Billions of tiny self-replicating satellites could unlock interstellar travel

Inspiration because space exploration can come from all corners. One of the most inspiring, or terrifying, inspirations for some in space exploration came from computer expert John von Neumann, who presented a framework for self-replicating machines in a series of lectures which he gave in 1948. Since then, scientists and engineers have debated the benefits and dangers of such a system.

However, while technology has indeed advanced a great deal since the 1940s, it seems that we are still a long way from having a fully functional von Neumann machine. Unless you turn to biology. Even simple biological systems can achieve absolutely breathtaking feats of chemical synthesis. And there are few people in the world today who know this better than George Church. The Harvard geneticist has been at the forefront of a revolution in the biological sciences for the past 30 years. Now he published a new article in Astrobiology think about how biology could help create a pico-scale system that could potentially explore other star systems at little cost.

“Pico-scale” in this context means weighing in the order of one pico-gram. Given that the smallest operational satellite ever created to date weighed just 33 grams, shrinking it to 10-12 times that size might seem ambitious. But that is precisely what biological systems could potentially do.

A typical bacterium weighs about one pico-gram. And with enough advanced genetic modification, bacteria can do everything from processing toxic waste to emitting light. Therefore, Dr Church thinks they could be an excellent tool for interstellar exploration.

UT video on the difficulties of going interstellar.

The basis of this argument comes down to a combination of costs and statistics. Cost is the simple explanation of the amount of money needed to put material into orbit. Researchers could launch trillions of pico-sized satellites for the same cost as launching a one-gram satellite into orbit. At first glance, this seems like a very good value proposition.

Statistics dictate the uncertainty that accompanies sending a probe to another star system. Since mankind has never done this before, it’s hard to know what chances one might have of surviving. But it’s clear that at relativistic speeds that would allow a probe to reach a star in a reasonable amount of time, impact with literally anything would mean the end of the mission, likely resulting in an explosion the size of several bombs. nuclear.

With trillions of smaller probes, there is a much higher probability that at least some could pass through and get to the destination star system. Even those traveling at relativistic speeds wouldn’t have too great an impact on anything they come in contact with, thus not necessarily eliminating all of their fellow travelers at once.

So there are obviously advantages to a pico-gram sized probe, but what happens when the probe reaches the star system? It wouldn’t be particularly interesting to just push a bacterium towards Alpha Centauri so that it does nothing but quickly traverse this star system upon arrival.

Von Neumann machines have the potential to revolutionize space travel, as Isaac Arthur explains. Credit – Isaac Arthur YouTube Channel

Church suggests that a single bacterium (or von Neumann probe) could, in theory, create a communication device that we could detect from Earth. To do this, it could use the presence of bioluminescence or reflectance.

Bioluminescence, or light emitted by biological organisms, would theoretically be detectable on the surface, or in the atmosphere, of exoplanets. The probe itself could be programmed to replicate and become fluorescent enough for us to detect. It could also, theoretically, send back some kind of information as part of that signal, for example by varying the frequency of the pulses or the wavelength of the light, if it had been properly trained beforehand.

Alternatively, another biological phenomenon could provide a basis for communicating using light. Reflectance, and even more interestingly changeable reflectance, could again serve as the basis for a communication protocol. Many biological materials have very high reflection rates, and some can be altered depending on the living creature controlling them. By reflecting a laser aimed at the planet on which it resides, a von Neumann probe could potentially send coded messages back to Earth by varying the wavelength of this reflected signal.

Even though experiments on these kinds of potential outcomes push the boundaries of what is known in biology, as Dr. Church himself willingly admits, as he repeatedly states in the article, much additional work on this topic would be an “interesting lab challenge”. That might be an understatement, but it helps remind those who are interested that inspiration and potential solutions can come from unexpected places.

This article was originally published on Universe today by ANDY TOMASWICK. Read the original article here.

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