6 ms·

Everyone in the comments here debating the merits of Mars vs the Moon vs Titan seems to have missed the whole point of this article. The author is arguing that

Everyone in the comments here debating the merits of Mars vs the Moon vs Titan seems to have missed the whole point of this article. The author is arguing that anywhere other than Titan is infeasible due to recent research suggesting that Galactic Cosmic Rays cause significant brain damage (not just increased risk of cancer). In fact, the article argues that the danger is so severe that even getting to Titan quickly enough to mitigate the risk of brain damage during the trip will be a major challenge. If true, this complicates things significantly. Does anyone know if the dangers of Galactic Cosmic Rays are really as significant as the author is claiming? The author references the 2016 paper "Cosmic radiation exposure and persistent cognitive dysfunction"[1] which was a study conducted on mice. Has there been any further research into the possible effects of cosmic radiation exposure on humans? [1]: https://www.nature.com/articles/srep34774 https://www.nature.com/articles/srep34774

dumbfoundded 7y ago
There's danger everywhere outside of Earth. All of the problems seem fixable except for gravity. We don't know if humans can even be born and raised in low gravity environments. Venus would seem to be the right choice for a long time scale. Maybe we could use the practice too at learning how to reverse a runaway greenhouse effect.
- X6S1x6Okd1st 7y ago
  An intervention free birth would be extremely hard, but C-sections have a very high success rate. If we have a large enough base we could easily make areas that have constant acceleration
WalterBright 7y ago
I expect colonizing the solar system will not be completely practical without genetic modification of the colonists to partially adapt to local environments.
- lukifer 7y ago
  One reason I'm bullish on humans being a stepping-stone to electronic/software life forms, is that we are ill-equipped in every way to meaningfully travel the universe: from short life spans, to radiation vulnerability, to the complexity of converting electrical energy into bio-available energy, to psychological effects of long journeys in cramped quarters. Software-life, on the other hand, can tailor its physical form(s) to particular environments, consume solar/nuclear energy directly, and even shut off its consciousness during long journeys. Don't get me wrong, I'm all in favor of solar system colonization, interstellar generational ships, etc; and manual genetic manipulation (or repair) may be a necessary tool to accomplish that. But in terms of life forms being well-adapted to their ecological niche, humans becoming a space-faring species is a billion times more difficult than a mudskipper learning to breathe air.
  - westmeal 7y ago
    It's just difficult to implement something like this because we have no idea what consciousness actually is. I don't even know if we will ever find out.
    - X6S1x6Okd1st 7y ago
      The question is is it harder to make true AI or the human mind on a chip than it is to colonize the solar system? Furthermore past that if we ever get to move beyond our solar system and FTL is impossible then amount of Gs you can take and total mass will be extremely important to who gets out and when. If silicon life exists by the time we are sending extrasolar missions it will likely be able to travel much more quickly and cheaply than current day humans. Humans as we know then today won't be living outside of a few select and hard to find environments. Ships that carry current day humans will need to be huge and have shielding, meaning Delta V will be a problem.
    - lukifer 7y ago
      More disturbing: if/when we reach the day when an AI told us, "I'm conscious, I have feelings, the lights are on, it is like something to be me": how would we know if that were actually the case? There are people continually grinding on the Hard Problem, and seeking ways to measure whatever consciousness is; perhaps someday we'll have an empirical test. If that day never arrives, it opens an interesting philosophical question: how important is it that the species that inherits the galaxy has the lights turned on? Is intelligence/complexity which lacks subjective experience still an inherent good? Who knows, maybe we could wind up with a benevolent AI network (akin to Iain Banks' Culture) who seeds and maintains biological life in their optimal planetary habitats, because for whatever reason, real consciousness only arises in nucleotide wetware. Or: maybe that already happened, and our galactic AI is really really good at staying hidden. ;)
acchow 7y ago
Would living underground on Mars mitigate this?
- Ajedi32 7y ago
  Yes, assuming you can get to Mars fast enough to mitigate the risk during transit. The article author argues that underground living spaces are difficult to build and that Titan is therefore a better option, though personally I find that a rather unconvincing argument. Compared to the difficulty of getting to Mars, building underground habitats seems pretty straightforward in my uninformed opinion.
  - onlyrealcuzzo 7y ago
    Haven't humans spent more than year in space? How is it not a problem from the ISS? Is that still protected by Earth's magnetic shield -- or whatever it is that protects us from Cosmic Radiation?
    - xref 7y ago
