In The News: Viruses, Life & Lunar Landers

[CraigS]

In the News and whilst not strictly Astronomy but related to the origins of life (maybe):

"Tracking viruses back in time"
http://www.physorg.com/news203001039.html

Viruses are a curious lot. The standard drawing of the tree of life, the one you find on the inside back cover of biology textbooks, is divided into three branches: Archaea, Bacteria and Eukarya. Viruses don’t make it onto the page.
That makes sense, some scientists argue, because they’re not alive. They can’t reproduce on their own; they require the cozy environment of living cells for their survival. Others disagree. Not only are viruses alive, they say, but genetic evidence indicates that they may have been the first forms of life on Earth, predating cellular life.

and here's the Astronomy related bit ...

The first virus they chose (for study) was Bacteriophage T4, “sort of the prototypical virus,” which has a well-known shape. It “looks like the lunar lander,” Stedman said.

Chuckle .. chuckle ..

Cheers

[mjc (Mark)]

I think the post is relevant (and hope this post is also). If we have difficulty identifying signatures of viruses from early Earth evolution then how can we find them on Mars - for example (but, then again, aren't viruses dependent on cellalar organisms to exist - which might be easier to identify?)

Maybe deviating here, some bacteria are really quite resiliant. Bacteria from the cliffs of a village called Beer (hmmm... b e e r !) on the South Coast of England survived on the outside of the ISS for 533 days
http://www.bbc.co.uk/news/science-environment-11039206

And prior to that when Apollo 12 recovered the camera of Surveyor 3 it was found that it was contaminated on Earth prior to being sent to the moon and the bacteria, when rehydrated, was alive (was on the Moon for nearly three years).

http://science.nasa.gov/science-news.../ast01sep98_1/

The Bacteriophage T4 is really fascinating - an animation of one infecting a bacterium is well worth watching here:-

http://www.seyet.com/index.php?optio...101&Itemid=204

The last one isn't really astronomy related except for the incredible similarity to a man-made probe landing on a moon etc. It's hard to believe that this little virus isn't technically alive (if one requires metabolism) - but is a superb little machine regardless.

With respect to the question of whether viruses are alive - try finding a universal or widely accepted definition. It's a challenge.

Mark C.

[CraigS]

Hey Mark;

The last one isn't really astronomy related except for the incredible similarity to a man-made probe landing on a moon etc. It's hard to believe that this little virus isn't technically alive (if one requires metabolism) - but is a superb little machine regardless.

The Intelligent Design (ID) folk are going to have a field day on this one !
Why do I do this to myself, I ask ???? I must be a masochist !!



Oh well .. the resulting science will be really interesting to see develop.
I read somewhere that human DNA contains quite a few dormant viruses.
How the ancient viruses got there (and remained) was the subject of that article.

Cheers

[mjc (Mark)]

Craig - when I loooked at that I had the same thought. I can understand why ID is such a tempting / convenient explanation of things for some people.

However, sometime ago I got to think about the language of describing evolution and I concluded that it is better to think in terms of "what does this do" rather than "what is this for". This technique tends to keep the mind on the correct perspective. This is very subtle - but it works for me - its so easy with everyday speak to talk about what things are for - and that implies intention of design.

Mark C.

[CraigS]

Good to have you 'round Mark !!

We could do with some more of this type of thinking.
(The conversations would be much less arduous)...

Cheers