It would be neat if it were a steampunk-style civilization traveling around their atmosphere in helium airships. But probably just helium escaping from rocks...
except where they are noting how helium is being allowed to escape and not being captured as was previously done by the now shut down U.S. National Helium Reserve.
It contains the story of how Carl Sagan convinced the Voyager crew to turn its sensors towards earth so as to see if life could be detected using its quite minimal sensor suite --- I thought it had a link to the original published paper.
The fate of the Strategic Helium Reserve is a different issue and there are many articles and op. ed. pieces on it --- the Wikipedia article should cover this:
6x time size (diameter?) or 6 times the mass. Evidently the Earth used to be much larger in size but not mass because of large amounts of trapped hydrogen/helium. It's since leaked from the crust and been blown off into space.
the catalog says 6.38x mass in one place and 5.6x mass in another
they must be able to calculate mass from orbital physics?
so you'd need a rocket 6x the size of SaturnV or whatever they are using for Artemis to escape it and most of that rocket is to lift the weight of the fuel for said rocket so it might be physically impossible to build such a creature at current level of tech
(might be yet another angle to "why no ETs" unless they are WAY more advanced)
Impossible to tell how much extra mass you need but it's exponential. Adding a unit of v_e [effective exhaust velocity] to escape velocity means you need 2.717 times as much fuel in an ideal rocket.
Earth escape velocity is 11000m/s ignoring atmosphere (which is not ignorable). If the new planet is 6x mass and 2x radius then √3 times escape velocity (about 1.73) would be about 8000m/s extra velocity which is about 3 times a random v_e which means you need about a 25 times bigger rocket. Ignoring the denser atmosphere which makes it even worse.
> Up above 10g, something really interesting happens that is kind of a theoretical limit. The mass of the rocket reaches a measurable fraction of the mass of the entire planet it's launching from.
The "view" at the bottom has an animation of the various routes. They're all EM-ME though...
If you pick some other interesting targets you can get EVJS or something like that (launch from Earth, Gravity assist at Venus, Gravity assist at Jupiter, rendezvous with Saturn)... and then the trajectory animations are much more interesting.
Don't these estimates assume launching from the surface, fully via rocket? On Earth, having air breathing stages to gradually build up speed, or using other launch mechanisms, isn't worthwhile because rockets are more cost effective here, but those tradeoffs change if you're on a planet with higher gravity and a denser atmosphere.
You still need to get to escape velocity that doesn’t change the delta v required does but not by that much you are looking at 5-10%. Maybe a bit more if the atmosphere is really really thick.
Unless you skip chemical rockets altogether there is a pretty hard cap on how much bigger a planet can be than earth before a space capable civilization becomes almost impossible.
Species is a rather arbitrary line here. Humans split from Neanderthal ~500k-800k years ago but could still interbreed 40k years ago. We’re likely more closely related to our common ancestors at that point of divergence than Neanderthal suggesting given the opportunity modern humans could interbreed with our ancestors ~500k-1m years ago.
Of course that’s just genetic compatibility, there’s plenty of other ways to define species.
> Homo Neanderthalensis is not Homo sapiens [sapiens].
Not the same species, but still capable of occasionally producing viable offspring.
Thus the common ancestor as essentially a midpoint between each population would be more compatible genetically. It’s essentially a ring species through time rather than space. https://en.wikipedia.org/wiki/Ring_species
NASA and Starlink have already been using ion drives with 10x ISP of chemical rocket engines. Using such drives a 3 stage with existing nuclear reactors as energy source can get to 150-200 km/s.
While it haven't been built yet, nothing seems to prevent ion drive even with 100x ISP of chemical rocket. That means we can get 1000-2000 km/s (acceleration with existing reactors would take about 100 years) and get to the closest star in 1000 years.
The problem is radiation. Empty space is not really empty, there are stray atoms floating around. Very scattered, but at a high impact momentum penetrate the ship ionizing anything in their way, and making the ship itself radioactive.
