A Dyson Sphere?

Question

Since the sun puts out a solar wind and particulate matter, wouldn't the inside of a Dyson Spjere eventually fill up??

Answer 1

Since it is virtually impossible to make such a sphere solid to solar wind and minute particulate matter, and most designs don't try as the source makes clear, "filling up" is unlikely. Next, consider how far out from the sun such a sphere would have to be built (beyond the orbit of Mercury in the solar system) to keep the materials from melting (and there are not enough higher temp materials to build it), if you expand the material that makes up the sun to that diameter, it is pretty tenuous. At Dyson's distance (1 AU) it is nearly a vacuum.
1.988 435×10^30 kg mass of sun wiki/sun
149.598×10^9 m 1 AU wiki/au
14023808 x 10^27 4/3 Pi R^3
1.4 x 10^34 m3
1.42 x 10^-4 kg/m3 = 0.142 gm/m3
in comparison, the density of air at STP is 1290 gm/m3 so the material in the sphere would be about like a vacuum of 1/10,000 atmospheric on earth,
And that is with the current density of the sun which would decrease with the creation of energy that the Dyson sphere is meant to capture.

Answer 2

The solar wind amounts to only 0.001% of the Sun's mass over 4 billion years. That might coat the inside of a Dyson sphere to a depth of 0.01 cm, probably less.

Answer 3

No. Solar wind is a stream of particles, just like lightning. Also even if one were to assume that the Dyson sphere and Star were a totally closed system. The overall mass / energy / momentum could only decrease.

Regards.

Answer 4

Well, if it were a closed system you could not add to the mass - and it would be mostly empty space (the solar wind is not exactly very dense itself).

But a Dyson sphere as a solid sphere would be impossible to construct phsyically because it could not be in gravitational equilibrium.