Here's one for your astrophysicists out there--what would happen if the sun was completely enclosed?

Question

In an impermeable barrier, let's say 1000 miles from the surface. Would the heat buildup eventually make it explode (thus presumably rebounding indefinitely inside there)? Or would it be able to absorb/distribute all that heat on its surface (and within) without catastrophic consequences? And if it would eventually detonate, how long before that would happen?

Answer 1

i notice that all three of the other people that answered this question chose to ignore the word "impermeable." of course no such barrier exists, but if one did, then we woul dhave no way of measuring it. i willt ell you what i think though. i think that the sun would continute to fuse hydrogen into helium and heat, and the pressure buildup would compress the metter more and more densly, until the sun started fusing helium into oxygen and other heavier elements. i believe that the pressure would just keep increasing until 1 of 2 things happened. either the sun collapsed into a black hole form the immense pressure, or it would just continue to use the pressure to fuse things into heavier and heavier atoms until it was releasing megajoules of energy with each fusion and the temperature was higher than imaginable. a temperature at which all know substances would vaporize and be stripped of electrons. if it was truely impermeable, this is what would happen, and we would receive no more energy than pluto. if it was impermeable save for heat energy, it would eventually exhaust all the fuel, if the pressure didnt compress it into a black hole or neutron star (forgot to mention that one) first.

but then again how would I know? those are just my theories. ask a real physicist.

Answer 2

It is called a Dyson sphere. Except that, as such, you are building it too close to the sun. Freeman Dyson proposed it in a Science paper in 1959. He was inspired by others before him who had suggested similar things.

The sun puts out energy at the rate of 3.85 x 10^26 Watts.
The Sun's radius is 696,265 km (435,165 mi) therefore its surface area (4*pi*r^2) is 6 x 10^12 km^2 or 6 x 10^18 square metres.

The surface flux is 6.3 x 10^7 W per m^2, which corresponds to a temperature of 5780 K (almost 11,000 F).

By building your sphere a mere 1000 mi above the Sun's "surface", you increase the radius by a mere 1600 km, which corresponds to an increase of 0.23% (less than one quarter of one percent). Therefore the total outside area of your sphere is 1.0046 times that of the Sun (an increase in area of less than half of one percent.

Eventually, the system (sphere + Sun) will reach thermal equilibrium. Nothing is impermeable to heat. Eventually, your sphere will let out 3.85 x 10^26 W but it will do so through a surface area a tiny bit bigger than the Sun's surface area. Therefore the temperature of the outside surface of your sphere will be a tiny bit lower than the present temperature of the Sun.

Temperature varies as the fourth root of the flux (W / m^2), so the outside of your sphere would be at 5770 K, only ten degrees cooler than the surface of the Sun. Which means that it would glow at the same brightness and color (within 1 %).

If your sphere were built of a perfect heat conductor (something close to a thin sheet of aluminium foil), then the inside would also be at the same temperature.

As for anything building up inside (for example, to increase pressure), that would take time as the corona of the sun is not very dense. If the inside temperature is the same as the outside temperature, there is no reason for a buildup of pressure due to heat. You may have a greater problem making your material resistant to the pressure of the photons. One photon may not have much energy, but when you have that many of them being stopped every second by a sheet of aluminium foil, that foil will act as a solar sail and will want to move out.

Dyson was thinking more of a sphere with a radius close to the radius of Earth's orbit. The sphere's radius would be (aspproximately) 215 times the Sun's radius. The area would therefore be 215*215 times bigger than the sun's area = 46,225 so that the flux would be 1,370 W/m^2.

The temperature of the sphere (once equilibrium is attained) is 5780 divided by the fourth root of 46,225 = 394 K (250 F).

Answer 3

If there was a way to completely enclose the Sun with something that would not melt or burn away.
This is what would take place, as the tempter goes higher an higher, the speed of the fusion will increase to where the sun would either use up it's Hydrogen at a high speed, or it would reach a point to where the speed of the fusion would cause a massive explosion, and our solar system would be no more.
But maybe beings on other planets can look across space and see the small Nebula that will be the remains of our Sun.

Answer 4

The irresistible force would quickly overwhelm the immovable object. There is no way that any sort of barrier could long resist the nuclear fusion of millions of tons of hydrogen per second.

Answer 5

the intense gravity would cause it to break down and be pulled into the sun, where it would then heat up to thousands of degrees celcius and begin fusing, thus becoming part of the sun's fuel, unless it was heavier than iron, in which case it would just melt and fall to the center.

Answer 6

At 1000 mi it will vaporize what ever structure you build.