Not even talking about stray high-energy particles from distant supernovas and magnetars -- those irradiate ship regardless of its speed.
If "closest star" is Proxima Centauri, we're talking 4.5 light-years. Getting there in 1000 years means an average speed of 0.45% of the speed of light. At that speed less than 0.01 cm of titanium is enough shielding to keep the radiation out according to figure 1c) in my source below. Which makes sense because because this is ~10% of the speed of "normal" alpha radiation which is stopped by just your skin.
anything going out there for those long journeys would/should be big, so there would be enough walls, storage of supplies, reaction mass tanks, etc. to provide significant protection.
Not really. Galaxy is 100k ly across, you can make the journey end to end in 1mil years at 10% light speed. Obviously talking about probes/tech, not "biologicals".
1mil years is really short in the grand scheme of things.
>Obviously talking about probes/tech, not "biologicals".
human brain has 100T synaptic connections. We already have 2 trillion parameter AI models. Parameter count grows more 3x per year. It means that in 4 years we'll have 100T model. My point here is that by the time we have probes to send even to the closest star, the biological brain would be the inferior option, and most probably we'd even be able to upload, just as fun small companions-observers, a bunch of people brains into what by the time would be a superintelligent 100000T+ parameter AI brain of the probe.
Yeah I never really believed in biological aliens here. But some kind of alien AI thing/tech...quite probable after all this time.
Still not sure as there's still a lot of things that can stop it, but it's possible some kind of synthetic thing could replace biology, eventually, everywhere where there's intelligent life.
It is the four layers of resources, each one is smaller than the next.
1. What is the total theoretical resource?
2. How much of it do we actually now the location of
3. How much is technically recoverable?
4. And most importantly, how much is economically viable?
The last one is really the crux of the problem nowadays, there is a lot of helium but most of it just isn't in a high enough quantity to make the investment to built processing for it. Thus most of it just float off into space.
There will come a point when the price hits high enough to justify the cost but that also means higher costs to the end user.
> 4. And most importantly, how much is economically viable?
But literally the least important factor beyond “should we have started yesterday”. The amount of waste humanity has perpetuated in just the last 100 years because something wasn’t “economically viable” this fiscal quarter makes my head hurt.
Which is why they pumped fracking waste water into deep aquifers, because it wasn’t “economically viable” to pull that water out of the ground. Fast forward a decade and people are up in arms that those fresh water aquifers are no longer viable sources of drinking water, wondering how anyone could have been so short sighted.
Just because something isn’t economically viable today doesn’t mean it never will be. That short term thinking is exactly why China is absolutely decimating the US in renewable energy.
That's a different matter, that's an unpriced externality, were the oil company required to pay to sort the water out didn't choose because they weren't forced to.
So the oil should be economically unviable but due to poor regulation, they were able to extract it.
That’s just a cop out. There are externalities to everything and they are never completely accounted for. So by definition only looking at “economic viability” is a failed experiment as I posited from the get go.
We make decisions based on objective reality, not a perfect theory in a lab.
There will come a point when the price hits high enough to justify the cost but that also means higher costs to the end user.
This makes me wonder if it'd be worthwhile starting a company to capture it now, and just stockpile it until it's rare enough to be able to use my stockpile to control the price. The DeBeers diamonds playbook applied to helium, or maybe the Peter Thiel build-a-monopoly-to-win approach.
First the bad: Helium is very expensive to extract and store. You'd need a lot of venture capital. And you'd have a tough time competing with Qatar which produces between 1/4 and 1/3 of the world's supply. Qatar already is the DeBeers of helium.
The good: When the US/Iran war started helium prices shot up, so there might be an opportunity for a helium supplier not dependent on the Strait of Hormuz.
A teal Hydrogen company that splits Methane (CH4) into Hydrogen (H) and Oxidized Carbon Nanotubes (O-CNT) would be significantly more profitable than one that splits into Hydrogen and Carbon Black. (Because after production costs, O-CNT have a significantly higher market price than carbon black.)
