Tip:
Highlight text to annotate it
X
Planetary Science 2014 – Part 7
There are several places here on Earth that extremophiles can be found. The thermal vents
in the Pacific Ocean have hydrothermal worms that look like something out of an old science
fiction movie; however, they are only the size of bacterium. Mono Lake in California
contains organisms that have a high phosphorous content and an astrobiologist subjected them
to an arsenic environment. The microbes exchanged the phosphorous with arsenic and continued
to function normally. In Alaska is the Cold Research Lab (CRREL), where frozen microbes
were found and brought above freezing. These organisms which had last been active 32,000 years ago
during the Pleistocene Era became mobile and seemed not to have been affected by a long
hibernation. The Crystal Cave in Naica, Mexico is 300 feet below the surface and contains
crystals that have grown to more than 25 feet in length over the past 100-200,000 years.
They were discovered by a mining company that drained the caves and will eventually flood
them again. The caves have a constant temperature of 166o F and a humidity of 98%. NASA astrobiologists
study this environment searching for extremophilic microbes. Even with their protective suits,
the scientists cannot stay in the caves for more than 20 minutes without experiencing
extreme dehydration. I had to show you this little guy – he has
the title of the most extreme of the extremophiles. Tardigrades are microscopic microbes that
resemble eight legged teddy bears. Tardigrades are about 1mm in length and live in lichen,
deep in the ocean, in the polar regions and even survive in space. Tardigrades have a face that only
a mother could love; however, they have even been taken up to the space station and subjected
to radiation and the near vacuum of space and they still survive. A word of caution
here – these examples of extremophilic microbes are all carbon based. Carl Sagan coined the
phrase “carbon chauvinism” – meaning that we are looking for carbon based extraterrestrial
life because that is what we are familiar with here on Earth. Life, though, does not
have to be based on carbon – but something totally outside of our experience.
The Jet Propulsion Laboratory (JPL) has a website that lists every mission – past,
present and future. It is an excellent site to use as a resource to learn which missions
have been sent to the planets, moons, asteroids, and comets listed in the event description.
Keeping all of the Mars missions sorted out will be the difficult as there are so many;
however, remember that the ones which have contributed the most important discoveries
related to the presence and movement of water are the essential ones to study. We have orbited
Mars, landed on Mars, and left robots on Mars – you would think we would be done with
Mars but no, we are still looking for the holy grail of evidence of past life on Mars.
Curiosity, besides taking a few moments to take a self-portrait, is busy drilling into
rocks and extracting the pulverized rock to study in the on-board lab for analysis. Curiosity’s
ultimate goal is Mount Sharp – where layers of sedimentary rock could possibly contain
evidence of organized organics and life.