OUR BRAINS CONTINUE TO SURPRISE

Two news stories about the human brain are worth passing along this week.

The first is a potential breakthrough by Australian researchers in the treatment of Alzheimer’s disease. One of the primary causes of Alzheimer’s is the build-up of what’s known as amyloid plaques between the nerve cells of the brain (neurons) that interfere with the transmission of signals. Drug-based treatments for Alzheimer’s have had limited success partly because the body’s own blood-brain barrier, meant to protect the brain from invaders, does a good job of keeping out helpful chemicals too. The new treatment involves using focused therapeutic ultrasound—gentle sound waves that nudge the blood-brain barrier open to help the body’s clean-up crew (microglial cells) to remove the offending plaques. So far, test results in mice have been very promising, restoring 75% of memory function without causing damage. That’s still a long way from curing humans, true. But having witnessed the ravages of dementia up close in the last years of my mother’s life, I appreciate any good news in the fight against it.

The second story involves a new calculation of the data processing capability of the human brain. Signals pass between neurons via special structures called synapses, so it’s not hard to understand that the ability of a neuron to pass signals will be affected by the number and size of the synapses it has. It was thought that there are only a few different types and sizes of synapses in our brains, but when a team led by the Salk Institute recreated brain tissue down to the nanometre scale for the first time, they discovered that synapses change according to how they’re used, and how often. The Salk scientists and their partners calculated that there could be as many as twenty-six different categories of synapses, adjusting themselves as needed, which goes a long way toward explaining how the brain accomplishes so much using so little energy (the power consumption of a dim light bulb, they say). But it also means that our brain’s capacity for storing information could be ten times greater than previously thought—possibly in the range of a petabyte (a million gigabytes) which is the equivalent of all the storage in the World Wide Web.

Are you feeling impressed with yourself yet?

A long-lived urban myth suggested that we only use about ten percent of the capacity of our brains. That claim has been thoroughly discredited by neuroscientists, but the Salk Institute findings have to make you wonder if there isn’t a way we could somehow make even better use of all the brainpower we have. It’s a vast amount of storage, yes, but what if we could improve our information processing, filing, and retrieval systems? For one thing, we might never again lose our car keys (!), but we also might have less and less need for digital computers. Since synapses respond to need, picture flicking a mental switch to turn on “mathematics mode” or “language mode” to temporarily divert cognitive resources to a specific task. We could be specialized  geniuses on demand! The idea of someday using a human brain to store secret data archives (like in the TV show Chuck or the movie Johnny Mnemonic) seems more plausible too.

But doesn’t it also make you wonder if there aren’t other potential capabilities within our brains that we’ve either forgotten how to use or just haven’t learned yet? Most scientists would scoff at the idea of so-called “paranormal” powers like telekinesis and telepathy, and most science fiction writers relegate such things to fantasy instead of SF. I’m not so sure. For one thing, I accept that there are dimensions of existence that we don’t currently perceive, but mathematicians and physicists readily include them in their theories about the universe. And I can accept that the universe includes an underlying level of information, call it what you will. Human beings don’t normally tap into such things because we haven’t needed to for our survival, but that doesn’t mean it’s beyond our ability if we only knew how.

I believe that each new discovery about the human body and mind in physical terms leads to a deeper understanding of ourselves in a holistic and even philosophical context. So news stories  like these reinforce my conviction that the human adventure is far from over and there are many wonders yet to come.

ADAPTING HUMANS TO OTHER PLANETS, PART TWO

In my last post I speculated about how we might adapt ourselves to the environments of other planets rather than trying to terraform them or forever be confined to enclosed settlements and space suits. I used Mars as an example of an “earthlike” planet we might consider colonizing.

A Mars-type planet would be an easy challenge compared to others like Venus. The Venusian atmosphere is also mostly carbon dioxide but the air pressure at the surface is ninety times that of Earth, like being a thousand meters deep in the ocean. We know that fish and other creatures can exist at those depths, and some whales can dive even deeper for a time—so it’s not inconceivable that our bodies could be adapted for it (maybe even encouraged to grow a hard shell?) But again, we wouldn’t be breathing—air at that pressure is basically a fluid. We’d have to get oxygen and/or energy another way. And Venus is hot—hotter than Mercury—about 460 C at the surface. If there is any part that might be relatively hospitable to humans it would be the upper atmosphere, about fifty kilometers high, where the temperature and pressure are nearly Earth-normal. There are obstacles though: winds over 300 kilometers per hour and clouds full of sulphuric acid!

