Why does'nt the sun collaps under its own graviataional attraction?

Answer 1

It **IS** collapsing. However, the pressure of the energy released by all the nuclear fusion going on in the middle counterbalances the gravitational collapse, so what we see is a meta-stable sphere.

When all the hydrogen is exhausted, the sun will collapse until it reaches a point where the helium starts to undergo fusion, at which point it will become meta-stable once again.

Answer 2

Because the tendency for the Sun to contract under its own gravity is balanced out by the outward radiation pressure driven by the nuclear fusion going on in its core. (All those photons making their way towards the surface of the Sun carry a lot of energy, and as they move outwards, they transfer some of that energy to the surrounding material.)

In fact, at the end of the Sun's life (over five billion years from now,) after it passes through the red giant phase, and nuclear fusion in its core comes to an end, the Sun will collapse under it's own weight to become a white dwarf (it's not massive enough to generate the kind of gravity needed to compress it further than that. But a white dwarf is still pretty condensed. It will be a dead corpse of a star with most of the mass of the Sun . . . compressed into a volume the size of the Earth!)

Answer 3

Actually, the sun IS collapsing under its own gravitational attrraction. However, that force is counteracted by the outward force of the fusion reaction at the core. This is exactly why the cores of stars shrink as they get older and the force of their fusion reaction slows down.

BTW, Jupiter is also collapsing under it's own gravity...and it really is getting smaller in diameter (very slowly) since it doesn't have a fusion reaction at it's core to offset gravity. The internal friction created by this gravitational collapse explains why Jupiter radiates more than twice the thermal energy it receives from the sun.

Answer 4

Because the heat of the fusion reactions at its core create enough outward pressure to counterbalance the gravitational force, just like in all stars. Eventually when fuel starts to run out it will first expand and then collapse into a smaller star.

Answer 5

There is one interesting aspect of solar bodies that has been neglected in the previous posts. It has to do with the mass composition. Were you to determine mass acceleration within our planet at the 0.717 mile location from is center, it would be found that mass acceleration in that location is within 25 mps of that of the speed of light. In our sun, were a person to determine mass acceleration with it at 400 miles from its center, it would be found that mass in that location would be exceeding that of the speed of light. These areas within solar masses allow support of great weights above with relative ease. Remember, also, that in a sphere forces are lateral also - like trying to break an egg in your hand by squeezing it.

Answer 6

Photon pressure.

The nuclear reaction in its core layers releases sufficient energy in the form of photons to resist the gravitational collapse. (You are correct that the thermal pressure would be entirely inadequate to accomplish this).

Answer 7

Because it is not you who takes tension in the mind and collapses yourself but it is a GRAND SUN and it will not collpse under its own gravitational attraction, coz it does not take tension even in the nights and the eclipses...