Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

ESA to search for life, but not as we know it

19.09.2002


This week, astrobiologists are discussing what ESA`s Huygens spaceprobe might discover when it parachutes to the surface of Saturn`s mysterious moon, Titan, in 2005. Titan possesses a rich atmosphere of organic molecules, which Huygens will analyse. Recently some scientists have begun to think that, by redefining life, in broader terms, what we may find on Titan may be life. If this is the case, it certainly will not be life as we know it...



Titan is an astrobiologist`s dream laboratory. Its atmosphere is composed of nitrogen and methane gas. Ultraviolet light from the Sun can break the methane molecules apart, leading to the formation of complex organic molecules by which scientists mean molecules containing carbon. Carbon compounds are the first step towards life, as we know it on Earth. Life, itself, is based on extremely complicated carbon molecules such as DNA. Some scientists believe the composition of Titan`s atmosphere closely resembles that of early Earth, before life began on our planet.
Huygens`s investigations may reveal how life began on Earth. Jean-Pierre Lebreton, ESA`s Project Scientist for Huygens says, "One of the key questions we hope to address is how complex the organic molecules have grown in Titan`s atmosphere."

However, organic molecules are still a long way from life itself. So, what defines life? What is the difference between the living and the non-living? Scientists are still unsure. No satisfactory definition has been found so far. Any attempt to define life`s characteristics either excludes some types of life or includes some inanimate objects. When looking for an appropriate definition of life, there is one property all scientists seem to agree on: all life needs energy to sustain its metabolism.



For example, plants use sunlight, while animals extract energy from organic molecules in the food they eat. This happens not only in these higher-level organisms, but also in the simplest forms of life on Earth, microbes. Microbes are single-cell organisms that capture their life-energy from a dizzying array of inorganic chemical reactions. Such chemical metabolisms are so different from those in the animals and plants of Earth, that astrobiologists now wonder if life could arise in any place that can sustain a rich network of chemical reactions, such as on Titan. Moreover, on Earth, microbes have adapted to the extreme environmental conditions. Scientists therefore now ask, "Could life arise on Titan?"

By all standards, Titan is an extreme and hostile environment to life, as we know it. Any life on Titan would have to be totally different from all Earthly forms. Lebreton says, "The conditions on Titan are not adequate for the kind of life we understand today. It is very cold and there is no liquid water but we should be ready for surprises." Identifying life is tricky, especially when you are unsure what to look for. Huygens`s geological and environmental investigations, and Cassini`s mapping from orbit, might record chemical anomalies or curious geological structures that warrant further investigation as possible life indicators.

Another chemically puzzling place is the planet Venus. Similarly to Titan, Venus is a world that scientists would traditionally call hostile to life, as we understand it. However, there is something odd in its clouds. Venus`s chemically laden atmosphere displays some curious phenomena, such as the planet`s ability to absorb ultraviolet radiation. Scientists cannot explain this. Some speculate that perhaps microbes in the atmosphere are responsible. If ESA`s Venus Express is given the final go-ahead later this year, it might help solve the mystery.

For centuries, scientists have struggled to define life. Space investigations present the best chance for astrobiologists to find the missing link in our understanding of what separates the living from the non-living. When we know that, we will finally have defined life here on Earth.

Jean-Pierre Lebreton | alfa
Further information:
http://www.esa.int

More articles from Physics and Astronomy:

nachricht First evidence on the source of extragalactic particles
13.07.2018 | Technische Universität München

nachricht Simpler interferometer can fine tune even the quickest pulses of light
12.07.2018 | University of Rochester

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Research finds new molecular structures in boron-based nanoclusters

13.07.2018 | Materials Sciences

Algae Have Land Genes

13.07.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>