Search found 5 matches

by DonJones
Sat Nov 14, 2009 5:29 am
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Mayan Calendar - Era 2012 - Galactic Alignment
Replies: 84
Views: 15001

Re: Mayan Calendar - Era 2012 - Galactic Alignment

The calculations are more interesting if you compute not the absolute gravity force vectors, but the tidal forces. At least with tides you have a mechanism by which they might affect our planet or Solar System (and in fact, they do- in some cases measurably, even though the forces are still far too...
by DonJones
Sat Nov 14, 2009 5:02 am
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Mayan Calendar - Era 2012 - Galactic Alignment
Replies: 84
Views: 15001

Re: Mayan Calendar - Era 2012 - Galactic Alignment

Well, the false fears are more fun to play with because none of them are our fault. We tend to want to forget the ones we're to blame for. Hmm, That is an excellent point. Not only can one ignore real problems for which one also has some responsibility but one can also get very self righteous about...
by DonJones
Fri Nov 13, 2009 5:51 am
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Mayan Calendar - Era 2012 - Galactic Alignment
Replies: 84
Views: 15001

Re: Mayan Calendar - Era 2012 - Galactic Alignment

Galactic alignments, Planetary alignments, nearby asteroids real and imagined – OH MY! Once upon a time when I was still taking science classes (decades have passed – seems like a geological time scale), I tried my hand at figuring the comparative strength of gravitational vectors by the various wel...
by DonJones
Fri Nov 13, 2009 5:04 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: A Triple Sunrise Over Gdansk Bay (2009 Aug 04)
Replies: 338
Views: 53724

Re: Cause of Triple Sunrise (APOD 2009 August 4)

I have been enjoying this thread for about a day. For the ray tracers who have tried splitting a single ray – you have missed something. The only point the reflected ray and the directly transmitted ray have in common is the point of interception by eye or camera. I have a non-parallel double glazed...
by DonJones
Thu Nov 12, 2009 5:20 am
Forum: The Observation Deck: Latest Sky Photography
Topic: Multiple sunset
Replies: 2
Views: 651

Re: Multiple sunset

I spent over an hour looking at the first several pages of this thread. It seemed oddly familiar somehow. Then I went to bed and saw the double reflection of the red radio tower light some quarter mile from my relatively new double glazed window. I believe the window was manufactured somewhere near ...