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> Are they powered via PV Consider that light emitted from the Sun will decay with the square of the distance – as it is irradiated in all directions. To Voyag
by outworlder 7y ago
> Are they powered via PV
Consider that light emitted from the Sun will decay with the square of the distance – as it is irradiated in all directions. To Voyager, the Sun looks like an ordinary star – although one much brighter than the others. Not much energy can be harvested there.
Until recently, photovoltaics were useless as far away as Jupiter. Given the tech advancements, we can now use them there (and have). Farther than that and you are bumping into practical limits.
- iamcreasy 7y ago> To Voyager, the Sun looks like an ordinary star – although one much brighter than the others. Not much energy can be harvested there. This blew my mind. Do you have a reference that talks more on this topic?
- wyldfire 7y agoIf you're talking about its apparent size in the sky -- just a guess but I think this one is relevant: [1] [1] https://en.wikipedia.org/wiki/Angular_diameter https://en.wikipedia.org/wiki/Angular_diameter
- RosanaAnaDana 7y agoInverse square law: https://en.wikipedia.org/wiki/Inverse-square_law https://en.wikipedia.org/wiki/Inverse-square_law >(...) Intensity is inversely proportional to the square of the distance from the source of that physical quantity. Shit gets dimmer at the square of the distance. So if at a distance of 1 a thing has a brightness of one, at a distance of 2 it has a brightness of 1/(2^2), or 1/4. At a distance of 8, you are looking at a brightness of 1/(8^2) or 1/64th. Voyager 2 is ~122 AU distant. So the sun's apparent brightness would be 1/(122^2), or 1/14884, or 0.00067 % as bright as the sun as perceived at the earth-sun distance (ignoring the atmosphere of course).
- brownbat 7y agoNot as far out as Voyager, but I enjoyed this series of depictions of the sun from each planet, which illustrates the general point: https://www.iflscience.com/space/sun-looks-like-every-planet-solar-system/ https://www.iflscience.com/space/sun-looks-like-every-planet...
- Daniel_sk 7y agoVoyager snapped a picture of our Earch (sorry I thought it was the Sun) in 1990. It's the famous Pale Blue Dot picture. It's the small blue-white speck (or almost pixel) halfway down the brown band on the right. https://en.es-static.us/upl/2012/07/Pale_Blue_Dot.png https://en.es-static.us/upl/2012/07/Pale_Blue_Dot.png EDIT: Ooops, sorry - this is Earth and not Sun :-(.
- Cthulhu_ 7y agoYou should look up or play Elite Dangerous, it's (I believe) a fairly accurate / to scale simulation of solar system navigation. You can go at several hundred times the speed of light and you're still waiting for ten minutes to reach your destination.
- rezeroed 7y agohttps://space.stackexchange.com/questions/17419/most-distant-photo-of-the-sun https://space.stackexchange.com/questions/17419/most-distant...