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 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.
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.
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.
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.
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.
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.
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.
That right there is reason enough to try to synthesize it in massive quantities.
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/
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...
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.