But do our communities want fracking wastewater in our aquifer groundwater or on our farm fields?
When is the break-even point for cracking Helium from natural gas at current and predicted Helium market prices?
turquoise hydrogen: high-temp pyrolysis of methane
So e.g. [1] is turquoise hydrogen.
[1] "Production of hydrogen and carbon nanotubes from methane using a multi-pass floating catalyst chemical vapour deposition reactor with process gas recycling" (2025) https://www.nature.com/articles/s41560-025-01925-3
A renewable feedstock process that yields Hydrogen and O-CNT would be yielding teal hydrogen.
A natural gas process that yields Hydrogen and O-CNT would be yielding turquoise hydrogen.
That's where the government reguli could step in. It wasn't economically viable to capture natural gas so it's just flared off, but if the government fines oil companies for flaring off the natural gas, suddenly it's economically viable to capture it instead of wasting it.
It's economical to capture and sell the Helium out of natural gas even without a flaring penalty to encourage to be efficient with heat and material outputs.
It's also already economical to make Hydrogen and Carbon-based products like Graphene and spec Oxidized Carbon Nanotubes from natural gas.
> if the government fines oil companies for flaring off the natural gas, suddenly it's economically viable to capture it instead of wasting it.
If the government fines individuals for not digging holes in their back garden every day then suddenly it's economically viable to dig holes in your back garden every day, but it doesn't mean it's overall productive.
Alpha particles are essentially Helium, so by breeding large amounts of highly active alpha emitters you can produce Helium much more effectively than by fusion.
Given the neutron radiation from a fusion reactor, it's possible to synthesize Helium (He4) and more Tritium (T) and 3He using Lithium-6 with Boron-10 and Boron-11. An adjacent vertically-aligned (VA-CNT) battery would last for like 20 years and could power safety systems.
A Deuterated Vitrimer pipe with Li-6, B-10, and B-11 could be recycled to extract the T, 3He, and 4He.
Deuterated Vitrimers could also be disposed of in a waste burner.
It would be neat if it were a steampunk-style civilization traveling around their atmosphere in helium airships. But probably just helium escaping from rocks...
The transport elevator wouldn't be located in a light house now it?
Is it wrong that I was hoping for something along the lines of:
https://www.scientificamerican.com/article/how-would-we-know...
except where they are noting how helium is being allowed to escape and not being captured as was previously done by the now shut down U.S. National Helium Reserve.
Am I missing something or does that article only contain the back story and nothing actually noteworthy?
It contains the story of how Carl Sagan convinced the Voyager crew to turn its sensors towards earth so as to see if life could be detected using its quite minimal sensor suite --- I thought it had a link to the original published paper.
The fate of the Strategic Helium Reserve is a different issue and there are many articles and op. ed. pieces on it --- the Wikipedia article should cover this:
https://en.wikipedia.org/wiki/National_Helium_Reserve
wow 50 light years is indeed "nearby" in relative terms
nearly 6x the size of earth though, good luck trying to launch a probe off that surface
NASA has a neat "exoplanet catalog" which is about to leap in size next few years with new telescopes and techniques
* https://science.nasa.gov/exoplanet-catalog/lhs-1140-b/
6x time size (diameter?) or 6 times the mass. Evidently the Earth used to be much larger in size but not mass because of large amounts of trapped hydrogen/helium. It's since leaked from the crust and been blown off into space.
the catalog says 6.38x mass in one place and 5.6x mass in another
they must be able to calculate mass from orbital physics?
so you'd need a rocket 6x the size of SaturnV or whatever they are using for Artemis to escape it and most of that rocket is to lift the weight of the fuel for said rocket so it might be physically impossible to build such a creature at current level of tech
(might be yet another angle to "why no ETs" unless they are WAY more advanced)
√(G × mass÷radius) [escape velocity] = v_e × ln(m_0 ÷ m_f) [Tsiolkovsky]
Impossible to tell how much extra mass you need but it's exponential. Adding a unit of v_e [effective exhaust velocity] to escape velocity means you need 2.717 times as much fuel in an ideal rocket.
