What will happen if the Sun loses hydrogen?

Answer 1

A red giant star.

It depends on the mass of the star. A star combines hydrogen atoms into helium and releases energy, some of it as light.

When there isn't enough hydrogen to keep the process going, the star starts consuming helium and making heavier elements, elements that have more protons and neutrons in the nucleus.

A star that is about ten times the mass of the Sun will become a neutron star or a black hole, after exploding as a supernova.

A star the size of our Sun will become a red giant then a white dwarf, a kind of cosmic clinker.

Our Sun is almost 5 billion years old and in about 5 billion years from now, the Sun will be a red giant star.

Answer 2

"When the Sun runs out of hydrogen to fuse, the balance tips in the favor of gravity, and the star starts to collapse. But compacting a star causes it to heat up again and it is able fuse what little hydrogen remains in a shell wrapped around its core. This burning shell of hydrogen expands the outer layers of the star. When this happens, our Sun will become a red giant; it will be so big that Mercury will be completely swallowed! When a star gets bigger, its heat spreads out, making its overall temperature cooler. But the core temperature of our red giant Sun increases until it's finally hot enough to fuse the helium created from hydrogen fusion. Eventually, it will transform the helium into carbon and other heavier elements. The Sun will only spend one billion years as a red giant, as opposed to the nearly 10 billion it spent busily burning hydrogen. We already know that medium mass stars, like our Sun, become red giants. But what happens after that? Our red giant Sun will still be eating up helium and cranking out carbon. But when it's finished its helium, it isn't quite hot enough to be able to burn the carbon it created. What now? Since our Sun won't be hot enough to ignite the carbon it its core, it will succumb to gravity again. When the core of the star contracts, it will cause a release of energy that makes the envelope of the star expand. Now the star has become an even bigger giant than before! Our Sun's radius will become larger than Earth's orbit! The Sun will not be very stable at this point and will lose mass. This continues until the star finally blows its outer layers off. The core of the star, however, remains intact, and becomes a white dwarf. The white dwarf will be surrounded by an expanding shell of gas in an object known as a planetary nebula. They are called this because early observers thought they looked like the planets Uranus and Neptune."

This is taken from http://imagine.gsfc.NASA.gov/docs/science/know_l1/dwarfs.html

Answer 3

As the hydrogen in the Sun fuses, it creates helium and releases energy. You can think of the helium as sort of like "ashes" in the bottom of a fireplace. The delicate balance between the hydrogen fusion generating heat and pressure (causing the Sun to expand) and its own gravity (causing the Sun to collapse) is maintained.

Once the Sun gets to be about 50% hydrogen, the helium "ash" in the core will begin to interfere in the hydrogen fusion, and the Sun will begin to collapse under its own gravity. The collapse will cause the Sun to become more dense and will increase its core temperature enough so that the helium "ash" will itself begin to fuse, and generating a LOT more energy. This will cause the Sun to expand into a red giant.

When this happens, Mercury will certainly be consumed, and probably Venus as well. The Sun may expand enough to consume the Earth, but probably not; however, the Earth will be burned to a cinder and all life on Earth will probably perish.

That's probably about 4 billion years in the future.

Answer 4

Fused into the next element up the line until iron. Then super novas are responsible for the forging of elements heavier than iron.

Answer 5

The sun will burn it's hydrogen fuel until it runs out in a few billion years. Its thought that it won't lose hydrogen prematurely, if it did, it's life would be shortened.