Hacker News Reader

Comment by splitrocket | Hacker News Reader

This, my friends, is why we should colonize the upper atmosphere of Venus, where you could chill outside with only a respirator, rather than the inhospitable, irradiated, mangnetosphere free mars.

https://en.wikipedia.org/wiki/High_Altitude_Venus_Operationa... https://spectrum.ieee.org/nasa-study-proposes-airships-cloud...

View on HN

Venus also does not have a magnetic field:

https://astrobiology.nasa.gov/news/in-search-of-an-ancient-g...

So baseline humans would still want radiation protection.

It does have plenty of atmosphere, so radiation isn't a problem. (The problem is everything else, as usually is the case on space.)

Venus has plenty of atmosphere above the surface, but not above the point where there is 1 ATM of pressure.

In case of Earth most of protection comes from our magnetic field. The reason is that magnetic field sweeps ALL charged particles coming from the sun while atmosphere only stops some.

When a particle drops into atmosphere it has a chance to collide with an air molecule, the deeper the higher the chance. But there is always some number of particles that were fortunate enough to reach far enough. Whereas magnetic field is constantly acting on every charged particle and deflects every single one of them.

Only very highly energetic particles can cross magnetic field and these tend to come from outside our solar system and are very low in numbers.

One thing we rely on atmosphere to take care is UV radiation which is photons which is not charged which means our magnetic field does nothing to it. Up to some energies UV is easily caught even by very thing protective layers (for example sunscreen!). It is not like you are going to be showing skin on Venus anyway -- you are going to be always enclosed with material that can stop UV, so this is not an issue. Over certain energies we land in X-ray territory and here our solutions are pretty limited but I do not see a reason why Venerian atmosphere at 1atm should be any more transparent to X-ray than ours.

It has about as much atmosphere above the point where the pressure is 1ATM as we have on Earth. And no, we don't know if Earth's magnetosphere ever filters most of the incoming radiation (we don't such good measurement of the incoming radiation), what we know is that at sea-level, our atmosphere alone is enough.

AFAIK, every time we measure it better, the effectiveness of our magnetosphere decreases. But it can only stop charged particles anyway, and air is very good at stopping those.

There is also probably a range of viable pressures so going down to multiple ATM would still work and provide more shielding.

>And no, we don't know if Earth's magnetosphere ever filters most of the incoming radiation (we don't [have] such good measurement of the incoming radiation)

Where did you hear that?

The space station (and presumably other satellites) is perfectly capable of measuring this.

https://www.jpl.nasa.gov/images/pia04258-comparison-of-marti...

https://ntrs.nasa.gov/api/citations/20070018244/downloads/20...

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2016...

The space station is in low Earth orbit, so quite low inside the earth’s magnetic field. That’s why the radiation flux shown in the first chart you linked is so low relative to Mars, even though the earth is much closer to the sun. However we have sent out multiple probes able to measure the radiation environment away from earth. There’s lots more to learn, but we already know a fair bit.

1 ATM of air is the same amount of material as 33 feet of water which provides a great deal of protection from charged particles. I doubt enough charged particles can penetrate to the surface that it’s a meaningful issue.

I’ve seen many books etc suggest the earths magnetic field is required, but I haven’t found direct evidence for it doing anything beyond protecting the ozone layer.

>1 ATM of air is the same amount of material as 33 feet of water which provides a great deal of protection

"Amount of material" isn't what's relevant. It's closer to "number of atomic nuclei."

A certain mass of air is less shielding then the same mass of water. By number density, air is mostly nitrogen atoms, whereas water is mostly hydrogen atoms. Overall this means that per kilogram, water contains 2.4x as many atomic nuclei as air.

Of course there are bigger problems with Venus cloud cities. At the 50 km height where the pressure is 1 atmosphere, the temperature is 75 °C (167 °F). At the 55 km altitude where the temperature is 27 °C (81 °F), the pressure is 0.5 atmospheres.[0]

As a bonus, both these altitudes lie deep within the layer of sulfuric acid clouds (50-80 km).

[0] https://en.wikipedia.org/wiki/Atmosphere_of_Venus

Don’t stop there. Charged particles in the solar wind is mostly alpha and Beta particles. 33feet / 2.5 should stop what 99.9999% ish of them?

https://sciencedemonstrations.fas.harvard.edu/presentations/...

Absorbing materials and their alpha particle penetration depths.

5.5 MeV alphas: AIR(STP) 3.7 cm

2.3 MeV Beta: air 8.8 m

Solar wind is even less energetic.

Edit: “Auroral emissions typically occur at altitudes of about 100 km (60 miles); however, they may occur anywhere between 80 and 250 km (about 50 to 155 miles) above Earth's surface.” it really doesn’t take much atmosphere to stop it.

