[HN Gopher] Mars Now
___________________________________________________________________
Mars Now
Author : 1970-01-01
Score : 140 points
Date : 2022-12-13 17:35 UTC (5 hours ago)
(HTM) web link (mars.nasa.gov)
(TXT) w3m dump (mars.nasa.gov)
| kuprel wrote:
| Wonder if the stars are accurate. The Sun is missing
| moffkalast wrote:
| That's not the only thing that's missing. Where's the Mars
| Reconnaissance Orbiter?
| ledauphin wrote:
| This is neat but the mouse controls are maybe 5x too twitchy on
| my fairly standard Mac in Chrome. Google Earth's tuning is very
| usable in a way that this is not.
| reset2023 wrote:
| Can't get the fascination with this desert? It's like post
| apocalyptic Earth.
| z3phyr wrote:
| Short answer: It is in space and relatively easier to get to
| than other planets in the system. It is a gateway to becoming
| space-faring civilization.
| idlewords wrote:
| The second part of this answer is a non-sequitur. Why Mars in
| particular? The technology needed to get there doesn't carry
| over to any other destinations except the Moon and Venus, and
| it's much easier to build next-generation rockets on Earth.
| Why not just skip Mars and go straight to step 2?
| mlindner wrote:
| You need resources to build with. Venus isn't an option
| because you can't get resources from it. (If there's two
| things you need, it's energy, and physical materials.) The
| Moon is certainly an option, but while Mars is a desert,
| the moon is volcanic rock and never had active geology that
| concentrates metals. Additionally while Mars has an
| atmosphere of sorts, the Moon has none which means anything
| mounted on the surface of the moon is in an equivalent
| environment to being in deep space. This means there's zero
| protection (besides the planetary body itself) from
| radiation and micrometeorites (and bigger meteorites). They
| rain down constantly on the moon slowly carving divots into
| whatever you build things out of or punching holes in them.
|
| Also I disagree that the technology to get to Mars or the
| Moon is inapplicable to elsewhere in the solar system. And
| most of the other options are generally worse than Mars for
| one reason or another. I'd like to hear what you think
| "Step 2" actually is.
| idlewords wrote:
| We have resources at home!
| mlindner wrote:
| We do! And for a long while most of the resources will
| come from Earth. However you can't keep doing that
| forever as the costs will grow to an unsustainable level.
|
| If you could magic up a civilization on Mars today, it'd
| exponentially cheaper to launch materials from Mars to
| elsewhere in the solar system than to launch those same
| materials from Earth. Similarly it'd be cheaper to dig
| those materials out of the ground for use on Mars than it
| would be for them to be used directly on Mars.
|
| Counterintuitively, it's cheaper to launch materials from
| Mars to Earth's Moon than it is to launch them from
| Earth's surface to the Moon.
| mlindner wrote:
| One note on the "exponentiality" in the other comment.
| Getting from Earth's surface to the moon (without
| staging) requires a rocket that is approximately 99% fuel
| by mass (calculated using rocket equation and engine
| performance of a high quality engine). That leaves you
| with very little margin for building a rocket's structure
| which means it needs to be built extremely carefully with
| little room for error. Also in order to get reasonable
| payloads, you need to make rockets of tremendous sizes in
| order to get reasonably sized payloads to locations.
|
| On the other hand a rocket that flies from Mars surface
| too Earth's moon only needs to be 90% fuel which is a lot
| easier to do with modern materials. This also means that
| you can carry significantly more payload as your total
| mass.
|
| With some napkin math, this allows you to launch, with
| the same rocket, from the surface of Mars to Earth's moon
| a payload 10 times bigger than if you launched it from
| Earth. The penalty you pay getting stuff out of Earth's
| gravity well is just simply huge.
| xboxnolifes wrote:
| It's not just the technology to get there we need. We need
| the technology to _live_ there.
| idlewords wrote:
| Absolutely true, but my point is that there's no
| destination beyond Mars reachable with the spaceships we
| build to get there. So I don't get how it's some sort of
| gateway rather than a detour / dead end.
| lmm wrote:
| > The technology needed to get there doesn't carry over to
| any other destinations except the Moon and Venus.
|
| The technology for living there, and some of the technology
| for going places, does. Would you really want to try to go
| to Epsilon Eridani without going to Mars first?
|
| > it's much easier to build next-generation rockets on
| Earth
|
| Ultimately probably not; Earth's gravity well is too deep.
