible 0 hour.

I don't think the line will be moving in the next 200 or 300 years.

even the Greenwich meridian itself is not quite what it used to be—defined by 'the centre of the transit instrument at the Observatory at Greenwich'. Although that instrument still survives in working order, it is no longer in use and now the meridian of origin of the world's longitude and time is not strictly defined in material form but from a statistical solution resulting from observations of all time-determination stations which the BIPM takes into account when co-ordinating the world's time signals. Nevertheless, the line in the old observatory's courtyard today differs no more than a few meters from that imaginary line which is now the Prime Meridian of the world."