May 2011 Meeting Notes
Our business meeting this month included a discussion of preparations for our Astronomy Day Star party, information about our efforts to have a booth at this year's Sunfest, an update on our Skull Creek dark sky observing site, and a request for a volunteer to temporarily assume publicity coordinator responsibilities. After the business meeting, John Grismore gave a brief introduction to on-line club resources and Daryl Doughty gave an update on the upcoming quadruple planet conjunction in May. Our main program of the evening, titled "The Past and Future Habitability of Planet Earth," was presented by Virgil Reese.
Introduction to BAS On-Line Resources - John Grismore
Electronic communications and on-line information have transformed the way that almost all of us communicate and interact, and organizations like BAS have benefited significantly from this digital revolution. John gave a brief review of some of the on-line club information now available to members and other interested individuals.
The simplest way to find BAS information on the internet is to enter the phrase "bartlesville astronomy" into a search engine. At least for Google, doing so will return the BAS website home page at the top of the results list. Our website can also be reached by typing the web address below into a browser, or clicking the link directly.
The BAS website home page includes a brief summary of the club, an announcement of the next meeting and a list of future programs. The navigation column on the left side of the page has links for additional information, including Contact BAS, Join BAS, Newsletters, Notes, Observations, Hints Tips & Recommendations, Events, Files and Astro Links. The first two will be of interest to those wishing to Contact BAS or join the club. The Newsletter and Notes links provide several years of club newsletters and notes about club meetings and events. Observations is intended as a place for reports of astronomical observations made by members, and Hints, Tips & Recommendations includes helpful information for amateur astronomers of varying expertise. The Events section is a very tentative club calendar, and the Files section contains club related files for download.
Of particular interest may be the Astro Links page, which provides a list of external links in categories such as Bartlesville Astronomy, Sky Conditions, Weather, Tools, Astronomy Clubs, National Organizations, Astronomy Publications, Astronomy Blogs, Star Parties and Astro Travel, Observatories, Pro-Am Sites, and Vendors. This can be a good jumping off point for exploring the wider world of astronomy. One of links in the Bartlesville Astronomy category leads to our private, members only, BvilleAstro Yahoo Group. Since this forum is accessible only by invitation, it's a good place for more specific information, such as a centralized member list, club photos (many of recent meetings and events, thanks to Carroll) and a message area to allow members to ask questions of others and exchange ideas. It's also a good place for event planning. All BAS members are encouraged to join the BvilleAstro Yahoo Group.
At the meeting James Campbell agreed to serve as the coordinator for our club's on-line presence. In the brief time since then, he has already established a BAS Twitter account and a BAS Facebook page. You can follow BAS Tweets at @BvilleAstro and become a friend of BAS at <http://www.facebook.com/pages/Bartlesville-Astronomical-Society/186316818082958> (or search Facebook for "Bartlesville Astronomical Society").
Quadruple Conjunction in May - Daryl Doughty
Daryl reminded meeting attendees that an unusually tight conjunction of four planets will occur during the first half of May. Around May 11, Venus, Mercury, Jupiter and Mars will form the tightest grouping of planets so far in the 21st century. A nearly unobstructed view down to the eastern horizon will be necessary to see this "four planet dance", since the grouping will be only three or four degrees high about 30 minutes before sunrise. Daryl displayed star maps demonstrating the ever changing configuration of the planets over a period of several weeks, and showed some of his recent photos highlighting Jupiter and Venus as they begin their close approach. Members are encouraged to plan ahead to find a clear observing location for this rare and striking planetary gathering. To learn more about this celestial event, go to <http://www.skyandtelescope.com/observing/highlights/117347948.html>.