| Mars is, AFAIK, the only place we could conceivably build a
| space elevator with current materials technology, so if we
| assume interstellar rockets will need to be built with
| materials from both asteroids and planets then Mars orbit
| is likely the best place for that.
| algo_trader wrote:
| I logged in to un-down-vote you.
|
| Going to Mars is a legitimate goal.
|
| But i would also like to see a make-the-Sahara-green-(ish)
| program.
|
| Why not a Neom-but-in-a-viable-way program.
|
| ALso, an even bigger debate is Appolo-mission-to-Mars vs
| 10-other-unmanned-programs-for-the-Solar system.
| kitsunesoba wrote:
| Intentionally radically altering the climate of large areas
| like the Sahara seems very dangerous in a way that nothing
| that could be done on other celestial bodies could ever be.
| Not that it shouldn't be considered, but I think it calls for
| a far greater degree of caution than e.g. experiments to
| bring life to small domed areas of the surface of Mars.
| idlewords wrote:
| If you have the technology to make small domed oases, make
| them in the Sahara (or Antarctic, or wherever). No need to
| change the climate, and you save the cost of a Mars trip.
| airstrike wrote:
| I upvoted you because it's a fair question, but I would argue
| it is easier to criticize than to offer solutions.
|
| What other solar system destination would you propose instead?
| It's not like we have a lot of convenient alternatives to
| choose from.
|
| I'd rather visit Mars than Venus, that's for sure.
| idlewords wrote:
| We can visit everything for much less than the price of Mars
| if we drop the requirement to send people. There's cool stuff
| in the solar system and the future where you can flip between
| live feeds from every moon is much more fun than watching
| space dads sit in a radiation shelter on Mars for 17 months.
| AnimalMuppet wrote:
| Venus is great! Come visit! Stay at the beautiful Hyatt
| Floating Resort! It's got everything you want - Earth
| temperature and pressure, _lots_ of solar energy to power
| your every whim, beautiful sunrises and sunsets.
|
| Just don't visit the _surface_. It 's really, really nasty
| down there.
| verdenti wrote:
| kossTKR wrote:
| After researching this a bit it's mostly a money and reputation
| laundering scheme for the elite classes that millions of upper
| middle class westerners buy into to smokescreen what's wasted
| on war and geopolitical efforts to protect various western
| family dynasties hold on power.
|
| Even though it's a future that is grotesquely unfeasible and
| unwanted for anyone besides the richest 100 people on earth as
| as ultra decadent projects while 95% of the population on earth
| lives in societies on their way to collapse from resource
| depletion and rising inequality.
| ultramegachurch wrote:
| This is a shockingly cynical and reductive take on Mars
| exploration. The enthusiasm for human exploration of the
| solar system is earnest and valid, and I assure you, not a
| cog in an international conspiracy. One doesn't have to
| choose between space exploration and addressing resource
| depletion/inequality. You can care about both.
| kossTKR wrote:
| I was a huge sci fi and science nerd 10 years ago and still
| am, and honestly i would love to go back and care less
| about how the world works, but to me the very real
| fascination with "actual scientists" and "actual science"
| has been overshadowed by the siphoning, the false promises
| and the cooking of statistics that happens while everyones
| tax dollars get channeled into a fog somewhere between
| "external enemies" and technooptimist drivel.
|
| The fact is that we could use our money on something real,
| something tangible like saving earth instead of war
| machines and false promises while the gini coeffecient goes
| crazy and public education fails.
|
| And i mean this is not just a perspective i've got from
| researching economics, but from having lots of family in
| academic science - i've seen how much is about grant money,
| towing the line and about furthering some state or
| corporate cause sadly.
| idlehand wrote:
| The US military budget is ~3.5% of GDP. It makes up about
| 10% of all government spending. 90% of your tax money
| does not go to war machines.
| melling wrote:
| Yes, we could explore the solar system much more quickly
| and much more cheaply, if we simply leave out the humans.
|
| This has been explained repeatedly for decades.
|
| There will be more humans on Mars in 100 years, if we skip
| sending the humans now and develop the technology to
| automate process first.
|
| maybe someone can find Weinberg's detailed explanation for
| others to read.
|
| https://www.space.com/4357-nobel-laureate-disses-nasa-
| manned...
| burkaman wrote:
| If you discovered a post apocalyptic Earth somewhere in the
| solar system, you wouldn't have any interest in checking it
| out? It's ok to say no to this, but just be aware that most
| people consider "because it's there" to be a legitimate and
| relatable answer to your question.
