Biology ignored some of the most abundant elements because they can't be worked with under the constrained temperature and pressure conditions where biological systems operate. Biology barely uses any silicon, even though it is the second-most common element in the biosphere. Biology does not use aluminum, the third-most common element, at all. Biology does use iron but cannot reduce it to the pure metal. In fact, bi…
> In fact, biological systems produce no metals I'm going to be very pedantic and point out a counterexample: https://en.wikipedia.org/wiki/Scaly-foot_gastropod
Is greigite a metal? It is definitely a more interesting mineral, I'll give you that.
Biology ignored some of the most abundant elements because they can't be worked with under the constrained temperature and pressure conditions where biological systems operate. Biology barely uses any silicon, even though it is the second-most common element in the biosphere. Biology does not use aluminum, the third-most common element, at all. Biology does use iron but cannot reduce it to the pure metal. In fact, bi…
The most abundant elements are the ones biology works with (except for Helium ).
This whole story is so nonsensical - we can't make self replicating probes because the materials are very hard to extract - extract from what? Perhaps if that is the case, it's because you have to get the metal from that mineral-rich rock that's like 0.1% of said metal by content. Why not build probes from the rest? Common atoms like carbon etc.
This whole story is so nonsensical - we can't make self replicating probes because the materials are very hard to extract - extract from what ? Perhaps if that is the case, it's because you have to get the metal from that mineral-rich rock that's like 0.1% of said metal by content. Why not build probes from the rest? Common atoms like carbon etc.
I imagine the extreme physical constraints will force us to explore alternative and unconventional forms of machines and computers, built from different materials available. For example, molecular or microscopic scale of self-replicating machines might be "easier" to build than what we typically think of as machines.
This whole story is so nonsensical - we can't make self replicating probes because the materials are very hard to extract - extract from what ? Perhaps if that is the case, it's because you have to get the metal from that mineral-rich rock that's like 0.1% of said metal by content. Why not build probes from the rest? Common atoms like carbon etc.
1. Carbon quality would need to be ensured somehow - sounds like extraction/refinement still necessary
Somewhat famously with life, you aren't necessarily replicating the same thing at the end as you are at the beginning, which is an awkward property for an engineered system.
So that adds some extra "benefits" (mutation and natural selection improves the probes over time) along with some extra difficulties - how do you keep the self-reproducing probes "on-task" from one generation to the next? How do you instill "explore and report home" as an innate goal to a mutating system?
> how do you keep the self-reproducing probes "on-task" from one generation to the next?
This is, indeed, the exact question one must ask before attempting to build and launch biological Von Neumann probes.
Any chemical bond is a potential source of energy. Plenty of sources of potential energy too able to be converted to work.
That's the source, but for chemical reactions you also need a sink. For instance gasoline is not usable as an energy source without an oxidant. Take away the oxygen in Earth's atmosphere (an asteroid has no atmosphere at all) and now gasoline has no potential energy available. Asteroids have no available oxidants (regolith was already fully oxidized long ago).
If it has been oxidized, there's your oxygen source.
Somewhat famously with life, you aren't necessarily replicating the same thing at the end as you are at the beginning, which is an awkward property for an engineered system.
So that adds some extra "benefits" (mutation and natural selection improves the probes over time) along with some extra difficulties - how do you keep the self-reproducing probes "on-task" from one generation to the next? How do you instill "explore and report home" as an innate goal to a mutating system?
Judging by our behavior on the current rock we're on, don't give them the choice. Humanity has been around for a long time. In that time, I don't believe I've ever heard discussion of changing the direction the Sun and Earth are headed. If there were something deep inside the Earth, or another planet that would activate in another 10,000 years that would do the phone home step, we still don't know about it. So while we're hypothesizing about sci-fi Von Neumann probes, just scale the entire thing up to the size of a solar system and send that off in the right direction. Collect all the mass in our system that isn't Sol, Terra, (and Luna), and build a rogue planet with an underground civilization, and then don't give them engines. Unless the civilization on the planet advances too the point that they can create engines, decide they don't want to go where you've sent them, voila, generational ship. Just bury a computer deep I side the rogue planet's core that activates once it reaches the destination.