Tag Archives: alien-life

Are we alone?

saucersTranshumanist blogger George Dvorsky points to a debate between astrophysicist Brandon Carter and a team of Serbian researchers, the core of which revolves around how long complex (and intelligent) life takes to evolve:

Prior to ‘recent times’, universal mechanisms were in place to continually thwart the evolutionary development of intelligence, namely through gamma-ray bursts, super novae and other forms of nastiness. Occasional catastrophic events have been resetting the “astrobiological clock” of regions of the Galaxy causing biospheres to start over. “Earth may be rare in time, not in space,” they say. They also note that the rate of evolution is intimately connected with a planet’s environment, such as the kind of radiation its star emits.

For further discussion of our place in the universe see the Copernican Principle, which exhorts us to avoid assuming that humanity, Earth, and our place in the universe can be assumed to be unique and special.

Further the notion of punctuated equilibrium to describe evolution is interesting: might it be extended to describe other evolutionary phenomena? Eric Beinhocker‘s superb The Origin of Wealth describes both technology and the economy in terms of evolutionary systems, both of which experience a form of punctuated equilibrium.

[image from eek the cat on flickr]

You think the Earth is rare? I got a dozen just like it out back…

Planet EarthOne of the better known responses to the Fermi Paradox is the Rare Earth hypothesis – the supposition that our planet is rare or unique in its ability to harbour life, and that hence we are unlikely to encounter life-forms elsewhere beyond our own biosphere. [image by Aaron Escobar]

Well, George Dvorsky isn’t having any of it.

I’ve always thought, however, that given cosmologically large numbers that this sort of thinking is symptomatic of our small minds and limited imaginations. It’s easy for us to throw up our hands and sheepishly declare that we’re somehow special. Such a conclusion, however, needs to be qualified against the data involved, and by the mounting evidence in support of the notion that ours appears to be a life-friendly universe.

Dvorsky goes on to attack the assumptions of Rare Earthers methodically.

It’s a myth, for example, that it took life a long time to get going on Earth. In reality it was quite the oppoite. Our planet formed over 4.6 billion years ago and rocks began to appear many millions of years later. Life emerged relatively quickly thereafter some 600 million years after the formation of rocks. It’s almost as if life couldn’t wait to get going once the conditions were right.

This isn’t to say that Dvorsky thinks that we’re being visited by little green men on a regular basis, though; he has a more worrying idea about why we’ve not heard from our neighbours yet.

My feeling is that the Rare Earth hypothesis is a passing scientific fad. There’s simply too much evidence growing against it.

In fact, the only thing going for it is the Fermi Paradox. It’s comforting to think that the Great Silence can be answered by the claim that we’re exceptionally special. Rare Earth steers us away from other, more disturbing solutions –namely the Great Filter hypothesis.

Of course, only evidence of alien civilisation will ever answer Fermi’s famous question; it’s always struck me as a kind of science fictional restatement of the argument for the existence of god. Maybe that’s why it’s such a fascinating subject for debate? A bit of teleology never fails to get people thinking…

The lone survivor: single organism ecosystem discovered

Scientists has discovered a new bacterial organism called desulforudis audaxviator that is an entirely self-sufficient ecosystem in and of itself, 2.8 km below the Earth’s surface the desulforudis audaxviator’s genome contains:

everything needed for the organism to sustain an independent existence and reproduce, including the ability to incorporate the elements necessary for life from inorganic sources, move freely, and protect itself from viruses, harsh conditions, and nutrient-poor periods by becoming a spore.

This is a beautiful discovery, and a testament to the diversity and splendour of Life. Also, it suggests there is no theoretical reason why life cannot survive in similar conditions on other planets:

“One question that has arisen when considering the capacity of other planets to support life is whether organisms can exist independently, without access even to the sun,” says Chivian. “The answer is yes, and here’s the proof. It’s sort of philosophically exciting to know that everything necessary for life can be packed into a single genome.

[image from eschipul on flickr]

Potentially life-supporting planet found

The four space-based 3 metre telescopes of DARWIN will work together to find other planetsAstronomers have discovered a planet in the 55 Cancri system that orbits constantly in what is know as the ‘habitable zone’ of the solar system. Although the planet is a gas giant some 45 times the size of Earth, there’s a good chance one of its moons might have liquid water and hence encourage the development of earth-like life. Planets are found by studying their transits across the light of a star. By studying the amount the star dims when the planet crosses, the size of the planet can be estimated. This is limited to larger planets currently but future missions like the Kepler and Darwin projects may be able to find rocky planets like our own.

The search for ‘exoplanets’ outside our solar system is hitting its stride and regularly more are found. Whilst the planets found to date are all ‘Jupiters’ like the gas giants further out in our home system, we know that Jupiter, Saturn, Neptune and Uranus all have large satellites. If any of these were in the habitable region where Earth is, the possibility of liquid water and hence bacterial life would be likely. If 55 Cancri did support life on one of its moons it would resemble the world of Coyote in Allen Steele’s excellent series.

[via the guardian, image of Darwin project via Astronomy Online]