Earth escape velocity is 11000m/s ignoring atmosphere (which is not ignorable). If the new planet is 6x mass and 2x radius then √3 times escape velocity (about 1.73) would be about 8000m/s extra velocity which is about 3 times a random v_e which means you need about a 25 times bigger rocket. Ignoring the denser atmosphere which makes it even worse.
From the archives ... How much bigger could Earth be before rockets wouldn't work? https://space.stackexchange.com/q/14383 Feb 3, 2024 https://news.ycombinator.com/item?id=39243303
And related...
https://worldbuilding.stackexchange.com/questions/178131/wha...
https://physics.stackexchange.com/questions/117347/when-a-pl...
Man I love this.
> Up above 10g, something really interesting happens that is kind of a theoretical limit. The mass of the rocket reaches a measurable fraction of the mass of the entire planet it's launching from.
one thing about physics, particularly astro-physics, is it's NEVER boring
been diving into PBS-Space-Time and DrBecky past few years as distraction from the endless nightmare of the world we are living in
this has been a great educational thread on HN too, I knew rockets would have to be bigger but didn't realize exponential and the 10g upper-limit
also puts the "Mars sample return" mission into perspective, very difficult
Playing with the trajectory browser at NASA is kind of neat.
https://trajbrowser.arc.nasa.gov/traj_browser.php?NEAs=on&NE...
The "view" at the bottom has an animation of the various routes. They're all EM-ME though...
If you pick some other interesting targets you can get EVJS or something like that (launch from Earth, Gravity assist at Venus, Gravity assist at Jupiter, rendezvous with Saturn)... and then the trajectory animations are much more interesting.
Don't these estimates assume launching from the surface, fully via rocket? On Earth, having air breathing stages to gradually build up speed, or using other launch mechanisms, isn't worthwhile because rockets are more cost effective here, but those tradeoffs change if you're on a planet with higher gravity and a denser atmosphere.
You still need to get to escape velocity that doesn’t change the delta v required does but not by that much you are looking at 5-10%. Maybe a bit more if the atmosphere is really really thick.
Unless you skip chemical rockets altogether there is a pretty hard cap on how much bigger a planet can be than earth before a space capable civilization becomes almost impossible.
Perhaps that's why they're attempting to build a starship out of helium.
or it's all the "pollution" leaking from their fusion reactors ;-)
Do you have any reference for that? I have a hard time seeing how that would be true once the components were coalesced but maybe before that.
Only 880,000 years at our current average speed. Mind blowing, that.
That’s still a few times older than our species.
Species is a rather arbitrary line here. Humans split from Neanderthal ~500k-800k years ago but could still interbreed 40k years ago. We’re likely more closely related to our common ancestors at that point of divergence than Neanderthal suggesting given the opportunity modern humans could interbreed with our ancestors ~500k-1m years ago.
Of course that’s just genetic compatibility, there’s plenty of other ways to define species.
Homo Neanderthalensis is not Homo sapiens [sapiens].
> Homo Neanderthalensis is not Homo sapiens [sapiens].
Not the same species, but still capable of occasionally producing viable offspring.
Thus the common ancestor as essentially a midpoint between each population would be more compatible genetically. It’s essentially a ring species through time rather than space. https://en.wikipedia.org/wiki/Ring_species
NASA and Starlink have already been using ion drives with 10x ISP of chemical rocket engines. Using such drives a 3 stage with existing nuclear reactors as energy source can get to 150-200 km/s.
While it haven't been built yet, nothing seems to prevent ion drive even with 100x ISP of chemical rocket. That means we can get 1000-2000 km/s (acceleration with existing reactors would take about 100 years) and get to the closest star in 1000 years.
