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EXOBIOLOGY (A.K.A. ASTROBIOLOGY)

IMPORTANT ASTROBIOLOGY LINKS:

ASTROBIOLOGY MAGAZINE - NASA's excellent online source of Astrobiology news and information.

ASTROBIOLOGY (the journal) is a prime source of peer-reviewed published research conducted in this field.

EXAMINING HARDY EARTH LIFE - Extremophiles, durable forms of life on Earth, have been found living as: sulfur loving bacteria around deep ocean hot water vents and hot springs on land, as bacteria in Antarctic glaciers and lakes, as Antarctic worms, as bacteria living in high radiation environments, as microbes found at thousands of feet high in our atmosphere, in giant cyanobacteria mats in Lake Huron sinkholes, and growing as filamentous ropes in caves, and miles below the surface of the Earth.

SOME INTERESTING EARTH EXTREMOPHILES:

TARDIGRADE - 8 legged polyextremophiles, they are extremely resistant to low and high temperatures, radiation, chemical reactants, dry places and high to zero atmospheric pressures.

There are more than 1000 species of Tardigrades and they have been found in the Himalaya mountains over 6,000 meters above sea-level, and in the ocean deeper than 4,000 meters below sea level and everywhere in the world including Antarctica.

FOODS - mostly plants and bacteria

MAX TEMP = 151 deg. C

MIN TEMP = 1 Degree above absolute zero for several minutes or -200 C for several days.

MAX PRESSURE = 6000 bars (6 x greater than the deepest Earth ocean.)

MIN PRESSURE = zero gravity for 10 days

MAX RADIATION = full solar radiation (in space) including ultra-violet radiation for 10 days, can also survive very high doses of ionizing radiation.

STASIS = can live at least 10 Years in dehydrated state, can also go into stasis in harsh chemical environments.

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STRAIN 121 - hydrothermal vent bacteria

FOOD - Hydrogen sufide.

MAX TEMP = 121 deg. C (can reproduce at this temperature too!)

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GIANT TUBE WORMS - Hydrothermal vent marine invertebrate. Can live over 250 years!

FOOD - Hydrogen sulfide converted by bacteria residing inside worms into food for worms.

MAX TEMP = water inside vent can reach 400 deg. C, but is much cooler near worms, water can be as acidic as vinegar.

MIN TEMP = 1 to 3 degrees C.

MAX PRESSURE = >1000 bars

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METHANE ICE EATING WORMS found under high pressures.

FOOD - found in the Gulf of Mexico eating methane calthrate ice (which contains a bacteria that metabolizes the methane into food for the worms.)

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SALT-LOVING ALGAE - DUNALIELLA SALINA - found living in sea-water evaporation ponds that are many times saltier than the oceans.

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RADIATION-LOVING BACTERIA DEINOCOCCUS RADIODURANS - Found living and spoiling a can of food after being irradiated with what was thought to be a lethal dose of radiation. It's extremely resistant to ionizing radiation, ultraviolet light, desiccation, oxidizing and chemical agents.

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Another interesting field of investigation for Astrobiologists (and other biologists, and us) is PROTOBIONTS AND THE ORIGIN OF LIFE.

Everywhere we look on the Earth, it seems life has found a niche. Maybe it's elsewhere in our solar system too?

ABODES - Possible other abodes for life in our solar system could include moons with ice encrusted oceans such as Jupiter's moons: Europa, Callisto and Ganymede; Saturn's moon's: Enceladus and the methane-rich Titan and even possibly Neptune's moon Triton (which is known to be geologically active and shoots geysers above it's surface.) Mars is still a candidate because large amounts of water ice have been found on Mars by orbiting spacecraft and the NASA Phoenix Lander, which also found that the soil is capable of supporting Earth plants too. Methane is outgassing from Mars, but it is unknown where this gas is from; it could be biogenic, but it also could be geologic in origin. There are carbon tests that may prove this one way or the other.

Hundreds of exoplanets have been found since the 1990's, some of which are in regions near their star that would permit a liquid ocean. You can find a nice guide to these abodes at

NASA's PLANETQUEST: EXOPLANET EXPLORATION PAGE

ASTROCHEMISTRY - Chemicals necessary to Earth life have been found throughout the cosmos, these include:

Oxygen, water, carbon dioxide, methane, hydrogen, polyaromatic hydrocarbons (PAH's are the most prevalent class of carbon molecules in the Universe and are commonly found in meteorites and comets too), amino acids (even in meteorites), nitrogen, cyanide, formaldehyde, alcohols, acids and ketones.

Other investigations of Astrobiology include consideration of PANSPERMIA (see that Wikipedia Panspermia link for details.)

For more information about Astrobiology, visit the links that the top of this page or you can visit this

WIKIPEDIA ASTROBIOLOGY LINK

Thanks for visiting, and KEEP SEARCHING!

This page barely grazes the surface of the immense subject of Astrobiology

Super extremophile - Tardigrade