The room where the meeting took place ...
... at first a little frosty.
The talks startetd Monday at 8.30 a.m. The hotel management must have thought we were some kind of extremophile life forms, as they cooled the meeting room down to arctic temperatures. In the course of the week the temperature inside improved, though.
|
|
|
The first day was marked by talks about organic chemistry. Complex organic molecules are the precursors of life. Therefore many astronomers explore the various chemical reactions in protoplanetary disks around young stars, in interstellar molecular clouds within our galaxy and in other galaxies. The precise way of organic molecules from their source to the surface of a planet is still debated.
The afternoon was dedicated to objects in the outer reaches of our solar system. The exploration of the surfaces of Kuiperbelt objects (e.g. Pluto, Charon, Eris), Centaurs, and comets will teach us about the changes in organic molecules up to the point when the building blocks of life are formed.
Towards the end of the afternoon Pascale Ehrenfreund gave her invited talk about "The Aromatic World: From Interstellar Molecules to the Origin of Life". She sees PAHs as a possible linking molecule between organic chemistry and life. Born in Vienna, Pascale Ehrenfreund is today an authority in the field of astrobiology at the University of Amsterdam.
|
|
|
The first poster session ended Monday's program. Besides the talks posters are a further possibility for scientists to present their work. Poster sessions offer the chance to talk to scientists, working in the same field. Cheese, sweet things and drinks made the session interesting for everyone!
|
|
|
Tuesday's talks focused on Titan and Mars
Data and images from the Cassini and Huygens probes have changed the mysterious moon Titan into a real and concrete world. Many analogies between Titan and Earth make the exploration of the largest of Saturn's moons an interesting project. Both worlds have been and are still formed by similar geological processes. The water cycle on Earth corresponds to the cycle of methane on Titan. Both worlds are constantly changing.
Previous models of Titan's atmosphere are still valid, even though some surprising new details have been discovered. Tholins are complex organic solids, that are constantly being created in Titan's atmosphere and sink down to the surface. In the lab scientists investigate what happens to them under different conditions (e.g. contact with liquid water). With the help of Cassini and ground based telescopes such lab results are then compared to the real observations.
Some speakers also addressed the question of possible life on Titan. Life on the surface is hardly plausible, but models of the moon's interior indicate the existance of a deep ammonia-water ocean. Cassini should soon be able to prove this theory. Such an ocean might harbour life in form of microorganisms.
Another of Saturn's moons - Enceladus - is also a candidate for an ocean underneath the surface. The TANDEM Mission, part of ESA's "Cosmic Visions 2015 -2025" program, might probe the surfaces of Enceladus and Titan in the not so far future.
Two invited talks about Mars revealed the latest research at the Red Planet by NASA and ESA Missions. Dave DesMarais of NASA's Ames Research Center summarized results of the two Mars Exploration Rovers. While data collected by the Opportunity Rover in Meridianum Planum hint at a complex history of water at and under the surface, the first results by the Rover Spirit showed no evidence of past water in Gusev Crater. Only when Spirit climbed the Columbia Hills, 2,5 kilometers (1,6 miles) from the landing site, it was possible to probe older layers of rock, which showed evidence of past water.
Jean-Pierre Bibring of the Institute d'Astrophysique Spatiale in France found critical words about the search for the history of water on Mars. ESA's Mars Express probe is mapping the surface of the Red Planet. Structures in the landscape that have obviously been formed by liquid water do not prove that water was stable there for a longer periode.Mars Express data show that stable water was only possible in the earliest times of the planet's history. Only in this period life could have developed on Mars. About 3,8 billion years ago strong vulcanic activity - the formation of the Tharsis area - changed climate and conditions on the planet considerably. If you want to look for evidence of past life on Mars you therefore have to explore the highlands of the southern hemisphere and not those valeys which were only shortly in contact with liquid water.
The talks at a meeting like this one have to be of a certain legth. Invited talks must be 30 minutes, contributed talks should be 15 minutes (both times include 5 minutes for questions!). These times seem to be very short but otherwise it would be impossible to get through the full program in just four days. The chair of each session has to see that speakers keep to the times - which is not always an easy task! Differnet chairs used different methods to notify the speakers about the end of their speaking time: asorted alarm clocks, not quite serious threats ("I am going to use the Robespierre-methode!") and, last but not least, a wand which produced swooshing sounds. Harry Potter's influence does not stop at bioastronomy.
Thursday morning was dedicated to certain biological topics: The origins of viruses, cellular functions and life in extreme environments (which did NOT refer to freezing cold meeting halls and sauna-like buses!). These fields of research are interesting for astronomy because they contribute to the search for possible life outside Earth.
In the afternoon we heard several talks about differnet aspects of the origin of life on Earth and early life on our planet. In her talk "Life, Gravity and Everything" Catharine Conley explained how experiments with worms help to understand more about the effects of gravity on organisms. The tiny worms adapted astonishingly well to microgravity as well as to hypergravity.
Friday, the last day of the meeting, started with two sessions on extrasolar planets. Different methods of detection, like the transit method or the search for gravitational microlensing make it possible to find more and more details about planets around other stars. In the near future better and better ground based instruments and new space telescopes will boost the search for exopalnets enormously.
The discovery of these planets around distant stars made former models about planet formation obsolete. Especially the formation of gas giants like Jupiter is still puzzling astronomers. Did they start out with an solid core, accreting gas or did they form out of denser spots in the proto-planterary disk? Observations with future telescopes in differnt frequencies might solve the mystery. But there are more questions waiting for answers: Can habitable planets exist in "extreme" systems (double star systems, planetary systems with so called Hot Jupiters, ...)? What are the effects of supernovae or gamma ray bursts on the emergence of life in a near system? How do the other planets in a system influence the origin of life on a terrestrial planet? Scientists exploring extrasolar planets will not be out of work soon!
There are a few exoplanets where is possible to find out details about the atmosphere. Just a few days before the meeting the detection of water in the atmosphere of a "Hot Jupiter" was announced. Giovanna Tinetti introduced these findings of her team.
Ambitious missions like NASA's Terrestrial Planet Finder (TPF) or ESA's Darwin will enable astronomers in the next decade to find and study Earth-like planets. Therefore it makes sense to find out which spectral signatures in a planet's atmosphere that would be detectable with these future instruments would hint on the existance of life. Methane, ozon and water vapor are among the most promising molecules.
The last session belonged to the Search for Extraterrestrial Intelligence (SETI), their current and future programs. The meetng ended with some thoughts about how to use the trilling topics of astrobiology to raise public awareness about these fields of research and science in general. American institutes are much more aware of the importance of public outreach programs for scientific research than their European counterparts. I would therefore like to end with a sentence by the last speaker of the meeting, Ed Prather of the Univ. of Arizona, "Education and outreach isn't a side issue." It is important how the public thinks about science. - Well, I will try my best to share my enthusiasm about astronomy and astrobiology with as many people as possible.
Text and photos: Anneliese Haika
