h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

In post 27 I said "Noon is early now (long evening, short morning); after Dec 21 it will get late."

That's not it. Noon is early now, *short* evening, *long* morning. It is swiftly approaching the average noon time (12.25 GMT in Dublin) and will run later as the new year comes in, steadying to about 12.41 before turning back around the end of January; making the evenings take a spurt of lengthening from now on, particularly as we get closest to Dec 21 and the motion of the noon-locus approaches its most orthogonal to the meridian.

Am I wrong to expect the shortening of the day to be most pronounced at this time, what with the low angle of the sun's path over the horizon? Has anyone worked out the maths for shortening day vs. lengthening evening?

Would a joke from the joke thread a few weeks back bear repetition?
Why do mathematicians tend to confuse Hallowe'en with Christmas? Because oct 31 = dec 25 (true).

By the way the pastry hat was quite tasty, though it could have done with a little salt. But I know better than to take the Gnomic pronouncements with a pinch of salt now . . .

I learned this from a boss I used to have, who specialised in ludicrous pronouncements that happen to be true:

Distilled water is one of the most corrosive substances known to man!

When driving on ice, you should use as high a gear as possible!

and so on.

More! More! I believe you!

Put it to a vote...how many think this conversation should be compressed into an entry somehow?

I vote aye.
-MotDoc

F/b

I take it that also encompasses your willingness to write the entry, then, MotDoc?

B

Grey Woodpigeon of Ithilien came up with most of the astronomy . . . and has the astronomy software. Coo! Go for it.

Yes, I thought so earlier (post 26). Can I vote twice?

But Woodpigeon is busy looking after his newly arrived twins (arrived the 17th), so he has his hands full.

I'll take credit for editing it, although my actual writing contribution wasn't that great. Give me a few days to compile everything you blokes have been putting out there.
-MotDoc

Blokes???????


F/b

Yes please! I would appreciate a comprehensive entry, although the link www.analemma given above would be hard to beat - especially as the animations can't easily be reproduced here.

I went to look for a table of sunset and sunrise times and found more very interesting and well-illustrated versions of the story. Got involved reading them and forgot to look for the timetable. Our perception of sunrise and sunset is difficult at this time of year when sometimes it's so dull it's hard to believe that the sun has risen at all - even by lunchtime.

And don't forget to mention the lovely sunsets that Zarquon's saw - we have been having some beautiful ones here, too, lately. Is the redness and (at least subjective) lengthiness of these sunsets also due to the angle of the sun?

As I recall, the redness of the sun is a factor both of the angle of the sun to the horizon and the relative thickness of the atmosphere which blocks light rays of lower frequencies. I have no idea what might cause sunsets to appear longer, although that might be a factor of the general haziness which diffuses the light more. On the other hand, sunsets in New Mexico, which is known for its dryness, are also spectacular. I can't remember how long they were since I haven't visited in 5 years.
Oh, and F/b I regret having referred to you as a bloke when it is clear that you are actually a chick.
-MotDoc (working on the editing at this very moment)

And neither TC or I are blokes either!

Not that I claim any great contribution!

I like to discredit my own contribution (whatever that may have been), having a fairly heavy project on my hands for the time being.

B

Apology accepted MotDoc Nobody's called me a chick in years!

More like up here in Scottishland...


Frenchbean

Elsewhere on BBCi there has been mention of this phenomenon
http://www.bbc.co.uk/weather/features/winter_solstice.shtml
and for a rather lovely photo of the analemma taken in Greece see
http://antwrp.gsfc.nasa.gov/apod/ap030320.html

That's a cool picture of the analemma at Delphi!