Specifically, a positive leap second is inserted between second of a chosen UTC calendar date and second of the following date.

The definition of UTC states that the last day of December and June are preferred, with the last day of March or September as second preference, and the last day of any other month as third preference.

Who is lea thompson dating video

Eventually, this definition too was found to be inadequate for precise time measurements, so in 1967, the SI second was again redefined as 9,192,631,770 periods of the radiation emitted by a caesium-133 atom in the transition between the two hyperfine levels of its ground state.

of the mean solar day as averaged between years 17.

The Tomatometer rating – based on the published opinions of hundreds of film and television critics – is a trusted measurement of movie and TV programming quality for millions of moviegoers.

It represents the percentage of professional critic reviews that are positive for a given film or television show.

All leap seconds (as of 2017) have been scheduled for either June 30 or December 31. On clocks that display local time tied to UTC, the leap second may be inserted at the end of some other hour (or half-hour or quarter-hour), depending on the local time zone.

A negative leap second would suppress second of the last day of a chosen month, so that second of that date would be followed immediately by second of the following date.

Therefore, if the UTC day were defined as precisely 86400 SI seconds, the UTC time-of-day would slowly drift apart from that of solar-based standards, such as Greenwich Mean Time (GMT) and its successor UT1.

The purpose of a leap second is to compensate for this drift, by occasionally scheduling some UTC days with 86401 or (in principle) 86399 SI seconds.

Do you wish you had a way to know — for sure — what’s real and what’s not? You'll be joining over 80,000 smart subscribers who every Wednesday, get the most important news, trends and scams to avoid. You’ll find lots of great free resources here on how to avoid the most popular scams, identity theft threats, and urban legends making the rounds. To the right, you'll find our most popular articles.

And if you're looking for a specific scam, you can use the Search tab at the top right side on every page.

However, for the past several centuries, the length of the mean solar day has been increasing by about 1.4–1.7 ms per century, depending on the averaging time.