Thursday, January 1, 2015

Waiting for the perihelion

January 1st is an odd day to start a new year. While the importance of time is a human conceit,its divisions are based on the natural world, a world too few see anymore.

Every night the starry sky shifts about a degree. (Degree is another word losing its meaning when few folks play with tangents and secants--we have machines have all the fun nowadays.)

In about a year's time, our closest star returns to where we last left it 365 days ago.

The Earth's rotation is (on average) slowing down while humans keep speeding up. A day used to be exactly 86,400 seconds, and still is, so long as you define seconds as 1/86400 of the time it takes the Earth to make a complete rotation (relative to the sun's position in our sky).

With atomic time, a second as defined today will be the same length as a second defined a billion years from now. How long will a day be then?

Depends--if we keep the astronomical definition, a day will still be 86,400 seconds. If the Earth is slowing down enough to add about an average of a 20 millionths of a second to a day each year, then we'll have over 5 more hours to get a days work done in a billion years.

In just three days, Earth will be as close to the sun as it gets in a year. This is a big deal (to three or four of us, anyway). Why not slide the new year to something of more import than some Roman two-faced god? Better yet, why not slide it back 10 days to the winter solstice, when our unconquerable sun starts its return journey to its place high in the sky?


Brian Bennett said...

...and in three days, we'll still have people baffled about why we're cold if we're as close to the sun as we'll get this year.

Thanks for fighting the good fight year after year. I'm looking forward to 2015.

doyle said...

Dear Brian,

Hey, it's all we can do.
Happy New Year!

Kate said...

Hey, it's important to at least five of us.

doyle said...

Dear Kate,

If we can recruit one or two more (are you listening, Frank Noschese?), we could start a movement!