If the Sun was made from the inward gravitational pull of a large gas cloud....?

Question

then why did it not turn into a black hole and keep sucking itself inwardly or why did it stop? If it took millions of years for the sun to form, then it should still be increasing in size as it takes on more matter from the gravitational pull. It doesn't make sense to me that the sun would form into the shape that we all know and then just decide to stop?

Answer 1

Like everything in life, there is always a balancing force. When the central core build up its mass via gravitation, It gets hotter. But the outward thermal pressure is not enough to counter the inward gravity, so the accretion continues. Eventually, the center is so hot that it trigger the nuclear fusion. The radiation of the star would easily overwhelm the gravity and stop the mass build up. The star would then stay at this mass for a long time (the main sequence) until its fuel is used up for nuclear fusion. Collapsing into a black hole become a possibility depending on its initial mass

Hope this answers your question

Answer 2

there is a certain critical mass required to form a black hole. (i cant thnk of it though)all a black hole is is an object that has so much gravity, its escape velocity is greater than the speed of light. since nothing can as fast as light, everything is sucked in.

as for how the sun formed, scientists arent sure because we have never seen a star form. they think that stars form in nebulas, but just because there a bunch of stars surrounded by gas, that does not prove that the gas is forming them.

Answer 3

First off, these are all just theories as scientists have never been able to witness the birth of a star.  There is no way of proving that the Sun was created by a large gas cloud.  It is just a theory.  

As far as black holes go, that is the last stage in a stars life cycle.  When it dies, then it sucks its own life force into itself creating a black hole.

Answer 4

"How did our Sun form?

Our Sun and the solar system formed from a huge, slowly rotating molecular cloud made of hydrogen and helium molecules and dust. Under its own gravity, the cloud began to compress. As it compressed, it spun faster and faster, like an ice skater who spins faster as he pulls his arms in closer to his body. The spinning flattened the material into a giant disk. Most of the mass was concentrated at the center of the disk, forming a gas sphere. The sphere continued to attract material from the disk. As new material was added, the sphere compressed, increasing the temperatures and pressures until they were sufficient to fuse atoms in the very center of the sphere — and at that point a star — our Sun, was born. The planets and other components of the solar system formed from the remainder of the disk. By exploring our universe with tools such as the Hubble Space Telescope, scientists have discovered stars in various stages of formation. This helps them understand how our Sun may have formed.

How much longer will our Sun shine?

Our Sun will shine as it is for about another 3 to 5 billion years! It will then evolve into a Red Giant over a few more billion years. Scientists arrive at this estimate by calculating how fast the hydrogen in the Sun's core is being converted to helium. Approximately 37% of our Sun's hydrogen has been used since it formed four and a half billion years ago."

Additional info from me:  Basically, our sun didn't just stop growing.  It still is growing, just at a rate we won't notice in our species' lifetime.

Per why it didn't form into a black hole, there's good info here:

http://cosmology.berkeley.edu/Education/...

Also, read Stephan Hawking's "The Universe in a Nutshell."

Stephan Hawking is the expert on black holes.  There's a really good chapter on how black hole's form, which stars can become black holes, and more.

Answer 5

because that's not next in the cycle.

Eventually when all stars die... they close in on themselves.

Answer 6

A black hole can only occur if there is enough mass to overcome the various forces that resist further compression. In all cases, there is a pause in the contraction process, ranging from a few million years for very massive stars, to trillions of years for red dwarfs, while the star fuses lighter elements into heavier ones. The fusion reaction creates an outward pressure that balances the inward pressure caused by gravity, and contraction stops. Fusion begins when the temperature and pressure at the center of the gas is high enough.

Eventually, the fusion reaction runs out of fuel and contraction continues. A star like our sun will collapse to a white dwarf. It won't get any denser than that because because the compressive force of gravity is balanced by the resistance of electrons to being packed too tightly. This state of mater is called electron degeneracy.

In larger stars, the final contraction proceeds rapidly and violently, leading to a supernova explosion. What is left afterwards depends on the mass of the remaining core. Masses of just a few times that of our sun will collapse to a neutron star. The gravitational compression there has overcome electron degeneracy, but not neutron degeneracy.  To form a black hole, the core has to be massive enough that its gravity overcomes all these resiting forces.