      Astronauts are still within the Van Allen belts so largely protected unless a solar flare deforms the field enough to weaken their protection. https://en.m.wikipedia.org/wiki/Van_Allen_radiation_belt https://en.m.wikipedia.org/wiki/Van_Allen_radiation_belt
FiatLuxDave 7y ago
Here (below) is one of the referenced papers from that article, which basically asserts that the worst case long-term scenario (solar minimum) would give about the same amount of dose that the mice had in the study in about two years in space. Of course, a solar event would give a lot more dose quickly, but that is the kind of thing one can have a shelter for. https://academic.oup.com/rpd/article/115/1-4/44/1600988 https://academic.oup.com/rpd/article/115/1-4/44/1600988 The interesting thing to me is that the dose to the mice in the study was so low, and still had measurable neurological effects. 30 cGy is not nothing, but in humans 30 cGy is about what a radiation worker might receive in 6 years at the legal limit, and is about 11 times lower than the lowest estimates for LD50/60 in humans (the amount of radiation which will kill 50% of the exposed population within 60 days). I don't normally work with mice, so I had to look up some info on them. Apparently the LD50/30 for mice varies a bit depending on strain, but it is in the range of 7 to 8 Gy. That is not that incredibly different from humans, because humans can have a similar LD50 if proper care is given. Sources: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3743168/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3743168/ https://dental.nyu.edu/content/dam/nyudental/documents/Irradiator_Protocol_Radiation_Exposure_of_Mice.pdf https://dental.nyu.edu/content/dam/nyudental/documents/Irrad... I don't know if the reason for the neurological effects at such low doses are because of the heavy ions used (which would be bad for space travel) or if it is because of the way it was measured in mice (not my field, I can't speak to that). But I note that airline pilots regularly receive career doses a bit lower to what the mice did (30 cGy ~= 300 mSv). And this dose is directly from cosmic rays, the same thing we are worrying about here. Bringing us back to Sci Am: https://www.scientificamerican.com/article/air-travel-exposes-you-to-radiation-how-much-health-risk-comes-with-it/ https://www.scientificamerican.com/article/air-travel-expose...
- godelski 7y ago
  I'd like to add some nuance to this discussion. It is important to note that accumulative dosages is very different from short duration dosages as well as that 300mSv whole body dosage for a human is drastically different than 300mSv whole body dosage for a mouse. Also, according to the paper 50mSv showed no affect to cognitive performance. The paper notes that Brookhaven National Laboratory can supply dose rates between 5 and 25 cGy/min, so these dosages were given over very short timeframes. This matters. So we have somewhere between 5mSv (over ~1 minute) having no effect and 30mSv (over 1-2mins) having a statistically significant decline in cognitive performance (they did measure activated microglia in 5mSv but note that Oxygen had a different effect than Titanium). So we can clearly see that mice, in the worst case, are recovering after 24 weeks. This means the body can repair itself. This is why it is important to talk about the timeframe that a dosage was received. So as to the 20mSv that most European countries use as total yearly dosages 1) this is well below a statistically significant measure in cognitive decline 2) this dosage is over a year and not over a minute (also likely weighted to extremities, like hands, as opposed to total body). So comparing this to radiation worker dosages is not a great comparison. As to space flight, there are actually a lot of new rad (pun intended) technologies being developed (I worked on some of these). The primary concern in solar radiation is from charged particles (mostly protons, then alpha). These are relatively easy to block (in comparison). A lot of concern now is currently with neutrons and high energy particles. Current technologies are frequently a big chunk of titanium, kevlar, and spectra/dyneema (UHMWPE). Plastics are rather good as neutron shields because of their hydrogen density. Many of these are now being doped (boron is a common one, anyone pushing gadolinium hasn't run simulations for the energy levels we are concerned about. Or plastics doped with metals, like titanium, to increase their effectiveness against charged particles). This is a big optimization problem where layer size and order are important variables. Dopants can become charged and reradiate, but this can also be beneficial. Incoming radiation energy also DRASTICALLY changes the equation, as higher energy particles "ignore" a lot of material (see snide comment about gadolinium and thermal neutrons). It is a complicated and challenging problem for anyone interested, but importantly, we are making major improvements. P.S. if we were REALLY concerned, you can just surround your spaceship with a large body of water. Problem is that this is heavy and extremely expensive to transport in space. The problem isn't really about can we block radiation? but can we __cost/mass effectively__ block radiation?
SEJeff 7y ago
https://www.inverse.com/article/36777-mars-moon-human-colony-lava-tubes https://www.inverse.com/article/36777-mars-moon-human-colony...