| JumpCrisscross wrote:
| > _most people consider "because it's there" to be a
| legitimate and relatable answer to your question_
|
| I don't think hackers, explorers and founders have ever been
| most people.
| burkaman wrote:
| No, but most people think hacking, exploring, and founding
| stuff is cool even if they don't do it themselves.
| bavila wrote:
| What data do you have that demonstrates what "most"
| people think is "cool" in this respect?
| sophacles wrote:
| You are correct: historically hackers, explorers and
| founders are significantly more likely to respect "because
| I can" as a reason for doing something than the average
| person.
| burkaman wrote:
| I think "because it's there" is the more respectable
| subset of "because I can", covering stuff like climbing
| Mount Everest and venturing to the South Pole. "because I
| can" for me often implies something like asserting power
| over other people or just generally being an asshole.
| idlewords wrote:
| Venus is the post-apocalyptic Earth you're looking for.
| justinpombrio wrote:
| Just want to clarify, in case someone reads this and thinks
| "like in the movies, where after the apocalypse it's barren
| and radioactive and very hot or cold and you can't survive
| outside unless you're wearing a suit". That's _not_ what it
| 's like on Venus.
|
| The atmosphere is made mostly of CO2. At the surface, it
| has a pressure of 93 times that of Earth, and temperature
| of 464 degC / 867 degF. This is sufficiently hot and
| pressurized that the atmosphere is neither a gas nor a
| liquid, it's a supercritical fluid. Wikipedia says that we
| use supercritical CO2 industrially because of how good it
| is at dissolving things.
|
| The record survival time for a _stationary probe_ on the
| surface of Venus is 127 minutes.
|
| https://en.wikipedia.org/wiki/Venus#Physical_characteristic
| s
|
| https://en.wikipedia.org/wiki/Supercritical_fluid
|
| https://en.wikipedia.org/wiki/Observations_and_explorations
| _...
| idlewords wrote:
| Venus is also pretty cozy if you're willing to bring a
| blimp. At 52 kilometers, the temperature is 27 C and
| pressure is about half of Earth sea level. If it weren't
| for the sulfuric acid clouds, you could sit on a platform
| outside in just your shorts and an oxygen mask. Not many
| other places in the solar system can offer that!
| TEP_Kim_Il_Sung wrote:
| Venus became that way because of its' oceans and no
| counterbalancing moon.
| ipnon wrote:
| To be fair plenty of Earthlings say the same about their own
| planet. I for one am glad enough people do not share your
| opinion, which is completely valid, so that we can do the
| adventurous and exciting things that make life wonderful.
| matheusmoreira wrote:
| It's an entire planet. Full of resources, land, opportunity for
| the entire human race if we could only get there and tame it.
| Surely everone can agree that it's a noble goal.
| [deleted]
| molsongolden wrote:
| > _Earthers get to walk outside into the light, breathe pure
| air, look up at a blue sky, and see something that gives them
| hope. And what do they do? They look past that light, past that
| blue sky. They see the stars, and they think, 'Mine.'_
|
| (from The Expanse)
| CamperBob2 wrote:
| So? That's what got us out of the caves in the first place.
|
| The first words spoken on Mars should be, "Cool. Now, how far
| is Jupiter from here?"
| [deleted]
| idlewords wrote:
| We've known since Pioneer 11 that Jupiter is a no-go for
| the type of spaceships that can get to Mars. Too much
| radiation on the way, and too much around Jupiter. Mars is
| the end of the line until we can build spacecraft in the
| 10,000 ton range.
| AnimalMuppet wrote:
| Why? (Not saying you're wrong, just...
| explain/substantiate your claim.)
| idlewords wrote:
| The general problem is cumulative exposure to cosmic rays
| on long-duration flights. It's not clear if even a Mars
| mission has acceptable risk, and flights past Mars mean
| everyone gets a very high risk of cancer and radiation-
| induced cardiovascular disease.
|
| To shield against the high energy component of cosmic
| rays, you need to wrap the crew compartment in something
| like a few meters of polyethylene or water. This is far
| heavier than anything we could launch today, but would
| work on something like a nuclear pulse rocket (that has a
| minimum weight requirement!)
|
| There's an additional problem around Jupiter, which is
| what Pioneer 11 discovered. The strong magnetic field
| causes lethal radiation levels at the inner moons. Again
| you can solve this by wrapping yourself in crazy amounts
| of water or plastic, but it's far beyond our capability
| now.