The problem is radiation. Empty space is not really empty, there are stray atoms floating around. Very scattered, but at a high impact momentum penetrate the ship ionizing anything in their way, and making the ship itself radioactive.
Not even talking about stray high-energy particles from distant supernovas and magnetars -- those irradiate ship regardless of its speed.
If "closest star" is Proxima Centauri, we're talking 4.5 light-years. Getting there in 1000 years means an average speed of 0.45% of the speed of light. At that speed less than 0.01 cm of titanium is enough shielding to keep the radiation out according to figure 1c) in my source below. Which makes sense because because this is ~10% of the speed of "normal" alpha radiation which is stopped by just your skin.
"Radiation Hazard of Relativistic Interstellar Flight" by Oleg Semyonov: https://arxiv.org/abs/physics/0610030 via Project Rho: https://projectrho.com/public_html/rocket/slowerlight3.php
anything going out there for those long journeys would/should be big, so there would be enough walls, storage of supplies, reaction mass tanks, etc. to provide significant protection.
Not really. Galaxy is 100k ly across, you can make the journey end to end in 1mil years at 10% light speed. Obviously talking about probes/tech, not "biologicals".
1mil years is really short in the grand scheme of things.
>Obviously talking about probes/tech, not "biologicals".
human brain has 100T synaptic connections. We already have 2 trillion parameter AI models. Parameter count grows more 3x per year. It means that in 4 years we'll have 100T model. My point here is that by the time we have probes to send even to the closest star, the biological brain would be the inferior option, and most probably we'd even be able to upload, just as fun small companions-observers, a bunch of people brains into what by the time would be a superintelligent 100000T+ parameter AI brain of the probe.
Yeah I never really believed in biological aliens here. But some kind of alien AI thing/tech...quite probable after all this time. Still not sure as there's still a lot of things that can stop it, but it's possible some kind of synthetic thing could replace biology, eventually, everywhere where there's intelligent life.
There is a market shortage of helium but shouldn't be:
There's also helium in methane, but unfortunately few places crack out the helium from natural gas.
TIL Helium kills Kudzu and powers fusion power plants.
It is the four layers of resources, each one is smaller than the next.
1. What is the total theoretical resource?
2. How much of it do we actually now the location of
3. How much is technically recoverable?
4. And most importantly, how much is economically viable?
The last one is really the crux of the problem nowadays, there is a lot of helium but most of it just isn't in a high enough quantity to make the investment to built processing for it. Thus most of it just float off into space.
There will come a point when the price hits high enough to justify the cost but that also means higher costs to the end user.
> 4. And most importantly, how much is economically viable?
But literally the least important factor beyond “should we have started yesterday”. The amount of waste humanity has perpetuated in just the last 100 years because something wasn’t “economically viable” this fiscal quarter makes my head hurt.
Doing economically inviable things is waste. It's pumping resources into something worth less than the sum of its inputs.
Apropos of nothing, see one trillion dollars into datacenters.
Which is why they pumped fracking waste water into deep aquifers, because it wasn’t “economically viable” to pull that water out of the ground. Fast forward a decade and people are up in arms that those fresh water aquifers are no longer viable sources of drinking water, wondering how anyone could have been so short sighted.
Just because something isn’t economically viable today doesn’t mean it never will be. That short term thinking is exactly why China is absolutely decimating the US in renewable energy.
That's a different matter, that's an unpriced externality, were the oil company required to pay to sort the water out didn't choose because they weren't forced to.
So the oil should be economically unviable but due to poor regulation, they were able to extract it.
That’s just a cop out. There are externalities to everything and they are never completely accounted for. So by definition only looking at “economic viability” is a failed experiment as I posited from the get go.
We make decisions based on objective reality, not a perfect theory in a lab.
That is exactly it - how do we define economically inviable? There are many answers, very different.
