Tuesday, October 12, 2010

An Earthlike planet?

Gliese & Gliese 581g
Gave my extra terrestrial life lecture again in Cork on the 11th.  I became aware of two developments after the Galway lecture, but in time to include them in Cork.  I can't hazard an estimate of their importance because I haven't yet come across any commentary in Nature or New Scientist, which is where I normally take my cue for what's significant in the world of science.

One was the announcement of a planet that was in the news on 29th September.  That was Gliese 581g.  Gliese 581 is the name of a star, and several planets have been detected called a, b, c etc. The illustration is an artist’s impression showing the star in the background. The planet in the foreground, has, apparently, been named “Zarmina's World”.  It’s worth stressing that any illustration you see of extrasolar planets will always be an artist’s impression. Their existence and their properties turn up as data on a computer, not as photographs.  Notice how in this illustration the artist has added seas. So far there is no warrant for those seas.      

The Guardian reported the story like this: “Astronomers have discovered a potentially habitable planet of similar size to Earth in orbit around a nearby star. A team of planet hunters spotted the alien world circling a red dwarf star called Gliese 581, 20 light years away. The planet is in the ‘Goldilocks zone’ of space around a star where surface temperatures are neither too hot nor too cold for liquid water to form.” 

Early indications seem to be that this is the most Earthlike extrasolar planet discovered so far. This however will need to be confirmed. I don’t know how long the confirmation process will take.  Dr Lewis Dartnell of UCL is quoted in The Daily Telegraph as saying it’s undeniably very exciting, but we don’t know if there's any water there.

The other story broke in the Irish Times last Friday, October 8. It was a report of work done at NUI Maynooth by a Dr James McInerney.

Simply put, there are two types of cell. Cells with a nucleus and cells without a nucleus.  All complex life – animals, plants - consists of cells that do have a nucleus.  But the first cells didn’t have one, and the question is, how did the first cell with a nucleus come about?  There is a view that unlocking this puzzle will answer the question of how life on Earth became complex and eventually intelligent.

The work at Maynooth seems to provide such an explanation.  Justifying the relevance of this in a lecture about extra terrestrial life,  I said that we’re hunting for freakish, chance events in the story of life.  But we’re hunting for them in the same way that you may hunt at home for unpaid bills.  We’re hunting for them and hoping not to find them. Because if there are no freakish, chance events in the story of life, then our hopes rise that life will have emerged elsewhere, given the right environment.

I'll say more when I’ve seen what Nature and New Scientist think.

Subsequent info here


  1. Very interesting Pete. Two things - from what you say no-one has any idea what the planet is like visually, so why bother with an artist's impression, or why not use the same one every time, and secondly does this convince you that somewhere out there there MUST be some lifeform, which is as evolved as us (if not more), or which will one day be as evolved as we are now? Surely it's a mathematical probability that there is?

  2. I think the illustration does serve a limited function, in that it shows the scientists’ best guess at the relative size and distances of the sun and the star, and informed speculation as to their appearance. Most other extrasolar planets detected have been “hot Jupiters”, so the artist’s impressions depict a huge planet much closer in.

    As to it being a mathematical probability that there is life, yes, provided you make one assumption : that life arose on Earth without anything freakish going on. There is a wide divergence amongst scientists about how reasonable that assumption is. Some say the universe is so huge that however unlikely life is, it MUST have appeared in numerous other places. Others say that since we simply don’t know HOW life arose, we are not entitled to make any such statement. Life may be SO unlikely that it’s only happened once in the entire history of the universe. The fact is there's no evidence. So the debate isn't science but philosophy.