OK, so maybe Venus-like worlds will be beyond biological adaptations and require either full space suits or at least extensive mechanical adaptations.

Gas giant planets don’t hold much attraction as homes-away-from-home, but many of their moons might. With a tough enough skin and a metabolism that uses chemosynthesis instead of air-breathing, maybe we could survive in a near-vacuum, but it’s hard to imagine that we could ever adapt our bodies to temperatures that can freeze water as hard as granite. On Jupiter’s moon Europa, for example, the temperature at the equator (you know, the beach resort zone) averages about -160 C. Where there is a possibility of survival, however, is under the icy surface in an ocean of water. Someday we may create humans who can function as aquatic creatures, in which case our own planet’s oceans will provide a vast amount of space to explore and inhabit.

There’s a chance that we’ll discover planets elsewhere that are almost identical to Earth and already support life. In that event, our problem will be that some of the life, particularly microorganisms, could be utterly hostile to humans. Deadly germs or bacteria. Then we’ll need to either adapt our immune systems to cope with the pathogens, or adapt our whole bodies to co-exist with the alien organisms (although, to be accurate, we’ll be the aliens).

I haven’t even touched on the whole area of technological enhancements to the human body—turning us into partly-cybernetic organisms, or cyborgs. Maybe in another blog someday. And, of course, there are huge philosophical and ethical questions involved whenever the question of bio-engineered humans is raised. Is it too big a risk? If such genetic engineering had to occur at an early age or even at the fetal stage, could we make such decisions for our children? Most of all, how much can you change someone before they’re no longer human? We don’t mind the idea of fictional superheroes transformed by a radioactive spider bite or gamma radiation—the reality might evoke feelings that are quite different.

For now, I’m content to leave this as an exercise of the imagination, but the time will come when we achieve the capability for such things. I hope we’ll have resolved our questions about it by then.

COULD HUMANS BE ADAPTED TO OTHER PLANETS?

In a recent post I mentioned that there are huge amounts of water elsewhere in the solar system—much more than actually exists on Earth. And when scientists assess the potential of other star systems to host life, the foremost yardstick they use is the presence of water, especially liquid water. Where there’s liquid water, there could be life that we would recognize. So a planet orbiting its sun in the so-called “Goldilocks zone” (not too hot, not too cold) might have liquid water and thus be capable of supporting life. Maybe.

This fairly narrow view isn’t so much based on the idea that we only want to meet aliens that look like us (as in most Star Trek episodes) but more because we want to visit places that will present the fewest obstacles to our survival there. Lots of oxygen in the air would be nice. Clean drinking water. Reasonable weather. Gravity that doesn’t make us feel like we’re wearing lead overcoats.

You’ve probably heard news stories about “earthlike” planets being discovered around other stars. That description usually only means that they’re rocky planets instead of gas giants, and they’re not frozen or roasting hot. That’s it. Everything else about them might be far different from Earth—we just don’t know because those planets are too far away. We do know about the planets in our own solar system, and by the above standards Mars would be considered earthlike, except a little cold. But we certainly can’t live there. At least, not yet.

For humans to survive on another planet—in this solar system or any other—there are three ways to do it. The ways that get the most attention are: 1) building habitats (even domed cities) that will protect us from the planet’s hostile elements and enclose a simulated Earth environment; and 2) change the planet’s entire ecosphere into a close approximation of Earth’s—what is called terraforming. Enclosed habitats will always be very restrictive and costly to expand, while terraforming some place like Mars would take thousands of years.

The third option is to change the human body itself in ways that will adapt us to the alien environment.

On Mars that would require quite a few changes. We know that people can adapt to colder climates (especially over a number of generations) but even Mars’ most hospitable climes would require genetic tweaking to rev up our metabolism, increase blood flow, and grow much thicker layers of insulating fat under our skin. We’d have to grow a tougher skin, too, with closable orifices—even skin pores and tear ducts—to prevent the low air pressure from boiling away our bodily fluids. These things aren’t inconceivable as we get better and better at gene splicing—we’d find organisms with those traits here on Earth (perhaps creatures that live in extreme environments) and splice the necessary genes onto our own genome. Even so, a few more mechanical implants might also be in order, like heating coils in our nostrils to warm our inhaled air!

