Grapefruit-sized sun

[davekhps]

@oogabooga

familiar enough with to do for you, it gets hard to say, here. One thing is for sure - it would completely wreck Earths current orbit, which would eventually result in it’s demise.

Let’s be specific-- that’s only if our grapefruit-sun was here on Earth, or in another place in our Solar System.

Replace the Sun with a black hole of the same mass and the gravity is the same-- we wouldn’t notice a difference (well, gravitationally, at least-- it would, however, get a tad. . . chilly).

[aerodave]

@ZenBeam

Anyway, the contribution due to a grapefruit sized volume of the Sun fusioning is completely negligible. The Sun has about 1.4 10[sup]30[/sup] time the volume of a grapefruit, and radiates 3.8 10[sup]26[/sup] Watts, so an average grapefruit sized volume generates less than a milliwatt.

But that energy doesn’t come from the entire volume of the sun. There’s only a limited volume at the core where the density is high enough for fusion to take place. I don’t konw how big a sphere that is, but that’s the region of which you’d have to consider a grapefruit-sized piece.

[Damp]

So, being that it’s hypothetical there is several different situations you can set up, considering the original question was rather unspecific…

the sun, being a star is massive enough for nuclear fusion, which meaning it would easily consume the planet either in a fiery implosion or explosion.

the new sun, being the size of a grapefruit is of the same composition as the sun, so you have a superheated mass of hydrogen and helium, this is i believe what most people have described… which would be a far more local destruction.

or being hypothetical the new sun acts in and on itself as if it were in a seperate universe of smaller proportions and acts on other things in the same way as the natural sun does just to a far lesser extent probably proportionate to volume, which zenbeam did the math on… finding it producing less than a milliwatt. So it wouldnt even produce enough light to be observed?

So in summary
Boom!
Bang!
Dud.

So all boring in a long term observable perspective, gee I guess it IS the right size.

[ZenBeam]

@aerodave

But that energy doesn’t come from the entire volume of the sun. There’s only a limited volume at the core where the density is high enough for fusion to take place. I don’t konw how big a sphere that is, but that’s the region of which you’d have to consider a grapefruit-sized piece.

From the link (see the Core section), the core is considered to be the portion out to 0.2 times the solar radius, and produces 0.3 W / m^3.