Helium escaping from atmosphere of nearby rocky exoplanet in a habitable zone
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Re: Helium escaping from atmosphere of nearby rocky exoplanet in a habitable zone
#2Is 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.
Re: Helium escaping from atmosphere of nearby rocky exoplanet in a habitable zone
#3wow 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
Re: Helium escaping from atmosphere of nearby rocky exoplanet in a habitable zone
#4wow 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.
Re: Helium escaping from atmosphere of nearby rocky exoplanet in a habitable zone
#5wow 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)
Re: Helium escaping from atmosphere of nearby rocky exoplanet in a habitable zone
#6Earlier quoted context omitted.
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 n…
[deleted]
Re: Helium escaping from atmosphere of nearby rocky exoplanet in a habitable zone
#7Earlier quoted context omitted.
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 n…
√(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.
Re: Helium escaping from atmosphere of nearby rocky exoplanet in a habitable zone
#8Earlier quoted context omitted.
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 n…
√(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 vel…
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...
Re: Helium escaping from atmosphere of nearby rocky exoplanet in a habitable zone
#9Earlier quoted context omitted.
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 n…
√(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 vel…
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.
Re: Helium escaping from atmosphere of nearby rocky exoplanet in a habitable zone
#10There 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.