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.
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:
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
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.
And related...
https://worldbuilding.stackexchange.com/questions/178131/wha...
https://physics.stackexchange.com/questions/117347/when-a-pl...
> 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.
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
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.
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.
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.
That right there is reason enough to try to synthesize it in massive quantities.
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.
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.
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.
Apropos of nothing, see one trillion dollars into datacenters.
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.
So the oil should be economically unviable but due to poor regulation, they were able to extract it.
We make decisions based on objective reality, not a perfect theory in a lab.
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.
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.
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
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.
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...
Of course that’s just genetic compatibility, there’s plenty of other ways to define species.
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
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.
Not even talking about stray high-energy particles from distant supernovas and magnetars -- those irradiate ship regardless of its speed.
1mil years is really short in the grand scheme of things.
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.
"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