June 2011 Meeting Notes
This month's business meeting included a summary of recent events (Astronomy Day, Spring Star Party and Sunfest), a brief discussion about future events (July Meeting Program, Summer Star Party), an update on the status of our new Facebook and Twitter efforts, and a request for a volunteer to handle club publicity during the summer, while Carroll Ritchie is away. After the business meeting, Daryl Doughty presented a short "Introduction to Summer Constellations". The main program, introduced by Mike Woods, was a DVD lecture by Neil deGrasse Tyson, titled "The Greatest Story Ever Told".
Introduction to Summer Constellations - Daryl Doughty
Presenting the next in his on-going series, Daryl donned his "Astro Wizard" hat and introduced us to the Constellations of Summer.
Beginning at the heart of the Milky Way, he described Sagittarius, the archer (also recognized as a "teapot"), and Scorpius, the scorpion, both occupying the southeastern region of the sky as dark descends on early summer nights. These constellations frame the center of our galaxy and host an impressive concentration of celestial sights, including nebulae, open clusters, globular clusters and galactic dust lanes. Nestled between these two constellations, not far from the position of the actual center of the Milky Way, are two striking open clusters, cataloged by Messier as M6 (the Butterfly Cluster) and M7 (Ptolemy's Cluster). South of these, peeking just a few degrees above the southern horizon later in summer, is Omega Centauri, one of the nearest, largest and most outstanding globular clusters in our skies. Travel to south Texas, or further south would probably be required to fully appreciate or photograph the grandeur of this object.
Moving further north along the pale white glow of the Milky Way brings us to three bright stars in a distinctive asterism. Altair in the constellation Aquila (the Eagle), Deneb in the constellation Cygnus (the Swan or the Northern Cross) and Vega in the constellation Lyra (the Lyre) form a large triangle known as the "Summer Triangle". Daryl pointed out that in the past, before GPS satellites, this was also known as the "Navigator's Triangle", serving as an important guide for navigators and pilots.
At the opposite end of Cygnus from Deneb is a colorful double star named Albireo, composed of a 3rd magnitude yellow star and a 5th magnitude blue star. The two are well separated in a telescope with low power, and their colors are obvious and delightful. Between the southern most pair of stars forming the parallelogram of Lyra is M57, a planetary nebula named "The Ring Nebula". A telescope will reveal it to be a small, donut shaped cloud of glowing gas and dust left over from the explosion of a central star. Daryl displayed one of his own astrophotos to highlight its location within the constellation. Also in Lyra is Epsilon Lyrae, a "double double". This star is a double which is easily separated by modest amateur telescopes. But each star of this double is itself a very close double star, which is more challenging to split into separate components.
Moving even further north, Daryl pointed out Ursa Major (usually seen as the Big Dipper) and Ursa Minor (the Little Dipper). Between the head of Ursa Major and the handle of the Little Dipper are M81 and M82, two large spiral galaxies about 12 million light years away, currently undergoing gravitational interaction. The middle star in the handle of the Big Dipper is a widely spaced double, named Mizar and Alcor. With good eyes and clear skies, this can be seen as two separate stars. Legend has it that this was used as an eye test for Roman soldiers. Positioned at the end of the handle of the Little Dipper is Polaris, the North Star. Because the Earth's axis points very near to this star, the rest of the sky appears to spin around it as the Earth rotates.
Regardless of your preferred star gazing method, naked eye, binoculars or telescope, the Summer Constellations offer many of the best views in the entire sky. Don't let the season slip by without appreciating the beauty of the night sky.
The Greatest Story Ever Told - A DVD Lecture by Professor Neil deGrasse Tyson
Our June program, provided and introduced by Mike Woods, was a DVD video lecture by astrophysicist, popular science communicator and Director of Hayden Planetarium, Neil deGrasse Tyson. Synthesizing the most important discoveries in physics, astrophysics, chemistry and biology, Tyson presented a coherent story of the birth and evolution of the cosmos from the first ten million, trillion, trillion, trillionth (10^-43) of a second after the Big Bang to present day. During that immense span of time, and the equally unimaginable transformation of physical conditions, a series of extraordinary milestones occurred.