| 082349872349872 wrote:
| Oye sesata unte beratna; kewe tolowda?
| kitsunesoba wrote:
| This is a great quote from a series I love, but I think it's
| important to consider other angles.
|
| Earth, metaphorically speaking, is humanity's "cave". A very
| nice and comfortable cave of course, the possibility space
| for the development of our species is bounded by it. It's in
| our best interest to develop the ability to venture beyond
| the cave for increasingly longer periods and eventually
| become able to live outside of it indefinitely.
|
| With this in mind, the moon is too close and convenient for
| long term self sufficiency to develop. Mars on the other hand
| is only reasonably accessible once every couple of years or
| so, which forces the issue of self-sufficiency right out of
| the gate. The first few decades of human presence there will
| be focused almost exclusively on self-sufficiency. This is
| important, because that means it has a far better chance of
| continuing to exist if/when political will for it wanes.
|
| The upper layers of the Venetian atmosphere may seem
| attractive at first glance but it has several
| impracticalities, namely having to stay permanently aloft and
| total inaccessibility of the resources on and below Venus'
| surface.
|
| Will some take part in efforts to move beyond Earth's surface
| with greed as a driving factor? Undoubtedly, but I don't
| think it's a valid reason to not do it.
| yrgulation wrote:
| Without the desire to explore and expand there would be no
| America. If the Spanish and Portuguese would have waited to
| solve all of humanity's problems first and then set out to
| explore new worlds the world would be a different place today.
| Same with space exploration. It is in our dna as the most
| advanced life forms to go out there. It is also a duty to all
| life on this earth to expand beyond. Finding even a hint of
| former life on mars means life is a rule not an exception in
| the universe. Being able to colonise it means we can outsource
| all our destructive resource gathering to mars. Or even better
| we can live on it. Doing so would mean trade with earth and as
| a result development on a scale never seen before.
| UI_at_80x24 wrote:
| >Without the desire to explore and expand there would be no
| America.
|
| Please don't act like Europeans getting lost trying to find a
| shortcut to India was a good thing.
| bavila wrote:
| I'd prefer our most brilliant technologists tap into the
| desire to explore and expand the domain of robotics. Once I
| own a robot that can reliably clean every surface of my
| bathroom without my intervention, maybe then Mars might sound
| a bit more interesting.
|
| But, hey, that's just me.
| HillRat wrote:
| The Americas and Africa would probably like to have a word
| about the legacy of Spain and Portugal's decision to "explore
| new worlds"...
| klyrs wrote:
| The analogy is apt. Look at how Musk treat his employees.
| What's he going to do on a planet with no labor laws, where
| it costs millions of dollars per head to bring them back to
| earth?
| mlindner wrote:
| The ride home is free because the vehicles need to come
| back anyway to carry more people.
|
| And not within our lifetimes will we be in a situation
| where people stop being the citizens of the country on
| Earth they are from.
| ben_w wrote:
| The vehicles have to come back, but the people have to
| eat and breathe on the way. And right now, I'm more than
| a little worried he's heading the same way as the French
| royal family, even if "Qu'ils mangent de la brioche"
| predates Marie Antoinette.
| klyrs wrote:
| > And not within our lifetimes will we be in a situation
| where people stop being the citizens of the country on
| Earth they are from.
|
| Sounds like you aren't familiar with maritime law.
| Slavery is still a common practice on _this_ planet, due
| to a lack of jurisdiction.
|
| https://www.humanrightsatsea.org/news/eradication-modern-
| sla...
| yrgulation wrote:
| Unfortunately the only thing to motivate most people is
| greed. I am aware of the legacy, but the way to sell this
| is by highlighting the profit that can come out of it. And
| fortunately there is nothing to kill on mars in the
| process. It's a win win.
| TEP_Kim_Il_Sung wrote:
| While I in no way disagree, I would like to note that some
| of the bad activities attributed to foreigners in Africa,
| have been practiced for millennia by the locals, and the
| World over.
| jcranmer wrote:
| > Without the desire to explore and expand there would be no
| America. If the Spanish and Portuguese would have waited to
| solve all of humanity's problems first and then set out to
| explore new worlds the world would be a different place
| today.
|
| Of all the examples you could have picked, you picked the one
| that was most explicitly not about desire for exploration.
| Europeans were not exploring the world for exploration's
| sake; they were stridently motivated by the promise of loot.
