Solen og Månen idag

Månens fase idag
Solen lige nu fra SOHO

Nyhedsbrev




RSS Feeds

RSS Feeds

Online Brugere

Vi har 86 gæster online
Banner
"Bio-zonen" udvidet
Skrevet af Henrik Røsenørn
Onsdag, 21. april 2010 22:49
Udskriv
Astronomi - Exobiologi/SETI

Fungis

"Bio-zonen" er den sfære om en stjerne, hvor temperaturen på planeter om den kan understøtte liv.

Et nyt studie viser at mikrober kan leve helt ned til -80°C, hvilket udvider biozonen fra det traditionelle begreb om flydende vand

Jordens atmosfære var oprindeligt en nitrogen/CO2 atmosfære, indtil mikrober dannede int nok til at planter kunne overleve og dermed bidrage til at ilte atmosfæren.

Dermed kom vore velkendte atmosfære ikke af sig selv, men blev skabt af mikrober og deres efterkommere planterne.

Forskerne bag opdagelsen har studeret hvordan stoffer der erkendt for at bringe uorden i makromolekyler (chaotroper), kan udvide mikrobernes vækst vindue, ved basalt set at virke som frostvæske, så de ikke fryser ved 0°C, men kan fortsætte med at fungere aktivt helt ned til -80°C.

"Denne viden kan forbedre præcisionen af modeller der bruges til at beregne om fjendtlige miljøer inklusive fremmede planeter, kan understøtte liv" skriver forfatterne af artiklen

Kilde og yderligere læsning: Proceeding at PNAS

Fungis

"The bio-zone" is the distance around a star, in which temperatures will support life. New research proves that fungus can live at temperatures as low as -80°C, widening the zone from the limits of presence of fluid water


Microbial cells, and ultimately the Earth's biosphere, function within a narrow range of physicochemical conditions.

For the majority of ecosystems, productivity is cold-limited, and it is microbes that represent the failure point. The study was carried out to determine if naturally occurring solutes can extend the temperature windows for activity of microorganisms.

The researchers found that substances known to disorder cellular macromolecules (chaotropes) did expand microbial growth windows, fungi preferentially accumulated chaotropic metabolites at low temperature, and chemical activities of solutes determined microbial survival at extremes of temperature as well as pressure.

This information can enhance the precision of models used to predict if extraterrestrial and other hostile environments are able to support life; furthermore, chaotropes may be used to extend the growth windows for key microbes, such as saprotrophs, in cold ecosystems and manmade biomes.

Source and further reading: Proceeding at PNAS

 


:confused::cool::cry::laugh::lol::normal::blush::rolleyes::sad::shocked::sick::sleeping::smile::surprised::tongue::unsure::whistle::wink:

1000 Characters left

Antispam Refresh image Case sensitive