Answer 7

Star formation stops because the onset of hydrogen burning in the core of the protostar results in a burst of energy at the center of the protoplanetary nebula that disrupts it and brings accretion and planetoid formation to a halt.  Basically, the energy from the newly-formed star blows out most of the gas that is not already encorporated into the star or various planetoids around the star.  The beginning of hydrogen burning occurs when the protostar is considerably less than one solar mass, whereas the mass needed to collapse into a black hole exceeds one solar mass.  This is why most stars have masses somewhat less than a solar mass.

Answer 8

The sun didn't continue to "suck itself inward" because as it gathered more and more material its core became hotter and hotter. At about 10-million degrees Kelvin nuclear fusion began. The outward push from that energy offset the inward pull of gravity, thus stabilizing the size of our sun.

Even if nuclear fusion hadn't begun in our sun it still wouldn't have become a black hole. To do that the original sun would have needed 10 times more mass.

Finally, the sun doesn't take on any significant additional mass because the material from which it and the rest of the solar system has been used up in forming all the bodies of the solar system.

Answer 9

Because the sun is maily made of hydrogen and helium. In the formation of the sun, when all of this mass was comming together the great preassure of all the matter greated heat which ignited the entire thing. Beacuse of the ignition it cause a chain reation. The way the sun keeps emitting heat is because of nuclear fission. The heat is so great it causes the gases to break apart into the form of radiation (heat) and theres so much hydrogen thier it keeps burning. When a star dies that means theres not enough energy to sustain it. So it enlarges and becomes a more redder color. And then depending on how big it is it will eighter implode and become whats called a white dwarf or it could become so unstable it will collapes under its own gravity and become a black hole.

Answer 10

1. There isn't enough mass in the whole system to

form a black hole.

2. When the pressure rose to the point where fusion

began, the energy heated the core.

This translates to higher particle velocities which

resist further compression so even had the mass been

available the density would not rise to the required

level for black hole formation. (This occurs in more

massive stars.)

Answer 11

Well, I don't think the Sun was formed by such a chaotic theory of randomness and particle attraction.  I think God formed the Sun.  Therefore, I would have to say that the Sun serves its purpose as God intends it and it will not become a black hole or continue to grow.

Answer 12

The sun is a star just like every other star in the galaxy and it has a life expectancy to go with it.  It is constantly consuming hydrogen energy and after a couple of billion years will eventually move on to its next stage in its life - the dwarf stage.  

Also to note, the actual color of the sun is white not yellow, it is just that the ultraviolet light refracted through the atmosphere gives it a yellow tint.

Answer 13

The laws of physics determine the formation of a star. A black hole is never the result of a forming star, if a massive star in its final stages of activity has enough mass it may die as a super nova and become a black hole. When our sun began the fusion of hydrogen into helium an outward pushing force of radiation balanced the crushing force of gravity and the sun's size stabilized. Our sun contains 99.9% of all the matter in the solar system, if any forign body wanders too closely it will consumed by the sun with no effect to its size. It did take millions of years for the sun to form, it has been active for five billion years consuming five million tons of hydrogen each and every second, it will continue to do so for five billon more years, then the loss of mass be enough to allow radiation pressure to overcome gravity and the sun will enter the final stage of its life, it will expand into a red giant and end its life as brown dwarf star.

Answer 14

The gas cloud that gave birth to the Sun contained just enough amounts of lighter elements like Hydrogen and Helium.

As the gas cloud contracted under the influence of gravitational attraction, the gravitational potential energy converted into the kinetic energy of the molecules, thereby increasing the temperature of the entire mass.

Once this contracting mass reached a critical density and a certain temperature, the molecular Brownian motion resulted in very high speed collisions .. eventually, firing up the nuclear fusion processes.

The nuclear fusion increased the temeprature of the mass even further and caused some expansion of the "blob".

Eventually, the mass within the Sun settled at a configuration where the gravitational pull was balanced by the tendency to expand due to thermonuclear reactions.

I think, that's how it just decided to "stop".