| The Spanish in particular explored the New World primarily to
| find new cities of gold to plunder, destroy, and loot, as was
| done to the Aztecs and Incas, with these entradas funded by
| people hoping for a share of the loot (unfortunately for
| them, there was nothing else on the scale of the Aztec or
| Inca Empires). Later, other countries sought less to actively
| loot the place but instead monopolize control over raw
| resources (beaver pelts being key in North America).
|
| Better examples would have been, say, the Polynesian
| migrations that settled isolated islands in the Pacific
| Ocean, which the navigators would have had no reason to
| believe even existed.
| idlewords wrote:
| This logic applies just as much to the Moon, but no one seems
| to be lining up to board lunar colony ships.
| lmm wrote:
| Mars is easier to send material to; gravity and rotation
| are also better there.
| googlryas wrote:
| There are no lunar colony ships.
| idlewords wrote:
| There are just as many lunar colony ships as Mars colony
| ships.
| googlryas wrote:
| Which tons of people signed up for a yearlong simulation
| of run by NASA. Granted, I bet a lot would drop out if
| presented with the actual prospect of spending a year in
| a bubble with 5 others.
| ben_w wrote:
| FWIW, I think we should aim for the moon before mars.
| Things _will_ go wrong, the moon is close enough to mount a
| rescue if that problem is "the food is all gone", whereas
| Mars... the gap between launch windows is long enough for
| things to go from "fine" to "everyone's starved to death,
| including the ones who turned to cannibalism to survive".
|
| Then there's the practicalities: while the moon has long
| days and nights, there's no global dust storms, and we can
| send power from the light side to the dark side with a
| simple wire (the lunar regolith and the vacuum are both
| insulators, there's nothing alive or tectonic to mess with
| one just draped on the surface, only impacts). The Martian
| atmosphere is so thin it's only useful for aerobraking and
| drones, not breathing, and the lack of atmosphere on the
| moon means non-rocket-based launchers are much easier,
| which in turn makes the long-term economics easier (though
| still terrible with current tech).
| civopsec wrote:
| > Without the desire to explore and expand there would be no
| America.
|
| ...
|
| Is that good or bad?
| [deleted]
| Zigurd wrote:
| Humans living for more than months at a time in space or on
| another planet is a fantasy. The attempts will kill the
| participants.
|
| That is for machines or post-human life, designed for the
| purpose, to do, if it is even possible. The answer to "Where is
| everybody?" is likely to be "They're home" having learned that
| trying to leave is deadly.
| coolspot wrote:
| Umm... https://www.nasa.gov/feature/jeff-williams-racks-up-new-
| time...
| nvahalik wrote:
| Those days are spread out over the course of over a few trips
| over nearly a decade.
|
| Nowhere near to the amount of time you'd log on a trip to
| Mars and back.
| idlewords wrote:
| The radiation flux in low earth orbit is also much milder,
| about 1/4 what you would be exposed to en route to Mars.
| AnimalMuppet wrote:
| You don't think you could get to Mars and back in 520 days?
| Why not?
| tpmx wrote:
| At least kind of related:
|
| I'm worried that NASA will mess up their livestream of the
| Artemis 3 mission to the moon, just like they did with the
| Artemis 1. Compared to what we've been getting used to with
| SpaceX, it just wasn't that great.
| edgyquant wrote:
| Did SpaceX livestream the entire trip around the moon in real
| time?
| tpmx wrote:
| (Well, NASA didn't do that. Most of the time it was an
| animation. When they did have a camera feed the production
| quality was very uneven.)
|
| Have SpaceX livestreams set high expectations?
|
| Look, I want NASA to look good, but I'm worried that they are
| treating the streaming as an afterthought.
| tppiotrowski wrote:
| Way back in 2006, as a CS major with networking emphasis, I did a
| summer internship at NASA APL (Applied Physics Laboratory) My
| task was to modify Linux networking stack to simulate deep space
| communication packet loss and throttling. Then to implement
| something called Bundle protocol over UDP and run a lot of
| throughput simulations.
|
| The idea was to maximize data throughput between Mars and Earth
| by routing data packets from the rovers to the orbiters because
| the orbiters circled every 90 minutes and the rovers had to wait
| hours for Mars to rotate to get line of sight with Earth. Also,
| some orbiters can send at higher throughput than others.
|
| It was a fun project but way over my head at the time. I do
| remember walking into mission control a few times and ESPN was
| playing on the big screen. World cup was going on that summer.
| Tepix wrote:
| I hope we get that greenhouse on Mars sooner rather than later.
| Seems more important than Twitter.
