Friday, November 6, 2015

A Dyson sphere, my eye!

The central dot in this image represents a star surrounded by a Dyson ring of solar power collectors, 100 million miles out from a star. Many rings would make a Dyson sphere. Loopy!!
Image via Wikipedia.
When it comes to extraterrestrial life and space colonisation by humans my intuitive response is, this is fantasy stuff, and not worth a second glance.

I'm thinking in particular of the notion that star KIC 8462852 may sport a Dyson sphere. And what, pray, is one of those?  Oh yes, it's a hypothesized artificial structure surrounding a star. A structure the size, say, of Earth’s orbit around the sun, consisting of a shell of solar collectors. The idea being that with this model, all (or at least a significant amount) of a star’s energy would hit a receiving surface where it can be used. The physicist Freeman Dyson speculated that such structures would be necessary for the long-term survival of a technological civilization due to its escalating energy needs.

But madness or not serious scientists looking at the data from the recently discovered KIC 8462852 think it's behaving so strangely, that this Dyson sphere conjecture is worth exploring.  Jason Wright, an astronomer from Penn State University, is quoted in The Guardian  “Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilization to build.”

Even as “the very last hypothesis” this is surely loopy!  … and yet ... as a mere bystander,
who am I to say, no this cannot be?

When I need an image for a space colony I invariably seem to revert to this representation from the Mars One website

Space colonies aren't quite so far out and yet I struggle to take them seriously too. Dr Cameron Smith is someone who’s caught my eye. An archaeologist at Portland State University, he has arresting views on how space-born descendants of explorers would evolve culturally and genetically.  His theme is the biological and cultural dimensions of human space colonisation. 

This will be a process of adaptive evolution, and he thinks evolutionary studies can help plan for its success. He proposes to found a new science that he calls exo-anthropology. He envisages different models of space colonization:-

•    Terrestrially-tethered colonies
•    Independent colonies on other solar system bodies
•    Independent colonies aboard 'closed-system' spacecraft

I recommend listening to an hour-long audio file of a teleconference held last year with scientists from NASA and the University of Texas.  There are slides to accompany his talk, and you can find them on this page. (Look for a pptx file.)

Space colonisation will be a natural continuation of 4 million years of adaptation, he believes.  Against our nature?  No … ever since the human dispersal out of Africa, we’ve always found new places to live. Why would that stop with the atmosphere, he asks?  Plenty of technical reasons maybe, but no reason against space colonisation either philosophically, or evolutionarily. Humans have always perceived new environments and then gone on to colonise them.

All except Antarctica that is. There are some scientific stations,  but where are the colonies, where are the children, huh?  There's the flaw is his scheme surely.  Mars is many times less hospitable than Antarctica.

He says we require a science of extraterrestrial adaptation. It will be an evolutionary transition on a par with our ancestors coming down from the trees.  Humanity has long considered colonising space, and at present we're at the exploration stage, thinking of individuals and how they could survive on Mars. But  as an anthropologist he thinks of groups. Biocultural evolution, co-evolution of genes and culture, that’s what anthropologists study.  Up to now the anthropologists have looked at the present and the past. Cameron Smith wants them to turn their attention to the future.

Dr Cameron Smith, exo-anthropologist
He cites the example of high-altitude societies in the Andes and Tibet. Here genetic mutations allow more efficient blood oxygenation. There's cultural adaptation too, for example in the Andes mothers move down to lower altitude before giving birth. Maybe on Mars there will be a need to give birth in 1g gravity, so, by analogy with practice in the Andes, mothers perhaps will ascend to an orbital station with artificial gravity.

We can expect both beneficial and deleterious mutations to arise off-Earth he says.  Evolution will be driven by selection pressures arising from the different  gas composition, lower atmospheric pressure, and lesser gravity.  All these factors will differ from the Earth conditions that have shaped human embryo development for millions of years.  On Mars we'll see the return of natural selection, big time.   There will be an increase in infant mortality, he sees no way round this.

The Q&A session following his talk is worth listening to as well. A Mars colony would be physically fragile at first, and highly susceptible to sabotage by any of its members who went awry.  A whole new approach to mental illness will be called for.

If a one-hour audio file is too much to digest, Dr Smith also gave a 10-minute talk for SETI Big Picture Science, called “And to space we return”.