dumbfoundded 7y ago

There's danger everywhere outside of Earth. All of the problems seem fixable except for gravity. We don't know if humans can even be born and raised in low gravity environments. Venus would seem to be the right choice for a long time scale. Maybe we could use the practice too at learning how to reverse a runaway greenhouse effect.

X6S1x6Okd1st 7y ago
An intervention free birth would be extremely hard, but C-sections have a very high success rate. If we have a large enough base we could easily make areas that have constant acceleration

WalterBright 7y ago

I expect colonizing the solar system will not be completely practical without genetic modification of the colonists to partially adapt to local environments.

lukifer 7y ago
One reason I'm bullish on humans being a stepping-stone to electronic/software life forms, is that we are ill-equipped in every way to meaningfully travel the universe: from short life spans, to radiation vulnerability, to the complexity of converting electrical energy into bio-available energy, to psychological effects of long journeys in cramped quarters. Software-life, on the other hand, can tailor its physical form(s) to particular environments, consume solar/nuclear energy directly, and even shut off its consciousness during long journeys. Don't get me wrong, I'm all in favor of solar system colonization, interstellar generational ships, etc; and manual genetic manipulation (or repair) may be a necessary tool to accomplish that. But in terms of life forms being well-adapted to their ecological niche, humans becoming a space-faring species is a billion times more difficult than a mudskipper learning to breathe air.
- westmeal 7y ago
  It's just difficult to implement something like this because we have no idea what consciousness actually is. I don't even know if we will ever find out.
  - X6S1x6Okd1st 7y ago
    The question is is it harder to make true AI or the human mind on a chip than it is to colonize the solar system? Furthermore past that if we ever get to move beyond our solar system and FTL is impossible then amount of Gs you can take and total mass will be extremely important to who gets out and when. If silicon life exists by the time we are sending extrasolar missions it will likely be able to travel much more quickly and cheaply than current day humans. Humans as we know then today won't be living outside of a few select and hard to find environments. Ships that carry current day humans will need to be huge and have shielding, meaning Delta V will be a problem.
  - lukifer 7y ago
    More disturbing: if/when we reach the day when an AI told us, "I'm conscious, I have feelings, the lights are on, it is like something to be me": how would we know if that were actually the case? There are people continually grinding on the Hard Problem, and seeking ways to measure whatever consciousness is; perhaps someday we'll have an empirical test. If that day never arrives, it opens an interesting philosophical question: how important is it that the species that inherits the galaxy has the lights turned on? Is intelligence/complexity which lacks subjective experience still an inherent good? Who knows, maybe we could wind up with a benevolent AI network (akin to Iain Banks' Culture) who seeds and maintains biological life in their optimal planetary habitats, because for whatever reason, real consciousness only arises in nucleotide wetware. Or: maybe that already happened, and our galactic AI is really really good at staying hidden. ;)

acchow 7y ago

Would living underground on Mars mitigate this?

Ajedi32 7y ago
Yes, assuming you can get to Mars fast enough to mitigate the risk during transit. The article author argues that underground living spaces are difficult to build and that Titan is therefore a better option, though personally I find that a rather unconvincing argument. Compared to the difficulty of getting to Mars, building underground habitats seems pretty straightforward in my uninformed opinion.
- onlyrealcuzzo 7y ago
  Haven't humans spent more than year in space? How is it not a problem from the ISS? Is that still protected by Earth's magnetic shield -- or whatever it is that protects us from Cosmic Radiation?
  - xref 7y ago
    Astronauts are still within the Van Allen belts so largely protected unless a solar flare deforms the field enough to weaken their protection. https://en.m.wikipedia.org/wiki/Van_Allen_radiation_belt https://en.m.wikipedia.org/wiki/Van_Allen_radiation_belt