| tagami wrote:
| Off-world crop production can benefit life here on the
| Homeworld. We are working on that with our ExoLab missions. Our
| 10th mission is currently on the ISS looking at legumes for
| protein and vitamins like thiamine.
| https://magnitude.io/exolab-10
| TEP_Kim_Il_Sung wrote:
| Freeze peach always seems unimportant until you lose it.
|
| Good thing that goes hand in hand with economic improvement,
| based on historical evidence, and make greenhouses on Mars more
| likely.
| AlexandrB wrote:
| If our free speech rights depend on the whims of billionaire
| media owners we don't have those rights in any meaningful
| sense. I don't think that Twitter changing hands moved the
| needle one way or the other.
| TEP_Kim_Il_Sung wrote:
| Twitter is just one, now fully exposed, symptom of a larger
| problem, which will be easier to deal with now that more
| people are watching.
| ericbarrett wrote:
| Gonna have to figure out how to deal with relativistic iron
| nuclei:
|
| https://pubmed.ncbi.nlm.nih.gov/11540033/
| JumpCrisscross wrote:
| > _relativistic iron nuclei_
|
| The Martian atmosphere is 1/166th the density of Earth's [1].
| At the ISS's altitude, it's something like a trillionth.
|
| [1] https://en.wikipedia.org/wiki/Atmosphere_of_Mars
| idlewords wrote:
| The Martian atmosphere does not provide meaningful
| shielding against heavy ion radiation unless you're way
| down in the Hellas basin (where no one particularly wants
| to land). You reduce the flux by half compared to deep
| space just by having a big rock blocking half of the sky,
| but you'll still get all the cancer sooner than later.
| mlindner wrote:
| The Martian atmosphere may not but the surface of the
| planet does, cutting half the yearly dose versus being in
| deep space. And I'm not sure I buy the argument that the
| atmosphere provides little protection. There's a lot of
| atmosphere there still, enough you can push down on it
| and rise into the sky if you have some carbon fiber
| blades moving at very high speeds. I'd think a iron
| nuclei would hit a lot of atoms on the way down.
|
| > you'll still get all the cancer sooner than later.
|
| Cancer risk from radiation is probabilistic. If you spend
| all day outdoors then you increase your lifetime risk of
| cancer by a significant degree, but it's not like you're
| definitely going to get cancer. Additionally, most
| habitation modules, at least early on, are planned to be
| buried in martian regolith.
|
| Also the moon is worse than Mars in all respects with
| regard to this so you're effectively arguing that humans
| should never leave the orbit of Earth. I'm not a fan of
| that future.
|
| (BTW, we deal with much higher radiation levels in hot
| cells in reactors here on Earth, and those even have
| windows into them. I'm sure we can work out something.)
| idlewords wrote:
| You don't have to buy the argument; you can look up the
| scientific papers. Heavy ion radiation is hard to shield
| against and creates high energy secondary radiation when
| it hits air, metal, or rock. Moreover, there is strong
| evidence cancer risk from heavy ions is considerably
| greater than predicted by the absorbed dose model we use
| for other kinds of ionizing radiation. Search on "non
| targeted effects heavy ions" to read up on this; it's a
| fascinating topic. The upper error bar right now for a
| 1000 day Mars mission is upwards of 20% risk of
| radiation-induced death; most of this is from the heavy
| ion component of cosmic rays.
| mlindner wrote:
| Rather than speculation it'd be useful if there was more
| hard science on the subject, you know by actually doing
| long term experiments on life in space being exposed to
| these heavy ions.
|
| You can find scientific papers on a lot of subjects where
| it's hard to get at objective fact arguing one way or
| another and it's hard to tell how factual they really
| are.
|
| Also why would you quote the "upper error bar"? I'd like
| to know the size of that error bar and what the median
| is.
|
| > The upper error bar right now for a 1000 day Mars
| mission is upwards of 20% risk of radiation-induced
| death; most of this is from the heavy ion component of
| cosmic rays.
|
| This is just an argument that you need to bury things in
| regolith, at least early on, until we get better
| shielding designed for heavy ions.
| idlewords wrote:
| Here's the specific citation:
|
| Assuming 940 day mission, percent risk of radiation-
| induced death for a 40 year old woman is:
|
| * mean: 8.8; 95% confidence [2.78, 21.0]
|
| For a 40 year old man:
|
| * mean: 6.49; 95% confidence [2.58, 13.6]
|
| Source is "Cancer and circulatory disease risks for a
| human mission to Mars: Private mission considerations",
| Acta Astronautica, 2018.
