Thoughts on Life’s Diaspora

Here is a continuation of the discussion regarding Panspermia, which is the idea that life can move from one planetary body to another, in effect seeding a lifeless world. It is a claim that is passed off as science fiction conjecture, in some circles; as perhaps a claim not entirely worthy of scientific investigation. Others, both scientists and laypeople, helpfully counter that the idea of panspermia, as it concerns the origins of life on Earth, is just passing the problem from one place to another without answering the fundamental question, which is "How did life first arise?"

I disagree with the first point, and largely agree with the second. The search for life outside of the Earth IS a goal worthy of scientific investigation. Due to the very reasons that the origins of life are, thus far, inexplicable, so should we regard with seriousness the search for extraterrestrial life as part of the effort to understand the mystery of life's origins. We have no clear answers as to why life arose here on Earth. Even if we do find that mysterious genesis and it sheds some light on the process, we will probably not have a clear understanding of the events that transpired in life's first steps. That will be the case until we have a clear, unambiguous example of non-Earth life with which to compare us to.

The Tardigrades: Earth's Toughest Lifeform?

Photo courtesy of http://www.sciencephoto.com

Hank Green gives us a quick introduction to the Tardigrades, a kind of extremophile. Tardigrades, sometimes known as "Water Bears" or "Moss Piglets" live in water, have eight legs, feed on moss, and are very small - microscopic, in fact. They live worldwide in many different altitudes and environments including various levels of the ocean. They are known as very tough organisms, despite being so tiny. NASA sent these guys into space just to see if their reputations for toughness bear out. It turns out that Tardigrades are, unusually, one of the toughest organisms on Earth.

They were sent into space and tested in two controlled sets of populations. The first water bear population set was exposed to both the vacuum of space and to the solar radiation emitted by the sun. The second population set was exposed to just the vacuum of space and NOT the harmful solar radiation. Many of the Tardigrades survived the exposure and the trip back to Earth, where some of them even reproduced after their experience.

One of the implications of this experiment informs us on the possibilities of Panspermia. Panspermia is the idea that life can be seeded onto a dead world, perhaps naturally...that life is tough enough to survive a journey from one planetary body to another in a solar system. The Tardigrades's experience in space certainly opens up the possibility of a Panspermiated Solar System. if they can survive this, then what else is possible? Check out Hank Green's video below. After the video, check out some gnarly Water Bear photography #WaterBearPorn

Isn't he cute? Photo courtesy of http://www.sciencephoto.com