After more than 3 years in space, using the pressure of sunshine to adjust its orbit, LightSail 2 has ended its mission & burned up in the atmosphere. Here are some of the views it sent back along the way: https://www.planetary.org/articles/lightsail-2-completes-mission #space #exploration
@coreyspowell I love talking about this space ship when we cover radiation pressure in class.
@physgal @coreyspowell As soon as someone mentions radiation pressure, I can't' help but think of how so many people incorrectly demo the light-mill, in relation to this.
If you haven't already read it, a nice discussion of this confusion can be found here:
https://math.ucr.edu/home/baez/physics/General/LightMill/light-mill.html
@level98 @physgal @coreyspowell we The light mill may have been a misstep, but it was part of the confused arguments about whether light was corpuscular in character, or a wave. Depending on the crowd, I teach teach Adolfo Bartoli —> Boltzmann —> Planck, starting with some version of Bartoli’s thought experiments showing that the Second Law requires all forms of radiant energy to carry momentum.
@MQMLab @physgal @coreyspowell
TIL Bartoli. But AFAIK issues around the explanation for the light-mill were not specifically related to wave/particle confusion but just determining which physical mechanism was most significant in this particular situation e.g. as described in the link I gave, with the right setup (sufficiently high vacuum, coated vanes) one can make it move due to radiation pressure. It's just that's not the most significant effect n relation to the classic light mill.