My Impressions of the 27th IAU General Assembly
August 03 -14, 2009, Rio de Janeiro, Brazil The International Astronomical Union (IAU) was founded in 1919. Its mission is to promote and safeguard the science of astronomy in all its aspects through international cooperation. Its individual members are professional astronomers from all over the world, at the Ph.D. level and beyond, and active in professional research and education in astronomy. The IAU has 10145 members in 90 countries worldwide. The IAU General Assembly (GA) meeting takes place once in every three years in different countries at the invitation of the host country. The next IAU General Assembly will take place at Beijing, China in 2012. Approximately 3000 Astronomers from all over the world attended the GA at Rio.
The year 2009 was declared as the Year of Astronomy to coincide with the 400th anniversary of the invention of telescope which gave birth to modern Astronomy. One of the IAU objectives for the 2009 is to organize global efforts in Astronomy Education and public understanding of importance of Astronomy in the context of human culture. A strategic plan for enhancing Astronomy Education in the developing world was created for this purpose. The strategic plan was a major topic of discussion in the GA at Rio and had several meetings dealing with building Astronomy infrastructure in the developing world. A "Global Development Office" was created for this purpose. The US National Virtual Observatory will provide the non-proprietary data and software resources to Astronomers all over the world for research and instructional purposes through the Global Development Office. We intend to investigate the possibilities of using this resource for instructional and research purposes at Capitol College. Another important issue discussed at Rio was the gender balance among the Astronomy professionals around the globe. A commission dedicated to enhancing the gender balance has been active in this area during the year.
There were many concurrent sessions on recent advancements in different sub fields of Astronomy. There were also administrative sessions for various Commissions. Being a member, I attended the meetings for Commissions 27 and 42 for Variable Stars and Close Binary Stars, respectively. In Commission 27 meetings, a major area of debate was how to define and classify a variable star. In the recent years all stars, including the sun have been found to vary. The question was what distinguishes a "variable" from any other star. The question remained unresolved until more inputs are obtained. There were also invited review lectures on subjects where major advances were made during the last three years.
One of the major advances of modern astronomy within the last decade is the definitive determination of the "Hubble Constant" which is related to the expansion of the Universe and ultimately to the age of the Universe. The collaborative work of Wendy Freedman, Robert Kennicut and Jeremy Mould was critical to the determination of the value of the Hubble Constant at 72.2 km/s/mpc, which translates into the age of the Universe to be 13.7 billion years. For their work, the team was awarded the prestigious Gruber Foundation Cosmology Prize.
A large number of sessions were devoted to Extragalactic Astronomy and cosmological implications of observations of extremely faint far galaxies made with large telescopes on the ground and observatories in space. Cosmology has been put in firm observational foundation with these observations. It is now universally accepted that the familiar matter only constitutes four percent of the content of the universe. Approximately 20 percent of the content of the universe is "dark matter." That leaves more than three fourth of all content of the universe unaccounted for. This "dark energy" is unlike anything that present day science understands. It exerts a repulsive force that makes the universe expand with accelerated speed. These issues were of much interest to many of the attendees at Rio.
Extra-solar planetary systems were also a major topic of interest. As the technology of the detection systems improved, the number of detected extra-solar planetary systems also increased significantly. There are now 375 planets detected in stellar systems other than the sun. Associated with the detection of planets is the question of which ones may have liquid water, a major requirement for life (as we know it) to exist. A review lecture titled "Water on Planets", discussed the conditions required for water to exist on a planet’s surface.
Last Semester, Capitol College hosted Dr. Mark Sykes of Planetary Science Institute in Tucson, AZ. In his talk he discussed the controversy about calling "Pluto" a planet. In 2006, during the 26th General Assembly in Prague, the IAU decided that Pluto will be called a "Dwarf Planet." In March 2009, European Southern Observatory's Very
Large Telescope revealed unexpected amounts of methane in Pluto’s lower atmosphere. According to a paper presented at the meeting, Pluto may even harbor a subsurface ocean. Even Pluto's moon, Charon, may have a subsurface ocean. Ice deposits have been discovered on Charon from spectra obtained with the Near Infrared Imager and Spectrometer on the Adaptive Optics System at the Gemini Observatory.
The role of major instrumental facilities was very evident at the meeting. Displays of these facilities occupied large spaces in the halls of Sul America Convention Center. These displays featured facilities that included the ground based facilities: the twin 8-meter telescopes of Gemini Observatory, one on top of Mauna Kea, Hawaii and the other on Cerro Pachon, Chile (GTT), 42 -meter European Extremely Large Telescope (E-ELT), 30-meter Telescope (TMT), 24.5 meter Giant Magellan Telescope (GMT), 22 meter Large Binocular Telescope (LBT), 10.4 meter Giant Telescopio Canaries (GTC), Atacama Large Millimeter/Submillimeter Array (ALMA). Then there were number of Space based observatories like the James Webb Space Telescope (JWST), Herchel, and Planck. We will investigate how to participate in some of these endeavors for instructions and research at Capitol College.
The story of the asteroid named 2008TC8, first reported at the meeting, was extremely interesting. This is the first time a collision of an asteroid and the earth has been directly observed and documented. The asteroid was discovered on October 6, 2008. The orbital calculations of the asteroid predicted that it would become the first observed asteroid to hit the earth in the early morning of October 7, 2008, barely 20 hours after the discovery, in the Nubian Desert of Sudan. The shape and rapid tumbling of the asteroid were measured from ground based observations. The impact was recorded by several satellites. One satellite reported an explosion when it was 37 km above the ground. The sonic boom of the impact was detected from Kenya. One airline pilot reported seeing three flashes near the horizon. Thousands of people in Sudan saw the fireball and some took pictures of it. Dr. Peter Jenniksens of SETI Institute organized a search for the remnants of the asteroid. He and Dr. Muawia Shaddad and a student, Mohammed Alameen of University of Khartoum discovered the remnants of the asteroid in the middle of Sahara Desert. The meteorite was found to be a rare kind linked to F-class asteroids. Jennikens brought a piece of the meteorite to the meeting.
There were, of course, many other topics discussed, including chemical compositions of galaxies and stars, relationships of galaxy evolution and the central super massive black holes, the extraordinary exploding star Eta Carinae and many other - too many to describe. Many, I was not able to attend because of simultaneous sessions.
The meeting was not totally without the cultural aspect. The astronomers went sight seeing on the weekend including Cristo Redentor on top of Corcovado Mountain, and there was a fabulous banquet on top of the Sugar Loaf Mountain.
All in all, it was a great occasion to meet with old friends, make new ones and learn new things.
Ashit Sanyal, PhD