Mars’ atmosphere is mostly carbon dioxide with very little oxygen, so to avoid the need to carry air with us we’d have to either re-engineer our body cells to use some energy source other than oxygen, or get assistance from something that can make the oxygen we need from CO2. Plant life uses photosynthesis to produce food energy from carbon dioxide and water using sunlight (but it’s slow). Creatures that live around deep-sea volcanic vents use chemosynthesis instead, getting their energy, not from sunlight, but from the oxidation of compounds like hydrogen sulphide gas. Giant tube worms, crabs, clams and others are filled with proteobacteria and archaea—some of the earliest life forms on the planet—which replace their usual digestive tracts of stomach, intestines etc. And we know many kinds of algae and bacteria that can produce oxygen from materials in their environment, including the bacteria Methylomirabilis oxyfera which extracts oxygen from nitrates in the river mud where it lives. Since our bodies already carry around hundreds of types of bacteria that help keep us alive, it’s not a huge stretch to believe that a few additional species might help us exist on other worlds.

Mars would be one of the easier planets for us to adapt to. And, of course, there’s the whole ethical question of whether or not we should tinker with the human body to that extent at all. But that topic will have to wait until my next post. In the meantime you can read some other people’s thoughts about this here, here and here.

WATER AT HOME AND OUT THERE

At a time of year when my part of the world gets its fresh supplies of water in the form of snow, water was on my mind because of a number of science news stories.

People writing about climate change often mention the estimate that if all of the ice pack on Antarctica were to melt it would raise the sea level of the world’s oceans by about twenty-three feet. That figure can certainly be argued, and I don’t think most scientists expect all of the ice to melt (a controversial study released last year claimed that at least parts of the Antarctic continent were gaining ice), but a new report is cause for concern. Until now, it was thought that Antarctica’s ice structure itself would buffer much of the ice melt and slow the melt water’s progress to the sea. That’s because much of the continent is covered with a thick layer of very porous ice called firn that lies on top of the hard glacial ice and is capable of trapping a lot of melt water in its spaces. But new research says that heavy melting, particularly in 2012, filled the upper layers of firn and then refroze to create hard ice. That new hard layer is preventing melt water from getting down to the porous spaces beneath it so a lot of potential storage space is out of reach and the water is running off into the ocean more quickly than expected. What the results will be, no-one is sure.

The cloud cover over Antarctica also affects the rate of melting, and for the first time since the late 1960’s scientists will be doing extensive in-place measurement of those clouds in a project called the Atmospheric Radiation Measurement West Antarctic Radiation Experiment (AWARE), which got underway a couple of months ago and will run until early 2017. Predicting the effects of climate change is incredibly complex, and every bit of data will help. (A voice in my mind just started humming, “I’ve looked at clouds from both sides now…”)

I have a great idea for a novel that involves tunnelling through the ice of Antarctica (no, I’m not going to call it Firngully) but so far just thinking about on-site research has given me chills.

While on the one hand climate change is a threat because of rising seawater (and the unknown effects of large amounts of fresh melt water on salty ocean currents), a hotter climate also poses a serious threat to the planet’s fresh water supplies. California’s recent drought years could be just a taste of things to come.

Maybe we need to hijack one of Jupiter’s moons.

A Scientific American article reminds us that there is a lot of water in our solar system. Jupiter’s moon Ganymede alone might contain as much as thirty times the amount of water in Earth’s oceans, and that’s liquid water beneath ice. It’s not alone—there’s good evidence that Jupiter’s moon Europa and Saturn’s moon Enceladus have liquid water, and a number of other moons probably do. Of course, to bring any of it back to Earth would be a formidable technical challenge, but liquid water “out there” improves our prospects of creating colonies, farming installations, or manufacturing facilities elsewhere in the solar system. There ought to be more science fiction stories about that—maybe fewer spaceships and more submersibles, fewer spacewalks and more extraterrestrial swims!

Aaah, just picture it: tying up the boat and putting away the waterskis, then cracking open a brew while you sit on the dock and look up at Jupiter waxing overhead. That’s the life!

OK, so maybe the snow is getting to me.