Saturday, March 9, 2013
A space telescope to detect extraterrestrial life
The Space Research Institute of the Netherland thinks it may be possible to identify signs of alien life within the next 25 years, without the need for a space mission.
A new method
Astronomers have speculated for decades about how observations of exoplanets could provide evidence of extraterrestrial life.
We can observe certain gases exhaled by the bodies in the atmospheres of exoplanets (planets orbiting stars other than the Sun). This idea, which has been around since the 1960s, has been linked to a new observation method using large telescopes reflectors relatively inexpensive flow collectors.
To investigate the presence of oxygen
About 20% of the Earth's atmosphere comprises oxygen. The gas in the atmosphere because the plants is produce huge amount of this during photosynthesis. Without this biological activity, would cause oxidation soon disappear all the oxygen in our atmosphere? If oxygen is detected in the atmosphere of an Earth-like exoplanet, this could, therefore, be a sign of extraterrestrial life.
It was thought that such observations should be performed using space telescopes. The oxygen in Earth's atmosphere would cause too much interference for observations to be made from earth. However, the plans of the European and American scientists for a large dedicated space mission, as Darwin or the Terrestrial Planet Finder (TPF), have been frozen for several years, making it unlikely that these telescopes are launched over the next 25 years.
Observations from Earth
A group of astronomers from the University of Leiden and the SRON have now shown that the same can be achieved with ground-based observations using a special method. "The way to distinguish the oxygen in the atmosphere of an exoplanet oxygen of our own atmosphere is very accurately measure the wavelengths of the absorption lines," says Ignas Snellen of Leiden University. "The high speed of such planet Earth with respect to the mean oxygen lines are shifted by the Doppler effect, and therefore do not coincide with those of our atmosphere. Consequently the telescope does not need to be out of our atmosphere, allowing great cost savings. "
The European Extremely Large Telescope
The team has shown how the oxygen in the atmosphere of a hypothetical twin Earth, seen against the light of a red dwarf, which is cooler and smaller than the Sun, could possibly be seen with the planned European Extremely Large Telescope (European Extremely Large Telescope, E-ELT). "But we need a bit of luck," says researcher Remco de Kok (SRON). "The telescope will be able to do so only if extraterrestrial life is very common and can, therefore, be found relatively close. Even the E-ELT cannot be big enough. "
Capturing light telescopes with mirrors
The equipment therefore suggests what is known as flux collectors. For spectroscopic measurements of bright stars and planets does not need to build a telescope as the E-ELT you can make very sharp images? What is important is to capture as much light as possible, which can be done with large telescope mirrors of a much lesser quality, which can be constructed by a fraction of the cost. "With the amount of flux collectors covering an area the size of a few football fields, would be able to perform a statistical study of extraterrestrial life on the planets of our solar neighborhood. There is still a long way to go, but it should be possible within 25 years, "says Snellen.
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