January 2006 - Utah-Astronomy - mailman.xmission.com

Today's perihelion and global warming
by Canopus56 05 Jan '06

05 Jan '06

The near coincidence of the perihelion (the EarthÂs closest approach to the Sun) and the winter solstice reminds me of some recent conversations with one of my conservative relatives who listens to talk radio. We disagree on whether global warming is human caused or whether it is simply the result of natural climate cycles. To be clear, I am no global warming apologist. The human planetary chemical experiment of increasing CO2 levels 30% over a century and a half is the most likely cause IMHO, and the appropriate precautionary principle response would be a massive and expensive conversion to renewable energy and sustainable technology. But, some would say that global warming is caused by changes in the Earth's relationship to the Sun, invoking a form of the Milankovitch cycle. Thus, there is nothing that requires a response, since the change is Âall natural.Â << http://en.wikipedia.org/wiki/Milankovitch_cycles >> This was brought home to me today (and tomorrow) by the relative closeness of the Sun's perihelion to the winter solstice. In another book I am currently reading, the author states that the Sun's solar longitude moves by 1.7463 degrees every 100 years. So, about 5,200 years ago, perihelion would have coincided with spring (about 90 degs of solar longitude away from its current solar longitude), and about 10,000 years ago, at the end of the last ice age, perihelion would have coincided with summer solstice. The solar aphelion (the EarthÂs farthest passage from the Sun) would have coincided with the winter solstice. Again, although I believe in human chemical-based cause for global warming, the current position of the solar perihelion would seem to support the idea that global warming is a consequence, at least in part, of natural climate cycles. - Canopus56(Kurt) __________________________________________ Yahoo! DSL Â Something to write home about. Just $16.99/mo. or less. dsl.yahoo.com

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Satellite constellations
by Chuck Hards 05 Jan '06

05 Jan '06

A few Websites concerning satellite formations: http://www.technovelgy.com/ct/Science-Fiction-News.asp?NewsNum=95 http://spaceflightnow.com/news/n0007/04satformation/ http://www.spaps.com/autoback.htm I saw my particular constellation this morning within a few minutes of 6 am MST. __________________________________________ Yahoo! DSL Â Something to write home about. Just $16.99/mo. or less. dsl.yahoo.com

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Chuck hit the nail on the head (Today's perihelion and global warming)
by Dave Gary 05 Jan '06

05 Jan '06

For some compelling data to back up Chuck's statements take a look at this article: Science 25 November 2005: Vol. 310. no. 5752, pp. 1313 - 1317 Stable Carbon Cycle–Climate Relationship During the Late Pleistocene Urs Siegenthaler,1 Thomas F. Stocker,1* Eric Monnin,1 Dieter Lüthi,1 Jakob Schwander,1 Bernhard Stauffer,1 Dominique Raynaud,2 Jean-Marc Barnola,2 Hubertus Fischer,3 Valérie Masson-Delmotte,4 Jean Jouzel4 A record of atmospheric carbon dioxide (CO2) concentrations measured on the EPICA (European Project for Ice Coring in Antarctica) Dome Concordia ice core extends the Vostok CO2 record back to 650,000 years before the present (yr B.P.). Before 430,000 yr B.P., partial pressure of atmospheric CO2 lies within the range of 260 and 180 parts per million by volume. This range is almost 30% smaller than that of the last four glacial cycles; however, the apparent sensitivity between deuterium and CO2 remains stable throughout the six glacial cycles, suggesting that the relationship between CO2 and Antarctic climate remained rather constant over this interval. In other words, the increased CO2 levels we are recording today (with resultant increase in average global temperatures) are not part of some "normal" cycle.

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Re: Today's perihelion and global warming
by Chuck Hards 05 Jan '06

05 Jan '06

Ed Lunt stated a key part of the question. Undoubtedly earthly (and Martian) climate has extreme variations over time. Human collective memory- any kept human records, for that matter- are but the briefest eyeblink. For anyone to think that the climate we historically experience is some kind of natural state of "normalcy" is ridiculously naive. That said, if we are currently experiencing a natural cycle of global warming, it would be just as naive to think that man-made contributions are inconsequential. The evidence is there, in various forms, clearly showing a warming trend over the course of a single lifetime. The implications for the massive populations living in coastal regions are ominous, both in terms of shrinking coastlines and storm frequency and severity. Even relatively minor climate shifts can have serious repercussions in food production. Ecosystems are changing in ways we cannot always predict. It only makes sense to do everything in our power to not accellerate those changes. Even if examinined in purely ecconomic terms, it becomes clear that by ignoring man-made contributions to global warming for short-term ecconomic gain, it will cost vastly more in the long run. We have to think in terms of generations, not simply our own lifetime. The slower the climate changes, the less it affects our collective pocketbooks ("human misery" factor aside). Dismissing the man-made contributions completely is a case of "The Emperors New Clothes". Actually it's probably more simple than that, just plain old greed. "Leave no trace" is more than just a good camping policy. Especially since we have no idea what the "end state" of such change will be. --- Edward Lunt <lunco(a)yahoo.com> wrote: > I read somewhere, about two years ago, that the > polar ice caps on Mars were receding due to higher > temperatures on the planet. The suggestion was > that > if Mars was experiencing global warming, then > global > warming of the earth was in part, at least, to > natural causes. __________________________________________ Yahoo! DSL Â Something to write home about. Just $16.99/mo. or less. dsl.yahoo.com