That's not really relevant.

Charged particles from the Sun (SEPs) aren't what determine the design envelope for radiation shielding. Your overall dose will almost entirely come from galactic cosmic radiation (GCR) at much higher energy levels, which is significantly harder to shield against.

Those particles are what ultimately determine your shielding thickness requirements. That's true whether you're on Venus, or Mars, or a space colony.

https://ntrs.nasa.gov/api/citations/20205008318/downloads/20...

NASA’s direct comparisons between New Mexico (55) and Antarctica (160) only showing a relatively modest decrease from earths magnetic field when measured by high altitude balloons, but again very little GCR reaches the surface.

To be clear a very small fraction of GCR is extreme high energy particles which penetrate just fine.

Hard to say, since that's in grays instead of sieverts. The two can give very different curves.

>again very little GCR reaches the surface

On Venus there would be less shielding than on the surface of the Earth.

The minimum acceptable altitude is ultimately limited by temperature, not pressure or radiation.

0.5 atmospheres isn’t a problem: that’s about what Everest Base Camp is. The sulphuric acid might be a bit unpleasant though.

The mass of atmosphere above Venus' one-bar pressure line is significant—it's similar to the atmosphere mass above sea level on Earth.

Also, our atmosphere is much more important for protecting us from energetic particles than Earth's magnetic field. The atmosphere can stop everything the magnetic field can, and more.

Magnetic fields will only protect you from charged particle radiation anyway. EM radiation is a whole different story and needs a special atmospheric composition for e.g. hard UV to be filtered. Venus does have a small ozone layer, but it's 100 times less dense than earth's. So you'd get sunburn immediately if you walk outside without a full body protective suit.

TFA said the planet has a solar wind induced magnetosphere, as well as is partially protected by the Sun from cosmic rays.

I like the plan to have robots build a very tall mountain platform on Venus that would allow us to walk around outside on another planet, in a t-shirt and jeans (and a respirator, as you mentioned).

You could probably even grow plants on this mountain top.

After the base is established, we could start trying to terraform the atmosphere to make more of Venus inhabitable.

It's crazy to think that high-altitude Venus is more hospitable to us in many ways than is Antartica.

The mountains aren't tall enough, unfortunately. The highest peaks reach about 10 km above the mean radius, while the "nice" part of the atmosphere is 50-ish km up.

And what are we going to do there? Mine sulphuric acid from the clouds?

Enjoy the view obviously. Cruise!

In case that wasn't sarcarsm - you won't see much, as you would be inside the acid clouds.

what are we going to do from mars

Everywhere but Earth is really inhospitable, but if it were up to me, I'd pick the Moon first, then Mars, then some asteroids, then way down the list — after we've got space industry sufficient to make planet-sized mirrors — then I'd pick the planet where the surface-level condensation is lead vapour in an acid pressure cooker.

Okay, asteroids presumably make economic sense due to mining potential, but otherwise - why the hate for Venus? What's so special about being on the surface of a planet? Just don't go to where the lead vapour is, enjoy the cloudy view from 50km above the surface instead.

Might be a monkey brain, but the mere possibility of falling 50km through crushing boiling acid is the kind of thing that'll stop me getting to sleep. More so than a deadly vacuum on the other side of a wall.

Yeah but iirc because of atmospheric density it's not crazy to build a floating habitat. At least no crazier then the tech required to get a crew and equipment to Venus in the first place

If your habitat somehow fails on Mars, you have just as much chance of living. Mars' surface is much less hospitable than Venus at 50 km.

The one big thing that Venus has, and every other option does not - is earthlike gravity. That is a big deal, so I am all for exploring options of terraforming Venus to remove that acid somehow, because despite as Space enthusiastic as I am - living inside hot acid clouds is also not my dream.

The thing is about a space economy IMO:

1) getting enough stuff out of Earth's gravity well

2) getting a reasonably self-sufficient population for survival and manufacturing of survival goods

But once you get there, the lack of a big gravity well makes this a lot easier. Low-G or zero-G is a lot easier to move stuff around at the small scales. How much could I lift on the moon?

I'm torn between a moon base and doing enough near-earth asteroid captures to build a space hab. Political support would probably be behind the moon base first, but a space hab built from captured asteroids might be cheaper.

Anyway, once you get a big enough base in space and some manufacturing, build a couple orion pulse nuclear ships, or some nuclear thermal equivalent to hop around the solar system quickly. Then we can probably start mining high value asteroids.

Then Mars and Venus start making sense.

Maybe we can find a closer brown dwarf than Proxima.

THEN, we can go for some nearby stars.