The Past and Future Habitability of Planet Earth
Speaker - Virgil Reese
How rare is life in the universe? How unique are the conditions that have permitted life to evolve and thrive on Earth? Virgil addressed these and many other issues in his fascinating discussion of the habitability of Earth. Beginning with a detailed evaluation of the conditions necessary for the emergence of life, Virgil discussed a wide range of important factors, including the host star type, the "Goldilocks Zone" where planets are at the right distance from their star to sustain liquid water on the surface, size and composition of the planet and its atmosphere, and even the importance of the tilt of the planet's rotational axis and the presence of a large orbiting moon. Slight variations in any of these factors could be enough to make a planet inhospitable to life. In addition, there appears to be a galactic habitable zone. Closer to the galactic center the increased density of stars and molecular clouds could result in chaotic conditions and dangerous high energy events and radiation bursts that could sterilize the surface of planets, preventing the development of life. Further out, beyond the galactic habitable zone, stars and planets may have formed from proto-stellar nebulae lacking in elements heavier than helium, which are necessary for life. Only within the galactic habitable zone would conditions favor the long term development of life.
In addition to these factors, Virgil emphasized the immense time required to evolve complex, intelligent life on Earth. Although simple single celled organisms appeared in the fossil record surprisingly early in Earth's history, it has only been relatively recently that complex, multicellular life appeared. And humans have occupied Earth for only the briefest moment of Earth's history. This could suggest that even if other planets in our galaxy meet all the criteria for habitability, the likelihood of all the conditions remaining stable and tightly constrained for billions of years may be small enough to make intelligent life extraordinarily rare or even unique to Earth.
Despite the billions of years of habitability on Earth, there are cosmic events that could change all that. Such future events could include asteroid or comet impacts, ballooning of the Sun into a red giant, close encounter of the solar system with a nearby star and gamma ray bursts. We are all familiar with the evidence that mass extinctions, including disappearance of the dinosaurs, might have been triggered by the collision of an asteroid with the Earth. The talk surveyed past extinctions, most of which are suspected to have been caused by large space object impacts, even though volcanism and a few other causes are still possibilities for some extinctions. Although there are currently no extinction level asteroid encounters predicted, we are still in the early stages of finding all the major Earth threatening asteroids. Developing the technology to detect and deflect such threats could one day become necessary to our survival.
Gamma ray bursts are the most luminous electromagnetic events in the universe. They occur when extraordinarily intense radiation is beamed momentarily (from microseconds up to about 40 seconds) along opposing axes of unusual supernova events. Although observed so far only in distant galaxies, it is believed that if such a gamma ray burst occurred within our Milky Way Galaxy, and aimed toward the Earth, it would lead to mass extinctions. The chance of such on event seems to be vanishingly small, but at our current level of technological development, detecting and surviving such a threat is difficult to imagine.
Pondering the past and future habitability of Earth is on the one hand, fascinating and thought provoking, and on the other, humbling. In summarizing the issue, Virgil emphasized the importance of not taking for granted the rare, and perhaps unique conditions that have allowed our home planet to evolve and support life. He suggested that our best strategy to help extend Earth’s habitability is to focus on anticipating and reducing any threats to the continued advancement of human civilization, especially the threats of global warming, population pressures, and declining energy and other key natural resources. And he argued that tackling these problems will require not just a continued commitment to basic and applied science, but a willingness to recognize the need for a science of actually improving human brains, along with continued efforts to improve civilization’s “collective brain”, which is a product of large scale human cooperation and collaboration.
Monday, June 6,
Mike Woods will show a DVD presentation by Neil deGrasse Tyson titled "The Greatest Story Ever Told."
in the Bartlesville Public Library Meeting Room,
synthesizes the greatest discoveries of physics, astrophysics, chemistry, and biology to present a coherent story of the birth and evolution of the cosmos.
For more information, see the meeting announcement on our website home page at <http://sites.google.com/site/bartlesvilleastronomyclub/> .
BAS Public Website: http://sites.google.com/site/bartlesvilleastronomyclub/
BAS Yahoo Group: http://tech.groups.yahoo.com/group/BvilleAstro/
If you want to have your email address removed from the Bartlesville Astronomical Society mailing list, please send an email requesting removal to email@example.com .