|
| Narrowing this uncertainty range requires long-duration
| human or animal experiments outside the magnetosphere.
| ericbarrett wrote:
| A little napkin math says the columnar mass of the
| Martian atmosphere is 18 g/cm^2, versus 10g / cm^2 of
| aluminum shielding discussed in the paper. So being on
| the Martian surface would probably give you something
| like 1/10 (atmosphere + planetary mass + environment
| suit) the heavy ion radiation exposure of _deep space_.
| You 'd need to be pretty deep underground most of the
| time (no windows, at least) to be safe for the duration
| of a reasonable visit. I'll pass!
| idlewords wrote:
| The napkin math falls short a bit because the heavy ions
| that absorb in the atmosphere will create a shower of
| secondary radiation that reaches the surface. Similarly,
| heavy ions that hit the surface will create secondary
| radiation from rock. This factor is why partial shielding
| in a spacecraft can give the crew a bigger absorbed dose
| than having no shielding at all.
| ericbarrett wrote:
| You're right, actually, that means even more exposure
| than I calculated since even the relativistic ions that
| are absorbed will still have potential biological effects
| via the secondary particles. Do you know how to calculate
| the flux from those?
| idlewords wrote:
| This paper looks like a good starting point: https://www.
| sciencedirect.com/science/article/abs/pii/S22145...
| JumpCrisscross wrote:
| Nobody is arguing radiation isn't a problem on Mars. Just
| that heavy-ion bombardment _per se_ isn't something to be
| concerned with.
| idlewords wrote:
| That is not true; the heavy ion component of galactic
| cosmic radiation in particular is the single biggest risk
| factor in going to Mars (other than the spacecraft
| breaking).
| JumpCrisscross wrote:
| > _galactic cosmic radiation in particular is the single
| biggest risk factor in going to Mars_
|
| Sorry, I was unclear. It's absolutely an issue going to
| Mars. It isn't front and centre on Mars.
| idlewords wrote:
| It is, though. It's about half as bad on Mars (since the
| planet physically blocks half the sky) but it remains a
| showstopper. And trying to shield against it runs you
| into the problem of getting heavy construction equipment
| to Mars, plus you run afoul of rules against
| contamination that we're bound by international treaty to
| follow, including a ban on digging.
| throwawaytemp29 wrote:
| Lol - let's have a Mars colony without digging.
| stronglikedan wrote:
| The Twitter takeover solved a real, current problem. Those are
| always more important than future problems.
| tasty_freeze wrote:
| > a real, current problem. Those are always more important
| than future problems.
|
| You mean like addressing climate change, vs spending
| trillions trying to terraform a planet to make it barely
| habitable.
| rglover wrote:
| Maintaining free speech will allow people to discuss and
| shed light on actual--not heavily manufactured--issues like
| the climate change movement being used as a distraction
| while banks and corporations implement natural asset
| corporations. [1]
|
| [1] https://unlimitedhangout.com/2021/11/investigative-
| reports/u...
| kmonsen wrote:
| There is no evidence there is more free speech on Twitter
| after the Elon takeover. It's just different people being
| banned and for more arbitrary reasons.
| JoshCole wrote:
| I could understand saying something like the totality of
| the evidence doesn't support the conclusion that there is
| more free speech after Elon's takeover. So that is
| probably what you mean. What you actually said though is
| factually inaccurate.
|
| There is evidence both for and against more free speech
| on Twitter. If someone can't admit that, chances are they
| are plagued with cognitive dissonance and highly partisan
| in their reasoning. For example, there is evidence that
| Twitter has granted amnesty to accounts that were
| previously censored and according to stated motivations
| this was done for the sake of freedom of speech.
|
| I happen to suspect that you are right and that currently
| some rulings are made with input outside the policy team
| and that this is currently happening more frequently than
| it used to. One thing that convinces me of this is that I
| frequently see people reaching out to Elon Musk directly
| and reporting that they have been censored in some way or
| the other. Then these cases seem to be resolved, with the
| other person praising him for ending the censoring of
| their political thoughts, which implies that he
| intervened in a policy decision.
|
| However, I'm not sure I could call this proof that
| banning decisions are made more arbitrarily than before
| since these are blacklist removing interventions rather
| than bans.