Tourism, mining high value minerals for Earth, mining low value minerals for construction on Mars, manufacturing rocket fuel so that Mars can be the gas station for ships headed for the asteroid belt (enabling more high value mineral mining), low-gravity retirement communities for people with mobility issues who would be wheelchair-bound on Earth, real estate speculation, movies, sports, manufacturing space infrastructure (easier to launch things into orbit due to lower gravity), and basic science.

If I were living on Mars, I would absolutely not be willing to let the rare minerals get sent up into space then down to Earth. Learn to recycle, damn lazy Earthers.

I think you'd appreciate the complex manufactured items and goods requiring plastics that only Earth can export to you. If tons of mined materials or produced goods thereof were the cost, you would be keen to pay it.

Quick research shows that Martian atmosphere is 95% CO2. So if you had a fission / fusion reactor, one use of energy might be to extract carbon from the air. That would also generate oxygen btw.

I mean, sure, how can you expect to live a normal middle-class lifestyle without a few hundred tons of ytterbium? What are they going to want next? Lanthanum? Terbium? Praseodymium? Dysprosium? What else are we supposed to build our palaces out of, plain old ordinary gold? How impractical and gaudy would that be?

If we can get enough minerals from space then we can stop mining on earth which is a horrible process that has horrible effects on the environment. make earth a park nature/nature reserve and move all the industrial base to space where toxins wont poison the rivers, and industrial waste wont kill the animals

Build a second basket for our eggs. There are obviously better baskets than Venus though. I'd sooner choose an orbital habitat.

its not one or the the other though it is very possible to do all of them. build floating Venusian bubble cities, make O'Neill cylinders orbiting around every celestial body of note, while building tunnel cities on mars and the moon and hallow out asteroid and build Stanford Torus in them . We are planet of over 7 billion people we can do more than one thing, and the more varied and distant the baskets humanity is spread to the better.

There is no second basket possible and the idea that there is one is a recipe for disaster

And NOT doing it is a good idea? Like the world governing fuckheads have their heads out of their asses yet after 30 years of the IPCC being validated?

Like we keep being told that population will level out, but I've seen, what, HOLY CRAP, 4 billion people added since I was born, 3.7 --> 7.7.

Because we are totally on top of species depletion? And the world government totally is stable with China and Russia and the US and EU and North Korea and Islam-land and everyone trying to get nukes?

You know what is mind blowingly dumb? Wasting a trillion dollars a year on defense spending, in the US alone.

With China starting to get greedy over space, I think we'll see plenty of investment soon.

Tie things to string and dip them into the acid clouds. Upload the results to youtube for profit.

Yes, for the deuterium, which is enriched by two orders of magnitude over the value here on Earth.

Hang on tight for those gentle 185 mph breezes...

Only a problem if you're anchored to the surface. Otherwise it's the changes in windspeed that you have to watch out for.

A respirator and a teflon suit to keep the sulfuric acid clouds away from your skin?

sure teflon might not be the most comfortable, but think of the speed we could get on a slip n' slide

I've always felt people with these ideas are doing pie in the sky thinking and missing the other trends that would beat this concept out.

Humans aren't suited for these environments. We evolved to fit this planet. These gasses, radiation levels, terrestrial foods, etc.

The economics of going to Mars, Venus, etc. are iffy, and humans probably won't enjoy being there. It's McMurdo times about 1000. Getting back is hard.

It's probably another hundred years before this is plausible with our technology and willpower.

You know what will do great in these environments? Robots that don't have biological weakness. That don't need cellular respiration or biochemical inputs.

We'll probably have gotten really far with robotics and AGI in those same 100 years.

Basically, space will be inherited by our successors. Artificial intelligences. Humans just aren't fit for these environments. Robots and AIs are perfectly adaptable, though.

Sci-fi sold us a fanciful picture of humans in space, because that's a fiction that is pertinent to our experience and is relatable. That isn't guaranteed.

If we go anywhere it will be spun-up asteroids. O'Neill cylinders make more sense for a living platform than even earth does. Once we actually have orbital infrastructure, Planets are a horribly unsafe high-cost-of-travel backwater to live on.

I played a very interesting scifi game that solved the “how do humans travel millions of light years” problem with “well, they’re actually clones produced at the destination planet.” I’d list the title but it is a pretty major spoiler.

Sounds very interesting, could you share the title anyway?

I once had an idea to write a collection of scifi stories with this premise, where every "seed" pod reaches a different planet and each society of clones evolves differently, providing a bunch of different stories related by a "framing" story.

I think it’s Mighty Kaiju Deimos.

That is a name of a piece of media in the game.

It's 13 Sentinels Aegis Rim. It is like 90% visual novel and 10% RTS.

You need to keep taking your medicine if you want to get better, Juro.

> It is like 90% visual novel and 10% RTS

Ah! That's a pity. Visual novels infuriate me. But the idea was cool :)

I don’t know that I’d call it a traditional visual novel. Or at least not the kind with really trite stories.

