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Winter School
UH Lead Team
IfA Homepage
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Water on Earth and in Space - January 10-21, 2005
- Water Ice and Chemistry in Circumstellar Disks and the Interstellar Medium
Cecilia Ceccarelli (Laboratoire d'Astrophysique, Grenoble, France)
The interstellar medium contains the basic material out of which stars
and new planetary systems form. In the cold environment of dense
interstellar clouds, volatile molecules freeze out onto dust grains
and form icy mantles surrounding the silicate and carbonaceous
cores. Grain surface chemistry allows for the formation of more
complex molecules than is possible in the gas phase. These molecules,
including water, are then liberated from the grain surfaces through
heating by a young star. Determining the solid state processes in
dense clouds is thus essential for an understanding of the chemistry
and evolution of water ice. Observationally, there are three closely
related approaches to explore the role of water ice in the star
formation process. The first aims to quantify the presence of water
ice in the interstellar clouds, out of which stars form. The second
aims to understand the structure, kinematics, composition, and
physical properties of the circumstellar disks out of which planets
form, thus defining the general environment in which water will
exist. The third aims to determine the specific role of water ice in
these chemical and physical processes. We will discuss each of these
approaches in detail during this lecture series.
- Geochemical Processes and Microbiospheres in Hydrothermal Systems
Jim Cowen (Department of Oceanography, Honolulu, USA)
Volcanic and hydrothermal processes associated with the global
mid ocean ridge (MOR) system support potentially vast, complex
ecosystems on and beneath the deep ocean floor. Subseafloor volcanic
ecosystems may represent both the origin of life and/or its early
evolutionon Earth and a model for exploration for life on other
planets. These sub-seafloor ecosystems are linked to, and a
consequence of, the flow of energy and material from Earth's deep
mantle, through the volcanic and hydrothermal systems of the oceanic
basement, to the deep ocean. Furthermore, the aging ocean basement
that extends from the MORs to the ridge flanks, ocean basins and
ultimately to the subduction zones represents a continuum of
environments, which in turn may host potential biospheres varying
tremendously in both intensity and nature (e.g., metabolic diversity)
of activity. The linkages between life and planetary processes within
this continuum of environments will be examined through discussions of
a broad range of disciplines in geophysics, geology, chemistry,
biology and oceanography. Discussions will progress from a general
description of MOR systems to ultimately focus on several dynamic
habitats that represent the physical and geochemical diversity of
subsurface hydrothermal systems: near-field MORs (vent field);
sediment-buried aging basement (ridge flanks);
serpentization-influenced mud-volcanoes.
- Glaciers on Earth, Mars, and Europa
Thorsteinn Thorsteinnson (National Energy Authority, Reykjavik, Iceland)
At present, ice covers about 10% of the Earth's land surface, but the
past 2.5 million years have been characterized by the repeated growth
and decay of continental ice sheets in response to orbitally-driven
climate changes. A wealth of information on these past variations in
climate and atmospheric composition has been retrieved from deep ice
cores drilled on the Greenland and Antarctic ice sheets. Smaller ice
caps and mountain glaciers around the world are sensitive indicators
of current atmospheric warming trends and their study also yields
information on the dynamics and physical properties of natural ice
masses. In this lecture series, we will first present a general overview
of the science of glaciology, focusing on the internal structure of
glaciers and ice sheets, and on ice-core studies of climate-related
changes in the concentrations of oxygen and hydrogen isotopes. In the
astrobiological context, we will learn about studies of life in icy
environments on Earth, with special focus on subglacial lakes in
Antarctica and Iceland. This will be followed by a discussion of the
polar ice caps and ground ice on Mars, with emphasis on the possible
occurrence of liquid water beneath the surface of the planet. Finally,
we will discuss the possibilities of life thriving in the ocean
believed to exist beneath the icy shell of Jupiter's moon Europa.
- Icy Bodies in the Solar System and the Origin of the Earth's Oceans
Karen Meech (Institute for Astronomy, Honolulu, USA)
Comets are the primordial remnants from the era in the solar system
when the planets were accumulating. Forming at a range of distances
from the young sun, out in the vicinity of the giant planets, comets
contain a record of the chemistry and physics within the solar nebula.
Comets and other planetesimals forming closer to the sun were part of a
large flux of impactors which interacted with the early Earth, bringing
both water and organics to our planet. In this lecture strand, we will
investigate the properties of comets, learn about ice physics and what
this tells us about the early solar system and the connection to the
interstellar material out of which the comets formed. In addition, we
will examine the controversies surrounding how much of the Earth's
oceans were delivered by comets, by investigating the issues
surrounding the D/H ratio in comets and on Earth (and the other
terrestrial planets). Discussions will also include comet observing
techniques as well as some of the latest laboratory experiments on low
density ices, and the exciting experimental cometary science to be
undertaken with the NASA Deep Impact mission.
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