Archive for the ‘Earth’ Tag

Of Daylight and Darkness   Leave a comment


Here in the United States, we’ve pulled the plug on Daylight Savings Time. Oh, we’ll get it back come March, but for now, we’re darkening the evenings and lighting up the mornings just a tad. Some of us head off to work in darkness and come home when the lights come on. There seems to be something wrong with lights out at 4:30 in the afternoon. Sunlight, that is.

There are plenty of stories and studies about how harmful this rearranging of the clock can be. Circadian rhythms lose their beat. People become grouchy from the loss of an hour. Productivity slacks off at work. Accidents increase. And so on. Can’t argue with it, really. Losing that hour’s sleep in spring means I’ll have one less hour to hide under the covers and face reality. But then again, it’s so wonderful to have that extra hour once a year. It’s almost a free invitation to sleep in or stay out a bit longer than you normally would’ve.

We’ve tinkered with the time since DST was enacted in this country in 1918, just over 100 years ago. During World War II we had it year-round to make better use of sunlight. In 1975 DST was enacted in January. I remember that because I was a school kid catching the bus in the dark. Weird. And recently we’ve expanded DST to begin the last weekend in March and end the first weekend in November.

As for me, I enjoy the longer summer days. That sun comes up plenty early for me at 5:30 am and sticks around until 8:30 – in New York. Some parts of the US get even more. If the sun came up at 4:30 and set at 7:30, without DST, I’d feel cheated somehow. The last thing I want to do is get up that early and not be able to enjoy the pleasant rays of light hone I come home from work. Of course, there are plenty of people, like farmers and early shift workers who’d enjoy the sun rising that early.

The sun’s rays reach us for longer periods of time because the the tilt of the earth’s axis. It’s just the way our planet is positioned as it travels around the sun. But if one lives at the equator, days are fairly equal all year around. At the poles, it’s all or nothing.

It’s been deliberated that DST should end, but I can’t see that ever happening. Too many of us enjoy the long summer days, even if there’s the inconvenience of losing an hour’s sleep once a year. It might take a couple of days to adjust, but at least it happens over a weekend when most of us can sleep.

All I know is when DST goes back to Eastern Standard Time, I’m a little sad, because it means the nights are creeping closer and the daylight is drawing thin. Sunlight’s a precious gem, to be appreciated when it’s given, for when it’s gone, it’s dark out there, folks! But once December 21 hits, it’s all uphill from there.

In the meantime, appreciate the moon. It shines its highest and brightest in winter. There’s nothing so glorious as to see it glisten on the snow. Or lighten the nighttime skies in the Caribbean, where one might be taking a vacation to skip out on winter.

Posted November 3, 2019 by seleneymoon in Seasons, The Sun

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Analemma Dilemma   1 comment


Afternoon analemma photo taken in 1998-1999 by Jack Fishburn in Murray Hill, NJ.  Bell Laboratories building in foreground

Have you ever noticed in the mornings, from about mid-December to around mid-January that the sun rises the same time every day?  Even though the time of the setting sun changes, the dawn keeps breaking at 7:21 am (or whatever time your sun happens to rise, depending upon where in the world you live).  It’s as if it’s stuck, needing an extra nudge to get it moving.    Once again, from about mid-June to mid-July, the same thing happens with the sun once more.

As illustrated in the photo above, this phenomena is called an analemma.  The Merriam-Webster dictionary defines it as, “a plot or graph of the position of the sun in the sky at a certain time of day (as noon) at one locale measured throughout the year that has the shape of a figure 8; also  :  a scale (as on a globe or sundial) based on such a plot that shows the sun’s position for each day of the year or that allows local mean time to be determined.”

So, if one were to take a picture of the sun at the same time every day, from exactly the same position, you’d more or less wind up with a figure 8.  It’s proof that the Earth’s axis is tilted at 23.439°.  However, the angle at which it’s seen changes wherever one is located on Earth.  The above was taken at roughly 40° north.  Here is a picture taken at Veszprem, Hungary, which is latitude 47°:


Image Credit & CopyrightTamas Ladanyi – Analemma 2011 – taken at 9:00 am 

So at 47°, the sun’s angle’s a bit sharper.

Here’s an excellent link from the Washington Post that illustrates how the sun moves in the sky through the months.

And who can forget the moon?  Since it rises and sets, it too creates its own analemma.  However, the moon rises 51 minutes later every day, so in order to successfully photograph it, one has to take that into account.  Understanding that means the moon returns to the same position 51 minutes later, in accordance to its rising.  Still, with patience, one can create an excellent example of what the moon can do, although one has to also remember it has phases.  That creates a wonderful variety of shapes.  Here’s an example:


Credit & Copyright: Rich Richins

Earth isn’t the only place where the analemma occurs.  Any planet where the sun shines also shares this perspective, although it’s teardrop shaped on Mars:


Digital Illustration Credit & Copyright: Dennis Mammana (Skyscapes)

Why the different shape?  Here’s the explanation from NASA:

“On planet Earth, an analemma is the figure-8 loop you get when you mark the position of the Sun at the same time each day throughout the year. But similarly marking the position of the Sun in the Martian sky would produce the simpler, stretched pear shape in this digital illustration, based on the Mars Pathfinder project’s famous Presidential Panorama view from the surface. The simulation shows the late afternoon Sun that would have been seen from the Sagan Memorial Station once every 30 Martian days (sols) beginning on Pathfinder’s Sol 24 (July 29, 1997). Slightly less bright, the simulated Sun is only about two thirds the size as seen from Earth, while the Martian dust, responsible for the reddish sky of Mars, also scatters some blue light around the solar disk.”

Each planet, given its north-south axis tilt and shape of its orbit, has its own analemma shape:

  • Mercury – nearly straight line
  • Venus – ellipse
  • Mars – teardrop (as illustrated above)
  • Jupiter – ellipse
  • Saturn – figure 8, but with tight northern loop
  • Uranus – figure 8
  • Neptune – figure 8

Let me add that you don’t necessarily need a camera to record the sun’s analemma.  Think back to the movie “Cast Away” wherein Tom Hanks marks on stone where the sun travels throughout the year.  You can make note by just looking out the window and the same time each day, seeing where the sun happens to be at the same time each day.  It’s pretty cool.  Try it!

Posted January 14, 2015 by seleneymoon in Moon, Nature, Planets, Sci-Fi, science fiction, The Sun

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