What happens when the sun uses all its hydrogen?

Question

I need help with Earth Science, and thats one of the questions in the book. But I cant find the answer anywhere. Please help!

Answer 1

Stars burn (actually fuse) hydrogen for most of their lifetimes.
When they run out of hydrogen they start on higher elements trying to fuse them. They work their way up the periodic table of elements from helium to lithium all the way up to iron. They can't fuse iron and the collapse after that point.

In the case of our sun the diameter will increase and its heat will decrease as it tries to fuse higher elements. It will reach its iron limit and balloon up into a red giant. The size of the sun will reach almost to that of the orbit of the earth. Mercury and Venus will be destroyed and absorbed by the dying sun. Finally, the sun will collapse into a white dwarf to burn the remainder of its fuel.

A star about 4 times the size of our sun would explode into either a nova or a supernova. A sun about 19 times larger than our sun would form a neutron star, and a sun 20 times larger than our sun would continue to collapse into a black hole.

After the sun runs out of hydrogen it will start fusing helium, then lithium...to iron when it will have expanded into a red giant. At that point it will collapse into a white dwarf.

Answer 2

When the sun has used up all the hydrogen in its core the core will begin to contract as the energy from the fusion process is whats keeping it from collapsing in on itself. The core gets hotter and denser until the temperature and pressure is so great that helium fusion can begin and the sun starts generating energy again. The contraction of the core stops and the sun becomes stable once more. But now the sun has completely transformed. It has swollen and its outerlayers has gotten pushed out by the new temperatures in the core. The sun has become a red giant, a monster star big enough to swallow Mercury and maybe Venus. And earth will be a dead superheated cinder.

Answer 3

Do an Internet Search using the key words

Curious About Astronomy

That will take you to Cornell university's very excellent web site where you will find a complete discussion of the Sun and its future, plus many questions and answers on the subject.

Hope this helps,

Zah

Answer 4

Steven Hawking is the much revered author of "Red Giants, White Dwarfs". He explains what will happen to our Sun. But check this out, if we're smart enough, we will have escaped the wrath of the Red Giant by moving out into our Solar System:

In our Milky Way Galaxy there are 235 planetary bodies, of which 169 moons are in our Solar System. These 169 moons are the well documented satellite moons of the 9 planets. Jupiter alone has 63 moons. The challenge lies in how we can build atmospheres on them to support human life and all other living things. Also, we have to weed out the ones that are inhospitable.

Venus=0, Earth=1, Mars=2, Jupiter=63, Saturn=60, Uranus=27, Neptune=13, Pluto=3

The trick is to categorize them into planets/moons that either spin on their axis, or don't. Then, increase the surface gravity by inserting a Superconducting Magnet into the core. The magnet would range from 2 Tesla to 15 Tesla, depending on the amount of iron/nickel that is present in the core.

Finally, to introduce atmospheric gases (nitrogen, oxygen, and carbon dioxide) into the man made electromagnetic bubble.

This website gives the exact location of each of the moons of Jupiter: http://www.ifa.hawaii.edu/~sheppard/sate...

and this site tells us how to make an ATMOSPHERE on all the moons: http://www.atmospheres.5u.com/index.html...

while this site tells you how to build a Fischer Tropsch reactor to make fuel and water:
http://www.xybex.50megs.com/custom2.html

Answer 5

Only the hydrogen in the sun's core will get used up. After that it will burn helium instead for a while as a red giant, then collapse into a white dwarf.

Answer 6

Radiation decreases, reducing the outward force that holds back the pressure of gravity; gravity crushes the suns gases higher causing an increase in temperature to a point where helium atoms begin to fuse. At that point radiation once more balances the force of gravity and the sun becomes stable once more.

Answer 7

The solar will grow to be brighter over the subsequent billion years, mutually as nonetheless burning hydrogen. however the alterations is basically not drastic: it takes a extreme substitute in equilibrium to set off some thing like a helium flash and a transition to pink sizeable. nonetheless, even such "minor" alterations are going to spell doom for Earth's biosphere interior one billion years at maximum (if humanity does not shelter it first).

Answer 8

it will start to shrink, and the pressure will make it hotter enabling it to burn helium (which it created by fusing hydrogen). when that happens it will swell and engulf mercury and roast the earth, and humans will definately go extinct. it will use up all the helium in a few million years, and start to shrink and it will attempt to burn the carbon and oxygen created from the helium but its not large enough to do that (larger stars can fuse elements up to iron).

so it will cool and gavity will take effect and it will start to shrink. it would collapse compeltely but the electrons that were thrown off of the atoms (the sun is made of plasma, and plasma is elements super heated so electrons fly off) will begin to repel eachother and the pressure of the electrons will equal the gravity and it will stabilize, and it becomes a white dwarf.

since it is no longer generating heat it will cool off in billions of years into a black dwarf.


Dan S is partly wrong, our star isnt large enough to fuse anything above helium. stars with a mass about 40 times of our sun can fuse elements up to iron. after the it actually require energy to fuse iron and it doesnt release energy, so the star doesnt fuse it.

Answer 9

It will start using helium and become a red giant star.

Answer 10

Look up the evolution of stars