Total cost estimates should included unassessed environmental hazard, carbon, energy mix
There will come a point when the price hits high enough to justify the cost but that also means higher costs to the end user.
This makes me wonder if it'd be worthwhile starting a company to capture it now, and just stockpile it until it's rare enough to be able to use my stockpile to control the price. The DeBeers diamonds playbook applied to helium, or maybe the Peter Thiel build-a-monopoly-to-win approach.
This is both a bad and a good idea.
First the bad: Helium is very expensive to extract and store. You'd need a lot of venture capital. And you'd have a tough time competing with Qatar which produces between 1/4 and 1/3 of the world's supply. Qatar already is the DeBeers of helium.
The good: When the US/Iran war started helium prices shot up, so there might be an opportunity for a helium supplier not dependent on the Strait of Hormuz.
https://www.reuters.com/business/energy/helium-prices-soar-q...
A teal Hydrogen company that splits Methane (CH4) into Hydrogen (H) and Oxidized Carbon Nanotubes (O-CNT) would be significantly more profitable than one that splits into Hydrogen and Carbon Black. (Because after production costs, O-CNT have a significantly higher market price than carbon black.)
But do our communities want fracking wastewater in our aquifer groundwater or on our farm fields?
When is the break-even point for cracking Helium from natural gas at current and predicted Helium market prices?
teal hydrogen: electrolytic catalysis, renewable feedstocks
turquoise hydrogen: high-temp pyrolysis of methane
So e.g. [1] is turquoise hydrogen.
[1] "Production of hydrogen and carbon nanotubes from methane using a multi-pass floating catalyst chemical vapour deposition reactor with process gas recycling" (2025) https://www.nature.com/articles/s41560-025-01925-3
A renewable feedstock process that yields Hydrogen and O-CNT would be yielding teal hydrogen.
A natural gas process that yields Hydrogen and O-CNT would be yielding turquoise hydrogen.
That's where the government reguli could step in. It wasn't economically viable to capture natural gas so it's just flared off, but if the government fines oil companies for flaring off the natural gas, suddenly it's economically viable to capture it instead of wasting it.
It's economical to capture and sell the Helium out of natural gas even without a flaring penalty to encourage to be efficient with heat and material outputs.
It's also already economical to make Hydrogen and Carbon-based products like Graphene and spec Oxidized Carbon Nanotubes from natural gas.
https://news.ycombinator.com/item?id=48946629
And, it's surely also profitable to make more He3, He4, and T with a fusion reactor: https://news.ycombinator.com/item?id=48946533
> if the government fines oil companies for flaring off the natural gas, suddenly it's economically viable to capture it instead of wasting it.
If the government fines individuals for not digging holes in their back garden every day then suddenly it's economically viable to dig holes in your back garden every day, but it doesn't mean it's overall productive.
[dead]
The OP is about helium on an exoplanet. That's unlikely to impact helium supplies on Earth.
> Helium kills Kudzu
That right there is reason enough to try to synthesize it in massive quantities.
When you're done with it can I borrow your particle collider capable of mass synthesis of helium
Alpha particles are essentially Helium, so by breeding large amounts of highly active alpha emitters you can produce Helium much more effectively than by fusion.
Probably that's what they did at the rocky exoplanet. How much radiation do they need down there for it to be measurable as helium in the atmosphere?
The proper way to generate helium is to use a deuterium-tritium fusion reactor.
Given the neutron radiation from a fusion reactor, it's possible to synthesize Helium (He4) and more Tritium (T) and 3He using Lithium-6 with Boron-10 and Boron-11. An adjacent vertically-aligned (VA-CNT) battery would last for like 20 years and could power safety systems.
A Deuterated Vitrimer pipe with Li-6, B-10, and B-11 could be recycled to extract the T, 3He, and 4He.
Deuterated Vitrimers could also be disposed of in a waste burner.
Rocky, you say question?
Amaze amaze amaze
Turns out aliens love talking funny and safe balloons too.