But while technology has certainly come a long way since the 1940s, it still seems a long way from achieving a fully functioning von Neumann machine. That is unless you look to biology. Even simple biological systems can accomplish amazing feats of chemosynthesis. And few people in the world today know it better than George Church. Harvard geneticists have been at the forefront of a revolution in the biological sciences for the past 30 years.Now he has a new paper space biology I’m thinking about how biology can help create pico-scale systems that could potentially allow us to explore other star systems for almost free.
“Picoscale” in this context means weighing on the order of 1 picogram. The smallest operational satellite ever created weighs only 33 grams, so reducing its size by a factor of 10-12 may sound ambitious. But that’s exactly what biological systems are potentially capable of.
A typical bacterium weighs about 1 picogram. And genetically modified enough, bacteria can do everything from disposing of toxic waste to emitting light. Therefore, Dr. Church believes these could be excellent interstellar exploration tools.
A UT video about the difficulty of interstellar travel.
The basis for that argument comes down to a combination of costs and statistics. Cost is simply a description of how much it costs to get the material into orbit. Researchers can launch trillions of pico-his size satellites for the same cost as launching a 1-gram satellite into orbit. On the surface, this seems like a very good value proposition.
Statistics show the uncertainty involved in sending probes to different star systems. Humans have never done it before, so it’s hard to know if they have any chance of survival. It is clear that a collision with any two would end the mission, and would likely result in an explosion the size of a few nuclear bombs.
With trillions of small probes, it is much more likely that at least some of them will pass through and reach their destination star system. Even when moving at relativistic speeds, it doesn’t have much effect on anything it comes in contact with, so it won’t necessarily annihilate all moving companions at once.
A picogram-sized rover certainly has some advantages, but what happens once the rover reaches a star system? It’s not particularly interesting if it doesn’t.
As Isaac Arthur argues, von Neumann machines have the potential to revolutionize space travel.Credit – Isaac Arthur YouTube Channel
Church suggests that, in theory, a single bacterium (or von Neumann probe) could create a communication device that could be detected from Earth. To do so, the presence of either bioluminescence or reflectance can be used.
Bioluminescence, or light emitted by living organisms, is theoretically detectable on the surface or atmosphere of exoplanets. The probe itself can be programmed to re-fluoresce bright enough to detect it. It could also theoretically send back some kind of information as part of that signal, such as by changing the frequency of the pulse or the wavelength of the light, if properly trained beforehand.
Alternatively, another biological phenomenon may provide the basis for communication using light. Reflectivity, and more interestingly modifiable reflectivity, may once again serve as the basis for communication protocols. Many biological substances have very high reflectance, and some can be altered based on the organism that controls them. A von Neumann probe could send a coded message back to Earth by changing the wavelength of its reflected signal by reflecting a laser aimed at the planet on which it resides.
Experiments with potential consequences of this sort push the boundaries of what is known in biology, but as Dr. Church himself deliberately admits and reiterates in his papers, this topic More research on will be an “interesting laboratory challenge.” That may be an understatement, but it helps remind those interested that inspiration and potential solutions can come from unexpected places.
This article was originally published on Universe Today By Andy Tomawick. Read the original article here.