How is it possible that the sun is burning so long (4.5 billion years)?

Question

The age of the sun is 4.5 Billion years old, it had a core made up of Hydrogen and Helium gas. I'm curious to know why it's energy source/supply hasn't burned out yet.. Could anyone explain?

Answer 1

Our Sun is one of at least four hundred billion stars in the Milky Way galaxy, and it lives 8 kiloparsecs (2.5 billion billion billion miles) from the center of the galaxy. All stars in our galaxy and other galaxies come in different sizes and colors, and our sun is a medium sized star known as a yellow dwarf. The cloud from which it formed, fortunately for us, did not use all of its gas and dust to make the Sun; that which was left over, less than one percent of the original material, formed the 9 planets.

The Sun has been fusing hydrogen into helium and hence providing us with its rad iant energy for 4.5 billion years, and it is expected to continue to do so for another 3 to 4 billion years more. And then what? As the sun gets older, it will fuse more and more hydrogen in its core. Once all of the hydrogen is turned into helium, the star stops fusing hydrogen and loses its abi lity to combat gravity. Then gravity begins to compress the Sun under its own weight again. The introduction of more compression causes the new helium particles inside of the core to collide hard enough so that they can stick together and fuse. The core thus begi ns to fuse helium into carbon to make enough energy to maintain its balance with the crushing force of gravity. The making of carbon, however, gives off more energy than did the making of helium. The energy being pumped out of the core radiates through the outer layers of the sun called the envelope. The introduction of too much energy into the envelope heats up the envelope particles so much that the envelope expands (for the same reasons that steam rises). At this point in its life, the Sun's envelope will expand to engulf all of the inner solar system out to Mars. The temperature will drop in the envelope as well, as the particles become so spread out that they no longer are colliding enough to create tremendous heat. A drop in temperature in a star can b e seen in the change in the color of a star; cooler stars are redder than hotter, bluer stars. Thus, at this stage of its life, the Sun will be called a red giant.

When the envelope expands too far away from the Sun's core, the envelope will begin to float off of the core and into space. This floated-off envelope material is known as a planetary nebula. Since the bulk of the Sun is envelope material, when this material floats off, gravity does not work as hard to crush the remaining core, and the core stops fusing. The particles of carbon in the core are still very densely packed, however, and so the core is very hot, but tiny -- about the size of the Earth. This leftover hot and tiny core will be called a white dwarf.

Answer 2

This is like asking why a 32 year old hasn't died yet.

You may want to research the life cycle and the mechanism's of stars. Stars of different masses have different life cycles and deaths.

The equilibrium process in our sun works as follows. The sun is a big ball of gases and elements which causes it to shrink under it's own weight. As it shrinks, it gets hotter. As it gets hotter in the core, Hydrogen will fuse into Helium createing an outward pressure. The sun will stop shrinking when the pressure created by the fusion is enough to balance it's weight.

If there is too much fusion at any point in time the sun will expand and cool off some causing less fusion and so it will shrink back to it's equilibrium size. If there is too little fusion the sun will shrink, get hotter and more fusion will ensue, again keeping the sun at it's equilibrium size. There is enough hydrogen left to create Helium using this process for many billions of years but it will start running out.

When it's starts running out of hydrogen, the sun will shrink and get hotter until Helium begins to fuse. The sun will have a new equilibrium size and temperature until it starts fusing into Iron. After the element Iron, it takes more energy to fuse the elements than what is released by fusing them. This is important because eventually the fuel will run out again and the sun will shrink.

However, this time, the increased temperature caused by the shrinkage will not produce enough fusion energy to stop the ensueing collapse. Momemtum will increase faster than fusion can keep up with. There will be a point when the star will basically bounce off itself allthewhile fusion is creating elements as heavy as uranium. It will then explode into a supernovae and create a nebula of heavy elements from which new planets and new people can form.

We are all made of stars.

Again, a lot depends on the size of the star. Some stars will leave a black hole at it's core (caused by the explosion and implosion of the core, some will leave a white dwarf, and some a neutron star). These objects can be superdense obects only a few thousand meters across.

Answer 3

The life cycle of the Sun is today about halfway through its main sequence evolution, during which nuclear fusion reactions in its core fuse hydrogen into helium. Each second, more than 4 million tonnes of matter are converted into energy within the Sun's core. It sounds like a lot but is nothing compared with the size of the sun wit a mean diameter of 1.392×106 km (109 Earths), and a volume of 1.41×1027 m³ (1,300,000 Earths) , producing neutrinos and solar radiation.

The Sun will spend a total of approximately 10 billion years as a main sequence star.

The Sun does not have enough mass to explode as a supernova. Instead, in 5 billion years, it will enter a red giant phase, its outer layers expanding as the hydrogen fuel in the core is consumed.. While it is likely that the expansion of the outer layers of the Sun will reach the current position of Earth's orbit, recent research suggests that mass lost from the Sun earlier in its red giant phase will cause the Earth's orbit to move further out, preventing it from being engulfed. However, Earth's water will be boiled away and most of its atmosphere will escape into space.

Answer 4

The first process inside the hot dense core of the Sun is 2 protons combining to make deuterium (heavy hydrogen) + electron neutrino + energy. In the core the chance of 2 protons meeting to react like this is actually very low, and since this is the start of all subsequent reactions, the Sun has not yet run out of fuel. If this was a likely occurrence then the Sun would have burned out long ago.

Answer 5

The Sun is self-regulating. The natural fusion reactor in its core generates heat. This heat creates pressure in the gas, which holds the sun up against its own gravity. If the fusion reactor begins to cool, the Sun contracts a little and heats up in the core, making the fusion reactor go faster. There is enough fuel to keep this up for 10 billion years or so. This is just because the Sun is so very big and the amount of energy from a small amount of fusion is large.

Answer 6

The power comes from nuclear fusion (not chemical reaction) so a small amount of matter produces a great deal of energy. Eventually, the conversion will stop and gravity will take over and the Sun (and other stars) will collapse.

Answer 7

The sun is 2x10^27 tons of hydrogen. It burns 6x10^8 tons of hydrogen every second or
1.9 x 10^15 tons per year.
in one billion years that's
1.9x10^24.
in 10 billion years that's
1.9x10^25
So as you can see there is plenty of room left over for a margin of error!

Answer 8

There are so many unexplainable things about the universe.
All I know is sun has the fusion and fission reaction taking place at the same time. Unlimited source of energy is released. Radition is intense.

Answer 9

There simply is so much hydrogen that the sun is actually a self-sustaining fusion and fission reactor.

Answer 10

it is due to the neuclear fussion reaction between the helium and hydrogen neuclii resulting the emission of light [may be the reactents=emission of light + product]