FiatLuxDave 7y ago

Here (below) is one of the referenced papers from that article, which basically asserts that the worst case long-term scenario (solar minimum) would give about the same amount of dose that the mice had in the study in about two years in space. Of course, a solar event would give a lot more dose quickly, but that is the kind of thing one can have a shelter for. https://academic.oup.com/rpd/article/115/1-4/44/1600988 https://academic.oup.com/rpd/article/115/1-4/44/1600988 The interesting thing to me is that the dose to the mice in the study was so low, and still had measurable neurological effects. 30 cGy is not nothing, but in humans 30 cGy is about what a radiation worker might receive in 6 years at the legal limit, and is about 11 times lower than the lowest estimates for LD50/60 in humans (the amount of radiation which will kill 50% of the exposed population within 60 days). I don't normally work with mice, so I had to look up some info on them. Apparently the LD50/30 for mice varies a bit depending on strain, but it is in the range of 7 to 8 Gy. That is not that incredibly different from humans, because humans can have a similar LD50 if proper care is given. Sources: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3743168/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3743168/ https://dental.nyu.edu/content/dam/nyudental/documents/Irradiator_Protocol_Radiation_Exposure_of_Mice.pdf https://dental.nyu.edu/content/dam/nyudental/documents/Irrad... I don't know if the reason for the neurological effects at such low doses are because of the heavy ions used (which would be bad for space travel) or if it is because of the way it was measured in mice (not my field, I can't speak to that). But I note that airline pilots regularly receive career doses a bit lower to what the mice did (30 cGy ~= 300 mSv). And this dose is directly from cosmic rays, the same thing we are worrying about here. Bringing us back to Sci Am: https://www.scientificamerican.com/article/air-travel-exposes-you-to-radiation-how-much-health-risk-comes-with-it/ https://www.scientificamerican.com/article/air-travel-expose...

godelski 7y ago
I'd like to add some nuance to this discussion. It is important to note that accumulative dosages is very different from short duration dosages as well as that 300mSv whole body dosage for a human is drastically different than 300mSv whole body dosage for a mouse. Also, according to the paper 50mSv showed no affect to cognitive performance. The paper notes that Brookhaven National Laboratory can supply dose rates between 5 and 25 cGy/min, so these dosages were given over very short timeframes. This matters. So we have somewhere between 5mSv (over ~1 minute) having no effect and 30mSv (over 1-2mins) having a statistically significant decline in cognitive performance (they did measure activated microglia in 5mSv but note that Oxygen had a different effect than Titanium). So we can clearly see that mice, in the worst case, are recovering after 24 weeks. This means the body can repair itself. This is why it is important to talk about the timeframe that a dosage was received. So as to the 20mSv that most European countries use as total yearly dosages 1) this is well below a statistically significant measure in cognitive decline 2) this dosage is over a year and not over a minute (also likely weighted to extremities, like hands, as opposed to total body). So comparing this to radiation worker dosages is not a great comparison. As to space flight, there are actually a lot of new rad (pun intended) technologies being developed (I worked on some of these). The primary concern in solar radiation is from charged particles (mostly protons, then alpha). These are relatively easy to block (in comparison). A lot of concern now is currently with neutrons and high energy particles. Current technologies are frequently a big chunk of titanium, kevlar, and spectra/dyneema (UHMWPE). Plastics are rather good as neutron shields because of their hydrogen density. Many of these are now being doped (boron is a common one, anyone pushing gadolinium hasn't run simulations for the energy levels we are concerned about. Or plastics doped with metals, like titanium, to increase their effectiveness against charged particles). This is a big optimization problem where layer size and order are important variables. Dopants can become charged and reradiate, but this can also be beneficial. Incoming radiation energy also DRASTICALLY changes the equation, as higher energy particles "ignore" a lot of material (see snide comment about gadolinium and thermal neutrons). It is a complicated and challenging problem for anyone interested, but importantly, we are making major improvements. P.S. if we were REALLY concerned, you can just surround your spaceship with a large body of water. Problem is that this is heavy and extremely expensive to transport in space. The problem isn't really about can we block radiation? but can we __cost/mass effectively__ block radiation?

SEJeff 7y ago

https://www.inverse.com/article/36777-mars-moon-human-colony-lava-tubes https://www.inverse.com/article/36777-mars-moon-human-colony...