|
| So basically, when you claim that is now more arbitrary
| than it was before, that comes across to me more as your
| own speculation than anything definitive. We don't have
| proof of that. In sharp contrast, anyone who claims that
| the previous ownership did make arbitrary decisions does
| have proof. It is now a matter of public record that in
| some high profile cases (I happen to agree with some of
| them, but that is beside the point) Twitter did make
| arbitrary decisions rather than policy rooted decisions.
| In fact they did this often enough in decisions that
| weren't as high profile that there was a category label
| in the moderation reason, being called a one off.
|
| It seems the current Twitter wants to be much more
| transparent than the former. So it might be that at some
| point in the future we will be able to see the moderation
| metrics: if we could, then we could answer your
| implication with with actual data. Filter by moderation
| justification field and get a count both positive and
| negative and we would have a much better sense of whether
| decisions were being made arbitrarily.
| TEP_Kim_Il_Sung wrote:
| At least he managed to get red of CP.
| whythre wrote:
| I think it is way too early to make that call.
| kmonsen wrote:
| Fair point, but as of now I think it's a valid statement.
| hkpack wrote:
| At this point I think we just need to accept, that every
| issue of every severity is widely used by parties, who
| know how to benefit from it. It doesn't actually prove or
| disprove the issue (and its severity itself).
|
| For example: climate change is heavily used by people who
| know how to gain power by fighting it. It doesn't
| disprove the issue itself.
|
| All effective strategies includes natural forces, because
| it is very difficult to fight against them. So no wonder
| why climate change (as being a massive natural force) is
| used by people in power for their benefit.
| rglover wrote:
| > It doesn't actually prove or disprove the issue (and
| its severity itself).
|
| It does when you consider that the very people who are
| promoting that severity are doing what I linked above
| behind the scenes and their own behavior hasn't changed
| at all (e.g., all of them flying private jets to Egypt
| for COP, having multiple pieces of real estate, etc).
|
| The harsh truth is that the very people who are
| responsible for telling people to panic are, in fact, not
| panicked at all and are using fear as a smokescreen to
| take absolute control over the entire world (zero
| hyperbole in that statement). It's classic sleight of
| hand, just on a global scale.
|
| Because many people in the West lack any spiritual
| grounding, they've latched on to climate change (think
| about the term alone; of course the climate changes--it
| always has) as a pseudo-religion and defend it to
| absolutely irrational ends. This is why anyone who even
| remotely questons it gets labeled as a heretic ("climate
| change denier"). You may as well be saying "you're
| denying my god" which explains the often-hysterical
| backlash you get.
| AnimalMuppet wrote:
| > The harsh truth is that the very people who are
| responsible for telling people to panic are, in fact, not
| panicked at all...
|
| True. Or, at a minimum, they aren't doing anything
| concrete that you would expect if they actually believed
| what they're saying.
|
| > ... and are using fear as a smokescreen to take
| absolute control over the entire world (zero hyperbole in
| that statement).
|
| Zero? Really? I'm calling baloney on your claim here.
| rglover wrote:
| > Zero? Really? I'm calling baloney on your claim here.
|
| Yes. They're surprisingly overt about their end goals. I
| think the gullibility of "the masses" even surprises
| them. They want to flip the world economic system to be
| "stakeholder" based, meaning, they own everything
| (literally, down to the land itself) and you own nothing.
| It's neo-feudalism.
|
| The whole climate change brew-ha-ha is simple
| psychological manipulation, i.e., "we'll tell you the sky
| is falling with _our_ models, reinforce it via the media
| co 's _we_ control, and repeat it until you accept it as
| truth. " People who are terrified will listen to anyone
| who appears to have an answer or is operating from a
| position of authority (the last 2-3 years being a beta
| test that was successful). It's just the Milgram
| Experiment/Agentic State thing on a massive scale.
|
| These people believe they're the rightful rulers of this
| world and all other people are, for all intents and
| purposes: assets on Earth's balance sheet.
| ben_w wrote:
| I know it's not my money so I don't get a say[0], but I
| kind wish Musk had spent that $44 billion making a factory
| that makes shipping-crate sized Sabatier-process units to
| turn CO2 into methane.
|
| Needed for Mars, useful for Earth.
|
| [0] and, indeed, have used that argument against his
| critics when Musk was just a plucky upstart spending mere
| hundreds of millions on making the prototype that led to
| the Falcon
| malfist wrote:
| > solved a real, current problem
|
| Can you tell me what that problem was?
| whateveracct wrote:
| Couldn't dog whistle loud enough on Twitter
| TheHypnotist wrote:
| Too many people making fun of Elon, apparently.
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