At the earliest times (prior to 10^-43 second) the cosmos is assumed to have been a homogeneous, symmetrical "cosmic foam" of unimaginably high energy and density. Based partly on speculation, it is thought that the first event in this sequence of milestones was the separation of gravity as a force independent from the previously unified forces, by a process often described as a sort of phase transition. Shortly thereafter, the strong force, which is the force that binds protons and neutrons together in atomic nuclei, separated from the remaining unified forces. At 10^-36 second, triggered by the energy released by this second symmetry breaking phase transition, "cosmic inflation" is believed to have expanded the size of the universe by a factor of perhaps a trillion, trillion times in less than 100 million, trillion, trillionths of a second. From the end of this inflationary period, until about one 100 thousandth of a second is believed to have been an era of high energy photons and a sea of sizzling quarks. During this era, the separation of the nuclear weak force and the electromagnetic force resulted in the four forces known today. By about one millionth of a second after the Big Bang, the temperature of the universe had cooled enough that quarks could bind together to form protons and neutrons, setting the stage for the eventual creation of atomic nuclei.
For the next 380,000 years the universe was made up of hot photons, electrons, protons and neutrons, constantly interacting with each other. But, by this time, the temperature had dropped to about 3000 degrees Kelvin, allowing electrons to join with atomic nuclei to form stable, neutral atoms. With the disappearance of the opaque fog of free electrons, the universe suddenly became transparent to photons, revealing what we now observe as the Cosmic Background Radiation (CMB). Measurements of very small deviations in the CMB in different directions have provided much of the information that has allowed as to make intelligent assumptions and predictions about the earlier history of the cosmos.
By this time, the milestone changes in the universe slowed down and the overall structure that we now observe proceeded in a hierarchical progression. During the period of 150 million to 500 million years after the Big Bang, the first stars and quasars (active galaxy nuclei) formed. Since the only elements created by the nucleosynthesis of the early universe were hydrogen, helium and a small amount of lithium, the first generation of stars were fueled only by the fusion of these two elements. But these massive stars burned out quickly, forming new and heavier elements in their cores. When they reached the end of their life cycle and exploded as supernovae, they dispersed this complex mixture, including the elements of life, to eventually be incorporated into a second generation of stars. These second generation stars formed from a debris cloud with enough heavy elements to create planets, and ultimately, at least once, life. The hierarchy progressed successively from stars to galaxies, to groups of galaxies, then galaxy clusters and even superclusters of galaxies.
About 5 billion years ago our own Sun formed, followed half a billion years later by the accretion of the Earth. At first molten hot from continual bombardment by asteroids and planetesimals crowding the inner solar system, Earth eventually cooled, water appeared (possibly delivered in part by incoming comets) and oceans formed. Within a billion years of the formation of Earth, single celled organisms had appeared in the oceans. They processed carbon dioxide, producing energy for metabolism and reproduction, and released oxygen as a waste product. The free oxygen accumulating in the atmosphere eventually rose to toxic levels, wiping out a huge portion of Earth's anaerobic life. At the same time, the increased oxygen levels opened new opportunities for biological diversification by significantly increasing the free energy available to organisms capable of metabolizing oxygen. Over billions of years this led to the evolution of animals, primates and ultimately, humans.
Tyson speculated that perhaps, just perhaps, this grand progression from the incomprehensible kernel that formed the Big Bang, to modern day humans, with telescopes, supercomputers and robotic spacecraft, represents the universe striving to know itself.
Tuesday, July 5,
James Campbell will present "Dither and Drizzle for Astrophotos".
in the Bartlesville Public Library Meeting Room,
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/
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