# Does the sun have a black hole inside of it?

The Schwarzschild radius of the sun is approx. 3 km. It would be a black hole if all the mass of it were within the 3km.

However, even with the mass spread out couldn't the sun technically have a or several fluctuating in size and shape black holes within it depending on the distribution of mass?

• There are a bunch of problems here. How did the black hole form? When did it form? Why hasn't it swallowed up the Sun? Also, black holes generally have mass much greater than that of the Sun - yet the Sun has a mass typical of stars at the same place on its evolutionary track. – HDE 226868 Jan 9 '15 at 0:28
• en.wikipedia.org/wiki/Quasi-star – Mithoron Apr 2 '15 at 1:15

We don't know of any evolutionary track that would allow a star like our sun to develop a black hole inside it through gravitational collapse.

It's conceivable that the sun could capture a black hole that came from somewhere else. For instance, it's possible that there are primordial black holes that were formed in the big bang. Depending on the velocity and size of such a black hole, it might pass through the sun without interacting much, and therefore not get captured.

Assuming that such a black hole did get captured, the sun's normal matter would start accreting onto it. For a very small black hole, this process could be quite slow. There are hydrodynamic limits on how fast matter can be funneled into a small space, and a microscopic black hole is very small in radius, so the "funnel" can be very small. I haven't done the calculation, but one should be able to put an upper limit on how large such a black hole can be, based on the fact that geological records don't show the sun as having changed its luminosity dramatically.

For a description of this type of physics, see Giddings and Mangano, "Astrophysical implications of hypothetical stable TeV-scale black holes," https://arxiv.org/abs/0806.3381 . (This is a discussion of doomsday scenarios for the LHC, and because the doomsday scenarios are very easy to rule out based on standard physics, they consider some very nonstandard possibilities such as large extra dimensions.)

No, a star with 3 solar masses or more, will eventually become a black hole. After exhausting all the elements inside and expanding into the next phase to then explode in a hyper or supernova, it will become a black hole. So no, even if the Sun had that mass, it will take billions of years for that to happen.

• I think you're confusing the mass of the stellar remnant with the mass of the star. :-) – HDE 226868 Apr 1 '15 at 23:10
• So you were asking if the Sun have a black hole inside of it made by the mass of a stellar remnant or the mass of the star (the sun) itself? – JK-r. R5 171-A Apr 1 '15 at 23:12
• The OP wasn't asking about that, but your answer is wrong (regarding the mass limit) nonetheless. – HDE 226868 Apr 1 '15 at 23:14
• About "3 or more solar masses"? – JK-r. R5 171-A Apr 1 '15 at 23:15
• Yes, about that. – HDE 226868 Apr 1 '15 at 23:16

No, the sun doesn't have enough mass to become a black hole. it can only become a red dwarf. The black hole is only formed after the death of a very massive star. see https://en.m.wikipedia.org/wiki/Black_hole

• Welcome to the physics.se. It is best if you can provide reference for your statements, like some wikipedia link confirming your saying. – glS Jan 9 '15 at 9:34
• While it's true the the Sun doesn't have enough mass to become a black hole by itself, actually anything can in principle become a black hole, if its mass is compressed to be within its Schwarzschild radius. So, IF the Sun's mass were within 3 km, it would indeed be a black hole, as Joe claims. – pela Jan 13 '15 at 15:26
• it can only become a red dwarf. The sun will not evolve into a red dwarf. – Ben Crowell Apr 15 at 14:28

No, the sun have a critical mass to generate a black hole with a ray of 2943,56 meters, but it doesn't have a critical density focused on one point to generate it because of the convection flows of Hydrogen. When a star like the sun dies, it spread a good portion of its mass out of space, so the critical density is never achieved, generating only a white dwarf.

• There is no point in the future evolution of a main-sequence star in which it becomes a red dwarf. – Emilio Pisanty Apr 15 at 12:30

## protected by Emilio PisantyApr 15 at 12:31

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