Follow Slashdot blog updates by subscribing to our blog RSS feed

 



Forgot your password?
typodupeerror
×

Comment Re:Back to the 60s (Score 1) 70

Well, for starters, what hemisphere they're in. However, that isn't the point. To me, the tone of the ancestral post wasn't east vs west, but foreign vs domestic:

In the '60s we had enough workforce and disposable income to build rockets with western engineers right here and do it right.

Well, some of those "western engineers" weren't from "right here" and weren't part of "we".

Comment Re:An adjunct proposition (Score 1) 300

Tablets are an alternative to paper, but they are far from a practical alternative. You can't fold them up and put them in your pocket. You have to continually charge them to use them. You can't use them in cold weather. It's prohibitively expensive to give tablets away as promotional material. They don't make good bookmarks.

Comment Re:Fix NTP (Score 1) 289

Of course it would be a lot easier if the astronomers would let us know a few years in advance rather than six months, but then the offset between TAI and UTC could exceed 0.9 seconds, and as we all know that would bring Ragnarok.

Predicting earthquakes, land slides, massive storms, icebergs, and other events that alter the rate of rotation of the Earth by looking at the stars is a job for astrologers, not astronomers. Also, by definition, TAI and UTC differ by an integral number of seconds, and they currently differ by 35 seconds - far more than your battle inducing 0.9 second threshold.

There are three important time systems in play here. TAI, UT1 and UTC. TAI is a count of SI seconds based on atomic clocks situated around the world. UT1 is the count of "solar" seconds based on the angle of the Sun to the Prime Meridian. Because it is based on the rotation of the Earth, which can vary for a multitude of reasons (earthquakes, icebergs, etc), UT1 "seconds" are variable in length, However, unlike TAI there will always be exactly 86400 seconds in a day.

UTC is a compromise time scale. It uses SI seconds, like TAI, but there are occasional adjustments made so that it remains synchronized to within one second of UT1. These adjustments come in the form of leap seconds (or skip seconds).

The International Earth Rotation and Reference Systems Service (IERS) has the responsibility of adjusting UTC. The last minute of the last day of the month can be lengthened or shortened by one second in order to keep UTC and UT1 in step. By agreement, the first preference is to adjust in June or December. The second preference is to adjust in March or September. So far, there has been no need to adjust using a skip second, or to adjust in any month other than June or December.

Comment Re:Earth not _turning_ slower, but already is slow (Score 1) 289

There are regular intervals at which leap seconds *CAN* be applied (The last day of March, June, September and December may be one second longer or shorter than other days). However, leap seconds and skip seconds are not always applied. They are irregular because the turning of the Earth is irregular.

Slashdot Top Deals

We are each entitled to our own opinion, but no one is entitled to his own facts. -- Patrick Moynihan

Working...