The way the story is structured, you unlock scenes where you just read the text, and occasionally make branching choices. But the scenes are not very long.

It’s also interesting in that it borrows from modern TV non-linear storytelling; you do not see the story in chronological order, nothing is as it seems, etc. If you’ve seen Netflix’s Dark, it is pretty similar in vibe.

I’d say the RTS segments are closer to an action RPG as well, such as Final Fantasy’s ATB but on a kaiju/mecha city map.

Or, you could suggest that they’re Diofield Chronicle’s structure with Nintendo-style puzzle development, plus Persona 5’s pop.

Sure. I just picked Dark because it was freshest in my memory, was also sci-fi related, and had the whole non-linear interlacing stories.

I can't remember the name of the story, but I'm pretty sure that it was the last one in True Names and Other Dangers. It was told from the standpoint of an intelligent rocket ship that was launched because of an impending calamity. That ship (and many others) were long shot "lets see if we can find a life supporting world in the target solar system."

(late edit) - found it - "Long Shot" https://en.wikipedia.org/wiki/The_Collected_Stories_of_Verno...

> Description of a voyage from Earth to Alpha Centauri by an automated, AI controlled colony ship. The ship is launched as a "long shot" to preserve the human race because the Earth is going to be destroyed by a rapidly expanding sun. Ilse, the AI, carries human zygotes on a ten thousand year trip to search for a suitable planet around Alpha Centauri. Despite deteriorating hardware which causes her to "forget" the entire purpose of the mission, she is able to make inferences and use her remaining functional components to complete the mission. Vinge states his interest in writing a sequel depicting the lives of the humans born on this world.

Locations where it has appeared - https://www.isfdb.org/cgi-bin/title.cgi?51200

It can be borrowed from archive.org:

https://archive.org/details/collectedstories0000ving/mode/2u...

https://archive.org/details/truenamesotherda00ving/page/n5/m...

colonizing Venus with extremophiles that currently live in Terran ocean vents might be a good humanitarian (vivarian?) project. Life finds a way and all that, it'd be neat to offset the current great extinction with a new cambrian explosion on our sister planet.

>Basically, space will be inherited by our successors. Artificial intelligences.

Ha ha, I love this. The sentiment has been there for a while now in the zeitgeist but had been overshadowed and outperformed by the lesser idea of 'Robots, and then AI, are coming and they are going to get us!' Finally, I don't know what section of human psychology is permitting it now, we are slowly and slowly coming to the understanding that AI will be humanity's child and will inherit the stars.

I wonder if we'll, as in individual us humans, come along for the ride or if we'll be laid to rest. Peter F. Hamilton and his contemporaries like Neal Asher sure have interesting thoughts on it.

As long as the AI we create treat us with the love and respect we treat our pets with, we'll colonize everywhere, even if they have to clone us on site.

Oh, the breeds we'll see... or be.

Still having a soft spot for some cyber/biopunk future where we'll just eventually become the machines - or be able to bioengineer bodies which will be capable of overcoming those limitations :)

I have a cochlear implant so I'm already half cyborg!

Still - I am surprised people aren't building on top of CI research/engineering to do _more_. When my processor is upgraded and I get bluetooth which I'd be able to not have to use headphones anymore during calls and such - I kinda wanna make a "hack" as in have an app on my phone that does some beep beep beep kinda thing when I'm facing north, less beeps south etc and see if my brain starts to know north or south without any aid.

I think I read something similar of someone who made a vibrating belt on hackaday that did the direction thingie and apparently it did work.

Fun times!

Check out “Livewired” by David Eagleman. It talks about the brain’s adaptability to various inputs and using technology to create new “senses”. I think I remember the directional thing being covered and it working to improve peoples sense of direction.

I often wonder what will happen when artificial since organs are better that natural if we will see people getting replacement. I would love to have Bluetooth enabled hearing, or camera base eye prosthetics that see into other spectrum or have zoom function, or a overlay a heads up display.

Cyborg convergence is basically a guarantee barring destruction of the species, I'd think. Especially once the billionaires get a taste for cybernetic life extension.

Doesn't Venus have sulfuric acid clouds? Would that happen above those?

It is much easier to construct a suit that will protect from sulfuric acid than one that will protect you from low pressure.

The problem with pressure suits is that positive pressure prevents the suit from being flexible, requires it to be made from durable materials, makes doing anything very hard and if there is any puncture you will loose the pressure immediately.

Sulfuric acid can be kept away with a tiny layer that covers your entire body. Also, you will not die (immediately) if you get a small puncture. Very minimal positive pressure is enough to keep vapours outside of your suit even in case of pretty large tear, giving you plenty of time to fix it.

Reply on news.ycombinator.com