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OT - James Cameron's "Aliens of the Deep"
by Ann House 04 Jan '06

04 Jan '06

I thought I would pass along my enjoyment of this 3-D movie. I love the ocean and thought this movie was just another documentary of strange critters that live deep in the sea. I had also heard that the 3-D technology was worth the visit (gone are the red and blue glasses). But it is more than that. A significant portion of the movie details NASA's planned nuclear-powered Jupiter Icy Moons Orbiter (JIMO) mission and the possible landing of a probe that would melt through Europa's surface to explore its subsurface ocean. The graphics are well done and it was a fun way to spend an hour. It is playing at Thanksgiving Point. -A

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Donation for SPOC?
by Patrick Wiggins 03 Jan '06

03 Jan '06

So, anyone care to buy this C-14 Schmidt camera and donate it to SPOC? :-) http://cgi.ebay.com/CELESTRON-14-F1-7-SCHMIDT-CAMERA-Telescope_W0QQitemZ757… Patrick

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Re: Jan 3 - Latest sunrise of the year was today (off list)
by Canopus56 03 Jan '06

03 Jan '06

--- Patrick Wiggins <paw(a)trilobyte.net> wrote: > Is my math off or should that have read 1/3 > _minute_? Thanks for catching that. The units in the ephemeris is minutes. It is 1/3 of a minute. > Patrick (aka: the picker of nits) Please, pick those nits or nit those picks, or whichever way it is, whenever you want. - Canopus56(Kurt) __________________________________________ Yahoo! DSL Â Something to write home about. Just $16.99/mo. or less. dsl.yahoo.com

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03 January 2004: What a day!
by Patrick Wiggins 03 Jan '06

03 Jan '06

Anyone here remember the goings on of this date two years ago? Reading through my journal I see that it was snowing heavily all day and I was doing a lot of shoveling. But, as you might expect, that's not what I'm talking about. It was two years ago today that MER A (aka Spirit) plopped, bounced and rolled to a stop on Mars. And then there was that agonizingly long several minutes when it seemed the craft had died... Augh! And then when everyone started applauding (and breathing) when the signal was reacquired. What a day! For those that might be interested our most excellent list master Cynthia still has all of the list's postings that day archived. Find them starting at: http://mailman.xmission.com/lurker/mindex/utah-astronomy@20040103.070000.00… BTW, channel 7 (KUED-TV) will be airing a program tonight starting at 8:00 entitled "What Went Right". It's about the MERs (there was a notice to that effect in this morning's News but it seems a problem at Qwest is keeping today's News in limbo until the problem is resolved). Patrick

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Jan 3 - Latest sunrise of the year was today
by Canopus56 03 Jan '06

03 Jan '06

Jan. 3 - latest sunrise was today (even though shortest day occured was 2 weeks ago. The Sun will reach perihelion, its closet distance to Earth, tomorrow, 1/4/2005, at approx. 18 UTC (11AM MDT). Even though the Sun is about 3 million kilometers closer to the Earth, the tilt of the Earth causes the Sun's rays to travel through more atmosphere, thus offseting the Sun's increased brightness. >From a geocentric perspective in Utah, the Sun transits and reaches its closest point at about 12:45 pm MDT. As compared to July 2006, the Sun's light takes about a 1/3 of second less to reach the Earth. - That's not counting the persistent cloud layer in the last 1000ft. -:) - Canopus56(Kurt) __________________________________________ Yahoo! DSL Â Something to write home about. Just $16.99/mo. or less. dsl.yahoo.com

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Rob Ratkowski on Spaceweather.com
by daniel turner 03 Jan '06

03 Jan '06

Rob Ratkowski has a nice picture on the spaceweather.com webpage today. Check it out. http://www.spaceweather.com/ DT __________________________________________ Yahoo! DSL Â Something to write home about. Just $16.99/mo. or less. dsl.yahoo.com

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