Pm got me thinking about this as a challenge. The most obvious approach being the use of convection, would a (theoretical) laser be designed to be focused on possibly a polar region of the sun that would induce He to the surface?
Riff-in-Thyme said:
Pm got me thinking about this as a challenge. The most obvious approach being the use of convection, would a (theoretical) laser be designed to be focused on possibly a polar region of the sun that would induce He to the surface?
there may well be some helium out there where a star has been ripped apart by something and has disrupted the fusion process
Riff-in-Thyme said:
Pm got me thinking about this as a challenge. The most obvious approach being the use of convection, would a (theoretical) laser be designed to be focused on possibly a polar region of the sun that would induce He to the surface?
I assume this is a follow-up to the thread where we discussed delaying the Sun becoming a red giant.
The Sun already spews out huge amounts of matter in the form of the solar wind. It would need to be a mind-bogglingly powerful laser to make a difference. You aren’t just fighting gravity and pressure. There are intense magnetic fields affecting the solar plasma.
And how is this laser supposed to preferentially target helium?
To delay the Sun becoming a red giant it’s not sufficient to merely extract helium from the surface of the Sun – you need to remove it from around the core.
Note that the Sun already has very powerful convection currents, although they are mostly active in the upper regions of the Sun, where the temperature differential is highest. Convection does cause some mixing of the core matter with the higher layers, but it’s not enough to stop the red giant phase from happening. When the hydrogen in the core is mostly exhausted the Sun will have only used up roughly half of its total supply of hydrogen.
Once the rate of hydrogen fusion in the core gets too low, then gravity will cause the core to contract, bringing fresh hydrogen down where fusion can resume in a shell around the core, turning the Sun into a red giant.
See http://en.wikipedia.org/wiki/Red_giant#Evolution
PM 2Ring said:
To delay the Sun becoming a red giant it’s not sufficient to merely extract helium from the surface of the Sun – you need to remove it from around the core.
I was thinking, maybe, xray laser could be focussed on the core from a polar angle. Maybe introducing a particular harmonic to the core would agitate the He outward, or conversely agitate the H inward?
Energy requirements are irrelevant to this thought experiment.
Riff-in-Thyme said:
Pm got me thinking about this as a challenge. The most obvious approach being the use of convection, would a (theoretical) laser be designed to be focused on possibly a polar region of the sun that would induce He to the surface?
Hmm, my gut reaction was “impossible”, but perhaps not. There are already helium nuclei (alpha rays) aplenty in the solar wind, it is even possible to collect the results of this from where the solar wind has hit the Moon over 4 billion years, resulting in the collection of helium there. More economically important, Helium 3 from the solar wind has collected on the Moon.
The radioactive decay of uranium and thorium in the Earth’s crust leads to the production of helium there.
I don’t think that even a theoretical laser could bring Helium to the surface of the Sun. The Sun’s photosphere is about 500 km thick, which makes a mockery of any attempt to “focus” a laser on it. Also, the photosphere is already convective so already brings helium and helium 3 up to the surface.
The closest that I could get a spacecraft to the Sun without it melting was about 1 solar diameter out, though a shorter time closer in ought to be possible. The density there is quite low, something like 3*10^-18 grams per cubic centimeter (water is 1 g/cm^3).
mollwollfumble said:
I don’t think that even a theoretical laser could bring Helium to the surface of the Sun. The Sun’s photosphere is about 500 km thick, which makes a mockery of any attempt to “focus” a laser on it. Also, the photosphere is already convective so already brings helium and helium 3 up to the surface.
I was hoping that Xray laser might be useful. Could sound harmonics be applied to seperate elements in the core.
Riff-in-Thyme said:
mollwollfumble said:I don’t think that even a theoretical laser could bring Helium to the surface of the Sun. The Sun’s photosphere is about 500 km thick, which makes a mockery of any attempt to “focus” a laser on it. Also, the photosphere is already convective so already brings helium and helium 3 up to the surface.
I was hoping that Xray laser might be useful. Could sound harmonics be applied to seperate elements in the core.
Not with any power easily imaginable. If I remember correctly, the penetration depth of an ultra-powerful X-ray laser into the Sun would be blocked relatively near the surface, it couldn’t penetrate down even to the bottom of the Sun’s convection zone.
mollwollfumble said:
Not with any power easily imaginable. If I remember correctly, the penetration depth of an ultra-powerful X-ray laser into the Sun would be blocked relatively near the surface, it couldn’t penetrate down even to the bottom of the Sun’s convection zone.
What about elastic compression harmonics? Could vibrational harmonics be imposed on the sun theoretically and could this be employed to seperate materials within it? Theoretically………