How long is Earth's day? We now have the most precise answer to date

[Admin]

A laser gyroscope at an underground lab in Germany has detected the minute variations in Earth's rotation, an advance that may help scientists build better climate models.

How long is Earth's day? We now have the most precise answer to date : Read more

 

[smort058]

So what is the answer? Your article says we now have the most precise answer to date, but you don't say what it is.

 

[billslugg]

It cannot measure the length of the day. This device only measures changes in the rotation rate.

 

[Meteoric Marmot]

So what is the answer? Your article says we now have the most precise answer to date, but you don't say what it is.

The answer is "it varies" for the reasons spelled out in the article.

The "day" the article talks about is known as a "sidereal" day which means how long it takes the Earth to perform one rotation relative to an observer at infinite distance. In practical terms, this means one of the further stars.

Just to inject some confusion, a different "day" is the solar day which is how long it takes the Earth to make one rotation relative to the sun . This varies by several minutes throughout the year because the Earth's orbit is elliptical, not circular.

 

[frtillman]

So what is the answer? Your article says we now have the most precise answer to date, but you don't say what it is.

The answer is no matter what occurence causes lengthening OR shortening of the daym The setting of the SUN is the marker that designates when a da y ends and begins,