Why will the sun increase in size as it begins to burn off its fuel?

Answer 1

Stars are, essentially, controlled explosions...the force of gravity acting against the force of a tremendous nuclear fusion reaction. The short answer to why stars expand as they get older is that the force of gravity is no longer sufficient to hold onto the outer layers of the star and they kind of fluff off into space (at least for stars like our sun). Ironically, as the outer layers are expanding, the core of the star is collapsing (getting smaller and denser).

Answer 2

It is just the core of the sun that fuses hydrogen into helium. When the hydrogen runs out in about 5 billion years, the core begins to burn helium, then carbon, on up to iron. It takes more heat to fuse helium, carbon, etc., than it does hydrogen so the core heats up. The extra radiation from the core pushes the outer layers of the sun outward until it becomes a red giant star. Earth will then be within the sun's atmosphere. Hopefully, if humanity is still around, we will have bases in the outer planets' moons and maybe around other stars.

Answer 3

None of the above answers really answer the question correctly.

As the sun fuses hydrogen into helium, a core of helium builds up in the center. As this occurs, hydrogen fuses in a shell around this core. The core slowly expands as more helium is created which expands the outer fusion "shell" which causes more hydrogen to undergo fusion at any given time. This increased fusion also increases energy output which exerts more outward pressure on the star which causes it to grow somewhat (and become hotter a bit too) over it's life.

Answer 4

This rim around the sun is made up of gases,hence its increased size.It is part of Evolution look what happened to the Dinosaurs.(in other words the sun is a massive fire ball.)

Answer 5

There is now preasure in space so the gas thats left over will expand but it will remain round because of the iron core in the middle.

Answer 6

It will use fusion to turn hydrogen into helium, a denser element, causeing the sun to expand as it cools

Answer 7

Because as it burns off it's mass past a specific point it looses gravitational containment of it's surface area.

Answer 8

I will answer your question with a question. Ever hear of google? It's a search engine where you can get answers to questions like this. It's really easy to use. Wow, look, I just used it!

Do you not know how to look things up? Is that your problem?

Answer 9

Yes it will and in about 4 billion years it's predicted that it will swallow the earth.

http://en.wikipedia.org/wiki/Red_giant